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Hi,

New to the forum and to Vespas generally. Just got a 2002 ET2, and it doesn't like to start. When I use the electric start it cranks for about 20 seconds before firing, and the kick start doesn't work at all unless the engine is already warm.

So, here are my questions: I have read a lot on the forum about disconnecting the evap hose, but it seems like the ET2 did not have one, and most of the evap talk is about the 150cc models. Can someone confirm or deny? I couldn't find it on my carb (stock Weber).

Speaking of carbs, normally I'd think to give the carb a good cleaning at this point, but given that the bike has somewhat high mileage (4900) I am wondering if it's due for replacement, as I'm hearing that trying to rebuild these Webers doesn't usually have the best results. Any advice on what I should replace it with? I'd be happy with a slight performance boost but I am much more interested in engine life, reliability, and ease of use.

Thanks!
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Here's some useful tips if you experience problems starting and/or getting your 2 Stroke scooter to run properly.

To turn a scooter engine over and to get it to start, the engine needs three things....
- Fuel (The ratio of petrol/air must be correct)
- A spark (Sparking at the right time in the engine's cycle)
- Cylinder compression (Must be up to a sufficiently high level of compression)

If your scooter won't start its very likely to be due to one of the above. Before you start troubleshooting, make sure there is fuel in the tank by actually looking into it. Don't just trust the fuel gauge.

Electric Start
Most scooters have four things that need to be done before they can be started with the electric starter:
- The ignition has to be turned on
- The kill switch has to be in the "on" position (usually near the right handgrip. This usually only applies to most non-UK bikes that are fitted with a 'kill switch')
- One of the brake levers has to be pulled (usually doesn't matter which one)
- The starter button must be pressed.

If the scooter doesn't turn over when you've done all the required operations, there's perhaps an electrical problem with the battery. Make sure the battery is charged. If it is, make sure the fuse hasn't blown. If it hasn't, check to see if you are getting a voltage at the starter motor terminals. If you are, the starter motor is likely defective. You can check the voltage that the battery is giving out and if defective you should consider replacing the battery.

Many scooters have a kick start. If the battery is OK and the starter motor doesn't work, try kickstarting it. It's usually not too hard and your scooter should start ideally on the 1st kick, but 2nd or 3rd kick is OK too.

Engine does turn over but won't start
If the scooter does turn over but still doesn't start you should check for a spark and make sure fuel is getting to the engine. To check for a spark, remove the spark plug from the cylinder and re-attach the spark plug cap/lead back onto the spark plug. Hold the tip of the plug against the cylinder head and crank the engine.

You should see a blue spark across the gap, the spark should be strong! If you don't, there's possibly a problem with the ignition. This could mean that you have a faulty coil, CDI unit or electronic ignition module which will have to be replaced, or it could just be a loose wire. If the spark plug is fouled up/oily/overly blackened then it is very likely that it is the cause of your problems and you should consider replacing it as statistically, the second most likely fault with starting a scooter is a faulty/fouled up spark plug.

If you do have a strong spark, you next need to check that fuel is being delivered to the carburetor. Make sure there is fuel in the tank first and if so you can move on to checking the fuel valve. Most scooters use either a gravity fuel feed by locating the fuel tank higher than the carburetor, or some use a vacuum-fed petcock (on/off tap) controlled by the vacuum created at the carburetor. The carburetor has two fuel-related pipes connected to it. One is from the fuel tank and is for the fuel supply, the other provides a vacuum to suck the fuel from the fuel valve. If you disconnect the fuel supply pipe from the carburetor, fuel should flow out when you crank the engine (be careful to catch the fuel if you do this and don't do it with a hot engine), if fuel doesn't flow out then the fuel valve may be faulty. You can try applying a vacuum to see if fuel flows by sucking on the vacuum pipe(but make sure it's the vacuum line, not the fuel line if you try this!). Another Tip: If there is a spark but you are unsure about fuel supply... squirt a little bit of fuel (a spoonful) into the spark plug hole and then replace the spark plug and try to start the engine.....if it starts and runs for 5 seconds and then dies then you can check for fuel flow to the carb, or blocked jets.

If you are getting a strong spark, fuel supply to the carburetor is good and the engine is turning over on the starter, it's possible that the electrically operated automatic choke has failed. It's supposed to operate when the engine is cold, but if it's stuck or burned out, the mixture will be weak and the scooter probably won't start. The automatic choke is usually a black cylindrical object attached to the carburetor with a couple of wires coming out from it. It's the only electrical powered component attached to the carburetor, so it's usually not too hard to spot. If you have a meter you can measure the resistance across the leads of the choke, you should see around 10 ohms or less. If it's an open circuit its likely to be burned out and will need to be replaced. If it seems to be OK it may simply be stuck, or the wiring to it may have a problem/loose connection. You can also check to see that it's getting voltage across its terminals. A final check...remove the choke from the carb and plug the wires into a 12V source for about 5-10 minutes. The choke body should get warm and the protruding mechanism should extend slightly. Measure the length of the protruding choke mechanism - it should have increased in length by around 5mm more than when it was cold.

It's also possible that there is a problem with the cleanliness of the carburetor and if so you may need to remove it and clean it out. If the scooter has been sitting for a few months with fuel in the carburetor, the fuel may have evaporated and left behind a sticky "gum" that will prevent the carburetor from working properly and which must be removed. Statistically, the biggest problem for a scooter not starting is a gummed up carburetor/ blocked carb jets.

A very common problem is blocked jets in the carburetor. The jets have tiny holes in them that the fuel passes through to supply the carb and these become gummed up with fuel residue. You will find three jets in the carb (Main jet-used for Wide Open Throttle, Idle Jet-feeds the carb at idle/low revs, Choke/Power Jet-gives extra-rich fuel supply when starting from cold) and its easy to remove the jets and clean them out with a spot of Carb Cleaning Fluid and/or with compressed air. A tip is to blow through the jets with your mouth and then hold them up to the light to see if you can see clear daylight through the jet's bore. Whatever you do don't be tempted to prod the hole in the jet with a bit of wire or a needle as this will enlarge the jet's bore and be the cause of tuning problems at a later stage.

You could also be experiencing too rich or too lean fuel/air mixture to your carb. To set this you should screw the idle mixture screw fully in.... (Before you screw it in...look at where the screwdriver slot is at... then count how many turns it takes to go all the way in gently... 1 and 1/2 turns for example, and remember the number of turns for later)..... then unscrew it out by the number of turns that it states in your handbook - for my scooter it was 1 and 1/2 turns out.

If the automatic choke is problem free, the starter cranks the engine sufficiently, there's fuel at the carb and there's a strong spark then there may be an engine problem and you need to check the cylinder compression. To do this accurately you will need a compression tester. It screws in instead of the spark plug and measures cylinder pressure. When you crank the engine you should see a reading of approaching 125-150 psi. If it's 100 psi or less then its likely that you have an engine problem (probably failed piston rings) and you will need to remove the cylinder head to gain access to the piston rings. A trick to try if you haven't got a Compression Tester is to hold your finger tightly over the spark plug hole with the spark plug removed to see if your finger is forced away strongly when you try to turn the engine over - it may just indicate that there is very little compression if the force is very minor. Another tip is to add a teaspoon of engine oil through the spark plug hole and try to crank the engine again. If you then get a better compression its likely that the piston rings are shot, as the oil you added sealed the rings for a short period of time and hence temporarily gave you better compression.

In summary....probably the most common problems to starting a scooters' engine are a dead battery or carburetor problems due to bad adjustment or build up of gummy deposits, carburetor problems usually come on slowly though. If a scooter is OK one day and refuses to start the next day, I'd first suspect an electrical problem and look to check/replace the battery.
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I'm not an expert, but from what I've heard from a few mechanics 4.9k is about avg. for the top end needing rebuilt/replaced. The 2001 I got used has about 5k on the cylinder kit and has started having very similar problems (caused by poor compression)- even with a brand new carb, good spark, fuel flow etc.
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Thanks for all the help. I hadn't considered compression, but the more I think about it the more sense it makes. I'll check it ASAP.

If it's compression I'm thinking I may as well use the opportunity to get a cylinder kit. Any recs?
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For reliability, I'd choose a Malossi 2 ring iron kit.

I suppose it all depends on the application, if you are going for all out power but limited reliability then go for a single ringed aluminium racing kit, if you want some reliability then go for a 2 ring iron kit

Fabio

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Yes, reliability is the most important thing for me. I have never kitted anything before (my experience is with a Tomos moped and a FIAT car, so I focused entirely on keeping them running). Will purchasing the kit give me all the parts I need to solve the compression issue?
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hard starting
Check your vacuum operated fuel valve. if those leak , then engine can be flooded if it sits a while, and take a lot of cranking to clear out and start, depending on how well your carburetor float needle seals. mine does that, so I added a manual shut-off valve till i can figure out how to replace the bugger.
E. Risse (1997 ET2 Injection)
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Hi BostonAlex

Did you get any further with this???

Fabio

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Fabio,

I might have. The compression and spark were good and the carb was clean but just yesterday I noticed that with the carb removed fuel was still flowing from the tank so I replaced that valve.

It seems like this would explain all of the problems, especially since the starts had been getting smoky. I haven't cold started it yet and I'm away for the weekend so I won't know til Sunday but I'll post an update then.
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Update
Hello All,

Just wanted to post an update. Replacing the fuel tap helped for a time, but slowly but surely the starting problems have returned, now accompanied with occasional stalling. I am confused by the fact that the fuel tap solved the problem for a time, but am somewhat encouraged because it seems to narrow the problem down to something fuel related. Compression and spark are good, according to my mechanic and now I'm waiting for a chance to go through the carb.
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Hi BA

The two things that jump to mind are...........

1) If the scooter is stalling at idle, and its been stood around for a while unused, there may be a build up of fuel deposits in the carb.... it may be an easy fix as you can perhaps get away with cleaning out the idle jet. The idle jet only supplies fuel at idle and if its hard to keep it ticking over without revving the scooter then I'd start there. Its an easy fix and I can talk you through it, it will take you perhaps 30mins to do this.

2) If its cutting out/stalling at speeds higher than just ticking over then it may be fuel related, spark plug cap/lead related or a more dirty carb perhaps.

Can you describe to me exactly what happens so that I can understand better to be able to help you

Fabio

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Fabio,

Here is a list of what has been going wrong, in no particular order. Bear in mind that none of this happens all the time. I can go for days with strong, quick starts, and then have a day where it cranks for two minutes, and just when it sounds like the battery will die it starts up, weakly.

Starting:
-Cranks for a long time with electric starter, but eventually starts.
-When this is happening, the kickstart NEVER works.
-Most of the time when it does start, there is a very thick white smoke. People on the street give me dirty looks, and one time an older lady came out of her apartment to yell at me. In other words, not normal 2 stroke starting smoke.
-Usually giving it some throttle while starting helps. Sometimes, however, throttle hurts. A few times it has started weakly and repeatedly stalled upon giving it gas. In these cases, letting it idle for a few minutes solves this problem.
-There has only been one time where it absolutely refused to start. I left it overnight, came back, and it started relatively fine.

Stalling:
-Happens at idle, when the bike is not fully warm (though it sounds like the choke is off).
-I will sit at a red light, bike will have an irregular idle, and when the light turns green and I go to give it gas it stalls out. Even if I keep the revs up at idle, trying to get moving stalls the bike.
-At high revs it seems to run very strong, and once the bike is warm it idles OK

Other things:
-I think the choke is working, because the sound of the idle changes noticeably once the bike is warm.
-The most frustrating part of all of this is that I have taken it to a very well-regarded scooter mechanic four times, and each and every time it has started immediately and run perfectly for him. He did, however, soak the carb in carb cleaner once, and while the carb was off he noticed that fuel was still flowing so he replaced the fuel tap. When the starting problems returned, he checked to make sure the new fuel tap was working properly, and he says it was.
-It is now with a different mechanic, so I won't be able to try anything for a few days, but my fingers are crossed that he will find the problem.

I hope this helps. If I missed some important detail I will add it when it comes to me. Please ask any questions that you think might help.

Thanks so much for reading and helping.
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Hi BA

I'll try to help by adding some notes to your paragraphs, it will probably make sense that way....

Starting:
-Cranks for a long time with electric starter, but eventually starts -When this is happening, the kickstart NEVER works -Most of the time when it does start, there is a very thick white smoke. People on the street give me dirty looks, and one time an older lady came out of her apartment to yell at me. In other words, not normal 2 stroke starting smoke. At initial read this sounds like one of two things...either too much fuel is getting into the carb before it can ignite (faulty fuel tap is flooding the carb) or that the spark isnt powerful enough or that the spark plug cap/lead are duff, how old is the spark plug?...also have you checked to see that the vacuum driven fuel tap is working correctly and not just open constantly and flooding the carb

-Usually giving it some throttle while starting helps. Sometimes, however, throttle hurts. A few times it has started weakly and repeatedly stalled upon giving it gas. In these cases, letting it idle for a few minutes solves this problem. This sounds fairly normal in a weird 2-strokey kinda way

-There has only been one time where it absolutely refused to start. I left it overnight, came back, and it started relatively fine. This also sounds like flooding of the carb, there is too much fuel present, it evaporates overnight to allow you to get it started in the morning

Stalling:
-Happens at idle, when the bike is not fully warm (though it sounds like the choke is off). This sounds like a faulty plug/cap/lead perhaps, I've had this recently on my GT125, or maybe that the idle mixture is adjusted incorrectly

-I will sit at a red light, bike will have an irregular idle, and when the light turns green and I go to give it gas it stalls out. Even if I keep the revs up at idle, trying to get moving stalls the bike. Again, sounds like plug/cap/lead or idle mixture

-At high revs it seems to run very strong, and once the bike is warm it idles OK This sounds correct as when the scoot is moving then the spark issues and flooding issues are less of an obvious problem

Other things:
-I think the choke is working, because the sound of the idle changes noticeably once the bike is warm. Ok

-The most frustrating part of all of this is that I have taken it to a very well-regarded scooter mechanic four times, and each and every time it has started immediately and run perfectly for him. He did, however, soak the carb in carb cleaner once, and while the carb was off he noticed that fuel was still flowing so he replaced the fuel tap. When the starting problems returned, he checked to make sure the new fuel tap was working properly, and he says it was. Visually check to see if the fuel tap looks new and that it has actually been replaced, you can also check the operation of the fuel tap by.........

The fuel tap/petcock is vacuum driven. What I mean by this is that there are 2 pipes connected to it. One is clear and thicker than the other and this is the fuel-supply pipe that provides fuel to your carb. The other is thinner and black, this is the vacuum pipe.

The clear fuel supply pipe only supplies fuel when there is a vacuum present at the black vacuum pipe.

The vacuum is created by the compression of the piston as the engine turns over to "suck" the fuel through the fuel-tap down into the carb.

To test your fuel-tap....

1) remove both pipes from the carb
2) check both pipes for splits/cracks/leaks
3) put the end of the clear fuel supply pipe into a container to catch fuel
4) suck on the black vacuum pipe
5) if it works ok and fuel flows into your container then the fuel-tap is likely to be ok
6) if no fuel flows then replace the fuel-tap


Hope all this helps, I know there are a lot of ifs and maybes... but what I would do is.........

1) Check the operation of the fuel tap as I've described above.
2) Have a good look at the spark plug/lead/spark plug cap and replace if any doubt - they are all relatively inexpensive.
3) Check the idle mixture screw, here's how... You could be experiencing too rich or too lean fuel/air mixture to your carb. To set this you should screw the idle mixture screw fully in.... (Before you screw it in...look at where the screwdriver slot is at... then count how many turns it takes to go all the way in gently... 1 and 1/2 turns for example, and remember the number of turns for later)..... then unscrew it out by the number of turns that it states in your handbook - for my scooter it was 1 and 1/2 turns out.

Fabio

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Thanks again, Fabio. The bike is at the mechanic (the only local dealer in Boston) now, so we'll see if he comes up with anything. I have to say, I'd be very surprised if my previous mechanic claimed to have replaced the fuel tap but didn't actually do it. Though he's been disappointing in diagnosing this problem, he is universally loved, so I don't question his honesty. Do you think it could be a gunked-up carb causing something to stick and flooding the engine?

As for the spark plug, it is brand new. I hadn't though that could be the problem because stalling is not an issue once the bike is warmed up.
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Yes it could be the float in the float bowl getting stuck perhaps.

Have a look at this this thread about stalling with my GT - it may help

GT125 stumbling/lurching on accel/idle - TOTALLY SOLVED!!

Fabio

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Update
OK, the saga continues. I will continue to update this until I get to the bottom of it, because I know that other people have had ET2 issues, and I hope this thread helps them.

I got the bike back from the shop on Friday. They had taken the carb apart for a cleaning. Started perfectly strong, and ran like a top on the way home. It sat all weekend while I was away, then I started it yesterday. Again, started perfectly. I rode it for about an hour.

This morning, back to the EXACT same problem as before. Starter cranked for about a minute, then finally a very weak, very smoky start. Rode it for about 15 minutes to work. No stalling issues.

My problem is that I live in an apartment in central Boston. My ability to take the bike apart and work on it is extremely limited, as I would have to work on the sidewalk. That is why i have been taking it to the shop and paying others to do this for me. The problem is that every time I have taken it in it has started perfectly for the mechanics, so they cannot troubleshoot.

I am now using a new mechanic (the dealer). I am bringing it back to them next week to replace the jets, and double check that my new fuel tap is actually working. They will also check the compression and spark to confirm that this is indeed a fuel supply issue. If the tap is working, compression is good, and spark is strong, what next?

Fabio, from reading your response it seems that a strong spark would eliminate the spark plug/lead possibility. As for flooding, that seems like either the tap or a stuck float, but the mechanic says that the float was working properly.

Soon I will be out of options. I got this bike for a relatively decent price this year, and I am honestly on the verge of scrapping it. I fear that I will be faced with either that or spending at least a hundred dollars on a new carb, and that that may be more wasted money on an unfixable bike. I really frustrated.

Thanks for all the help.
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I'm still inclined to think this.......
Fabio Dougie wrote:
At initial read this sounds like one of two things...either too much fuel is getting into the carb before it can ignite (faulty fuel tap is flooding the carb) or that the spark isnt powerful enough or that the spark plug cap/lead are duff, how old is the spark plug?...also have you checked to see that the vacuum driven fuel tap is working correctly and not just open constantly and flooding the carb.

Visually check to see if the fuel tap looks new and that it has actually been replaced, you can also check the operation of the fuel tap by.........

The fuel tap/petcock is vacuum driven. What I mean by this is that there are 2 pipes connected to it. One is clear and thicker than the other and this is the fuel-supply pipe that provides fuel to your carb. The other is thinner and black, this is the vacuum pipe.

The clear fuel supply pipe only supplies fuel when there is a vacuum present at the black vacuum pipe.

The vacuum is created by the compression of the piston as the engine turns over to "suck" the fuel through the fuel-tap down into the carb.

To test your fuel-tap....

1) remove both pipes from the carb
2) check both pipes for splits/cracks/leaks
3) put the end of the clear fuel supply pipe into a container to catch fuel
4) suck on the black vacuum pipe
5) if it works ok and fuel flows into your container then the fuel-tap is likely to be ok
6) if no fuel flows then replace the fuel-tap
Fabio

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Certainly seems plausible, except for the brand new (supposedly) fuel tap. The other odd thing is that I am the only person who has ever experienced this problem. That makes me think that there is something atmospheric (like the fact that I leave the bike outside overnight).
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To find out for sure just do the test youself, it'll only take 5 mins........


To test your fuel-tap....

1) remove both pipes from the carb
2) check both pipes for splits/cracks/leaks
3) put the end of the clear fuel supply pipe into a container to catch fuel
4) suck on the black vacuum pipe
5) if it works ok and fuel flows into your container then the fuel-tap is likely to be ok
6) if no fuel flows then replace the fuel-tap

When you stop sucking on the vacuum pipe it should stop, if it doesn't then your fuel tap isn't turning off which would lead to the carb being flooded and it struggling to start (exactly as you are describing).

Fabio

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It may be your spark. The CDIs go bad on these things, and when they do, it leads to intermittent problems, not a blanket "no spark ever" situation. Imagine this scenario: you go to start, you don't have a spark, you crank it for a minute without one, flooding the engine. Then a spark comes along and it starts. It runs like crap and your scooter blasts smoke because it's flooded with gas and 2-stroke oil from the last minute.

To test this hypothesis is easy: keep a spark plug wrench handy and use the scooter. When it gives you trouble starting, and you're becoming confident you are experiencing "one of those times" (say, it's been a good 30 seconds of cranking and you're getting nothing). Then stop and quickly remove the spark plug. Attach it back to the lead and ground the threaded part of the plug on the frame or metal of the cylinder. Carefully (don't shock yourself) try to crank it over again. You should see a good spark. If you don't, then I think your CDI is bad. You should also notice gas in the cylinder, if you don't then that is pointing us back to the fuel delivery vein.

If you're curious about the bad CDI symptoms, try a search on this forum - I experienced this myself long ago, and a few people along the way have had threads about it as well.

My sense is this is a fuel thing, but it's an easy thing to rule out and is an easy fix if it's the problem.

Also, the local dealer has done some sketchy mechanic work in my experience. If you have doubts about them and want some leads on other mechanics in the area, I know a guy I could point you toward (might be the one you were already seeing).
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XantuFrog and Fabio:

Thanks so much. I had seen your CDI tales of woe on the forum, and kind of wanted to believe that was the problem. Thing is, the bike starts virtually every time when warm AND (probably more importantly) the kickstart NEVER works unless the engine is warm. Absolutely never, not once. When the engine is warm it starts on the first kick. My sense is that if this were a CDI problem that wouldn't happen. Do you have thoughts on that logic?

Also, here is some more info. I just rode the bike for about 10 minutes and when I got home I disconnected the fuel line from the carb. Fuel was trickling out. Not a steady stream like before I replaced the fuel tap, but something. It stopped after a second, but then started back up. I had not touched the vacuum line.

So, here's what I am thinking: I left the fuel line unattached. I am going to leave it like that overnight, reattach it, and see how it starts. If it starts right up it would seem that I have confirmed flooding, and can try to track it back to the float or the fuel tap, right? If I just have the same problem then I can (I think) confirm it's not flooding as a result of the carb or tap, and can move on to other things, like the CDI. Right?

Finally, XantuFrog, is the other mechanic in Medford?

Thanks again!
Alex
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Doesn't sound like the CDI, no.

It sounds like you are doing some good troubleshooting with the tap... it should seal on its own with no vacuum, but I could imagine any remaining vacuum from the engine running might take a little bit to dissipate from the hose (I don't know this though) so that could explain a little post-shutoff trickle.

Here's the thing with the flooding issue, though - the float in your carb should prevent the gas from flowing willy nilly into the cylinder. For example, on old scooters sometimes you might forget to turn the fuel tap off (it's manual instead of the vacuum operated deal), yet they should, conceivably, still start the next day. If they don't, the float is probably sticking or the needle isn't sitting right. Along this line of thought (and I apologize if this was covered up above - there's a lot to read through), perhaps your float/needle isn't working perfectly.

I sent you a PM about the mechanic I know - he's a bit informal, but he gets the job done.

Thackery
BostonAlex wrote:
XantuFrog and Fabio:

Thanks so much. I had seen your CDI tales of woe on the forum, and kind of wanted to believe that was the problem. Thing is, the bike starts virtually every time when warm AND (probably more importantly) the kickstart NEVER works unless the engine is warm. Absolutely never, not once. When the engine is warm it starts on the first kick. My sense is that if this were a CDI problem that wouldn't happen. Do you have thoughts on that logic?

Also, here is some more info. I just rode the bike for about 10 minutes and when I got home I disconnected the fuel line from the carb. Fuel was trickling out. Not a steady stream like before I replaced the fuel tap, but something. It stopped after a second, but then started back up. I had not touched the vacuum line.

So, here's what I am thinking: I left the fuel line unattached. I am going to leave it like that overnight, reattach it, and see how it starts. If it starts right up it would seem that I have confirmed flooding, and can try to track it back to the float or the fuel tap, right? If I just have the same problem then I can (I think) confirm it's not flooding as a result of the carb or tap, and can move on to other things, like the CDI. Right?

Finally, XantuFrog, is the other mechanic in Medford?

Thanks again!
Alex
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OK, some good (or at least interesting) news.

I left the fuel line unattached, with a small plastic container under it to catch any fuel that leaked overnight. None had leaked, which seems to indicate it's not the tap. But when I reattached the line, it started immediately, on the first kick. As you may recall, the kickstart had never worked before when the engine was cold.

I will continue doing this experiment for the next few days, but it certainly seems to indicate that I have a flooding problem, no? Now here is where I get confused, mostly about the inner workings of the carb. It seems that since no fuel leaked out, something is creating a vacuum overnight that is pulling fuel into the cylinder. Seems like it would be a float/needle issue as XantuFrog has said? Where I get stuck though, is would that by itself create the necessary vacuum?

If so, I am not sure on my next step. I have had this carb cleaned twice by professionals, so whatever would make things stick should be dealt with. I still have the 12mm Weber carb on there, is this a good excuse to get the 17.5 Dellorto? Will everything work properly?

Thoughts are much-appreciated, you guys are amazing.
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BostonAlex wrote:
I still have the 12mm Weber carb on there, is this a good excuse to get the 17.5 Dellorto? Will everything work properly?

Thoughts are much-appreciated, you guys are amazing.
.

Yes its a fairly simple like-for-like swap, read here....... My 50cc Challenge - ET2

Fabio

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BostonAlex wrote:
I left the fuel line unattached, with a small plastic container under it to catch any fuel that leaked overnight. None had leaked, which seems to indicate it's not the tap.
.

Did it just evaporate maybe???

Fabio

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Fabio,

2 things:

1. I don't think it evaporated, because I walked by it a few times over the afternoon and evening, and there was nothing dripping or in the container. Possible, but from what I saw the flow was only right after I removed the fuel line.

2. It looks like your Dellorto is a PHVA. From what I can find online, the only Dellorto 17.5s are PHBG, whereas the model fitted to ET2s seems to be PHVA. Any idea if they are interchangeable? I have seen a few PHVAs but they do not include the automatic choke.
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Assuming that the fuel tap is working and my problem is in the carb (could it be anywhere else besides those 2?), what are the possibilities within the carb that could cause this? Could it be as simple as adjusting the needle? Doesn't seem like that could do it on its own. Is it most likely a sticking float? What would you all suggest for troubleshooting this?
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BostonAlex wrote:
2. It looks like your Dellorto is a PHVA. From what I can find online, the only Dellorto 17.5s are PHBG, whereas the model fitted to ET2s seems to be PHVA. Any idea if they are interchangeable? I have seen a few PHVAs but they do not include the automatic choke.
.

I think that they are very similar to be honest

Fabio

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In comparison....


Your photo (in the link that you supplied).....

External inline image provided by member with no explanatory text

My carb....

External inline image provided by member with no explanatory text

.....whereas a 17.5 PHBG looks more like this......

External inline image provided by member with no explanatory text
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Sorry, I am no expert on carbs, so it is tough for me to see, but it looks like your IS the same one as the link I sent? Was that your point, or that it wasn't? Just hard when looking at a different angle...
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BostonAlex wrote:
Sorry, I am no expert on carbs, so it is tough for me to see, but it looks like your IS the same one as the link I sent? Was that your point, or that it wasn't? Just hard when looking at a different angle...
Yes the link you sent looks identical to mine, the PHBG looks different

Fabio

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Thanks, sorry I'm a little dense, I just want to make 100% sure I'm getting the right thing....
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Solved Again
Hi Everyone,

Just posting an update so anyone else with this problem can follow along.

I just replaced the fuel tap again - it turns out it was faulty and had gone bad after less than a month! New fuel tap, problem gone. I am hoping this one lasts a little longer....
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Good to hear!
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Re: Solved Again
BostonAlex wrote:
Hi Everyone,

Just posting an update so anyone else with this problem can follow along.

I just replaced the fuel tap again - it turns out it was faulty and had gone bad after less than a month! New fuel tap, problem gone. I am hoping this one lasts a little longer....
.
Fabio Dougie wrote:
I'm still inclined to think this.......
Fabio Dougie wrote:
At initial read this sounds like one of two things...either too much fuel is getting into the carb before it can ignite (faulty fuel tap is flooding the carb) or that the spark isnt powerful enough or that the spark plug cap/lead are duff, how old is the spark plug?...also have you checked to see that the vacuum driven fuel tap is working correctly and not just open constantly and flooding the carb.

Visually check to see if the fuel tap looks new and that it has actually been replaced, you can also check the operation of the fuel tap by.........

The fuel tap/petcock is vacuum driven. What I mean by this is that there are 2 pipes connected to it. One is clear and thicker than the other and this is the fuel-supply pipe that provides fuel to your carb. The other is thinner and black, this is the vacuum pipe.

The clear fuel supply pipe only supplies fuel when there is a vacuum present at the black vacuum pipe.

The vacuum is created by the compression of the piston as the engine turns over to "suck" the fuel through the fuel-tap down into the carb.

To test your fuel-tap....

1) remove both pipes from the carb
2) check both pipes for splits/cracks/leaks
3) put the end of the clear fuel supply pipe into a container to catch fuel
4) suck on the black vacuum pipe
5) if it works ok and fuel flows into your container then the fuel-tap is likely to be ok
6) if no fuel flows then replace the fuel-tap
Fabio

.
Brilliant!! - I knew we were on the right lines with the fuel-tap being at fault.

Thanks so much for posting back with your results - its very useful indeed to know what fixed the problem.

Fabio

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Re: Solved Again
BostonAlex wrote:
Hi Everyone,

Just posting an update so anyone else with this problem can follow along.

I just replaced the fuel tap again - it turns out it was faulty and had gone bad after less than a month! New fuel tap, problem gone. I am hoping this one lasts a little longer....
It could happen again. The stock one often fails and I'm not certain if a piaggio replacement part is better. Your experience may suggest not. If it fails again, find a Kymco dealer and order a fuel tap for a Super 9.
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Re: Solved Again
BGK wrote:
If it fails again, find a Kymco dealer and order a fuel tap for a Super 9.
Interesting - is this a vacuum operated bolt-on swap, or do you need to modify to fit?

FWIW, I've had one bad tap in 2007. So they can last a while(ish)
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I'm having a very similar problem, Is there anyway to fix the fuel tap without having to replace it entirely?
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avex wrote:
I'm having a very similar problem, Is there anyway to fix the fuel tap without having to replace it entirely?
Not really. It's a closed part. Not super cheap, but not super hard to replace either.
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