Modern Vespa

Rode the Vespa to work today and all was good no problems at all. On the way home..different story. About 5 miles into the ride home I had to stop at a stop light. As I put it in 1st gear, I hear the engine sounding like it was going to die on me so I reved it up a little to keep me going. The next light, stop, put it in gear then it just dies. I roll it over to the side of the street..gave it a few kicks and it was running ok. I stopped by a near by parking lot to see what the hell was going wrong. Each time I would put it in gear..it would just die. I had to crank up the idle setting screw in all the way and this was the only way for it NOT to die in gear. I had to ride it like this to get home. I got home and turned off the engine...and as I was trying to start it again it just backfired on me really loud.

What the hell could this be? Of course any feed back is much appreciated.

Thanks -

Did you check your plug? What was your spark like? Did you ( something stupid sounding, but it's caught me so many times ) check your fuel level!??

I would check your junction box and make sure your wire to your HT coil is tight ... and that it's similarly tight back at the connection point on the HT.

what the backfire probably was was a few charges of unburnt fuel / air / oil going into your exhaust and then igniting in there ( you can do this yourself if you play around with your killswitch ....hold it a sec, let off it, etc. .. you can get your bike to backfire if you time it right.

Sounds to me like this is what's happening.. you've got something halting your spark, or giving you really sporatic or weak spark.

Fuel level is good. I think I have a shitty coil. I have a new one and a condenser that I haven't installed yet because it was running just fine this morning. I'm going to check the plug right now.

Where exactly is the junction box?

I pulled the spark plug and it looked good. Nice light chocolate brown color so all is good there.

I unscrewed the plastic spark plug cap from the coil wire. From the screw end, tt sort of smelt like a "burnt fried electrical" smell.

I'm ready to pull the old coil off and replace it with a new one that I have here. The only problem is the wiring looks a bit different.

On my old coil, there is a single yellow wire that runs from the bottom of the coil to a ground in the "junction box". The little yellow wire does not simply "unscrew" from the coil. It's a wire that come straight out of the coil. The new coil does not have a wire at all except for the wire for the spark plug. It has something that just looks like a wire could hook up to. Do I snip the yellow wire from the coil and attach it to the new coil?

Here are some pictures below:

I would just unhook the old HT coil, bolt on the new one, and just make some small red-wire with a circle end on one end and a spade connector on the other end, and hook it up as such.

( go with red wire, the color it's supposed to be )

Trust me...I didn't put the 12v system in. Red wire, do I use any kind of wire? So go to Home Depot and get a random red wire and connect a butt connector to it and just plug it into the new coil? This sounds too simple.

What about the burnt smell? Is this telling me the old coil is starting to take a shit on me or is that smell kind of normal from high heat?

Thanks Eric for saving my ass again.

My God, that is the cleanest electrical junction box I have ever seen, no joke.

As far as wire, any wire will do (get stranded before solid, trust me). I only rewire bikes with 16ga. but the originals were 18ga if you want.

Only one wire from your coil should go to the junction box and that should be the kill. IIRC, the other grounds to the engine, but I could be wrong (too much tequila).

The burnt smell is not normal, check that out and pin it down, if you can.

You might just have a shitty connection between the spark plug cap and the wire... cut a quarter inch of it off and screw the cap back on again into fresh wire.

Alright...got the new coil in, it started right up..put it in first gear and it didn't die on me all seemed good. Now, when I touched the light switch, there was a nice little spark coming from the little box on the head set. I mentioned before that when I touched my kill switch button, it gave me a good spark...anyways, I take it out and go through 3 then 4th gear and it just died on me AGAIN. I'm starting to think that I have a short in the kill switch button. I believe if I just disconnect the wire all together this may help? Any suggestions? This is driving me crazy..

I'm feeling kind of lame now. I was racking my brain on what it could be and I thought about my gas cap. I loosen the gas cap and heard a nice little pssst sound...like it was releasing pressue. So I fired it back up and went for a ride...no problems...So it's apparent to me that my carb was not getting gas due to no gravity flow from my gas tank.

My question is..has anyone make some sort of breather hole from the gas cap?

There should be breather holes in it already. Sounds like yours is blocked. Its fairly common. The petroil mix attracts a lot of dirt and dust. Give it a clean.

Andrea

Andrea...thanks for the twizzler candy with my last order!

Where in the hell are the breather holes located?

Wouldn't it be much better to have a nice breather hole from the top of the cap?

Flip the cap open and look on the bottom of it. You'll see two pin holes. Shove something similarly small through them to clean them out.

( your pecker should work for this task )






Also, it sounds like you're going to need to remove the handlebar switch and get those soldered ends of wire into the switch better, and then retighten. Sounds like one of them is arcing to the grounded headset.

oh snap!

zing.

Ah, you're a funny lad Eric...with your neat-o beard and all

There is 1 small hole at the bottom of the cap and 1 out the top. I simply drilled through both holes and created a new one. So now I don't have the vapor lock issue anymore.



I pulled the plug with coil wire attached and grounded it to the metal surface of the scoot. I gave it several kicks at first and didn't see much spark action...pretty sporatic spark here and there (with a new plug and old plug). I have one of those spark plug caps that have a metal screw at the bottom of it to screw into the spark plug wire. My question is, what is the correct way to connect the wire to the plug cap? Do I have the wires exposed from the coil wire and then screw the plug cap down into it or do I just cut the wire leaving none of the wires exposed and then screw the cap in ?

If I still do not get good spark...where do I look next? Do I need to replace the condenser? or ?

I use those spark plug caps with the screw and they work fine for me. I just cut back 1/4" or so of the wire so i have some fresh spark plug wire to screw it into.

There's only so many things that factor in with your ignition system that could be wrong.

1) the LT coil on your stator
2) Points
3) Condensor
4) HT coil
5) weak flywheel magnetism

Have you considered throwing an electronic ignition kit on there? It gets you 12v lighting, CDI-based ignition rather than points, and a nice new flywheel ( among other things. It will certainly fix any weak spark issues you have.

So with a electronic ignition kit will not rely on the points, condensor, coils on the stator, etc?

I found this electronic ignition kit here. I wouldn't need a new coil since I already have one. Should I just buy the flywheel and the CDI seperate?

http://www.scooterworks.com/Electronic_Ignition_Kit_60s-7_P2026C83.cfm

so, putting on the Electronic ignition kit is a tad more involved ...as you have to modify an old wiring harness to make it work, or pull a new one ...

So let me suggest these other, cheaper options first

1) Run your new HT coil on there ... see if the spark is better. Try a new plug while you are at it. Make sure you're touching the end of the plug to the engine case, and not some painted part of the frame or something where you won't get solid grounding

2) Pull your flywheel and send it in to scooterworks to get remagnetized for $25 bucks or whatever. That might help.

3) While you've got the flywheel off, check your points, run a little sandpaper through them, make sure the gap is set right, etc. ( have a set of feeler gauges? )

I am a big fan of electronic ignition kits ... but if you've never put one on it might help to have someone who's done it before help you out.

I tried to get the nut off the flywheel and it's a bitch. I'm going to try a breaking wrench for more leverage. When tighting back up the flywheel, what are the torque specs?

Ok yeah, I was grounding it to the surface of the scoot so I wasn't getting good spark that way I'm sure. I've hooked up the new HT coil and it looks sharp though. I did get a nice backfire from the carb.

What should the recommended gap be at the points and spark plug (B7HS)?

i had to buy an impact driver for a non-scooter project a couple years ago...but if i had always known how effective they are on flywheel nuts, clutch nuts, or any other damn irritatingly resistant fastener, i would have bought it for that purpose alone. if you've got $130 or so, i highly recommend getting one. (i still keep my homemade flywheel holding tool, though, as a backup.)

edit: scratch that...i originally bought it to get the variator nut off a CVT. an impact driver is indispensable for that job, straight up.

35 or 50 ft/lbs, I'm pretty sure. I'm leaning towards 50. Don't listen to me though because I just do stuff and damn the specs. I think it's around .020" (or is that mm?) Sorry, not too helpful today.

Oh yeah, +1 on the impact wrench. They're invaluable.

I use an impact wrench i got from harbor freight for $30 or so.

Also i got a 4' long piece of black-pipe from the hardware store and i use that as a breaker bar - sleeving it over the socket wrench i'm using to loosen or tighten a tough nut.

Thanks guys. I think Eric has been right all along about the weak spark. I've had to speed up the idle just for it NOT to die on me when I put it in gear or to keep it from stalling on me when trying to get out of first. Having to speed up the idle has caused havoc with the air/fuel ratio and that's why I'm getting the backfire from the exhaust/carb.

I'll post some pics and give you all an update on this damn thing. Thanks again for everyone's help!

Really, idle speed shouldn't have anything to do with air/fuel mix.

Are you messing with the screw on the TOP of the carb box ( idle speed adjustment ) or on the BACK ? ( idle air correction screw )

The idle screw on top of the air box. I've had to take the air box off to get to the fuel line becasue I had to replace the line, and I replaced the fuel tap in my tank. I also had to make sure I was getting fuel in the carb. Everytime I take the air box off, I had to remove the idle screw.

I haven't touched the screw out the back yet. I just figured that one was fine since it was running great until recently.

Well...I checked spark, fuel, compression and all is good. I did discover that my carb was not tighten down all the way. When I took off the banjo to the carb, the little washer had fell to the back side of the carb so I had to loosen it to pull the carb to the side....well....I obviously didn't tighten down the carb all the way. I had a good 3 1/4 turns on each bolt! I took it out yesterday and no problems so far. My question is how long does it take usually for fuel to get into the carb once you turn on the fuel?

I can only give you a good guess. I have two P200E's and it flows to the carb within a sencond or two. It's gravity flow so even when I turn the petcock off and run it dry then after sitting overnight it will usually start on the second kick as normal after turning the petcock back on.

What is the true purpose of running it dry with the fuel turned off? Do you flood your carb if you turn the fuel off but not burn the small amount of fuel that is left in the carb?

That's a good question. A couple of reasons I can think of is if the float is stuck or the needle doesn't seat correctly it won't stop the flow. I have a moped with this problem and it leaks gas all over the place unless I turn the petcock off. Because it is gravity flow and the carburator small with more intricate parts, float problems are more common. So in short it will stop the possible leak and keep your float in good condition.

Yup. Turning off the gas and running out the carb / line means that you won't have fuel draining through a needle valve that's not seating properly and flooding your engine while it's sitting there off.

If you have hard starts, and lots of unburnt gas / smoke coming out your exhaust when you finally get it going, it's a loose needle / bad seating needle valve / bad float.

Holy shit...sorry for this post going all over the damn place. Here is the list of things that I need to do or I have already done. Please let me know if I need to do anything else or have any advise. I need a good laundry list of shit I need to do to make this thing go:

1. Installed new HT coil and plug. I grounded the plug to the engine block and got nice blue spark each time I kicked it over.

2. Installed a new fuel tap and fuel line. Checked to see if fuel enters the bowl and it does.

3. Need to check the compression. Anyone ever used a compression tester before? The kick start gives good resistance and I can get it started 90% of the time. It's only when it dies on me that it gets hard to start back up.

4. Have a new condensor but cannot get the flywheel off. This is where I'm a little stuck. Any suggestions on how to take off the flywheel when it doesn't self extract with out breaking anything?

5. Carb. I still need to pull the carb and clean it completely out. I've checked the jets and both of them are clean. I'm starting to think maybe I have a bad float/needle? Maybe I should rebuild the carb while I have it pulled off? It really only seems to get fuel when I remove the top of the float bowl to check for fuel. I guess it's because when I pull the top of the float bowl the float points downward and the fuel starts to really come down.

6. Once I get it running and I can get it in gear with out dying on me...everything seems to be ok. After running it around for a while and when I come back into the garage and after I put it in gear it will stall and die on me. Sometimes it's quick to kick right back over then other times it's a pain in the ass and it won't start and it backfires on me through the exhaust.

7. If everything fails, I'm thinking about a 200cc conversion with electric start.

It's easy. Take out the plug, screw in the tester, kick over until the tester quits jumping. You ready to do the rewiring too? You'll need a battery setup for that one, plus some new headset switches, unless you get all ghetto. New bulbs and possibly new bulb housings.

Ok cool. I think I can get a compression tester locally here. Any idea on how much they cost?

I already have a battery set up with 12v conversion. Funny you mentioned the battery, I have 2 loose wires that plug into something. I don't know if they do anything seriously since I'm able to start and run the scoot with out them plugged in. When I get home later tonight I will take some pics and post them on here.

I would just buy the parts and have someone that knows what the f*ck they are doing help me install everything.

You should be able to go down to a local auto parts store and borrow one for a small fee. I don't think they're too expensive, though. Do that. If they're sticking out the engine side of the harness, they're probably for the neutral switch, but I could be wrong. Good luck with that. If I was in your area I'd be glad to help, but I'm getting sick of rewiring Ps. Already done two in the last few months...

I haven't been reading this thread apart from the one bit about the breather holes.

2 questions - Have you checked your points? What about your clutch adjustment? Is the cable too loose?

If it was running fine and then just suddenly started doing this it may just be that something slipped.

Andrea

That's a very good point, though may not be the issue. What I find odd is that it dies when putting it into gear. If everything else is the same (i.e. no touching the throttle, no switching anything electrical) doesn't it seem odd that it would suddenly die if the only change is not even the clutch lever being pulled, but only the action of putting it into gear? That's strictly mechanical, and nothing to do with fuel/air/electrics. On the other hand, maybe you're doing more than just that...

Does the scoot happily idle and allow you to roll on the throttle and let the engine spool up in neutral? Does it ever seem like it's bogging? The backfire definitely sounds like something's amiss; I only very rarely backfire and that's only if the engine's been running for a while and I turn it off and need more than a kick or two to start it. Over about 1100km of scooting this summer I've only backfired twice when kicking the engine over.

What's weird is that your scoot seems okay when under power and moving -- as if the problem is gone when the scoot is rolling and you don't have to worry about the clutch's friction point to get it in motion. <shrug> I'm talking out my a&& here, but am just wondering aloud.

I know when I had to replace a snapped clutch cable this summer it became difficult to start when I didn't have it adjusted perfectly right after the installation. It was no fault of the engine, but because the tension on the clutch cable needed some adjusting (on the clutch end, not the lever end) and the clutch was ever-so-slightly engaged even when the lever was fully released, causing the kickstarter to slip (like when you try and kickstart with the clutch pulled in, but not quite as severe). When it first happened I swore like a sailor, thinking something was wrong with the engine, then calmed down and thought it through. Then I had to play with the tension some more to make sure the lever engaged where I wanted it to -- the bike was definitely pulling forward just a wee bit (hard to detect, really) even with the clutch released, and the giveaway was the change in engine note, indicating there was a slight load on it.

Cheers,
phaetn

Thanks for everyone trying to help me out here seriously. Yes it is very odd that I can get it started fine initially, put it in gear no problems, ride it around, stop it on purpose, put it in gear no problems, take it on the main road and go 50-55mph no problems, then come back to the garage, turn it off, takes forever to get it started again with an occasional backfire, then once I get it started and get it in gear it dies. It makes you want to pull your f*cking hair out.

I'm going to try to tighten and adjust the clutch cable. The whole kickstarter to slip a little is familiar to me. When I go to kickstart, it's got good tension but after like 5 or so kicks it slips just a little. I'm not sure if that's just normal or like what phaetn said about the clutch cable needing adjustment and causing the kicklever to slip.

The first time it died on me when I put it into gear was on the ride home from work. I had to adjust the idle super high so it wouldn't die on me when I put it into gear. So what does that truly mean? It's crazy to think this has only happen to me?! WTF??


I mentioned before that I had some spark come out of the little control box on my headset. When I painted my scoot, I had tapped that all off when I was sanding, painting, etc. When I was finished, I put gas in the scoot and rode it around just fine. When I came to park it, I touched the kill switch and got a nice little spark. From then on, I've had problems.

I'm just wondering if I have a short there in the kill switch. Would the kill switch just kill the engine when placing it in gear if there was a short in it?? I've tried to take the control box off, but I don't know how. Do you think that this could be making the engine cut out when put into gear as well?



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I've had problems with my kill switch also. Occasionally it wouldn't shut off with the key or the kill switch. I took the cover off pulled it out a little put it back on and cracked the cover over-tightening it. Then it started to shut off as normal. A few days later I'm out for a ride and it shut down on me. Long story short I wiggled the switch as it is a little loose and its working again. I've orderd a new one and hopefully it will be here by Friday. I'll let you know how it goes. I would also like some advice on changing it out if anyone has done this before. It's not covered in the haynes manual.