Modern Vespa

I'm new to this forum. I recently purchased a 2001 ET2 50cc w 96 miles on it. It appears to be completely stock. Drained the fuel, replaced the fuel tap and the fuel and vacuum hoses. Took the carburator apart and cleaned it. Put it back together and by putting fuel in the spark plug hole 3 or 4 times was able to get it to start and idle just fine. I'm running 50-1 non ethanol fuel mix in it until I can be sure the oil pump is working properly. When I give it throttle it revs and then it bogs down. I'm guessing it bogs down due to either too much or not enough fuel. The spark plug is new.

1. Im trying to run the scooter without the air box connected as the foam air filter had deteriorated and I am waiting on a new one. Could this be affecting the fuel/air mixure. Does the air flow need to be restricted by the foam filter?
2. The carburetor is a small Weber carburetor. You can read "Weber" on top of the throttle assembly if this helps identify it. When I took it apart the only rubber parts I found were on the tip of the float needle and the float bowl gasket. Neither of the 2 other needles had rubber o rings or washers. Should there have been o rings in any other places? Is it possible that the deteriorated over time? Could this be my problem?
Thanks

Welcome! ET2s are great. Yes More or less. You can derestrict somewhat , but must up jet to compensate I can't think of any other o-rings or washers except gaskets creating the seal on the float bowl and the seal on the cap holding the throttle slide down with the spring

Premixing in addition to auto lube is a bad idea - not only will you foul plugs like mad but without up jetting the premix actually leans you out! Coupled with no air box set up you are probably running super lean and bogging out when you open the throttle. I'm on a mobile device so it's hard to find the link for you, but I posted in a recent thread about an ET2 not starting on how to test the auto lube. Try a search for that puppy. I would do this while idling and, presuming it is working, ditch the current oily gas for fresh stuff.

If you want to richen it up a bit to try puttering around without the air filter you could set up the air box without the trashed filter and then raise the needle in your carb a couple notches by lowering the clip a few notches. Careful not to drop that clip, you'll never find it again. Don't zip around if this works - you will still be lean at 2/3-full throttle, plus riding without a filter is dangerous. This advice is really just for diagnostics to see if you can get it to behave a bit

Hope this helps!

OK. This all makes sense to me except the reference to the "clip". Not sure what you are referring to with regards to the "clip" that I would be lowering. Thank you.

2-Stroke Carburetor Set-up Technique

Here ya go - it took me a while to figure out what "the clip" was when I started with these things. It can be hard to pop off and is springy - I've lost one trying to put it back on - make sure it clips down inside one of the grooves on the needle

Here's where to see how he said to check oil pump.
ET2 died mid-ride and won't start. Stumped!!

my ET4 did this when I had cracks in the vacuum/fuel lines. I'd start with those.

Reconnecting the air box w the filter solved my original problem. Thanks for the advice. The scooter now starts easily, idles and accelerates smoothly. Next question. This is a 2001 stock ET2 scooter w only 96 miles on the odometer. I took the carburetor apart and completely cleaned it and replaced the fuel tap, fuel line and the vacuum hoses. It is white (some people seem to be able to tell from the color if it was fully restricted). It has what I think is the smallest Weber carburetor that they put on the ET2's. It has a "Confuser Tube" appendix on the exaust pipe. It does not have a ring around the variator. Even if the gearing is restrictive should this scooter do better than 20 mph? Thats about all I can get out of it. Were any of the ET2's restricted such that they would only do 20 mph? If they were than maybe it's running great. If they weren't than I'm guessing that the carburetor is not adjusted properly? I have another Red ET2 (2005) that revs higher and easily goes 30mph on level ground. I set the fuel/air needle @ 1.5 turns but it doesn't seem to make any difference in the performance if I move the needle plus or minus .75 of a turn. Looking at the pictures on the carburetor set up link you provideds I would say that the plug is fuel fouled. What do you think? Is this just a fully restricted scooter that is running pretty good or do I have more work to do to get the most out of it. Thanks.

.

It should get you up to at least 28-30mph even if its restricted.

Have you taken the cover off the transmission and looked at the condition of the belt, in particular can you tell how far its reaching up the variator faces (try marking the variator face with a sharpie/marker pen and then take it for a spin, remove the cover again and see how far the belt traveled by looking to see how much of the marker pen was rubbed away). The belt should be travelling right to the outside edge of the variator to get the full benefit of the gearing)

https://modernvespa.com/forum/post1039456#1039456

Also, what size main jet is in the carb, is the carb a Weber 12.0?

Fabio

.

I was hoping it would do @ least 28 to 30 even if restricted and I'm ok w that as I'm not looking for a race bike. I have had the variator cover off and there is no visible wear. The variator, belt and the clutch looked brand new as it should w only 96 miles on it. I'm not sure where the markings are on the Weber. When I was getting parts @ the shop the guy told me that if you can read Weber on the top of the carburetor than that is probably the "smallest" version. On top of the throttle assembly I can read the word Webber. It has the large Idle screw that you can turn w your fingers. I'm thinking it is more of a carburation issue than a variator/belt issue as it does not whine at full throttle like the other ET2 I have but I will try the sharpie idea just to know. Thanks for your help.

.

If you haven't already done so then take a look at the following 2 threads that I wrote for the ModernVespa Wiki....

Getting Your 2-Stroke to Run Properly

2-Stroke Carburetor Set-up Technique



And also these 2 threads may be useful to you too.....

My 50cc Challenge - ET2

How a Carb Works


Fabio

.

Is this true? In the US they sold a "25mph restricted" ET2 - I don't know if they were truly restricted to under 25mph or not though. Maybe they hit 30 - I'm just asking since you are from a diff country.

OP: Mine was sold as a 25mph one originally, but it was derestricted by the dealer and would hit about 35 (with speedo reading 39) stock - that's with a passenger.

I think that extra tube on your pipe is a part of the restriction - the dealer had broken that puppy off and welded the hole shut as part of the derestriction. I've never gone through derestricting myself so I can't really help more on that front except to say both your bikes sound a bit slow for a derestricted but "stock" ET2.

Crikey - now your asking..........


Legally in the UK all 50cc scoots/bikes/mopeds are restricted to 28-30mph.


I have seen the UK 2 stroke ET2 (and similar Piaggio 2T units) restricted in a handful of ways....


1) Washer inbetween the variator faces - that needs removing

2) Confuser tube on the exhaust that messes with the scavenging - needs cutting off and welding up

3) Too small a Main Jet in the Carb

4) Too small a carb ( the Weber 12.0M's are pants)

5) Sometimes a brass plate (with holes in) that covers the mouth of the carb and restricts flow....it also directs mixture to the idle jet so go careful.

6) A washer in the mouth of the exhaust that limits flow



Fabio

.

OK. I'm going to start by removing the confuser tube from the exaust. I'll check for the restriction @ the mouth of the exaust. The scooter sounds like it is gagged. Thanks again for the advice and the links. Maybe it is not a coincidence that the ET2 that was being unrestricted w the flag painted on the side in the pictures was a white scooter.

Just to refresh. I have 2 recently purchased ET2's. The red one is a 2005 and has always run pretty good. I have since replaced the fuel tap, fuel and vacuum lines and thorougly cleaned the carburetor (ultrasonic) it now runs great. Idles good and smoothly accelerates to a top speed of over 40 MPH. Fast enough for me. The red one has a Dellorto 12mm carburetor w a 87 main jet. I have no history on the scooter to tell if the 87 was an upgrade. The white scooter only has 95 miles on it and likely sat for 11 years. It is a 2001 and it has a Weber 12mm carburetor w a 67 main jet. That carburetor was also thoroughly cleaned and fuel tap and lines were replaced but I can't get it to go much faster than 20 mph. Both scooters look like they are identical with the exact same air box, intake and exaust now that I have removed the "confuser tube" on the white one. When looking on line for a larger main jet to purchase I read a blurb on the Weber web site that explained that almost all carrburetors that were tuned to run on the gasoline refined 12 years ago need to be rejetted because the gasoline refined today is simply not the same w ethanol etc. This makes sense to me. When you take them apart the Dellorto and the Weber 12 mm carburetors are almost identical w only minor differences. I have to assume that if I put a larger main jet in the Weber it should perform just like the Dellorto w minor differences. What do you think? Where can I buy main jets for my Weber 12mm carburetor? Thanks.

Have you considered swapping the carbs from scoot to scoot, to see if the problem follows the carb or stays with the scooter?

You can also try slow manifold with fast carb/fast bike.

Problem solved. I will tie up the loose ends just in case it can help someone else. I tried to rejet the Weber carb and replaced the 67 w a 78. I had high expectations but no improvement. Decided to let it sit another month just as it sat for the last 11 years. Enjoyed the summer on my other Vespa @ the beach. Summers over. Decided to throw some money at the problem and purchased a new Dellorto 12mm carb. instead of taking it to the shop. It ran better but not great. Took the exaust off of my good running ET2 and installed it on my poor running ET2 and Voila! It took off like a bat out of hell. Called Scooter West to order a new exaust and was told that the new Cita replacement exausts were restricted by a cone welded into tube where it connects to the head. When I looked closely at the exaust from the 2002 ET2 and compared it to the one in my 2005 ET2 it was restricted .75 in. into the pipe such that the true opening was only half the diameter of the pipe. Used my dremel to completely grind out the welded blockage. Now it is running great. Bottom line - My white 2002 Vespa ET2 was restricted in three ways: 1)"Confuser Tube" appendage to the exaust which I had read about and removed months ago. 2) Small Weber carburator w a 67 main jet. 3) Welded restriction at the mouth of the exaust pipe which was not mentioned in any of the "restriction" articles I read. Had I noticed the restriction at the mouth of the exaust pipe earlier I probably could have made the Weber carburetor work but I'm pretty sure that the Dellorto I purchased is a much better carburetor. I'm happy to have a new carburetor for what I would have paid the shop to troubleshoot the scooter for me and had I done that I wouldn't have any of the knowledge I now have from getting my hands dirty and wasting some good TV time. If I break down on the side of the road I'm pretty sure there isn't anything attached to the outside of the motor I couldn't troubleshoot and fix. Thanks for the help.

excellent!