Modern Vespa

I have been doing alot of troubleshooting today... I am at a loss due to the fact that I have no idea what I should be looking for .. Everytime I ask a question on here you guys always help me out.. and thats one more thing I can throw into my book of knowledge... I really do appreciate all the help everyone gives me on here... Anyway...Let me give this a shot to describe what is going on... Il be riding for 10 or 15 mins cruising, downshifting, upshifiting... I go through 1st gear fine... hit second and when I start to get to higher revs it sort of just revs really high and says there with maybe 3/5 throttle... shift to 3rd same thing... shift into 4th and I only get up to about 45 tops... I was wondering if it maybe had something to do with the clutch, clutch cable... or something along the lines of that.... I then turn off my bike give it a rest... start her up... shifts through every gear AWESOME!!!!! The bike revs up to high rpms easily and doesnt coast in gear... I wish I could describe this better.... this pisses me off that I cant... hopefully this is enough for someone to give me some tips or troubleshooting methods... thanks!!!
~Dom

Dominic

it sort of just revs really high and says there with maybe 3/5 throttle

Are you saying the engine will not rev further than 3/5 throttle? That no further increase in revs after that point?

Al

yes thats exactly what Im saying Al

It stays at the same revs no matter if I go past 3/5....

Just a guess . Air leak? See if you're head is on tight .

awesome..!!! il def check into that tomorrow when there is some day light... any other things it could be....

could be clutch a bit tight and once warm starts slipping

What would be my best approach to checking into that... I have been thinking about replacing the clutch anyway... Good idea!?

If it is an air leak the motor will want to rev higher even in neutral.

A slipping clutch will be more obvious in higher gears and at higher rpm and when the motor is under a higher load.

Have you adjusted or replaced the clutch cable recently?

Have you changed or checked your gear oil recently?

Before you change your clutch, try changing your gear oil and check to make sure your cable isn't adjusted too tight. If it has been slipping and you've been riding it a lot it may be too late as the heat and friction will glaze the plates and cause the springs to loose temper. Be sure and get a new set of springs just in case.

I have Changed my gear oil within the last 300 miles... It does slip out of gear quite a bit... I just got a new cable installed about 2000 miles ago..

does it rev without throttle when you are sitting in neutral ?

or do you feel the clutch slip when you are riding under load?

The clutch pops out of gear and goes into a false neutral when riding under load .. But does not rev sitting in neutral

so it sounds like you have more than one thing happening. The popping out of gear is a bad shifting cross, it's a cheap part but you need to split the cases to get to it.

If your motor runs normally in neutral, that's good news in the airleak dept. I would say however that if you are going to have to split the cases to do a cross job and you need to fix your clutch as well, you might as well replace both the clutch and flywheel side seals while you're in there.

hmm that kinda sucks... Well i guess im going to need to figure out how I can do a sidewalk job engine rebuild haha.... As far as rebuilding the engine... how much dinero and what would be the EXACT parts I would need.. just so i can start making an excel sheet of everything and the cost..!! mike I would be totally down to shoot you like 200 bucks or so to help me do a rebuild and run a new harness.. If your down.. I mean I know how to follow step by step on vespa maintenance but it would be cool having someone experienced to watch over and give me tips and what not..

To rebuild your engine you should get:
New clutchside and flyside seals
New cruciform
New kickstart gear (not quadrant, the little gear it engages with is a wear part)
New gaskets
New o-ring seal for the kickstart quadrant
Maybe new rubber kickstart pinion return buffer



You can't really know until you are in there, but you may also need:
new bearings, new gearstack shim...

Those should just be checked for play and tolerance respectively while you are in there, and appropriate replacement ordered if necessary

Thanks man.. This is exactly what I needed!!!!

It's a P series - you have got to at least change out the fly side bearing as well. if your engine is this worn to warrant all these new parts - I bet the fly bearing is shot too.

Also - rings and hone

If you are hopping in and out of gear that bad expect to change a couple of gears as well.

Take crank to Barry at sf scooter or Erik at first kick and have them check if it's true.

Rebuild shifting box.

Good call Gary... I will def go and have someone check it out with a more professional ear

sounds like you need to make a friend with a garage!

edit: I will look your bike over if you like, just pm me