Modern Vespa

New to me p200e with a malossi 210, new crank (not sure what one) malossi box exhaust, and phbh30 carb. Stock 7 spring clutch basket, and stock gearing as far as I know.

Ive ridden around the city for a handful of days, not babying it what-so-ever, really ripping it around into the high revs, and it rides great, but never really exceeding 40ish mph and also not staying in a high rev for that long because of all the stop signs in the city.

Today I finally had some time to take it on the highway, and right as I was about mid rev range of 4th gear, really racing it, id guess around 50ish mph, it "felt" like it either slipping out of gear or the clutch slipped. I obviously closed the throttle immediately but then got back on it gently and it was fine, and then I proceeded to gradually accelerate and all was fine. I got off, the highway and then got back on in the same manner, really racing it through the gears and the exact same thing happened, same time of accelerating. Once it happens and I back off, it was fine, and was able to cruise fine no problems between 60/70 (I had gps speed app going). Could the clutch basket expanded and slipped? It doesnt slip when I race it hard through the gears at lower speeds. Or did it pop out of gear?

Also heres a photo, as it originally was built in California in the early 2000's and came with receipts from massimos, andys capital scooters, and some other scooter shop in orange county, maybe someone recognizes it.

So my first thought, irrelevant of your specific issues, is that a stock seven spring clutch is probably not capable of handling the load that motor will put on it if it's well built. Stock, they're only good to about 17-18 HP. Get one of the various VMC/SIP/BGM Super-strong Cosa2 style clutches with CR80 plates and you'll be good up to about 27-28 HP.

As to what happened...if it's the clutch slipping, you'll hear the motor continuing to accelerate, but not actually be accelerating to keep up. Even a little bit of clutch slip will eat the plates in no time. It will happen quickly, but it's not jerky--if anything it's the opposite, since you're not accelerating despite the motor winding up.

If you jumped out of gear, that's a lot more sudden and potentially dangerous. It's exactly like it sounds. One moment you're in gear, the next the motor is just revving freely. Possibly jumping back into gear with a pretty serious lurch.

If that's the case, it *might* just be that the cables need adjusting, but more likely, and unless this motor is freshly rebuilt, I'd guess you need to split the cases and replace the cruciform and possibly your loose fourth gear, depending on how thrashed the lands (the point on the gears where the cruciform makes contact) are.

-I have a banded clutch basket ordered, waiting for it to arrive. I have a built malossi 177 that ive been racing at the track that has a 7spring banded clutch basket and its been wonderful, and the motor is very fast for what it is, however I know its not as powerful as a 210.

-As for the exact feeling of what happened, its hard to tell, which is why i want to get some ideas from you guys. It happened so fast both times, and it wasnt so black and white as to if it was slipping and slowly getting grip back, or if it was more jerky like popping out of gear, but id prolly say more jerky than not. I let off the throttle so quickly and eased back in, but it also has never jumped out of any of the other gears while ive been ripping it through the city at lower speeds (mostly 1st through 3rd). I have receipts from the build and other work done to it, and as far as i can tell the cruciform was replaced less than like a couple thousand miles ago, at most.

Hmm...sounding more like worn cruciform/gears than clutch slip, I hate to say.

Did you pick up some stiffer springs to go with the basket? If the clutch basket stretches, the circlip will pop out and rattle around in your gearbox. It will be an experience you won't soon forget.

I had it happen to a motor on the bench recently and even then, it sounded pretty unhealthy:

And if you want to hear some fairly extreme clutch slipping, jump to 35 seconds in this video. Notice how the engine pitch changes, but the doppler effect doesn't.

based on these videos, what youre saying and my initial gut feeling, i also agree that it dosnt seem like the clutch was slipping. Something with the gears/cruciform. Well I have a race coming in a few weeks, and dont really have the time to split the cases to have a look, so I'm just gonna race it as is and hope for the best, and if it blows/breaks, ill have my winter project cut out for me. thanks for your input, and if anyone else has anything to chime in, im all ears.

I don't know how you are with a wrench, but I can swap a cruciform in an evening.

I'd be hesitant to race a bike that was jumping in and out of gears, because that's a great way to break gear teeth and crack cases. I proved this a little while back when I missed an aggressive shift to fourth gear. That pretty much shattered the cases and broke teeth off both fourth and the primary of one of my 187's.

That did close to a thousand bucks in damage in a fraction of a second, and that was just for the parts.

Soft seize?
What jets are you running?