hobbit lacks power

Eoban Binder /

What's wrong with my Hobbit? Used to do 30-35 mph all day, suddenly started topping out at 15 mph, and low-end power is gone.

Near-stock '78 PA50I -> PA50II conversion ('II' jug, intake, carb, ramp plate). Only other modifications are air filter, MLM sidebleed, 1.5k Dio springs, and drilled-out 'II' rollers, all of which it ran just fine with previously. Timing is spot-on the 'F' mark on the flywheel. Compression is ~150 psi. Jetted at 80.

I must be missing something simple, but I'm running out of ideas here.

Re: hobbit lacks power

Kiel the Canuck /

Could be a leak at the crank seals. My hobbit came to me because the seal behind the clutch blew out and caused a lean seize while the previous owner let his kids fuck around on it.

Re: hobbit lacks power

What ideas have you ruled out and how?

An air leak could can be tested with carb cleaner or by checking plug color. It could be a restricted fuel flow. It also may not be the engine at all. Your belt could be stretching or slipping. Check your wheels, Your brakes could be rubbing, maybe a bearing problem or anything else the could prevent the wheels from spinning freely.

Re: hobbit lacks power

sookia sookia /

it's probably a vespa

Re: hobbit lacks power

Eoban Binder /

Good ideas guys. I suspect crank seal is the hardest to check for sure.

Already checked for air leaks and there appear to be none. I'll swap a different belt on tonight and check the brakes/wheels.

Re: hobbit lacks power

variator sticking?

Re: hobbit lacks power

George Cruz /

prob the bearings or the crank seals. or check the trans.

Re: hobbit lacks power

Stephen Keller Wrote:

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> variator sticking?

If a hobbit tops out at 15-17, thats the magic number for a stuck vario....

just get a tjt and go faster.

Re: hobbit lacks power

sookia sookia /

^happened to me....can confirm 15 to 17

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