Compression tests
 

Well, I have done a compression test as I have checked almost everything I can to solve an odd running at lower RPM.

Anyway, I have tested them and peak psi is;

Front 220
Rear 200

What do you make to that?

Re: Compression tests
 

The front is 20 more than the rear, hth.

Re: Compression tests
 

The rear cylinder peak pressure is 90.9090909% of the front cylidner peak pressure.

Re: Compression tests
 

Very very generally speaking more than one atmosphere between cylinders is the limit, that said I reckon they're both good enough, if you have a slow speed running problem I think you'll need to look elsewhere.
Specific knowledge of your precise engine would be the best thing - find someone who knows those engines and ask there.

Re: Compression tests
 

There dont seem to be too many people around on the aprilia forums that know a great deal about this subject tbh...

Im clutching at straws atm trying to figure out why my bike is running like a **** at small throttle small RPM. I've done a lot of things like vacuum, injector spark plugs all that. Replaced most of it, still no good. Its something that has come on in the last few thousand miles and last 6 months, so its not really somethng that I have done as far as I can tell. Just odd.

Out of interest as a education, what would low compression on one cylinder feel like?