engine compression
 

About 2 months ago I take my bike to the shop because it wont start. Ran fine one day not the next. They thought it was not getting fuel but found out it lost compression so it wouldn't crank. They said they oiled and lubed the motor i guess the heads. Its ran fine put another 3K and now its doing the same thing. Any ideas, ever heard of a F4i losing compression?

Sounds like you might have a sticky valve. How many miles on your bike? Do you loose compression on all cylinders or just one? Your battery may be low too from cranking. Loss of compression won't normally stop the cranking of the engine.
mikey

the bike has 25K, I'm not sure about which or how many valves didn't have compression. Its headed back to the shop tomorrow

You might try taking it to a different shop. One that can fix it for good this time!

if it's losing compression on all cylinders then it might be jumping time

the only way i could see this happening would be if you have a manual cam chain tensioner that has backed out over time


if it's on one cylinder there are lots of things that could cause it, bad rings, worn or scorched cylinder, loose spark plug, bad head gasket, sticking valve, bad valve clearance