compression question

[repete11]

Howdy everyone!

I'm back riding after about 15 years off. I just got myself into a 2003 Yamaha yz250f (first time with a four banger). When I bought it the motor was completely rebuilt, valves everything. It was a bear to start in the beginning but after two short rides it seem that it is real easy to kick over. It feels like there is not much compression when I try to kick it. It starts right up and it runs fine so I'm trying to figure out if I'm having a problem (maybe valve adjustment) or am I just getting used to the bike. Any help would be greatly appreciated.

Pete

 

[mandark1967]

compression testers run about $23 at autozone if you need one. sounds like its just loosening up a bit though

 

[Ol'89r]

Pete.

Check your valve adjustment. The valves can lose their clearance very quickly after a valve job when everything seats in. It's a good idea to check them often.

 

[repete11]

Adjusting valves, is this something I can do myself (somewhat mechanically capable) or better left to a shop? Thanks for the advice.

 

[Ol'89r]

It is easy to check your valves. A little bit harder to adjust them. If you don't have a service manual for your bike you may want to get one. It explains the procedure for checking and adjusting valves, step by step.

If you are going to own one of the modern four strokes, it is very important that you learn how to do your valves.

You can also do a search. There is a lot of information on how to adjust your valves on this site.

A little tip. On your particular model, the most important thing to remember when adjusting your valves is to torque the cam caps to the proper torque using an inch pound torque wrench. DO NOT OVERTORQUE THEM.