TRF Forums

Newbie saying hi and wanting guidance please
Hi all. First thing first I'm Sam and I have had my xr250r 91 for about six months now and I'd just like to say bang for bucks it's brilliant. Got it quite cheap so just working my way through bringing it back to it's former glory. I have changed fork seals, air filter, oil,checked valve clearances and general tidy up. Now I have noticed that it seems breath in my opinion quite heavy through crank case breather. Now I have never had such bike before so I am only sumizeing this is a fault. On taking the oil filler of it does breath through there. I have decided that I would comp test . On doing the test I did it when cold due to not able to warm it up at such a hour. Now from cold I got around a 80/100 psi so quite low . I am now going to try when warm as you are ment to comp test working temp. Well thanks for reading and I will post up my results and we will see if I need to strip the piece of automotive history down and may be needing some advice cheers Sam

you should do three test
cold - will be relatively low compression
cold with a small squirt of oil in the cylinder and turn over once or twice by hand or kick - this will 'seal' the rings better so should show higher/reasonable compression if rings/piston are ok, else look to valves seating/adjustment or valves themselves
hot soon after running - running compression best check for overall as all well lubed at this point and at running condition (or close to)

If you try all of these you should get a fair idea of the state of your machine and if problems whether its rebuild time or re-grinding valves