CRF 450R engine owners.. Need some help

[YZ400EX]

Ok so here is the deal.. I bought a non running CRF 04 450R the other day. I bought it from an auction so I do not know its background and the problem is I am not totally sure why it did not run.. I figured this might be the best place to ask since some of you are running the CRF hybrids.. When I try and kick start it just backfires. I checked the timing and it is dead on.. I got pulled behind the quad I got it fired after running about 5 mph..Once it fires, it runs strong and smooth, but will not idle. once you let it die, again it will not kickstart..just backfires.. I know it isnt the carb because I have pulled it all apart and made sure it is completely clean. The jetting is good on it (at least close enough to start and run). I am thinking it might be low on compression. I dont know how easy these are to kick over, but my 04 TRX 450 was much harder. Can anyone tell me if this sounds right? Should the TRX be harder to kick than the CRF? Does anyone else have any ideas it may be? Any help on this is much appreciated. Thanks

[YZ400EX]

Nobody??:(

[Glamis400ex]

CRF should be a little harder to kick...more compression

[kodymx13]

the valves are extremely tight. just fixed a friends that was doing same.

[YZ400EX]

Originally posted by kodymx13
the valves are extremely tight. just fixed a friends that was doing same.

Would the valves being too tight make it have more or less compression though?? I am going to check the clearances on them.. any idea on what they should be?? This bike is an 04.. I have a manual for on 02-03.. will the specs be different?

[kodymx13]

if their really tight itll feel like no compression almost. spin it over by hand. thats the way this guys was. now its got good feel on the kicker and starts first kick. mines an 04 also. i like to have .006-.008 on intake. and .012 on exhuast. thats what my engine builder has always told me.

[YZ400EX]

Originally posted by kodymx13
if their really tight itll feel like no compression almost. spin it over by hand. thats the way this guys was. now its got good feel on the kicker and starts first kick. mines an 04 also. i like to have .006-.008 on intake. and .012 on exhuast. thats what my engine builder has always told me.

Yea I can kick this one over by hand also.. it does feel like it has a little compression, but not much since it is pretty easy to kick over (even with your hand) I will check the valves and post back with my findings.. I will wait until tomorrow though since I dont have any shims even if I did need them..

[2muchquad]

timing chain could be stretched as well,my yz426 showed those symptoms when mine was stretched.;)