Help me! 2008 crf450

[Darcyrawson]

Hey I have a 2008 crf450r and I can't get it started! I cleaned my carb, air filter and all vent lines! I checked my valve clearences and they are all right in spec! When I try to start it it backfires after a couple kicks but nothing else! I can't figure out what to do next

 

[Ol'89r]

When you cleaned your carb did you remove all of the jets and fuel screw and blow air through the orfices? If your bike has been sitting for a while, there is a good chance old fuel has clogged these orfices. Make sure you can see daylight through your pilot jet.

 

[Darcyrawson]

yes i blew air through everything and used a carb cleaner and there was still no luck with starting it, a buddy told me that it may be a seized or toasted valve!

 

[Darcyrawson]

by the look of the motor has never been tore apart so I'm assuming that its still stock valves in it and they have never been adjusted cause they are .006 inches and specs that i found say that they should be between .005 to .007 inches

 

[High Lord Gomer]

All of the modern 4 stroke race bikes tend to have their own starting ritual that works for just them. Some of them need 3 or 4 squirts of gas before kicking, some you can't touch the throttle at all, and some even like to have the throttle held slightly open. You have to experiment and figure out what works with your bikes through trial and error.

Have you tried push starting or even towing the bike with another or a 4 wheeler? I live at the top of a hill and if one of the bikes doesn't want to start within a couple of kicks I roll it down the hill to bump start it. It only sucks if it doesn't start before I get to the bottom.

 

[Ol'89r]

You may want to do a compression test. You will have to disable the auto compression release to do this properly. If it is a 2008 and if it has a lot of miles on it, I would just take it apart and do a top end rebuild. The valves in those bikes can break after excessive use and will do a lot of damage to your engine. Install the Kibblewhite stainless valves and you won't have to worry about your valves breaking. You probably need a new piston too. The 006" clearance is for your intake valves. The exhaust valves should have 010" - 011" clearance.

 

[Darcyrawson]

I found my problem, ****ed intake valve!