Jump to content
Sign in to follow this  

crf backfire!

Recommended Posts

just bought a used 2003 crf450r and it backfires when i let the engine slow the bike down... it does this everytime and its so loud...whats the problem??? and its hard to start cold and starts 1 kick hot (with hot start)

Share this post


Link to post
Share on other sites

deceleration pop is caused by a lean condition or an exhaust leak.

i would check your jetting first. try richening up the mixture with the fuel screw. it should get better. you may need to adjust your pilot jet to get it perfect.

Share this post


Link to post
Share on other sites

whenever i buy a used 4-stroke, i always clean the carb really well and then check the valves. a choked up pilot jet can have you chasing ghosts. out of spec valves will drive you nuts.

it also helps to know what jetting you have on your bike, so that you can get it jetted correctly if it runs funny.

good luck.

Edited by kskyles
edit

Share this post


Link to post
Share on other sites

Also if the carb was recently cleaned make sure the slider plate is in right side up. The 03 should look like the letter M when installed properly. If it looks like a W it is upside down. I bought mine used and chased it all over and this was the problem. Mine sounded like a machine gun shooting.

Jason

Share this post


Link to post
Share on other sites

My hotstart cable was rusted and keeping the valve open a small amount (lean) and it was popping nice, and idle was up and down too.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×
×
  • Create New...