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2007 CRF150RB runs very hot, does not idle well
Posted: Tue Jun 16, 2009 4:02 pm
by L.T.
My crf150rb runs HOT! It's been sitting for a month or so and when I started it up the other day the pipe was glowing red hot after just a couple of minutes and the coolant started overflowing. The bike is hard to start and when it finally gets started it doesn't want to idle. I've never had to deal with this issue and I'm not really sure on how to fix it. Has anybody in here ever had this happen?
Posted: Tue Jun 16, 2009 4:09 pm
by Asmith
Easy fix.
Clogged pilot jet. Remove, clean thoroughly, run a small wire through all orifices, reinstall.
Posted: Tue Jun 16, 2009 5:45 pm
by taylorrep
We have a 2008 CRF150RB and is started fine and never ran hot, however late last week it got to where it would not idle we checked to jets and all was fine then we checked the valves and we had 0 clearance on the right intake shimmed and now runs like a champ again. If you have the carb off and haven't checked the valves may as well do it while your there.
Posted: Thu Jun 25, 2009 6:58 am
by L.T.
Cleaned the pilot jet, still have the problem. I've found that when the choke is on, the bike does not get as hot. Maybe it's running lean? Maybe I should adjust the pilot screw?

Posted: Thu Jun 25, 2009 7:04 am
by Asmith
What size pilot are you running?
Posted: Fri Jun 26, 2009 5:45 am
by L.T.
The jetting on my bike is stock, which I've heard isn't very good. 135 main jet, 40 slow jet (pilot), NHNT needle, 68 leak jet.
Posted: Fri Jun 26, 2009 5:51 am
by Asmith
L.T. wrote:The jetting on my bike is stock, which I've heard isn't very good. 135 main jet, 40 slow jet (pilot), NHNT needle, 68 leak jet.
Correct...it's very lean.
Change the pilot to a 45. It will start easier and run cooler.