2004 CRF100F with BBR 120 Kit Won't Idle and other issues
  • jrgcbg49
    Posts: 5
    Joined: Mon Oct 19, 2015 7:31 pm

    2004 CRF100F with BBR 120 Kit Won't Idle and other issues

    by jrgcbg49 » Mon Oct 19, 2015 9:31 pm

    Hello experts, I just purchased a 2004 CRF100F with a BBR120 Kit installed by previous owner. I am having issues with it's inability to idle. This is what I know. I test drove the bike and it was very hard to start with or without choke.When it did start it would not stay at idle. If I kept the revs up I was able to ride it a short distance and went up to fourth gear. It seemed a bit underpowered but I'm also 5'8 200lbs. The owner said he purchased it for his daughter but with the idle issues and her being a new rider she didn't want to ride it anymore. I got it for a good price. He said the person he bought it from( the original owner) said the carb needed to be cleaned.

    This is what I've done so far:
    I tried it again at home the next morning. It started after a few kicks on choke.
    Still wouldn't idle and also had nothing in the top of the rpm range (sputter).
    Took carb off. Looked pretty clean inside despite fuel being a gold color and smelling like shellac. Took everything apart and let soak in Berryman B12 Chem. Noted that pilot screw was turned all the way in tight and it was difficult to remove.
    After an hour blew each part with compressed air and re-assembled. Noted Pilot Jet was plugged. Let it soak more and checked float level which was good. Tried to blow it out again but nothing still plugged. SO I drilled it out with an .040 bit. Smallest I had.
    Reassembled on bike. Starts good first kick but idle waay high. Tried 500 different pilot and air screw setting combinations but no luck either waay high idle or stall.

    Got new 035 pilot at local bike shop put it in. Same scenario as above. Went to forums and some said to just get a new carb off ebay for 30.00. So did that was a K27 or such. Had a weird bracket on the choke lever and was spring loaded closed? So swapped over the choke lever from oem carb. Fired it up,,,same exact symptoms. Waay high idle or stall. Back to forums. Think maybe timing is off. Took cam cover off. Noted bolts were loose, and at further inspection found they were just held in place by the rubber sleeve. The bolts were snapped off! So ordered new bolts but went to hardware and got similar till the new bolts arrive. Surprised it didn't leak oil? Speaking of oil, I changed it because it was black like coal. Used Valvoline motorcycle 10w40. The timing appeared to be right on but noted the chain was very slack. I performed the adjustment procedure and re-checked the timing. Now it appears to be one tooth off. With the flywheel on "T" the timing circle was between 12 and 1 o'clock. Just slightly like one tooth as was the left bolt was slightly higher than the right on the head deck.
    So I moved it one tooth, put everything back, adjusted the chain again and everything lined up as it should. Rotated engine by hand a few times rechecked good. Adjusted the valve lash while I had it open. Intake was too tight and exhaust too lose. Put everything back and started the bike. Idle great! More power just the top end of the rpm range sputtering. Figured it was timing all along I took the new carb off...cuz it was really cheap looking..and put the oem back on. Fired it up..darn high idle again!! Got it close with adjusting the screws but noted it was slow to return to idle after revving. Thinking air leak sprayed carb cleaner and it killed engine when sprayed on middle of rubber manifold part between carb and head. Took off again changed o-rings and gasket and used high temp rtv to try and seal middle of rubber manifold. Tried again and STILL idle high and sluggish return. Rode it to a field to see what the rest of the operating range was doing. Well from just after 1/4 throttle to high end of rpm range it was like night and day from day 1. It pulled hard all the way through all the gears. BUT still won't idle!!
    As a last ditch effort I hot glued the rubber piece. But same result won't idle and the glue melted! I also noticed the top of the carb cap where the cable goes in is loose. Sprayed carb cleaner there and rpms raised also. Is that supposed to be a tight connection? I think I read that its all one piece? So new cable as well? I will try to attach some video of the idle as well as the boot and spark plug. Compression was 165 by the way. I ordered the moose racing carb kit and going to check on the rubber piece hopefully its still avail.
    Any Ideas? Where to proceed next? (Pilot jet was 35S Main was 98



    Spark plug

    Sorry for such a long post!
  • jrgcbg49
    Posts: 5
    Joined: Mon Oct 19, 2015 7:31 pm

    Solved see my other post

    by jrgcbg49 » Thu Apr 21, 2016 1:59 pm

    Solved see my other post
    2004 CRF100F with BBR120 Kit

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