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CRF230F - Throttle Sticking - Help me troubleshoot

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Hi,

 

Just completed a project on my 2005 CRF230F.   I did the power up mod - pulled the baffle and replaced the stock exhaust with an FMF Q4.  Also, the carb itself was filthy - I don't know that it's ever been cleaned as I've only had the bike for a few months.  I took the carb apart and soaked in Pine Sol for a good part of a day and then washed it all off.  I also blew out every crevice and hole I could find in the carb with an air compressor.  The carb looks great.  While I was at it I replaced the 102/42 jetting that was in it with 120/45 jets.  I got the bike put back together and ran it up and down the street a couple of times  Like everyone else says - it's a night and day difference.  I can't wait to get out and do some riding with it.  Throttle response is immediate.  I'll do any additional tuning of the fuel screw and check the plug when I get somewhere that I can ride it a little bit.

 

But there is one problem and I'm not sure where to go from here.  The throttle doesn't snap closed when I release it.  It just stays where it's at.  It'll close if I manually twist the throttle...so it's not actually stuck.  I've looked at everything I can think of and hope that some of the experts here has seen this before.  

  • There was a small amount of play in the throttle prior to taking things apart.  Adjusting this play was part of the plan.  There is now minimal play in the throttle.  When I twist, the engine responds.
  • I also soaked the throttle valve in Pine Sol and it's become slightly discolored.  It's still smooth like you'd expect the stainless steel to be, but it's definitely discolored.  This doesn't seem like a contributing factor to my issue - but I'm putting it out there just in case.
  • When I reassembled the throttle assembly in the carburetor I tested the mechanics by manually twisting and then releasing the throttle drum with the carburetor in my hand.  I did this before I put the top cover back on.  As expected, the jet needle drops and the throttle snaps shut with a sharp, audible noise.
  • Next, when I put the top cover on and tighten the screws I tested it again.  The spring still slides the throttle closed but it sounds like it's fighting a vacuum inside now that the top has been sealed and it definitely doesn't "snap".  It closes, but it's not a quick motion.
  • When I put the carb back on the bike and hooked up the throttle cables it doesn't snap at all now.  The throttle simply stays put wherever I twist it.  This wasn't an issue before I took the carb off.  
  • I have followed the throttle cables and they don't seem to be pinched anywhere and there's pretty free movement in the cables when I twist the throttle.  It just doesn't snap closed when I release it.

I'm not sure what else to pursue.  The carb and throttle behave mechanically just as I'd expect when it's in my hand.  But when I put the top cover on it starts behaving oddly....like there's a vacuum inhibiting the movement of the slide.  And when I get it on the bike itself, the throttle becomes an entirely manual job.  

 

Any ideas?

 

Mike

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Just for fun you could try taking the throttle off of your handlebars and try it then...I only offer this suggestion because I swapped bars this morning and found out that they were 1" wider. This caused some unplanned tension in the throttle cables which 'appeared' ok but made the throttle stick. Maybe worth a try? The cables really have to be free.

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X2 on what he said. I rejetted and didn't get the carb turned just to the right position and had the same issue.

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X3...mine did that when I switched out my handlebars.  something was too tight..not cable wise but i put it too close to the electric start button, I believe, and it caused it to not flip back instantly like before...look at the basics before going all out..it's usually something simple.

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