2007 CRF50 Confusing Problem

I just picked up a 2007 CRF50 from someone. The bike is all stock except for a tall seat, higher bar mounts/bars, and a Red Barron throttle assembly/tube.

The owner said it had just been sitting in the garage for the past 18 months and no longer runs. He also mentioned that it might need a new throttle assembly. As he was not mechanically inclined so thought that this all meant that the carb was gummed up and simply needed a good cleaning. Upon inspecting it, the throttle was completely frozen. This was because when he routed the throttle cable it was binding against the frame. Quick fix, reroute the cable.

I also dissembled the carb and cleaned it all out, as well as the gas tank. Removed, float, needle, main jet, idle screw, and air/fuel screw. Cleaned everything with carb cleaner and resembled.

Now here comes the problem(s). I only have an 1/8th of a turn of throttle. I don't know 50s, but I would think it should have more than that. I've adjusted the throttle cable as much as possible with little effect. It looks like the cable is simply too short. This is what it looks like at the end that goes into the carb... not normal?



The other issue is that it will not want to run with the throttle on. I can it it to idle...barely. But when you hold the throttle open it will maybe increase to about 2500rpm for a few seconds and then want to die. I am thinking it could be a float issue?

I've gone through the carb twice. Removed the air filter and then the exhaust thinking it might not be getting enough air or a back pressure issue, but no change what so ever.

Anything else to check or ideas? (thank god these things are easy to work on compared to a 250F :) )


With your throttle issuse, there is a little nipple in the carb and on the throttle there is a slot that goes from top to bottom cut out. Make sure the slot on the throttle goes up and down on the nipple. You will know if it is alined correct because if it is not the throttle will be stuck and barly move. Hope this helps.

Thanks! yes slot is aligned correctly. I have some throttle (1/8th turn) and it returns as it should. I think the cable is physically too short and that is why the spring is kinked. Can anyone confirm that?

Your slide photos appear normal to me.

They do have a throttle stop screw.

Take the throttle off the bar and test it wil no tension. Meaning, move the throttle housing so it isnt binding and check to see if there is still 1/8 th turn. If there still is, then as mentioned before, check to see if that. Throttle has a stop and unscrew it. Finally, the cap can kind of go on and still not be properly seated. And the slots mentioned before can allowed the slide to "fit" but still be 180 degree in the wrong direction. The whole carb slide should easily fit in and not be visible when you reseat the cap and screw it down.

But yes, with taller bars and and aftermarket throttle housing, the stock cable is usually too short. Fast 50s makes a two inch longer cable that should work. You can call them and they will help you out for the part.

The spring isn't kinked. It just looks like that because it's compressed. If you take it off the cable and set it down, it'll be straight. I had the same concern on mine and when I pulled the spring, it was straight. Check the throttle screw to make sure it's all the way out.

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