CRF50 high revs at start

Been lurking for a couple months while i researched and bought a bike. Bought a 2007 CRF50. I've done a coupel garage mods like adding a UNI filter, BBR handlebar kit, BBR rev box, HD Spring front and rear, and a Tall seat. I do not claim to be mechanically inclined, but i figured this would be a great project to sink my teeth into. In adding the UNI filter, i've run into a couple snags. First i had read that i needed to adjust the needle in the carb, and more than likely wouldn't have to jet by only adding a air filter. Guy at the local honda shop told me to move the clip down on the needle to the bottom position, and I'd be good to go. Tore into the bike, and found out that the 2007 doesn't come with an adjustable needle. Ended up buying a needle kit for a 2005 that is adjustable. I put the new needle in at the specified notch, and put the thing back together. When i fire it up now, it revs super high. When i have it choked down to the first detnet, it seems to idle at a decent rpm, but it doesn't sound like it's running all that smoothly.

I've warmed it up with the choke on, turned the choke off, and attempted to adjust the idle screw on the carb to no avail. It still revs super high. I'm at a loss, haven't tried to adjust the needle too far, as the stock 2007 needle seemed to be at the 3rd position on this new adjustable needle.

Any ideas?

Unbolt the carb and manifold from the head, and then remove the air filter. Look inside from the filter end to make sure the throttle slide is closing all the way when the throttle is released. Possibly, the throttle cable is hung up on the carb cap, and not fully seated in place inside the rubber boot.

Also, a lot of times, you have to go to a #60 or #62 main jet when adding a UNI foam filter.

Thanks for the reply dirtbkr188. After talking with the parts guy down at my local honda shop, he said it's more than likely 1 of 2 things. Either an air leak, or its running way too lean.

I tore the carb down as you suggested today. Took the filter off, and the slide looks like it's seated correctly and actuating properly when i roll the throttle on and off. Gonna just haul the bike down there tomorrow and see if they will use their special D shaped screwdriver to adjust the air/fuel mixture to see if richening up the mix will fix the problem. If that don't do the trick, next stop will be replacing the main jet.

As dirtbkr says, sounds like the throttle slide isn't installed properly, the little cut-out on the bottom of the slide must be lined up with the idle screw. Then just slip it into the top of the carb, if you have to compress the spring to get the cap on, then it's not seated properly. An air leak can make it idle high but not super high as you describe. Also agree with going to a #60 or #62 main jet with the UNI filter.

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