TMX Mikuni is the worst carb ever

So I don't scare too many away...TL:DR = Idle screw will not screw into carb past a few turns...


This thing has been nothing but trouble since I got this bike, thanks honda.


Anyways heres the background. Raced all day sunday no problems bike ran great. The bike sat still until then, take it to another track yesterday and I kick the bike, it starts up running at WOT.....I'm super confused at this point, nothing changed and nobody touched the bike. I figure it has to be the carb, so I take it apart and it looks fine. Put it back together, bike does the same thing. Took it apart again, this time it looks like its the throttle slide not closing all the way. Get it to close, but it seems like theres still a tiny gap for air to leak through. Start up the bike, it idles as normal this time, take it on the track - holy shit, its running like a bat out of hell, and I can smell how lean it is. I cut it off and walked it back to my car.


Today I am seeking the root issue, it seems as if the idle screw was blocking the slide from coming down all the way. I removed the idle screw and drop the slide in, it appears to go all the way down. Not a &%$#@!ing clue whats going on here, as nothing was touched and the idle screw appeared to be in the same spot it always has.


Anyways, problem solved right? Idle screw was blocking it. No, its just never that &%$#@!ing easy. My idle screw is stripped so bad I had to use pliers to grip it and take it out until it was loose enough for my fingers. Luckily, I knew my carb had about 10 stripped screws and I've been sitting on a rebuild kit. I double checked the package, it fits the 00-01 cr125, I have an 01. I put the new screw in, after about 3 turns its impossibe to turn. Ok - threads are dirty, I spray about a can of brake cleaner through there every way imaginable. When I shine a light down there it looks immaculate. I put the new idle screw in again, gets too hard to turn with a screwdriver about 3 turns in again. I take the pliers and force it through the rough spot. A few short turns after, it just stops going any further no matter how hard I try. The end of the idle screw isn't even making it into the throttle slide chamber....For shits I try the stock screw again, I can screw it so far in the tip of the screw will touch the wall of the throttle slide chamber in the carb.


The 2 screws are identical, the threads on the new screw are fine, I've looked it over so many times my head is spinning. This whole issue popped out of nowhere, and instead of being a simple fix, its turned into a nightmare which is about to stop me from racing again sunday. I'm at a complete loss here, please help. I can post pictures of anything if that helps.



So aside the fact that the mikuni TMX is a sub par carb choice in my opinion, I have worse things to say about moose racing. I know their products are cheap, but their screw is the whole issue here. I was in denial of getting a lemon because I just didn't want to believe it. Gonna call and bitch tomorrow and never buy their shit again.


But the TMX still pisses me off.

Yes, the TMX sucks. Buy a rebuild kit off of eBay. Believe Shindy is manufacturer. If you really like the bike then buy a Keihin PWK from a 2000 CR250. Runs more consistent and requires less fiddling. No added power once dialed - at least that was my experience on a 250 Honda. 

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