Blatchy

TTR125 Mikuni VM24 carburetor. It works!

198 posts in this topic

After being frustrated for almost 2 years with my sons TTR125 and not being able to get it to run well without back firing, iratic idle and running hot, I bit the bullett and bought a new Mikuni VM24 carby for it. I could not find much info about what carby would fit and what other mods would be needed apart from the BBR kit which at $299 seemed a bit excesive. So I took a punt and went for the VM24 and hoped it would work. Much to my delight the carby fitted straight on using all the standard parts, with the only mod needed was to drill the top of the Carby cap where the cable goes in slightly larger to allow the standard TTR cable to fit through.

I installed the carby with the standard jets that came with it Pilot 17.5, Main 97.5 needle I moved from 2nd clip to 3rd (middle) and air srcew at 1&1/4 turns out. The bike started easier than ever, idled smoothly and ran crisp and clean, all without any further adjustments! Ive never been able to acheive this with the standard carby despite spending countless hours and lots of money on jets, needles seals and gaskets. My son is very happy and said it has heaps more power. Every thing fits well and the only negative is the airscrew is hard to reach when the carby is mounted, but only takes a few minutes to remove carby to adjust. It is running that well I dont think Ill need to change it often anyway.

Im going to buy another TTR125 for my other son soon and a VM 24 will be the first thing I do to it!

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Thanks for the info. After breaking the choke plunger on the stock one I'd much rather pay for a new, possibly better, carb than pay even more for a new cable/choke assembly.

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Ive put the needle back to the original position now, 2nd clip from top. I may even try a smaller main jet now as things warm up for summer over here, it still is running better than ever, though being slightly leaner should improve things again.

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I have been running the same carb for about a year now and it works great. I created an adapter that made the carb fit the stock boot. My jetting is a bit richer, I think there is a 105 in there. Bottom end was spot on, needle required a couple of changes.

Everyone loves the BBR round slide thing, I say lets get into the 1980's with a flat slide! :smirk:

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Just ordered a VM24 from Sudco for on of my 5 TTR's as after a year of playing with them all and cleaning the carbs constantly to keep them running good I have decided to try one with a VM24 and see if I can finally get one to start after sitting for a few weeks. The biggest problem I have had is the the Float sticking if I do not tap the side of the carb for a few minutes I can never get the fuel into the bowl. This is on all but one of the TTR's and yet all the floats are set the same no clue why this is such a issue. But I won't be a problem with the VM 24 from what I read. Cant't wait to get it and install. One question what jetting did everyone decide was best to start with on this carb my motor is stock other than a lightened flywheel and air box mods..

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I found that the standard pilot and needle are spot on. I am running a 105 main and that seems to work well, I cannot remember what I did with the needle clip position. My airbox is modified, and I pulled off the intake manifold and matched it to the intake port (it was WAY off). I have reverted back the the stock exhaust end cap due to the noise.

Here is a link with pictures: http://www.tjsconcepts.com/ttr

My carb is a Sudco unit.

Good luck! Post your results!

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I found that the standard pilot and needle are spot on. I am running a 105 main and that seems to work well, I cannot remember what I did with the needle clip position. My airbox is modified, and I pulled off the intake manifold and matched it to the intake port (it was WAY off). I have reverted back the the stock exhaust end cap due to the noise.

Here is a link with pictures: http://www.tjsconcepts.com/ttr

My carb is a Sudco unit.

Good luck! Post your results!

Yours is a different carby to mine. Yours is a flat slide mine is a VM24 round slide. I did not require a adaptor to fit. That might explain why we have different main jets.

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:ride:Got some free time last night and installed the Sudco Mikuni VM24 carb had to drill the throttle cable hole slightly larger to fit the cable through took about 10 minutes the carb is about 3/8 of a inch shorter in length than the stock one but I was able to fit it up. Turned on the gas pulled choke one kick the bike started it had site for a month and the temp was 40 degrees outside. This is the best mod For a TTR ever I have not played with the jetting or air screw yet and it runs great already. I would recommend this for anyone who has a TTR 125 no sticking choke cables either..

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indysbk,

Do you have a part # for that Sudco Mikuni VM24. I looked on their website, but didn't see a VM24...it goes from a VM22 to a VM26.

Thanks,

JD

Your looking at the wrong VM listing. I bet you are looking at the "Mikuni VM Sportbike Carburetors" section, right? I did the same thing when looking at their catalog.

Look four listings down from there and you will find the VM carbs you need for a TTR. Click on these links, pages 91 and 92.

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Sudco part number is

MI 001.005 it is a VM24-512 carb no adaptors needed I just added a Uni Pod Filter to mine and need to richen the needle for midrange but its cold here so I am waiting for a warmer day to play with it... It was about 20 degree's Saturday and I kicked it over it started without choke on second kick best investment yet..

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Try sudco #001-018 for the vm24. Its on page 117 of their vol. 34 catalog. I picked up a vm 26 for my 125/150 from them. The 24 should have a right hand side adjustments, the 26 has left hand adjustments and ran into some slight problems but nothing that I couldn't fix. Sudco has the real Mikunis, not cheap knock-off like other places. Call Sudco and ask for John, he helped me out alot.

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thanks blatchy for you post on thumpertalk. i like you messed with my daughters 2002 ttr125 carb forever.i purchased on ebay for $69.95 a new mikuni vm24 carb.slight mod to top cap exactly as you said and it runs great,starts easily,no problems at all . thanks again

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i wish i would have tryed that with my old drz125, it had the same problems that you described and yes it was a big pain!

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Man, you guys are life savers. I have been fighting the stock carb for a while, last night I took the carb off my sons 05 RM 65 and put it on and it worked great. Are you using the TTR stock throttle cable or are you changing the cable as well? I wasn't able to use it on the RM's carb, couldn't modify it needed it back on the other bike.

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OK for all you backyard mechanics out there, I bought the VM24 from E-bay. Can you tell me excactly how you modified the top of the carb? How does the throttle cable go through the top now. It has a screw in hole in the top. I'm not to handy when it comes to this stuff and I want to make sure I do it right! :-)

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Im using the stock TTR125 cable. Just remove the screw in cable adjuster from the carb cap and find a drill about the same size as cable end from the stock TTR cable and drill out the thread. Push the cable through and put the circlip on. From memory I used about a 6mm drill (1/4 inch) but check before you drill.

Cheers

Michael

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