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Post Info TOPIC: Fitting a Mikuni TM32


Super Guru

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RE: carburetor size
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Obviously not getting fuel or the pilot jet is too lean.

Refer to my post above.

Jarrah



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2000 TT-R250M-

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Newbie

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TM32 flatslide plus other carb testing
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Hi all, first post but have used the site for a while.

Thought I would add a little contribution to some carb mods I have tried. Bikes are 2003 ttr250 and 1994 ttr250 with staintune exhaust with silencer endcap in and hole in airbox side plus ground headers. Jetting specs may be off as Aussie fuel is in my testing a lot richer than other countries and I'm at sea level

On the blue one I found substantial response in low to mid by boring the carb oval to get rid of the teardrop shape, bending the pumper to come on right off idle and tsper off after 1/3rd throttle and the following tk jets

main 142

pilot 48

needle 1 richer

With this combo I ran 14 47 gearing and had wheel lifting grunt.

 

White one I have installed a 32mikuni flatslide non-pumper . 

First i tried the xr280 baseline jetting of 250 main, 45 pilot 6dh2 needle q2 emulsion tube, it was flat and fluffy with a small promise of power

I can't remember exactly what I ended up with but will have a look if anyone else wants to do it

From memory it was:

main 190

pilot  22.5

needle 6dh7 leanest clip

q-0 emulsion

This combo transformed the bike, more down low than the bored carb and way more in the mid and top, very responsive fast revving throttle feel and hard to bog out plus never stutters on rough ground, basically a very wide very linear  power curve. FWIW i went 32mm non pumper over 33pumper because in my experience pumpers over fuel to make up for too large a bore size, on old school tech bikes a well jetted smaller bore flatslide gives better low mid response with a tiny sacrifice up top to the 33mm. 

The needle or emulsion could still be leaner as it runs well on the leanest clip but it's so close as is I can't be bothered testing more.

Fitting requires a 2 stroke throttle tube and cable and I made spacers front and rear of carb as its a way shorter carb, these were just upsized exhaust pipe dremelled the fit and fitted with devcon or jb weld.

Hope this info helps someone, there wasn't much out there when I was doing it

 



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Super Guru

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Wow - quite a first post, thanks. Welcome to the forum.

Martyn



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Budleigh Salterton. Devon



Newbie

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Thanks Martyn, good to see the old ttr has a following. Mines a bit of a project to see how good a trailbike I can make out of it while keeping the longevity, tired of rebuilding ktm's ect, plus the short wheel base is a blast when it gets tight



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Super Guru

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Welcome to the forum matey!

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Pete. South Somerset, England.



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Update,

Did a bit more fine tuning, ended up with

q-0 emulsion tube

6dh7 leanest clip

12.5 pilot

air screw 1 turn out.

Airscrew now works in the range it should and after putting a 30mm hole in airbox sidecover the bottom to mid is fairly crisp. Emulsion could go a size or two down to get the needle back to the middle but its not too bad



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Newbie

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Got more response from midrange with p-6 emulsion tube and 6dh7 on richest.



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