fantic 300 pro Posted January 22, 2010 Report Share Posted January 22, 2010 Hi there, Will a Mikuni VM26 mm carb fit my 1977 TY250? Just picked up a very nice low hour bike (318 miles on working speedo). The original Yamaha carb has some wear around the float area. If the Mikuni fits can anybody please give me an idea of correct jetting specs? Thank you for your help Paul Quote Link to comment Share on other sites More sharing options...
richty250e Posted January 22, 2010 Report Share Posted January 22, 2010 (edited) Hi Paul, I think the Mikuni VM26SS 49362 was original equipment on the TY250D (1977 ish). It is fitted on my 78 model (engine number range 493 300xxx). Listed standard jetting is as follows: main jet 150 needle jet N8 Jet needle/clip position 4L6 / 3rd groove cutaway 3.0 pilot jet 35 starter jet 40 air screw 1 1/8 turns out float level 23 mm +/- 1 mm idle speed 1100 +/- 100 rpm hope it helps Rich Edited January 22, 2010 by richTY250E Quote Link to comment Share on other sites More sharing options...
feetupfun Posted January 23, 2010 Report Share Posted January 23, 2010 Paul, A current model Mikuni VM26 is nothing like the standard carby that came on twinshock Yamahas. Yes you can get new Mikunis to work on TY250 twinshocks, but don't expect to be able to buy jetting the same as what was in the TY250 Yamaha-Mikuni carby, and don't expect the needle jet, needle or throttle slide to be able to be transferred from the original carby to a current model VM26, they are dimensionally quite different. Parts for the original TY250 carbies are available. David Quote Link to comment Share on other sites More sharing options...
tony283 Posted January 23, 2010 Report Share Posted January 23, 2010 We spoke ! before the system went pear shaped..... and I see your other question has not been relisted re; reeds....... as I said if you buy a WM26 for trials application maybe a 2.5 slide is ideal and with the new reeds come down one size on the main and then test. I'm assuming you are familiar with how to achieve max perf from carburation, if not ask and we can go through it. Tony Quote Link to comment Share on other sites More sharing options...
fantic 300 pro Posted January 24, 2010 Author Report Share Posted January 24, 2010 Thanks to Rich, Dave and Tony for all your advice and help. The reason I want to swap my carb is my original unit is a little corroded around the float area. I suppose I could get away with it?? I was thinking about buying the VM26 then buying all new jets, needle and slide etc (same specs as provided by you guys). Will she run okay? Anyone ever tried a VM28. After much messing my 1980 350 Sherpa T runs great with one installed. Thanks again to all you fellas for your time. Paul Quote Link to comment Share on other sites More sharing options...
tony283 Posted January 24, 2010 Report Share Posted January 24, 2010 Paul, Not sure where you are located but in the US Bob Ginder does a complete jetted carb, Domino throttle and cable kit for $160 at www.bjracing.com and also the reed kit with extra spacers for another $40. I usually get my carbs from him and its just bolt on and go unless you need to alter jetting for high altitude. Tony Quote Link to comment Share on other sites More sharing options...
kttwofifty Posted January 24, 2010 Report Share Posted January 24, 2010 +1 for B&J carb from Ginder(dabbinbob). He won't have to guess...He actually knows. Quote Link to comment Share on other sites More sharing options...
fantic 300 pro Posted January 30, 2010 Author Report Share Posted January 30, 2010 Thanks again guys for your help. I will definately go down the B&J route. All the best, Paul Quote Link to comment Share on other sites More sharing options...
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