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

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, 201016 yr by richTY250E

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

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

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

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

+1 for B&J carb from Ginder(dabbinbob). He won't have to guess...He actually knows.

Thanks again guys for your help. I will definately go down the B&J route.

All the best,

Paul