OzVMX Forum

Clubroom => Tech Talk => Topic started by: William Doe on April 22, 2015, 02:33:22 pm

Title: IT 250G Jetting specs
Post by: William Doe on April 22, 2015, 02:33:22 pm

As per title
Could anyone tell me the std jetting (inc carb size and model if possible ) for an IT 250 G

Thanks Bill

Title: Re: IT 250G Jetting specs
Post by: Viper666 on April 22, 2015, 04:31:10 pm

Carby same size as many IT & YZ 250 & 400 465 etc. VM38SS

Looking from the reed valve side you should see 3R7 stamped near the choke plunger but really this means nothing as Yamaha used the same carby for IT & YZ 250, 400, 425, 465 & even 490's. Just the jetting & slide cut away that was different

Main #350 (340 or 360 alt) Pilot #70 Needle jet P-4 Needle 6F15-3 Slide no.2 cut away but a 3 will work if jetted right.

Parts catalog  http://www.shimwellsyamaha.co.za/images/photos%5CIT250%271980.pdf

Title: Re: IT 250G Jetting specs
Post by: William Doe on April 22, 2015, 11:03:56 pm

Thanks Neal appreciated Bill  :)

Title: Re: IT 250G Jetting specs
Post by: yamaico on April 28, 2015, 11:50:49 am

Not 100% sure Bill, but I thought that the IT250 used a VM36 carbie, with the jetting detailed by Neal. Happy to be proved wrong, of course  ;D
Pete.

Title: Re: IT 250G Jetting specs
Post by: Viper666 on April 28, 2015, 02:36:26 pm

Quote

but I thought that the IT250 used a VM36 carbie

So did I but that was the info I found but like you I'll stand corrected.

I have an IT250K at home I'll see what it is

Title: Re: IT 250G Jetting specs
Post by: cr4ever on April 28, 2015, 06:22:36 pm

http://www.yamahait.com.au/forum/index.php/topic,18926.50.html

IT 250H and J had a VM36SS Mikuni unique to Yamaha, with unique needle and needle jets that are almost unobtainable. Not sure about G.......
OE specs are:
Main jet: 400
Pilot: 50
Needle: 6F34-3
Needle jet: N-8
Slide: 2.0
According to the link above, 6F4/P6 is reasonably close......some great work has been done there......