A forum for owners of Yamaha TTR250 trail and enduro bikes!

claytronic · Veteran Member

just joined

TT-R250M · Super Guru

Hi Claytronic and welcome to the forum.

Did you get the 4GY OE shipped over here?

Jarrah

claytronic · Veteran Member

hi jarrah.i left it over there for transport when in philippines.i brought back carby and ignition because i'm having trouble.engine cuts out about 5000rpm

claytronic · Veteran Member

are you in sydney?

TT-R250M · Super Guru

I am in Far Nth Queensland unfortunately. Hard to find anyone from my area to ride with. :( lol

Tell me more about the problem that you were having.

Jarrah

claytronic · Veteran Member

half way to the philippines

claytronic · Veteran Member

when at wot.in neutral or in any gear,the engine cuts out at about 5000rpm,then when the revs drop to about 4000 it cuts in again.when riding with about 1/4 throttle it misfires at about 3000.it starts easy idles well.and rides perfect at low revs.i had two mechanics look at it.one said the carby is blocked,the other said not enough back pressure.

claytronic · Veteran Member

bike pic

TT-R250M · Super Guru

What jets do you have installed, mod's?

So far sounds like the main jet is either blocked or too large for your set-up.

Jarrah

claytronic · Veteran Member

i don't know?i have the carby here.i just noticed a photo of the bike just before i bought it.it had the original pipe.it now has a very loud pipe.how do i tell which jets it has?

claytronic · Veteran Member

main nozzle is vo5.i don't know history,speedo not working.has 43000k.13/4 in inside diametre pipe straight through.would be illegal in aus.

claytronic · Veteran Member

pilot jet #48.they have been cleaned.i don't know of any other mods.the bike has a lot of grunt down low
clayton

claytronic · Veteran Member

main jet is 143

TTRfan · Super Guru

Does it run better or worse with the airbox cover off?

claytronic · Veteran Member

i havn,t tried without air box

TTRfan · Super Guru

If your TTR runs better without the airbox then your mixture is too rich. If it runs worse then it indicates a lean condition. Nice simple test wink

Brian

claytronic · Veteran Member

a mechanic looked at the plug and said,too lean

TT-R250M · Super Guru

Considering that you are using a #143 main/#48 pilot with an aftermarket exhaust, I would also say that it is running lean. It would pay to check that the accelerator nozzle is not blocked also. I would suggest either #52/147 genuine Teikei or #52.5/#150 6 Sigma (if doing the airbox mod).

More info on the carb- HERE

I should have a #147 main jet lying around somewhere here, if I find it I'll let you know.

Jarrah

claytronic · Veteran Member

thanks jarrah.i think the nozzle is blocked i can't blow air through it or remove it.