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

Markvan · Guru

Exhaust valve color

TTRfan · Super Guru

The white parts are the valve stems. Slightly confusing as the TTR is bog standard confuse

In my experience they should be more of a brown colour rather than white.

I think you may be advised to clean the carb and jets in case of a partial blockage and maybe raise the needle a notch or two and check again after doing a few miles.

Hopefully Jarrah will be along to advise as he is the carb expert.

Brian

Markvan · Guru

Forgot to mention, only mod is exhaust restrictor in header has been cut out. ( from the dealer ship i think )

this is the original spark plug. 9000 km. which is now a spare.

TT-R250M · Super Guru

It is quite obvious to see that you are running lean. As Brian suggests, the valve stems should be a nice brownish black colour....

More here.. http://ttr250.activeboard.com/t51295235/used-valves-in-vgc/

I would suggest (first of all) to make sure that your accelerator pump is working correctly. If it is it should squirt a nice stream of fuel. While your at it check that your jets (including air jets) are not blocked.

Here is a thread that should assist in the carb cleaning etc.. http://ttr250.activeboard.com/t54826695/carb-cleaning-question/

If all of the above mentioned components are working correctly- I would suggest to raise the needle by dropping the jet needle clip position down 1~2 settings. If you can drop the jet needle clip position all the way to the bottom of the needle it suggests that you need a larger main jet.

Now...

What jets are currently installed?

Have you done any mods? (muffler, airbox, air filter?).

What elevation do you ride at? (I know Tweed Heads is basically sea level at 5m).

Average temp?

It is weird that you would be running lean with the standard #50 pilot and #147 main jet??? (unless you have non-standard jets??). On the other hand you are at a low elevation which could have something to do with it.

Jarrah

Markvan · Guru

Thanks Braian and Jarrah. Now im panicking . Air box is standard. Tail pipe standard. Previous owner said he bought it new and did no mods.

But the restrictor has been cut of in the header pipe. Bike runs well at all revs and twists of the throttle. I think it has heaps of power although it may have something to do with my weight. im only 75 kgs. i HAVE NOT ridden the bike in 3 months , but i HAVE started it every month, so thats 3 idles in my back yard each month with a couple of revs. Each time i also turned the fuel off and let it run untill carby dry. Then i drained what was left in the carby bowl. im hoping that may have caused the white valves. Thnx. Tried to check the air mixture screw but was abit hard while carby is on the bike. Also the 3 idles i gave the bike over 3 months i didnt over heat the motor. Thnx.

-- Edited by Markvan on Thursday 12th of September 2013 09:03:34 PM

TTRfan · Super Guru

Markvan wrote:
Each time I also turned the fuel off and let it run until carby dry.

I think that explains it biggrin

TT-R250M · Super Guru

Running the carb dry is not good for the engine or the carb for that matter. Once the fuel is left to dry up in the carb, the remnants gum up the float valve in no time at all. It also could do damage to the valves (and make them white) if this is done over a long period.

However, before jumping to conclusions it would be best to NOT drain the carb or run it dry and see if that sorts the problem out. If it doesn't- refer to my last post.

Jarrah

Markvan · Guru

Thanks again for the imfo. I will not run fuel out of carby for the next 2----3 times. And seeing the muffler is easily removed will check valve color again. But prob cant untill late october. Im am at ease now