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

It squirts fuel through it past about 3/4 revs. If you fill your carby bowl & push down gently on the diaphram assembly (part number #38 in diagram) you will be able to ''check'' your diaphram also.

Warning: Do not stick your head close or petrol will squirt in your eyes.

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Jarrah.

No problems,i enjoy helping people.

As you said you would have to go further than round the yard (over ''3/4 revs '' cruising) to notice.

Brian will know a good place to buy it in the UK.

...........................

Jarrah.

Good luck finding it cheap enough,should'nt be much.

The other part number that will fit is 4GY-14272-00

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Jarrah.

barra8 wrote:

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... If not i'm not sure how it would go without it?? 

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-MY First thought too Jarrah!

  Domsk1,

I noticed the same thing last weekend when I tore into my carb for MY first time.

I am pretty certain that the only other time carb has been off, was when my local shop had blown pilot jet out last summer. I thought he lost/left it out by mistake. Does anyone know if this a common issue?

 I own a US sold bike from central Texas. Did Yamaha's "Quality Check" folks not catch this or just leave this out? I kinda think so now that I read this post.

 ...I ordered "brass thingy" couple days ago. It's all I am waiting on before I throw mine back together. Wonder if this has been my issue, instead of clogged Pilot jet??

I'm confused2! 

greg

TT-R250M,
So sorry I have not replied to your question, I have just worked a 28 day straight stretch and have not been around lately.

According to the very well written instructions by Brian, posts by TT-R250M and barra8 (COME BACK MAN!) I tackled my first carb cleaning (of this bike) since I bought it (I have torn GM's 'RottenChester' and a Holley on some of the cages I have owned). Ya'll put confidence in my old hands. I don't have a ultra-sonic cleaner like some of you, I just used carb spray, a small brush & several wooden toothpicks to get most of the crud off. It wasn't really that dirty, it had been cleaned last year and not ridden much since then. I will say that ethanol is a HUGE problem around here and I now use a treatment for that.
I got a new check seat valve (it was missing!-see previous post), new main and pilot jets (both were a little dirty and are hard to clean, so it's only $$$), bowl gasket, diaphram & spring and little rubber seals. I should have checked float height, but I forgot.

I finally a chance to put it all back together yesterday. After a couple seconds on the starter, she fired up like a champ!
I rode it a bit in the yard (1st gear only) and everything seems to be going right so far. Friday I plan to take my grandson to the lake where we can really test her out.
I'm using the NGK-CR7E plug, slightly hotter than the stock CR9E, & noticed that it doesn't take long to get started and warm up. The guy at the shop I go to put the CR7E plug in the last time he fixed my carb and I have yet to even pull it for checking color. I will do that once I get a hard ride in.
Before I cleaned carb, I noticed exhaust pipe glowing pretty RED-HOT when I would run it for a few minutes. Now, I figure it was because the jets were dirty and it was running lean? I didn't notice any glow today, but I didn't run it hard or for more than about 5 minutes. I am 2 turns out on the air screw (or is it fuel screw, cause it is not on the air side of the carb?? I always thought that was how you tell the difference but sometimes I get mixed up) 

Brian, I have yet to put the parts on I got from you, but hopefully I will get that chance soon!

Thanks for everything folks, I really enjoyed fixing this myself.

greg

pedrosan wrote:

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Hi all,

I stripped my carb the other day to clean it out. I fired up the TTR after it had been sat for an indecent amount of time (due to the arrival of a very small person in the household) and it was leaking fuel out of the carb area when it ran. I assumed that the jets had blocked up with it being sat for such a long time.

Anyway, the white plastic thing in the picture isn't in the carb. It has run fine without it, but presumably it should be in there. Also, when I took off the smaller cover with two screws as per Brians guide, there was some kind of gunky red stuff round the perimeter, which I guess is liquid gasket sealant. Does it need more when I reassemble it, and why would it be there in the first place if not?

I reckon that to reassemble when I've cleaned it I will need the black carb body gasket (which looks flat to me) and  the white plastic thing as above. I take it motoward would be as good as anywhere? I used an American place in the past, but the name escapes me.

Thanks in advance,

Pete

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 If it was leaking fuel I would suggest that either your float valve has contaminants, the air boot has cracks/leaking or the accelerator pump O-rings or diaphragm is perished.

The fuel baffle should be installed, it stops the fuel sloshing about inside the carb and maintains a good fuel flow to the main jet. Not a biggie without it though.

Someone must have used gasket goo on the accelerator pump O-rings to ''TRY'' to stop it leaking. It will not work and should not be used! I use rubber grease on all O-rings and the diaphragm for a long lasting perfect seal.

Make sure that you check that your accelerator pump nozzle is not blocked (common problem). More details here- http://ttr250.activeboard.com/t56226503/mid-rpm-range-bogs-down/

If you don't mind waiting on parts, you can use http://www.boats.net/ or http://www.partzilla.com/. I have heard www.partshark.com is good also.

Jarrah