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

goodquest · Member

2006 TTR-250 Carburetor adjustment

TT-R250M · Super Guru

Hello goodquest and welcome to the forum

Did you replace the two O-rings while you were in there?

Did you make sure that the accelerator pump nozzle was not blocked? Did it squirt fuel when the throttle was applied?

More info here-

http://ttr250.activeboard.com/t53839715/rough-running-no-mid-range-power-bogs-down-in-top-problem-fi/

http://ttr250.activeboard.com/t56226503/mid-rpm-range-bogs-down/

If that does not help, let us know. In fact let us know either way. wink

Enjoy!

Jarrah

goodquest · Member

TT-R250M wrote:
Hello goodquest and welcome to the forum
Did you replace the two O-rings while you were in there?
Did you make sure that the accelerator pump nozzle was not blocked? Did it squirt fuel when the throttle was applied?
More info here-
http://ttr250.activeboard.com/t53839715/rough-running-no-mid-range-power-bogs-down-in-top-problem-fi/
http://ttr250.activeboard.com/t56226503/mid-rpm-range-bogs-down/
If that does not help, let us know. In fact let us know either way.
Enjoy!
Jarrah

Yes I did replace the two small o rings and the diaphragm assemble/accelerator pump was brand new. What has me confused is it ran perfect until

I replaced the diaphragm because of a little leak.

TT-R250M · Super Guru

Well that rules out one theory, you still did not answer my other question though-

Did you make sure that the accelerator pump nozzle was not blocked? Did it squirt fuel when the throttle was applied?

Jarrah

goodquest · Member

I did not check accelerator pump nozzle. The bike ran fine, so all I did was repair the leak.

TT-R250M · Super Guru

goodquest wrote:
I did not check accelerator pump nozzle. The bike ran fine, so all I did was repair the leak.

I would be doing so and report back the result.

Jarrah

goodquest · Member

TT-R250M wrote:
goodquest wrote:
I did not check accelerator pump nozzle. The bike ran fine, so all I did was repair the leak.
I would be doing so and report back the result.
Jarrah

Ok, I will check and see if it's blocked. How do you clean it if it's blocked?

Thanks again

-- Edited by goodquest on Wednesday 4th of June 2014 10:59:23 PM

TT-R250M · Super Guru

From the link I left you-

AP. To check the accelerator pump is working properly- Remove carb from bike and fill with fuel to check if the carb squirts fuel when the throttle is applied. You should see a nice stream of fuel. If not, repair AP.

So you have a better understanding of the diaphragm/fuel pump

The accelerator pump squirts fuel into the carburettor when the throttle is opened from just before half throttle through to just before full throttle . This prevents it getting lean when the throttle is applied all of a sudden & hence enhances the response.When the diaphragm is pushed down by the diaphragm lever arm (top of carb with a spring under it) sucks fuel from the one-way valve & pushes it up to the check valve. This is where you can check the other one-way valve & diaphragm by pushing down GENTLY on the diaphragm while the bowl is full of fuel. It should squirt the check valve out if it's not held down by the gasket so BE CAREFUL! Remember eyes aren't made to have fuel in them

Posted Image

It then goes up to the diaphragm/fuel pump nozzle.

Have a look from the other side (not the side shown in the pic below), there will be a small hole. Use a piece of fine wire to unblock it and also use carb cleaner or fuel. If you have trouble finding fine enough wire- cut an old cable (throttle, pushbike cable etc..). Compressed air also helps. It may take awhile poking and prodding but you will get it clean. I used a pair of long nose pliers to assist in holding the wire and prodding.

Once you have the carb together connect the fuel line to the carb & check that you have a nice stream of fuel squirting out the accelerator pump nozzle when the throttle is applied (obviously manually). Again... Remember- eyes aren't made to have fuel in them!

More info HERE.

Enjoy!

Jarrah

goodquest · Member

Thank you, I will work on this on Friday or Saturday,

TT-R250M · Super Guru

No problems!

Any questions-ask!

Jarrah

goodquest · Member

TT-R250M wrote:
No problems!
Any questions-ask!
Jarrah

Fuel squirts fine, and I just replaced the spring on the bottom of diaphragm. Since I have the carb apart I'm going to shoot air thru the jets.

Terrence R · Senior Member

My carb was leaking. It was the float bowl gasket. It was flattened right where the diaphragm tube passed up through to the nozzle. Everytime I hit the throttle it had a slight bog. Probably because it was loosing a small percentage of fuel that was supposed to be squirting up to the nozzle. Or/and it may have been taking in air there.

goodquest · Member

Since I had the Carburetor open I sprayed carb cleaner everywhere I could and used a compressor to blow everything Clean. I cleaned the pilot jet ,main jet and then replaced the spring on the bottom of the diaphragm. I did not replace the Needle valve because I was not going to deal with trying to remove the float pin. I put everything back together and the bike ran better, but would still stall about every third or fourth time with a quick turn of the throttle unless I had the RPMs up. I then adjusted the needle valve. I turned it all the way in and then went out about 2-2 ½ turns. That seemed to work
It does not stall, it might hastate a millisecond but it does not stall. Then being the curious George I let the bike warm up and turned the needle valve all the way in and the bike still ran, but would Stall upon quick turning of the throttle. So I adjust the needle valve again out 2-2 ½ turns and The bike ran great with only the millisecond hesitation.

Now this bike has an aftermarket pipe, I have not checked the spark plug but I would like To go up 1 size in both the Pilot and main jet to be on the safe side, but when I called Yamaha they told me there are not bigger jets for the 2006 TTR-250. Suggestions

Thanks again

Will

-- Edited by goodquest on Monday 9th of June 2014 07:59:58 PM

Terrence R · Senior Member

goodquest wrote:
Since I had the Carburetor open I sprayed carb cleaner everywhere I could and used a compressor to blow everything Clean. I cleaned the pilot jet ,main jet and then replaced the spring on the bottom of the diaphragm. I did not replace the Needle valve because I was not going to deal with trying to remove the float pin. I put everything back together and the bike ran better, but would still stall about every third or fourth time with a quick turn of the throttle unless I had the RPMs up. I then adjusted the needle valve. I turned it all the way in and then went out about 2-2 ½ turns. That seemed to work
It does not stall, it might hastate a millisecond but it does not stall. Then being the curious George I let the bike warm up and turned the needle valve all the way in and the bike still ran, but would Stall upon quick turning of the throttle. So I adjust the needle valve again out 2-2 ½ turns and The bike ran great with only the millisecond hesitation.

Now this bike has an aftermarket pipe, I have not checked the spark plug but I would like To go up 1 size in both the Pilot and main jet to be on the safe side, but when I called Yamaha they told me there are not bigger jets for the 2006 TTR-250. Suggestions

Thanks again

Will

-- Edited by goodquest on Monday 9th of June 2014 07:59:58 PM

If your bike is a US or Canadian model, I have the exact same bike. I've also had/have a hard time dialling in my carb, but I got it working great, but it's showing a little lean according to the spark plug. I got a 6 sigma jet kit on ebay. It came with a 140, 145, and 150 main jets, 2 pilot jets which are both 52.5 for some reason, and some other miscilainious stuff like shims and a drill bit for some reason. Just tell them your elevation and mods and they'll use that as a base on what to send. Also, I think Brian has some jets available if u wanna check.

TT-R250M · Super Guru

Looks like Brian only has the standard #50 available. If you ask him nicely he may order a #52 pilot and #140 main (of course, more info on mods, elevation, climate etc. would be good before making this decision).

AFAIK- The larger jets are not available to buy in AU (it's what I was told by a Yamaha dealer but they never tell the whole truth), it may be the same case in the US/CA.

Otherwise, search 6 Sigma on eBay.

Jarrah

goodquest · Member

I was told that larger jets were not available in the US either. I was told that I would have to manually drill out the jets using small drill bits, like what a dentist uses for a root canal. I will check out 6 sigma on eBay.

Thanks again for all your help.

TTRfan · Super Guru

I don't keep them in stock but the #52 pilot and #140 main jets are available in the UK. Not cheap though!

Just a thought. It is often recommended to do a "plug chop" to check the fuel mixture but how about just dropping out the header pipe enough to check the colour inside the exhaust ports? Very simple and no chance of dropping dirt or grit into the plug hole as can happen when taking out the plug. There is also a much bigger area to look at.

I did this the other day as the exhaust was crackling and popping a bit on the over run (sounded quite nice actually biggrin ) and there was a definite whitish tint inside the exhaust port.

The exhaust is the standard US version and no other mods have been done. The carb had one of the standard UK setups of #48 pilot and #142 main jet. I put in a #50 pilot and raised the needle two clips and it runs even better than before biggrin and the crackle has gone cry

Brian

goodquest · Member

TTRfan wrote:
I don't keep them in stock but the #52 pilot and #140 main jets are available in the UK. Not cheap though!
Just a thought. It is often recommended to do a "plug chop" to check the fuel mixture but how about just dropping out the header pipe enough to check the colour inside the exhaust ports? Very simple and no chance of dropping dirt or grit into the plug hole as can happen when taking out the plug. There is also a much bigger area to look at.
I did this the other day as the exhaust was crackling and popping a bit on the over run (sounded quite nice actually ) and there was a definite whitish tint inside the exhaust port.
The exhaust is the standard US version and no other mods have been done. The carb had one of the standard UK setups of #48 pilot and #142 main jet. I put in a #50 pilot and raised the needle two clips and it runs even better than before and the crackle has gone
Brian

I searched Ebay for 6 Sigma for the TTR and they have bigger jets. Right now the TTR runs great and my Honda 450x runs bad. I just can't win.

What is not cheap?

Thanks for the information

Will

-- Edited by goodquest on Thursday 19th of June 2014 02:26:26 AM

Terrence R · Senior Member

What year crf450x? They have a reputation for the valves wearing prematurely. That's 9 times out of 10 the problem when they start running rough and hard to start.

I have the 6 sigma jet kit for my 06 TTR. There's not much for jet choices, so u might be stuck with having to jet the 6 sigma kit. It's hard to believe how much a company can justify charging high amounts for these little pieces of brass. A local kawi shop here gave me a hand full of mikuni jets awhile back when I was building my kdx200. Yet, look at what we have to pay and deal with to get parts and jets for these ttr carbs. What was Yamaha thinking when they put this cheap "no name" carb on these ttr's? As fun as my ttr is, because of all these troubles I went through dealing with carb parts, I'll never buy a ttr again.

goodquest · Member

Terrence R wrote:
What year crf450x? They have a reputation for the valves wearing prematurely. That's 9 times out of 10 the problem when they start running rough and hard to start.
2006 And it was running great until I replaced the stock air filter with a no toil dual stage. Then it started to flame out on quick
cracks of the throttle or engine would bog and die. I purchased a new stock filter and replaced the no toil but the results are the same. I'm going to clean the carb and see what happens.

I have the 6 sigma jet kit for my 06 TTR. There's not much for jet choices, so u might be stuck with having to jet the 6 sigma kit. It's hard to believe how much a company can justify charging high amounts for these little pieces of brass. A local kawi shop here gave me a hand full of mikuni jets awhile back when I was building my kdx200. Yet, look at what we have to pay and deal with to get parts and jets for these ttr carbs. What was Yamaha thinking when they put this cheap "no name" carb on these ttr's? As fun as my ttr is, because of all these troubles I went through dealing with carb parts, I'll never buy a ttr again.
So far with the help of this site, the TTR Carb is very easy to work on compared to the Honda. With the Honda I have to remove
the seat, tank, lift rear frame and remove the rear shock. Then remove the Carb. If this does not work I will check the valves.

Thanks for the information

TT-R250M · Super Guru

Terrence R wrote:
What was Yamaha thinking when they put this cheap "no name" carb on these ttr's? As fun as my ttr is, because of all these troubles I went through dealing with carb parts, I'll never buy a ttr again.

The TTR250 does not have a cheap ''no name'' carb. It is a Teikei Y30P as my rebuild thread suggests HERE. Furthermore, I fail to see how it is cheap given that it is $531.99 MSRP and $372.94 discounted. You can double that if bought through a dealer. I was quoted over $1000.00 AUD from my local Yamaha dealer (which is no more expensive than anywhere else up this way).

The TTR250 carb is easy as once you know what you are doing.

Jarrah

Terrence R · Senior Member

TT-R250M wrote:
Terrence R wrote:
What was Yamaha thinking when they put this cheap "no name" carb on these ttr's? As fun as my ttr is, because of all these troubles I went through dealing with carb parts, I'll never buy a ttr again.
The TTR250 does not have a cheap ''no name'' carb. It is a Teikei Y30P as my rebuild thread suggests HERE. Furthermore, I fail to see how it is cheap given that it is $531.99 MSRP and $372.94 discounted. You can double that if bought through a dealer. I was quoted over $1000.00 AUD from my local Yamaha dealer (which is no more expensive than anywhere else up this way).
The TTR250 carb is easy as once you know what you are doing.
Jarrah

Sorry, you're right, it's not a cheap carb. But there's no arguing that Yamaha could've put something on it other than the Y30P. Not too sure about any of u guys that are outside of Canada or the USA, but it is freakishly terrible to get parts for these carbs. I can buy jet parts for any of the other bikes I've ever owned right through the dealerships with no hassles. Getting jets here for the Y30P is a job that brings me back home frustrated and having to look online. Even then, there's only 2 choices; 6 sigma, or here on this site. Nothing wrong with either source. But I don't want to pay shipping charges and wait for parts that I should be able to get over the counter. I can get mikuni jets and other common brand jets at any dealership locally the same day and I usually don't even have to pay for them.

But, don't get me wrong, the TTR seems to be a good bike. Not too many of them around in here In Canada at all. I'm just saying that getting jets for it is ridiculous compared to any other machine that I've dealt with.

TT-R250M · Super Guru

Terrence R wrote:
TT-R250M wrote:
Terrence R wrote:
What was Yamaha thinking when they put this cheap "no name" carb on these ttr's? As fun as my ttr is, because of all these troubles I went through dealing with carb parts, I'll never buy a ttr again.
The TTR250 does not have a cheap ''no name'' carb. It is a Teikei Y30P as my rebuild thread suggests HERE. Furthermore, I fail to see how it is cheap given that it is $531.99 MSRP and $372.94 discounted. You can double that if bought through a dealer. I was quoted over $1000.00 AUD from my local Yamaha dealer (which is no more expensive than anywhere else up this way).
The TTR250 carb is easy as once you know what you are doing.
Jarrah
I'm just saying that getting jets for it is ridiculous compared to any other machine that I've dealt with.

A far cry from your last post lol. :)

IMO- there is no better carb to use on a TTR250 than the Teikei. It is VERY reliable and good quality all round. Sure you need to order jets in but hey, I don't mind waiting and paying a bit extra to have the Teikei, instead of those hard to re-jet Mikuni jet sizes.

Each to their own.

Jarrah