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

MarkJ · MarkJ

I need to replace the two leaking o-rings, part number appears to be 5Y1-14397-00 but judging by the price of the genuine Yamaha part they must be made of gold. Hence does anyone know their size so that I can pick up some replacements from the local suppliers?

Spietfriek · Spietfriek

Did a first testride today on my secondhand 2006 TTR.setup at purchase : Stock airfilter with airbox snorkelStock exhaust with restrictor removed50 pilot jet 147 main jet14 x 48 chainset After carb clean replaced all o-rings + diaphragm + checked acceleration pump (ok) Starts fine and revs ou...

Terrence R · Terrence R

Just out of curiosity, I'm wondering what size pilot jets you guys are using in your ttr250's. I know that the 52 and 52.5 pilot jets seem to work good for a lot of people. Anyone using anything bigger? How about smaller? At what elevations? Any mods to justify?

Fladdem · Fladdem

Having trouble with my TTR again. I love her but sometimes I want to throw her to the scrap-man. After recently inadvertently putting diesel in the bike I have been having fuelling issues, I cleaned the fuel lines out, drained the tank and have cleaned the carb about 3 times. I can not see anything wro...

TTRfan · TTRfan

I have a carb that checked over fine. All jets cleaned or replaced, etc. However, there was an idle problem where on occasions the engine would run at a fast tickover and other times it would be OK. I know there is another post about these symptoms somewhere but darned if I can find it I took my own advice a...

ianttr · ianttr

Hi I live in the pyrenees at 650m say 2000 feet or so.My 2004 ttr blue came with the carb box cut open, all snorkels etc. cut off and an after market exhaust, it never ran right. The previous owner had not re jetted. I changed the jets to run with the after market exhaust and it ran great but far too noisy for th...

romeshs · romeshs

Hi All, i have recently bought a used 1993 TTR 250. Purple frame. bike was abused, but engine was remarkably well maintained. no unwanted noises, etc. my problem is that when im riding and through the revs, low end, runs perfectly, WOT, runns pretty well too. but in between, like with the throttle ope...

goodquest · goodquest

Just purchased a 2006 ttr-250 which ran perfect except I noticed it had a slow carburetor leak. I pulled the carb and replaced the diaphragm assembly which was stuck to the carb and bubbled. Now if I crack the throttle real quick the engine dies. If the choke is pulled out all the way it still dies abou...

BM Steve · BM Steve

Hi All Thanks To Jarrah, who kindly sent me some leftover carby bits, seals, gaskets, accelerator pump, O-Rings etc...and especially the 52.5 Main, my bike is running great now A bit more acceleration and power all over, it's great in the singles, smooth on rough uphills, just better all round I remo...

Terrence R · Terrence R

Ok, so the bike seems to be running really good. Nice throttle response and great power distribution from bottom to top. Looking at the spark plug, it looks grossly lean. I check the float height as follows: put a clear hose on the carb drain. Opened it up. Set the bike up level. Fuel filled up to as far as t...

Terrence R · Terrence R

I just found a part that I forgot to put back in my carb after fooling around with jetting. Oops!

how important is this? Is it ok to ride without it? Probably not, but I would like to make sure before I tear my carb apart for the 10th time within the last week. Please help.

Terrence R · Terrence R

I just got done modding my bike after ordering parts all winter. I drove it on a dry winter day in stock form and it worked great, but just needed a little extra arm pump. I just installed an FMF PC4, twin air filter and removed snorkel along with opening up the hole a bit, and 6 sigma jet kit. It came with 3 mai...

Archershome · Archershome

Hello yes its another question on jets... I am confused and have read other forums. Ok TTR250 04 plate, fitted new twin air filter and FMF Q4, snorkel still fitted as gone in some big puddles, bike seems a little sluggish in comparison to a friends with similar set up. I have a 14/52 sprocket set up and wo...

chrisstdt · chrisstdt

I have recently enlarged my airbox snorkel ,the bike is now running lean as i have uk standard 147 / 50 jets ,brian has suggested yamaha 150 / 52 but mikuni jats are cheaper and easier for me to get So my question is has anyone got experience of mikuni jets and how they compare to yamaha jets or am i best to st...

PlumasDude · PlumasDude

There was some question about stock jets on US models - for the record, I pulled the carb on my 2003 US model, which I'm pretty certain has never been touched, and the jets are in fact 137/50 (as Jarrah had opined) even though my manual says the pilot is 52. I was told this bike was originally sold in Alaska...

domski1 · domski1

Has anyone stripped a carb and found this item missing? I stripped and cleaned mine the other day and then had a look through one of Brian's guides on carbs and found I didn't have the valve in the photo below. I can't see how I have lost it but not sure how it would run if missing? Sorry for stealing you pic Br...

Kevingrahambutler · Kevingrahambutler

Just had the bike delivered yesterday, I started the bike on the choke, its a bit smoky then clears, then when its warm off the choke it's lumpy then stalls the guy has put a fmf exhaust on will he have needed to re jet it, I want to eliminate before I start to dig stripping things off, I will change the exhaus...

Padowan · Padowan

Overhauling and cleaning the carb on one of of my TTR's I clumsily catapulted the accelerator pump return spring (the little one under the diaphragm) across the garage never to be seen again. Can I get a replacement? Is the spring rate critical on that spring, or can I find something that fits and stic...

Maxim_X · Maxim_X

Yo! So it goes like this. I buy this bike and it's got a few things done to it. I busted it all open because it was surging when I was riding at a stead speed. The airbox snorkle is cut and the throttle stop is removed. I get on the google and it sais that this is a basic way to open up the bike, but it need jettin...

petenz · petenz

What is the standard main & pilot jet size ? I now know why the bike came with a nice new unused Yamaha GYTR pipe.. I put it on .. the bike runs like a X#@%&*^?.... EDIT.... Main 137 & Pilot 52 sound right ? "internet search" -- Edited by petenz on Saturday 27th of July 2013 04:44...

davecambo · davecambo

hi just wondering how hard it will be to adjust the main jet needle to 30mm as per staintune exhaust recommendation for installing slip on?

dfaz · dfaz

for anyone who hasnt read my Earlier post I have found a supplier for Jets they are called motocarb.3 Victoria rd West.Blundellsands.Merseyside.UK L23 8UG . tel. 01512384170 I ordered 2 jets all in stock delivered registered post next day £9.90 so if anyone needs jets he is knowledgable and reliab...

TTRfan · TTRfan

My turn to ask for help I am rebuilding a carb and want to go down from a 52.5 to a 50 pilot jet. The replacement jet looked right but didn't fit as the small diameter section was a tad too wide I have a new genuine Yamaha 50 pilot jet in my spares box but it is much shorter. See pic below: The shorter jet fits fi...

fwtian · fwtian

Brian i read your article at ttr250.com but i couldnt understand which main jet and pilot jet is the best for a 1993 model. My bike is 74mm,standard exhaust and Teikei30 carburator. You know which are the best main and pilot jets for this bike??

Topic		Started By	Replies	Views	Last Post
	Accelerator pump o-rings (Preview) I need to replace the two leaking o-rings, part number appears to be 5Y1-14397-00 but judging by the price of the genuine Yamaha part they must be made of gold. Hence does anyone know their size so that I can pick up some replacements from the local suppliers?	MarkJ	3	2381	Sep 30, 2014 by MarkJ
	Belgian TTR carb setting issue (Preview) Did a first testride today on my secondhand 2006 TTR.setup at purchase : Stock airfilter with airbox snorkelStock exhaust with restrictor removed50 pilot jet 147 main jet14 x 48 chainset After carb clean replaced all o-rings + diaphragm + checked acceleration pump (ok) Starts fine and revs ou...	Spietfriek	8	1530	Sep 18, 2014 by PlumasDude
	Who's using what pilots? (Preview) Just out of curiosity, I'm wondering what size pilot jets you guys are using in your ttr250's. I know that the 52 and 52.5 pilot jets seem to work good for a lot of people. Anyone using anything bigger? How about smaller? At what elevations? Any mods to justify?	Terrence R	15	1736	Sep 11, 2014 by TTRfan
	Revving up on her own (Preview) Having trouble with my TTR again. I love her but sometimes I want to throw her to the scrap-man. After recently inadvertently putting diesel in the bike I have been having fuelling issues, I cleaned the fuel lines out, drained the tank and have cleaned the carb about 3 times. I can not see anything wro...	Fladdem	1	1952	Aug 7, 2014 by Fladdem
	Carb with slow running problem (Preview) I have a carb that checked over fine. All jets cleaned or replaced, etc. However, there was an idle problem where on occasions the engine would run at a fast tickover and other times it would be OK. I know there is another post about these symptoms somewhere but darned if I can find it I took my own advice a...	TTRfan	12	4815	Aug 5, 2014 by TTRfan
	Carb tuning issues....help please! carb jets airbox original exhaust (Preview) Hi I live in the pyrenees at 650m say 2000 feet or so.My 2004 ttr blue came with the carb box cut open, all snorkels etc. cut off and an after market exhaust, it never ran right. The previous owner had not re jetted. I changed the jets to run with the after market exhaust and it ran great but far too noisy for th...	ianttr	1	2832	Aug 5, 2014 by TTRfan
	Mid range acceleration issue (Preview) Hi All, i have recently bought a used 1993 TTR 250. Purple frame. bike was abused, but engine was remarkably well maintained. no unwanted noises, etc. my problem is that when im riding and through the revs, low end, runs perfectly, WOT, runns pretty well too. but in between, like with the throttle ope...	romeshs	21	3721	Jul 1, 2014 by TT-R250M
	2006 TTR-250 Carburetor adjustment (Preview) Just purchased a 2006 ttr-250 which ran perfect except I noticed it had a slow carburetor leak. I pulled the carb and replaced the diaphragm assembly which was stuck to the carb and bubbled. Now if I crack the throttle real quick the engine dies. If the choke is pulled out all the way it still dies abou...	goodquest	22	11507	Jun 20, 2014 by TT-R250M
	Recent Carby Overhaul (Preview) Hi All Thanks To Jarrah, who kindly sent me some leftover carby bits, seals, gaskets, accelerator pump, O-Rings etc...and especially the 52.5 Main, my bike is running great now A bit more acceleration and power all over, it's great in the singles, smooth on rough uphills, just better all round I remo...	BM Steve	4	1501	Jun 17, 2014 by BM Steve
	Carb is makin me crazy! (Preview) Ok, so the bike seems to be running really good. Nice throttle response and great power distribution from bottom to top. Looking at the spark plug, it looks grossly lean. I check the float height as follows: put a clear hose on the carb drain. Opened it up. Set the bike up level. Fuel filled up to as far as t...	Terrence R	9	1553	Jun 9, 2014 by TT-R250M
	Oops! This looks important! (Preview) I just found a part that I forgot to put back in my carb after fooling around with jetting. Oops! how important is this? Is it ok to ride without it? Probably not, but I would like to make sure before I tear my carb apart for the 10th time within the last week. Please help.	Terrence R	8	1688	May 27, 2014 by TT-R250M
	Float level maybe? (Preview) I just got done modding my bike after ordering parts all winter. I drove it on a dry winter day in stock form and it worked great, but just needed a little extra arm pump. I just installed an FMF PC4, twin air filter and removed snorkel along with opening up the hole a bit, and 6 sigma jet kit. It came with 3 mai...	Terrence R	32	7127	May 20, 2014 by Yuraku
	Opinions Please.... Confused Jets Popping Exhaust (Preview) Hello yes its another question on jets... I am confused and have read other forums. Ok TTR250 04 plate, fitted new twin air filter and FMF Q4, snorkel still fitted as gone in some big puddles, bike seems a little sluggish in comparison to a friends with similar set up. I have a 14/52 sprocket set up and wo...	Archershome	7	2087	May 20, 2014 by TT-R250M
	jet sizes yamaha / mikuni (Preview) I have recently enlarged my airbox snorkel ,the bike is now running lean as i have uk standard 147 / 50 jets ,brian has suggested yamaha 150 / 52 but mikuni jats are cheaper and easier for me to get So my question is has anyone got experience of mikuni jets and how they compare to yamaha jets or am i best to st...	chrisstdt	13	5568	Apr 30, 2014 by TT-R250M
	stock jets 2003 US model (Preview) There was some question about stock jets on US models - for the record, I pulled the carb on my 2003 US model, which I'm pretty certain has never been touched, and the jets are in fact 137/50 (as Jarrah had opined) even though my manual says the pilot is 52. I was told this bike was originally sold in Alaska...	PlumasDude	3	1191	Apr 11, 2014 by TT-R250M
	Carb float bowl check valve (Preview) Has anyone stripped a carb and found this item missing? I stripped and cleaned mine the other day and then had a look through one of Brian's guides on carbs and found I didn't have the valve in the photo below. I can't see how I have lost it but not sure how it would run if missing? Sorry for stealing you pic Br...	domski1	15	9431	Apr 10, 2014 by pedrosan
	Bike running lumpy (Preview) Just had the bike delivered yesterday, I started the bike on the choke, its a bit smoky then clears, then when its warm off the choke it's lumpy then stalls the guy has put a fmf exhaust on will he have needed to re jet it, I want to eliminate before I start to dig stripping things off, I will change the exhaus...	Kevingrahambutler	2	1261	Mar 29, 2014 by Kevingrahambutler
	Accelerator pump return spring (Preview) Overhauling and cleaning the carb on one of of my TTR's I clumsily catapulted the accelerator pump return spring (the little one under the diaphragm) across the garage never to be seen again. Can I get a replacement? Is the spring rate critical on that spring, or can I find something that fits and stic...	Padowan	9	2472	Jan 24, 2014 by Padowan
	I can't get the jetting right. Or something else? (Preview) Yo! So it goes like this. I buy this bike and it's got a few things done to it. I busted it all open because it was surging when I was riding at a stead speed. The airbox snorkle is cut and the throttle stop is removed. I get on the google and it sais that this is a basic way to open up the bike, but it need jettin...	Maxim_X	9	2026	Dec 29, 2013 by ttboof
	Jets (Preview) What is the standard main & pilot jet size ? I now know why the bike came with a nice new unused Yamaha GYTR pipe.. I put it on .. the bike runs like a X#@%&^?.... EDIT.... Main 137 & Pilot 52 sound right ? "internet search" -- Edited by petenz on Saturday 27th of July 2013 04:44...*	petenz	13	2790	Jul 27, 2013 by petenz
	carb needle adjustment (Preview) hi just wondering how hard it will be to adjust the main jet needle to 30mm as per staintune exhaust recommendation for installing slip on?	davecambo	19	48749	Feb 27, 2012 by truslack
	supplier for Jets. (Preview) for anyone who hasnt read my Earlier post I have found a supplier for Jets they are called motocarb.3 Victoria rd West.Blundellsands.Merseyside.UK L23 8UG . tel. 01512384170 I ordered 2 jets all in stock delivered registered post next day £9.90 so if anyone needs jets he is knowledgable and reliab...	dfaz	1	1240	Jan 27, 2012 by Cubber
	Help! Pilot jet differences? (Preview) My turn to ask for help I am rebuilding a carb and want to go down from a 52.5 to a 50 pilot jet. The replacement jet looked right but didn't fit as the small diameter section was a tad too wide I have a new genuine Yamaha 50 pilot jet in my spares box but it is much shorter. See pic below: The shorter jet fits fi...	TTRfan	8	3209	Dec 8, 2011 by TTRfan
	Carburettor setup, jets & needles 1993 model (Preview) Brian i read your article at ttr250.com but i couldnt understand which main jet and pilot jet is the best for a 1993 model. My bike is 74mm,standard exhaust and Teikei30 carburator. You know which are the best main and pilot jets for this bike??	fwtian	7	1962	Nov 19, 2011 by TTRfan
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