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

jpv7774 · Member

NEWBIE NEEDS HELP WITH CARB MODS....

petenz · Super Guru

Brian has longer throttle & clutch cables....

HERE ====== > www.totallyttrs.com/

TTRfan · Super Guru

Hi Jim!

I would suggest you get it running properly on the standard jets before attempting modifications else it is difficult to pin down any possible problems.

The most common cause of slow running problems is the pilot jet. Even ultrasonic cleaners aren't effective. You need to put a bit of copper (so as not to damage the brass opening) up through to dislodge any particles of gunk.

Brian

PS Thanks Pete wink

locky · Guru

Yes good advise, just put a new standard pilot jet in and give the carb a good clean just to make sure that is the problem. Then if you want to carry on with the rejet and airbox mods .

I used Mikuni jets (sized different to other brands).
52.5 pilot jet (part number vm28/486).
140 main jet (part number n102/221).
Opened airbox up with aftermarket filter.
Aftermarket exhaust.

Jet sizing differs with different brands of jet and is measured in a different ways.
vmaxoutlaw.com/tech/dyno-mikuni.htm
www.4strokes.com/technical/carb-jetting-crossover/

This is where all the confusion comes from.

-- Edited by locky on Wednesday 2nd of September 2015 08:51:12 PM

jpv7774 · Member

Thanks guys.....I agree with your assessment. Plenty of info regarding removal and cleaning of carb here...not scared of that. Kind of surprised about the floats being so fragile but I will take the advice.

I will get her running good then start the mods......

Pete ..thanks for the Brian hook up.....sounds like he is my 1 stop shop for my TTR.

Brian......I see the longer throttle cable....but I didnt see anywhere that this fits a certain model year. Mine is a 2005/250 will this cable fit? I am also in need of a spark plug.....air filter....and skid plate. I will just buy them from you.....set me up with part numbers that fit my 05 and I will place the order.

I would also like to order the jets that Locky mentioned.......Easier to do all in one order....I hope u carry these jets. Thanks Locky!

Brian if u prefer we can go off line....not sure if u have a phone number for your shop or not....what ever works best for you.

Jim

TTRfan · Super Guru

Hi Jim

I have updated the advert in our eShop to show that our longer throttle and clutch cables fit all models and years of the TTR250 - thanks for the heads up on that!

It would be good if you can register on our eShop and place your order there.

Long throttle cables here - http://my-eshop.info/epages/699105d9-e4cc-4b32-b236-84e72cd67f84.sf/en_GB/?ObjectPath=/Shops/699105d9-e4cc-4b32-b236-84e72cd67f84/Products/TTR-0202

Standard CR9E spark plug here http://my-eshop.info/epages/699105d9-e4cc-4b32-b236-84e72cd67f84.sf/en_GB/?ObjectID=1718353

CR9EIX also available here http://my-eshop.info/epages/699105d9-e4cc-4b32-b236-84e72cd67f84.sf/en_GB/?ObjectPath=/Shops/699105d9-e4cc-4b32-b236-84e72cd67f84/Products/TTR-0164

Air filter here http://my-eshop.info/epages/699105d9-e4cc-4b32-b236-84e72cd67f84.sf/en_GB/?ObjectPath=/Shops/699105d9-e4cc-4b32-b236-84e72cd67f84/Products/TTR-0010

Bash plate here http://my-eshop.info/epages/699105d9-e4cc-4b32-b236-84e72cd67f84.sf/en_GB/?ObjectPath=/Shops/699105d9-e4cc-4b32-b236-84e72cd67f84/Products/TTR-0098

#50 pilot jet here http://my-eshop.info/epages/699105d9-e4cc-4b32-b236-84e72cd67f84.sf/en_GB/?ObjectPath=/Shops/699105d9-e4cc-4b32-b236-84e72cd67f84/Products/TTR-0047

I am sorry but we don't stock after-market jets because of the complexity of sizing and the difficulty in supporting customers in their use.

Brian

PlumasDude · Senior Member

Good idea to replace the pilot jet, but with your US model why not just try a new 50 and 137 first? If you're rich try moving the needle clip and opening up the airbox top (I'd open the airbox regardless). I don't think you can really uncork without different exhaust. Brian's bash plate is great, get his hand guards while you're at it, and the magnetic sump plug, high quality oil fill plug, and metal cylinder decompressor plug.

jpv7774 · Member

Thanks Plumas........
With Brians help I have some parts on the way. Getting the bike running correctly before the mods seems to make sense and there is pretty much no cost......I removed air box etc to reveal carb wasnt even attached to the airbox completely....and the clamp for the rubber boot was missing. Previous owner recently had an auto mechanic clean the carb....I have a funny feeling this auto mechanic was not the patient detail oriented type. Will remove the carb...give it a proper clean and adjustment and reinstall correctly to see if she runs better. Fingers crossed. Im in for the sump plug and metal decompressor plug....and oil fill plug.......all sound cheap and functional.......ok the sump plug is to gather the metal shavings I assume........quality oil fill plug I assume to replace el cheapo OEM part? And I have no idea about the decompressor plug.............please educate me on these parts. I just bought the bike...so havent had the chance to do much tinkering yet.

Thanks

PlumasDude · Senior Member

Hey JPV, I'm sure Brian can set you up on those little stocking stuffers -- I recommend them because shipping from UK is expensive for the little things, I wish I'd got them all at once. The stock filler plug/bolt seemed very soft (I stripped the head, operator error but its still made of cheese). I'm sure the compressor plug will start leaking that seems to happen to all these bikes (there was a string on the forum: ttr250.activeboard.com/t60377675/its-happend-to-mine-now/

But if you already ordered from the UK all those little things can be had in the US, just not necessarily the quality you'll get from TTRfan.

This has got to be one of the simplest bikes you can find, when properly set up it should run easy like an old Yamaha, so if somethings not right keep at it.

jpv7774 · Member

Thanks Plumas.......will get her running correctly.......then order some more toys from Brian. :)