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

Primo_ · Member

2000 TTR-250

ttboof · Super Guru

I'd start with a good carby clean. Otherwise it sounds good

-- Edited by ttboof on Wednesday 24th of February 2021 09:00:51 PM

TTRfan · Super Guru

Hi Ezra and welcome to the forum!

There is a pictorial guide to stripping and checking the TTR carb - see http://ttr250.com/Carb/TTR250_carburettor_strip_and_rebuild_guide.htm

There is advice on taking out the carb here http://www.ttr250.com/Removing_carb/TTR_carb_removal.htm

Also, there are a couple of tutorial videos showing removal and replacement of the carb here https://youtu.be/0k1EG1LuPBc and here https://youtu.be/Nlhl9aD9wHI

Totally TTRs sell a superb carb repair kit here which might be useful to have before you start work if you think replacement parts and gaskets will be needed.

Good luck!

Remember we are here to help if need be wink

Brian

Primo_ · Member

Awesome guys! I actually found that link there @TTRfan. Exactly what I need. I'm actually exited to start. Weird maybe?

Primo_ · Member

Getting used to the format on the forum. Sorry. So come to think of it, the carb was re-jetted and semi rebuilt. I wonder how good ? I feel the needle might not be setting right? I'll start there first , then cam chain.

rebuild kit.jpg

-- Edited by Primo_ on Thursday 25th of February 2021 01:19:06 AM

mossproof · Super Guru

Welcome to the forum Primo.
If the bike was running fine, then suddenly started playing up, it certainly sounds like fuel starvation to me. Tickover problems suggest blocked pilot jet to me, or possibly blocked filter behind the float bowl inlet (take great care checking this - broken float posts are common!),
unless the problems started when it was "rejetted"...

Primo_ · Member

mossproof wrote:
Welcome to the forum Primo.
If the bike was running fine, then suddenly started playing up, it certainly sounds like fuel starvation to me. Tickover problems suggest blocked pilot jet to me, or possibly blocked filter behind the float bowl inlet (take great care checking this - broken float posts are common!),
unless the problems started when it was "rejetted"...

Thanks moss👍🏼

Well here we go . Gonna check the accel pump nozzle first

Primo_ · Member

I think everything looks good? Don't think I need to strip it down? I'm going to slap it back on. Those ate the old parts

TTRfan · Super Guru

Did the emulsifier head break off when taking it out? Looks like it is in two parts cry

If you are not fitting a new pilot jet, please heed the advice in the guide on cleaning the original wink

Good luck

Brian

Primo_ · Member

The old emulsifier, ya I didn't even notice that. But looks that way. Pilot jet was replaced with new from the kit. Size 50, My main jet is 137 or so it's stamped.

BTW those youtube videos were great! I always enjoy hearing the English vocab too. "Petrol" My son was watching me for a bit and told him "I'm removing the petrol tube" He just stared at me smile biggrin

How would I go about doing this "Inspect / test the fuel inlet needle and seat for proper sealing, make sure the float height is adjusted to specs and not binding in it's arc of travel. "

I'm going to check the pet**** filter also. And the whole fuel line. Doesn't look bad with the naked eye however

-- Edited by Primo_ on Saturday 27th of February 2021 05:11:54 PM

-- Edited by Primo_ on Saturday 27th of February 2021 05:25:30 PM

mossproof · Super Guru

Measuring float height here:

ttr250.activeboard.com/t57547519/adjusting-the-fuel-level-in-the-carb-bowl-float-height/

If the fuel inlet needle is not seating properly the carb will leak "petrol" from the overflow pipe.

Remember it's not just the jets that get clogged, but the tiny air and fuel circuits in the body of the carb, like the fuel screw circuit and pilot jet circuit. Blow through all the tiny holes with carb cleaner and compressed air (but be careful not to blow it into your eyes - really stings!!)

-- Edited by mossproof on Saturday 27th of February 2021 09:28:51 PM

Primo_ · Member

I see leaking petrol from the diaphragm area. The o ring seals didn't look bad but I guess they are.

Come to think of it I don't think there wasn't a spring on the diaphram . #37

-- Edited by Primo_ on Sunday 28th of February 2021 07:49:07 PM

mossproof · Super Guru

O rings certainly look a bit flat.
Diaphragm spring can go boing if you are not expecting it. It is quite small and fine.

ttr steve · Super Guru

there are 2 springs stuck together in your photo of parts in the box

Primo_ · Member

mossproof wrote:
O rings certainly look a bit flat.
Diaphragm spring can go boing if you are not expecting it. It is quite small and fine.

Looking at my pic I even see one o ring missing there. Good thing for pics.

I was wondering about the 2 springs. Other than leaking fuel would that cause fuel starvation issues ?

Primo_ · Member

Ok. So it's idling nice now. Lots of white smoke from exhaust. But clears up . I gotta really let it warm up and see if it's a warm up issue. It got pretty dark and my neighbors get scared ....so I gotta wait till daylight.

I ended up putting in a new carb. But damn I hope I don't have to rejett and fine tune. Gotta fix the throttle play while I'm at it.

Pretty big bike . I'm more comfortable on my GSXR LMAO

Jeff B · Senior Member

Sounds lean. Idle is a bit fast and erratic. Stock pilot screw setting is 1.5 turns out from closed. Any exhaust mods will make it run lean. Higher altitude above sea level makes it run rich. Try adjusting the pilot screw out 1/4 turn at a time when its warmed-up. Then do a test ride each time. These engines need 10-15 minutes to fully warm up. While warming up, you may want to use partial choke (around 25%) a little longer until it won't stall.

Primo_ · Member

Jeff B wrote:
Sounds lean. Idle is a bit fast and erratic. Stock pilot screw setting is 1.5 turns out from closed. Any exhaust mods will make it run lean. Higher altitude above sea level makes it run rich. Try adjusting the pilot screw out 1/4 turn at a time when its warmed-up. Then do a test ride each time. These engines need 10-15 minutes to fully warm up. While warming up, you may want to use partial choke (around 25%) a little longer until it won't stall.

That could have been it. I warmed it up real good today , adjusted the pilot screw out a bit . About half turn. Rode fine. No hesitations or bogs. Throttle play is sketchy but at least I can adjust that.

Thanks guys