TTR 125L High Alt Jetting

[Yamahike]

Wondering if anybody knows of some good jetting for a TTR 125 at 5000-8000 ft. Getting ready to drill out the Air Box and pull the Snorkel and put a Thrust chamber on. I have read alot of posts to use a 110 - 112.5 main. I live in Colorado. Any help would be appreciated.

Thanks

Yamahike

WR 426
TTR125L-
PW50

 

[Gardener]

We have done all the mods you speak of on the wife's bike. As the mods tend to lean the jetting, i'd leave it stock and do a ride and feel followed by a plug check. You ride a little higher than us (3-6K), so you might need to lean it out a bit more but probably not since the little bikes seem to be a little lean from Yammie already.

 

[kjlovett]

I've read many current articles about TT-R 125 stock jetting is terrible. Many people have recommended that I use a 112.5 main jetting on my TT-R 125.

 

[Idaho Charley]

We have two TTR 125 Ls with thruster chambers, opened air filter boxs and run 5000 -9000 ft with them. 97.5 main jet, dropped the needle one e-clip position and raised the pilot to a 20. Bikes both start easier and run clean i.e. light brown plug at 5000 ft with medium dark plug at ~8000 ft. Bikes will not run clean at WOT even at 5000 ft without DROPPING the main jet. They still are slightly breaking up with MJ of 100 at 5000 feet unless you change the pipe.

 

[Yamahike]

Thanks Idaho Charley. This is exactly what i'm looking for. I'll lower the Main Jet to 97.5 drop the Stock Jet Needle 1 E Clip and put a # 20 Pilot Jet. A couple of more questions.
What is WOT? and slightly breaking up.


Thanks ALOT

Yamahike

WR426
TTR125L
PW50

 

[bulldog71169]

WOT = Wide Open Throttle?

 

[Idaho Charley]

WOT = Wide Open Throttle

"Breaking up" is the noise you hear from the engine when it is rev'd up tight in like third or fourth gear and is - just slightly rich. It is almost running clean but not quite!

If the main jet is much richer, like ours' were initially. the rich jetting will cause the motor to break-up to the point it is "stumbling" and will not fully rev out.

Be sure to check you plug color a various throttle settings after making the changes. Ours run very well and we do not re-jet during the summer. I would be somewhat concerned with the jetting I spec'd if you were riding at less than 40 degrees or significantly less than 5000 feet.

BTW - Yamaha has nylon washer spacers for the needlle to help with fine tuning. You probably noted that the e-clip positions are fairly widely spaced on the needle. The spaces allow you to make a .4 mm change in the needle position verses the 1.0 or 1.2 mm change.

Ride Safe and Have Fun Later......

 

[Yamahike]

Thanks again Idaho Charley. I will let you know how it goes. Will keep my old jet if I ever go down in elevation or under 40degrees. Glad you gave me this info as all the other posts I have read talked about how Lean this bike was out of the Crate. I'm ordering the Carb parts next week. I'm not a Mechanic by any means but this carb looks like I can tackle it.

 

[clutchcover]

Hey Idaho Charley,
I am from Pocatello. Where do you ride at? Just wonderin, I don't see many from Southeast Idaho on here.

 

[Idaho Charley]

Clutchcover - I'm in Idaho Falls. Spencer, Fall Creek, Leadore, Garnes areas; have been to Malad area a couple times. How about you?

I'm not familiar with Poky's riding areas but was thinking of going to American Falls with the IFTRA possibly next month.

What your ride? Im riding KTM.

 

[clutchcover]

I ride mostly in the Mink Creek and Pebble Creek areas. Up into Arbon which is pretty close to A/F.I have been to Malad a few times. Fished at Fall Creek, but never made it back up to ride. I ride a yamaha, but since it burned up, I've been looking for a new ride.

 

[Yamahike]

Idaho Charley
Bike is running great. Ended up using a 97.5 Main, 17.5 pilot, and leaving the Needle position the same and a Thrust Chamber . Still have to do some more test riding and keep an eye on the plug.

 

[gnarlykaw]

and more TTR125 help.........

Just read through the posts about this wonderful little bike, and I gotta admit, I am a auto tech, and have been riding 2-stroke all my life, and I feel comfortable with them. now my question. I just stepped up to my sons 125 and took off down the sand flats to see how well it ran. comparing it to his DS80, this thing runs like a honda minitrail70! I was afraid to "wind it up" for fear of floating a valve or worse yet, a flying rod. it sounded like it revved up some, and then, just stops going any faster. it felt VERY flat on the top end. now velcroboy is only 10, and dosen't know any better, but sooner or later he will, so is this the jetting problem that was discussed above? can you REALLY run this thing wide open???:scream:
open my eyes to the 4-strokes folks..........:cool:

 

[Lost]

Does anyone have a link to a site that show some pics on these airbox mods? I am running a 110 main with just a bbr pipe. Id love to hack open the air box but id like to see how other people have done it. Thx!

 

[ACS]

Try http://www.ttr125l.com