TTR 125 Problems

Is it a real VM24 or a china knock-off? I bought a knock off some time ago and found out the jets were not replaceable. Was supposed to be jetted to the bike but it was not. It ran like crap. I had to send it back.

I bought a genuine Mikuni and it runs good.

From the video looks like bike is running very rich and spitting up clouds or atomized fuel. It will run rough that way. Sort of like when you run with the choke on after the bike is fully warmed up.

 

I've had really good luck with the eBay knock off carbs with my TTR125. The jetting out of the box was good and it kicks over first try now, have you changed the plug out? If it was running rich it may have fouled.

 

It's a real deal VM24.

FML - bought a KX65 from a guy on here thinking I could ride that while I get my TTR serviced, and now that fucking thing is giving me problems. I'm fucking done with carburetors. They fucking suck and anyone who disagrees is an idiot.

Only silver lining is I've got a Grom en route to ride around the neighborhood with the kids.

 

Non ethanol gas. It will make your life better with carbs.

 

They both have only have Tru Fuel in them since the carbs being rebuilt. Was just doing research and it seems like Honder is making all their play bikes FI from now on.........

 

Interesting read, gents. I had a ttr 125 and had problems as well. Eventually, it wouldn't run at all. I had a real Mikuni VM24 on mine, had spark, and just couldn't understand why it wouldn't run. I disconnected the Mikuni at one point just to see what I could see and noticed in the process that the intake boot from the carb to the cylinder was ripped. Hadn't noticed before. So, instead of sucking air/fuel, it was sucking air/dirt. Just something else to check. Curious to know how it turned out.

 

Carbs suck, no question. But, just this morning I got to my son's ttr125 and got it running as well as possible given the jets in it. Even with jets that are a bit too small it now doesn't leak, starts on first max second kick, and is almost perfectly smooth through the rev range. As soon as I can I'm getting bigger pilot and main jets. Should run perfectly then.

 

Started by adjusting the float to stop the leaking. Small adjustments here, too much and you'll prevent enough gas getting into the bowl. Then cleaned both pilot and main jets. Finally adjusted the fuel screw. Because the pilot is too restrictive the fuel screw is completely screwed in.

 

Hey @SuddenBraking, are you still having issues?

I have a 2007 TTR125LE. They are bomb-proof, as are the XR/CRF100s. It just takes some tinkering but you'll spend pennies on the dime to get them fixed compared to the grom or big bike.

Sounds like an issue with the intake or a carb tuning. I run high-octane pump fuel with stabilizer, btw, and a fresh plug.

Single-carb engines are simple to work on, imo...assuming the rest of the engine (valves, cams, timing, etc) is verified to be working correctly and not causing the carb to 'mask' the real issue.

If you still need help, holler or PM me.

Going forward, here are two links that are helpful for the TTR:

https://thumpertalk.com/forums/topi...mods-questionsanswers-carb-jet-understanding/ (or google 'ttr125 tech tips mods questions' on thumpertalk.com)

Everything about carbs :
https://www.cycleworld.com/story/bi...rCCjM1Dc8M65IG8M_HSBiAi7q1DeOdrf62tXG9yM1ImAg

 

Haven't tried to fix it since my last temper tantrum - bought a KX65 to hold me over until the TTR125 was good to go, and somehow that bike is having issues now as well. I then said fuck it and bought a Grom with a 300 engine dropped into it

Handling a bunch of stuff around the house, but then will get to working on the bikes again (but need to put a pile of tires on my streetbikes first). I think there's some merit in post #33 that I may have put the new carb in incorrectly, but tbh with NJMP shutdown it hasn't been a priority to fix.

 

curious as to why you run high octane/super?? why the stabilizer? Are you running a high compression piston?

 

mixture screw?? Dont they turn out instead of in?? I know Ive lost at least 2... to the point I started safety wiring them in place.

 

Mine (sons) is completely screwed in. Normally it should be about 2 turns out.

 

Hey TurboBlew: my TTR125 is all stock and, yeah, it can run on lower octane. So, the high octane is 'overkill'. But I typically put in stabilizer in the TTR125 since it tends to sit more than my other bikes. No other special reason.

 

What process did you use to set the screw at completely seated?

 

Hey @pscook, the idle/air screw really shouldn't be seated. On most any carb, that screw should be 1-3 turns out from being seated. The process to accomplish that is determined by the size of your pilot jet, which controls the fuel amount dispensed at idle. Too small and, yes, you can completely seat the air screw. But that would be wrong. But, sometimes, in lieu of using the correct pilot jet, you can 'cheat' by turning the air screw way in or out to achieve proper idle speed. That can produce symptoms elsewhere in the throttle range (an off-idle bog comes to mind).

 

This, exactly this. Unfortunately because of the current situation I am unable to pop by a part store and simply pick up a new pilot jet. As soon as I can get new (slightly bigger) jets for the bike I will.
Regarding premium fuel, I use it as well in all our small engines not because they need it (I know they definitely don't) but because that's the only fuel I can buy that is ethanol free.

 

I only asked because I noticed a difference in the way the different fuels run in the single piston engines. Granted I'm at sea level and have access to pump fuels from 87 all the way to 100 octane with eth free in 89 & 92 flavors. The eth free, from a specific local distributor, works really well. I made the mistake of "trusting" a new station selling eth free which was just regular unleaded with an $.80 premium taxed. My sample size is my lawn/power equip, minis & scooters I ran exclusively for ~2yrs from the place. The bowls & jets in all of them were trashed which the only things that sat for anytime were my generators. I mentioned it to a small engine shop down the street and they confirmed that many of their small engine customers had problems from using that pirate stations fake fuel. Thankfully the scooters were FI'd. Nothing like overpaying for garbage fuel then having to do full scale cleaning/service I was overpaying to avoid in the first place...lol. My sample with the scooters has to do with fuel range... which I could go ~130 miles on a 2 gallons of eth free. Put eth blends in the same quantity and the range drops to under 100 miles.
I have a neighbor that is a boat mechanic... he gave me some insights on the "fuel stabilizers" and how much money they make him. Again paying a preventative premium for no return or result. The best method is to drain the bowls/jets and fog the passages.

 

I know that the screw shouldn't be seated, that's why I asked what method was used to determine where the screw setting was. I'm pretty familiar with jetting all manner of bikes/carbs, which is why I wanted to know the method so we can see what can be done to fix the problem.

 

Gotcha, man. It wasn't clear to me if you were actually trying to seat the idle screw or not. Hence, my lengthy post. Lol.