A Sick YZ125

[theclinkster]

I have a 2000 YZ125, and am running BR8ES in it. There is a good bit of smoke on cranking, and starting off, and it sounds alittle bogged down. Once it gets going it is awesome, it has a problem going slow. The bike fouls plugs at least 1 in riding it each time on the track. The plug when we remove it has a good bit of oil on it, and it is obviously dark, and burnt. We have adjusted the airscrew, and have it set at 1 1/2 turns out. The idle sounds good, so I think we have it set good on there. Any ideas on what to try next. I got this bike back in December, and it came from Tennessee, and we are in Charlotte, NC. Do you think that may be enough altitude change, and temperature to be causing this jetting problem.

 

[jandm'smom]

Any suggestions, or ideas on this one. I would be interested also.

 

[nikki]

If the plug is brown and fouled, this sounds like the bike is too rich. If it was hot, the plug would be white (lean). You want the plug to be a nice tan color.

I would try one step leaner on the pilot jet.

To get to the pilot:

-loosen the carb clamps (one that goes to the airbox, and one that goes to the clyinder)
-twist the carb so you can see the big nut underneath (I think it's a 14 mm, maybe 17 mm?)
-remove the nut, beware, the gas in the float bowl will drain out
-you'll see both the main jet and the pilot jet in there - if I remember right, main is in the middle (hex head?), and pilot is off to the side (small flathead screwdriver to remove it)

Check what size pilot, and maybe try one-two steps smaller. Adjust your air screw again with each pilot change.

Good luck! :cool:

 

[nikki]

Another thing - what kind of premix and what ratio are you using? The whole smoke/oil thing indicates maybe it's something other than jetting.

 

[jandm'smom]

We are using 32:1 ratio. As a premix we use Yamalube 2-R 2 Stroke Racing oil. Thanks for the ideas, and let me know about the premix.

 

[jandm'smom]

Also do you think the elevation is part of this problem? The bike is from Knoxville Tenn. we are in Charlotte NC.

 

[klunk yed]

try rm 250 it goes through 4 plugs in two and a half hours

 

[nickyd]

try rm 250 it goes through 4 plugs in two and a half hours

why not fix the problem?

you could have - bad jetting, bad crank seal on the tranny side among other things..

 

[bumf]

are u using the right plug my 125 uses a br9es

 

[CamDayKX125(4)]

my bike runs a BR9ES OR EG whichever we can find. were pretty sure the top end is my problem because i foul anywhere from 2-4 plugs on my kx 125 every time i go to TNT.