the one that sticks out the side a ways is your idle screw, it should possibly have a srping on it as well. the one next to the air filter i dont worry about. as far as your jets go, i have the same problem with my ogm, i just posted a thread asking someone if they have played with the jetting yet to figure out what they need to run. the problem you are having it is way to rich and drowning it out as well. thats what the choke is doing to cutting off air so there is a richer air to fuel ratio. i dont know what jet to use. i wish i had a kit i would try them all and let you know. i think i am going to try a 165 or 170 first. also your needle you want the clip all the way at the top of the needle this is goin to put the needle all the down into the carb letting less fuel come up from the bowl, therefore makeing it leaner, than as you find the right jet, move the needle clip down the needle until you fine the mixture that you want. i go by the spark plug, smell, and sound.

 

set your needle clip in the middle. turn your airscrew 1.5 turns out. turn up your idle. start the bike and let it warm up. once warm, make sure the idle is high. now turn the airscrew in clockwise until the idle starts to drop. turn the airscrew back out until the revs pick up and remain steady.



the stock jets should work with the 140. if you dont have any other jets, adjust your needle clip.

 

That main is way too big for where we are (800 ft). I would run a 155 or even 145 on that setup here. Start with your clip in the middle with that main and fuel screw 1.5 turns out.

 

dont mean to post whore but I just got a 140 that came with a molkt 26, vm 26 knock off, I think the alt is around 1200 here, any idea where to start with jets?

 

That main is way too big for where we are (800 ft). I would run a 155 or even 145 on that setup here. Start with your clip in the middle with that main and fuel screw 1.5 turns out.

thats what I thought, when I first started it and revved it, there was some black smoke. I will go to the store tomorrow and see if I can pick up a 155. also the overflow tube for the float bowl is spilling gas, I made sure its not stuck, is there a way to fix this?

 

pm sent.

 

dont mean to post whore but I just got a 140 that came with a molkt 26, vm 26 knock off, I think the alt is around 1200 here, any idea where to start with jets?

Try a 25 pilot jet and a 115 OKO main jet in the MOLKT. Air screw about a turn out.

 

ok, played with it a little, needle all the way down and air/fuel screw 1 1/2 turns out. has great top end, but when I give it a lot of throttle at once while at idle it still bogs. Im still gonna put a smaller main in, but is the 22.5 pilot the problem? thanks for the help.

 

ok, went to the store today and got a 150, still no luck. So I went back and got a 140, and a 25 pilot. Still poppin and doin some weird funky stuff, and the plug is BLACK. In the higher revs it pops too. Got the needle all the way down, and the screw about 4 or 5 turns out and still not performing the way I want it to. Should I get a 130 or a 125? or both? theyre only 3 bucks.

 

keep going down on the main until the plug turns brown

 

I went down all the way to a 110, and it still bogs a little when I give it alot of gas at once, but I think its a typical 4-stroke thing, my 450 does it too. right now Im running 110 mainjet, 25 pilot, needle all the way down, and 2 turns out on the screw. Problem is I still think its rich, and the local shop doesnt have less than a 110 mainjet. the plug is cleaning up a bit but its still blackish. Is it possible for it to be running rich with this jetting setup? or is something screwed up? Ill go to sudco and see if I can find a 100, but it seems like everyone else is running 140 and higher on their vm26's. So i guess my question is, should I keep going down on the mainjet? or should I play with the pilot? The top end is running great, but the bog in the low rpm's is leading me to believe its still rich.

 

Why do you leave the needle at the lowest setting? Get the clip in the middle or your bottom end will continue to bog while your top end dangerously leans out.



I use a 185 main, 20 pilot with needle at middle position and my motor is only 124cc. Runs perfect set up this way.

 

Why do you leave the needle at the lowest setting? Get the clip in the middle or your bottom end will continue to bog while your top end dangerously leans out.



I use a 185 main, 20 pilot with needle at middle position and my motor is only 124cc. Runs perfect set up this way.

Good catch, I checked again and I was wrong, the needle is at the highest for best performance. So I guess I gotta go back through all my jets and try all of em again, and find which one works best when the needle is at the middle. If the needle is all the way up, then I gotta go richer on the mainjet right? I got 110, 120, 130, 140, 150, and 190 which do you suggest to go back to? thanks for the help.

 

If its popping on top it's because you are going too extreme and leaning the motor out. You definitely do not want to keep going down on the main. You are dealing with two different issues. The main jet should be around a 170 or even higher depending on the color of the plug. You need to get an accurate plug reading by having the motor warmed up and a sustained above middle-upper throttle rev. I recommend you ride it so as not to overheat sitting on the stand.



Your plug is most likely bogging on the bottom because your pilot it too big, thus

giving you a black plug and leading you to think your main is the problem. Try going down on the pilot to a 22.5 or 20

 

Hey Mark, why would an OGM 140 need a 145 or 150 main in the vm26 when my OGM 150 has a 102.5 stock? And you had me go even leaner. Just curious, wouldn't a 140 suck less fuel?All the guys I talked to at southwick were running between 115 and 135. Dave

That main is way too big for where we are (800 ft). I would run a 155 or even 145 on that setup here. Start with your clip in the middle with that main and fuel screw 1.5 turns out.

 

DO you have a REAL Mikuni VM26 Carb or do you have a knockoff VM26 Carb. They take different main jets and therefore the numbers are not the same!



If you are running a REAL mikuni VM26 carb, you should wind up around 20-22.5 on the pilot and 140-170 on the main. Your air screw should never be more than 3 full turns out or you have the wrong pilot jet in there.



And putting your needle all the way up or down is a dead give away your jets are off.



So, do you have a REAL VM26 or a knockoff? Post pics of what main jets you are using if you don't know the difference.

 

If its popping on top it's because you are going too extreme and leaning the motor out. You definitely do not want to keep going down on the main. You are dealing with two different issues. The main jet should be around a 170 or even higher depending on the color of the plug. You need to get an accurate plug reading by having the motor warmed up and a sustained above middle-upper throttle rev. I recommend you ride it so as not to overheat sitting on the stand.



Your plug is most likely bogging on the bottom because your pilot it too big, thus

giving you a black plug and leading you to think your main is the problem. Try going down on the pilot to a 22.5 or 20

I put the 150 back in, and have a 25 pilot, and the needle all the way up. I will go out today and buy a 160, 170, and 180, because those are the only ones I dont have. I will try the 170 first, with the 22.5 pilot that I already have, and the needle in the middle. see what that does.

 

150s sound high but I guess its your locals. Cause here we never break the 120s thats.

 

150s sound high but I guess its your locals. Cause here we never break the 120s thats.

Again...different carbs. A real VM26 carb uses different jets which in turn use different numbers



A 120 in a REAL mikuni will be small for a stock 70cc at 2000ft and lower



For me...a 146cc jets about perfect on a mikuni vm26 at 22.5/180 at 2000 ft

 

People keep giving jetting advice but tend to confuse which exact carb the user has. A real mikuni vm26-606 looks like this.

if this is th ecarb you have then start with a 180/needle in middle/screw 1.5 out. start it up and adjust your air screw like i posted earlier. this should clear up your bottom end throttle response. for top-end, you gotta run it at least in 3rd gear wot and notice how the rpms build or if it bogs or spits.

you also have to adjust your float height to keep your carb from overflowing like that.

 

yep, thats my carb. Which way is which for the air screw, In=leaner or out=leaner? what pilot you runnin? I got a 22.5 and a 25. in the last couple posts I was told to run my 22.5, but the 25 ran way better before. right now I got the 190 with the 22.5 pilot, air screw 2 turns out, and needle 2nd from all the way up. and the throttle is still crapy. I will try a 170, and 190 with the 25 pilot and see if there is a difference. the only jet I do not have is a 180, but I can get one if need be. Ill update later

 

yep, thats my carb. Which way is which for the air screw, In=leaner or out=leaner? what pilot you runnin? I got a 22.5 and a 25. in the last couple posts I was told to run my 22.5, but the 25 ran way better before. right now I got the 190 with the 22.5 pilot, air screw 2 turns out, and needle 2nd from all the way up. and the throttle is still crapy. I will try a 170, and 190 with the 25 pilot and see if there is a difference. the only jet I do not have is a 180, but I can get one if need be. Ill update later

out is leaner

 

out is leaner

's what I thought, thanks.

 

Mikuni VM26-606 and VM26-665 are very different in setup.



I am running #150 in a VM26-665 with K&N filter at sea level on a YX140.

Do not know which pilot jet is in, have not had the need to open the float bowl yet.

 

Think I found the best im gonna get. 170 main, 25 pilot, air screw 2 turns out, needle right in the middle. tried it with the 22.5 pilot, just bogs alot when I give it alot of throttle. choke still kills it when its on, i guess I will just not use it. Still some bog from idle, but only when I give it more than 1/2 throttle. thanks for the help along the way.