[Knoc]

I am and have been having carb problems for a while now. It started out with a boggy 1st and second gear. Since then Ive rebuilt the top end (Which popped one day)(I dropped in a Wiseco piston, stock size, head was fine, just needed to be acid washed and honed) Put in some new Active Reeds, new gas line, and Ive had the carb apart numerous times. the jet is clean and so is the needle, but I just cant seem to get it tuned it. What is the best way to get it tuned? 1st and second gear are boggy and smoke, and 3rd gear it finally seems to clear its though and get up and go. Then in 6th gear when Im going it sometimes will hicup.. Anyone have any pointers? Im frustrated and almost ready to bring it to the dealership and have them do it. Its a 1989 Rm 125 with a Makuni carb on it. Please help if ya can, Im desperate... :-|

 

[Knoc]

Everyone bring there bikes in to get stuff worked on or what? Anyone??

 

[Superbird]

man if it was a car i could help you out but i dont know anything about carb bike engines. If it was a car i would tell you to hook up a vac gauge on ur carb and get a timing gun and tune ur engine that way but i dont know about a bike

 

[Clint]

It doesn't make sense that different gears would behave differently. Can you describe the situation from an rpm or throttle position standpoint? They should be consistent across gearing.

 

[Knoc]

Well the more throttle I give it the more boggy it gets. But it only does it in 1 and 2nd gear, then in 3rd gear when I give it the gas it goes, and clears out.. It really has me stumped.. I mean this is my 2 stroke, but the power should just be there instantly in the gears right? I mean with it like this, a wheelie is damn near impossible... any help would be GREATLY appriciated.. Thanks

 

[dirtyfingers]

Have you ever tried messing with the jet-needle? Unscrew or unbolt your carb slide, & get the needle out of it. You'll Notice it has a snap ring and probably 5 grooves. You can make the main jet come on sooner or later depending on this clips position. With the clip at the top, it will run leaner. Clip at the bottom will make it run richer. Try this and let me know what happens.

 

[Knoc]

Yeah I had just done that. I moved it up a notch and it seemed peppier but the 1st two gears are boggy stilll... Gotta be the jets.. If not I give up and I guess Ill have to take it in the rear withe the dealers labor rates... Just pray the jets are off..lol

 

[Hunter]

Take it back to the shop that fixed it and have them set up the carb.

 

[87gsxrnut]

Your diagnosis makes no sense. If it bogs when you give it more gas and are hard on the throttle (3/4 or more), try a SMALLER main jet. When you are giving it more gas are you really twisting the throttle most of the way? Does the bike idle OK? Are you actually backing off the throttle a bit once you get going because you are moving finally and don't have to give it as much gas? Or, because you are moving faster in 3rd gear are you feeding it MORE throttle?

Jetting is somewhat of a black art. You should have several main and pilot jet sizes available when tuning.

Just remember not to lean it out too much with a 2-stroke, or that piston will sieze.

- Nut

 

[Knoc]

I know it has me stumped too.. When I take off, the 1st two gears are boggy as hell, when Im giving it gas.. Then in third gear its a little boggy at 1st then clears out and 4th 5th run like a champ and 6th is good but when I get to a certain point, its boggs. then I give it more gas and open it up and it runs good. I ordered a new Jet Needle and couple of jets for the next 3 sizes smaller. They should be in by the end of the week so hopefully thatll fix it..

It had a 330 jet in it, is that the common size?