Rebuilt motor bored .04 over boysen reeds dg exhaust +1 sprocket. It's running majorly rich and I can't figure it out? I tried mix (32/1) now adjusted air to fuel but still major rich
Running rich? HELP
- Thread starter ballin89blaster
- Start date
Yeah, you need to post what exact engine work you got. What exhaust pipe you got. Any porting, what air filter/airbox/pod filter setup you got. What carb are you using (if its aftermarket and not the stock one), what size is it, etc.
If its a Keihin I can help you jet it (theres several others on here as well)
If its a Mikuni, theres guys on here who can help you with that as well.
If youre running rich, its going to be a result of your jetting for sure. Heres a basic rule of thumb when jetting:
To start, get the pilot dialed. 1.5-2 turns out on the airscrew when warm to idle. You SHOULD have to choke it if the engine is cold to get it to start. If you have to turn it all the way in to get it to idle, youre too lean and need to go up a pilot size. If you have to turn it all the way out to get it to idle, youre too rich and need to go down a pilot size.
Get it idling nicely and then set the main. Put in a main that bogs when you go WOT, (keep going up in main till it does this), then start pulling back size at a time until you can go WOT without it bogging. Now youre in plug chop territory. Do some WOT plug chops and make sure your main is where you want it.
Once youve set the main, then you figure out driveability. Thats done with the needle. When you rev it, the engine sould pick up crisply and not rev too high too fast, just a nice steady wind up and a good healthy exhaust note. If it revs up too fast, youre lean and your needle needs to go down on the clip (which pulls the needle farther away from the jet so more fuel flows through the main on transition), if it picks up slowly and it bogs, go up on the clip which will put your needle farther down into the main restricting the flow of fuel to lean it out so youre not too rich on transition.
If its a Keihin I can help you jet it (theres several others on here as well)
If its a Mikuni, theres guys on here who can help you with that as well.
If youre running rich, its going to be a result of your jetting for sure. Heres a basic rule of thumb when jetting:
To start, get the pilot dialed. 1.5-2 turns out on the airscrew when warm to idle. You SHOULD have to choke it if the engine is cold to get it to start. If you have to turn it all the way in to get it to idle, youre too lean and need to go up a pilot size. If you have to turn it all the way out to get it to idle, youre too rich and need to go down a pilot size.
Get it idling nicely and then set the main. Put in a main that bogs when you go WOT, (keep going up in main till it does this), then start pulling back size at a time until you can go WOT without it bogging. Now youre in plug chop territory. Do some WOT plug chops and make sure your main is where you want it.
Once youve set the main, then you figure out driveability. Thats done with the needle. When you rev it, the engine sould pick up crisply and not rev too high too fast, just a nice steady wind up and a good healthy exhaust note. If it revs up too fast, youre lean and your needle needs to go down on the clip (which pulls the needle farther away from the jet so more fuel flows through the main on transition), if it picks up slowly and it bogs, go up on the clip which will put your needle farther down into the main restricting the flow of fuel to lean it out so youre not too rich on transition.
