Posts
68
Joined
10/10/2017
Location
IL
US
Edited Date/Time
10/25/2017 3:33pm
So we got a 2018 CRF50 this year for my son. Runs ok. Has never idled correctly. Dealer says its normal and not supposed to idle for more than a minute. I think thats bullshit.
Anyway forget the dealer. I see several online where people show them idling for a long time with no issues. Furthermore we decided to ditch the stock filter assembly after he dumped it a few times and the filter enclosure was filled with oil.
So now its rocking a UNI pod filter and its running as bad as ever. I assume with the extra air its running super lean. Now it wont let you go WOT without bogging bad. It will start to run better as it gets to full temp, but unless I take it out and run it to WOT in 3rd, my sons riding style never lets it really get to full temp.
So I have been reading articles about changing the a/f it with some imaginary A/F screw that our 50 doesnt have. It has what looks like a brass cap. HOW THE HELL DO I ADJUST THIS THING?? WIll I need to rejet? What the hell is the needle jet and so on.
I pulled the carb and blew out every hole I could find with carb cleaner. The bike will start first kick even dead cold. Just wont barely idle. One of us has to keep it going while he gears up, and when he stops to talk to me it dies and I have to pull him off and kick it over again. Huge pain in the ass. And now its doing this bog thing. Keep in mind this is a 2018 with maybe 5 hours on it. Oil has been changed twice and only shell 93 has been used. Its literally a brand new bike. So "clean the carb" not only has been done, but is obviously not the problem. See the pic for the brass fitting. Any ideas other than buy an older carb with the adjusters??
Anyway forget the dealer. I see several online where people show them idling for a long time with no issues. Furthermore we decided to ditch the stock filter assembly after he dumped it a few times and the filter enclosure was filled with oil.
So now its rocking a UNI pod filter and its running as bad as ever. I assume with the extra air its running super lean. Now it wont let you go WOT without bogging bad. It will start to run better as it gets to full temp, but unless I take it out and run it to WOT in 3rd, my sons riding style never lets it really get to full temp.
So I have been reading articles about changing the a/f it with some imaginary A/F screw that our 50 doesnt have. It has what looks like a brass cap. HOW THE HELL DO I ADJUST THIS THING?? WIll I need to rejet? What the hell is the needle jet and so on.
I pulled the carb and blew out every hole I could find with carb cleaner. The bike will start first kick even dead cold. Just wont barely idle. One of us has to keep it going while he gears up, and when he stops to talk to me it dies and I have to pull him off and kick it over again. Huge pain in the ass. And now its doing this bog thing. Keep in mind this is a 2018 with maybe 5 hours on it. Oil has been changed twice and only shell 93 has been used. Its literally a brand new bike. So "clean the carb" not only has been done, but is obviously not the problem. See the pic for the brass fitting. Any ideas other than buy an older carb with the adjusters??
2)You should not have to adjust your air screw from the factory setting. But, if you feel the need, you have to remove that brass cap to get at it. As explained in your other thread it has to be drilled/pulled off as it is pushed in there with a light press fit.
3) I would ditch the aftermarket filter setup and go back to stock. You are correct that it is making the bike much leaner and is likely the root of all your probs. The reason the stock airbox filled with oil was probably because either the bike was laid over at some point or the engine oil was overfilled. The parts circled in red are the engine breather that vent the crankcase to the airbox. Oil will come up this and get in the airbox if the bike is laid on its side. The part circled in blue is the airbox drain. The part circled in green is a plug that must be removed from time to time to allow any collected oil or moisture to drain. Clean all the stock stuff well, put it back on, don't lay the bike over or overfill the oil, and drain that tube every few rides. Your life will be much easier.
The Shop
After the bike is warmed up, turn the air screw out until it starts to misfire and then slowly turn it back in until the idle is the fastest and smoothest. You should end up about 1 to 2 turns out from seated. You might need to turn down the idle speed and repeat if the idle is too high.
My kid's PW50 is extremely sensitive to this issue. I always run fuel stabilizer in the gas and it definitely helps.
Post a reply to: For the love of God, please help me tune this CRF50 carb. Getting frustrated.