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Post by keikara on Jun 10, 2015 11:20:08 GMT -5
So I have a 2013 Jonway 150cc scooter, just replaced the motor about 500 miles ago, along with the motor replaced the cdi, starter solenoid, and carb, carb has stock pilot jet, and a 106 main, with uni filter. Scooter will start right up with just an easy push of the starter button, revs up and drops back correctly. However when I take off the scooter starts to move at 3k rpm and will pull to 4k with power, once I hit 4k it falls on its face, can hear a slight bog, but slowly picks up speed. Once at almost 5k scooter will stop bogging and start to pull again all the way to wot. Have pulled plug and plug looks good not running rich or lean. My question is do I need to change the pilot jet to a bigger jet, or just fiddle with the a/f mixture. If I take off while the enricher is still on the bog is still there but not as bad.
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Post by ricardoguitars on Jun 10, 2015 12:47:48 GMT -5
I have a similar problem, it happens only when the scoot is cold, I replaced the carb recently with a bigger carb, so in my case I believe the problem is it is running rich, I haven't bother to fix it because I will be installing a BBK soon, I hope that will fix it.
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Post by keikara on Jun 10, 2015 12:52:18 GMT -5
I have a similar problem, it happens only when the scoot is cold, I replaced the carb recently with a bigger carb, so in my case I believe the problem is it is running rich, I haven't bother to fix it because I will be installing a BBK soon, I hope that will fix it. My scooter does the opposite, it has less bog while cold and as it warms up the bog gets a little worse, I have had on a warm almost 100 deg F. day that after about 20 min of riding the bogging or loss of power between 4-5k rpm was very noticeable. I have a new quality kehin (sp?) carb. |
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Post by JerryScript on Jun 10, 2015 13:34:29 GMT -5
Running good when cold and suffering when hot usually indicates you are too rich. Since it only happens at 4-5k RPMs, you should try lowering the needle by raising the clip on it, or removing washer spacers if used.
Be sure to thoroughly inspect the diaphragm, though tears/holes in the diaphragm usually make it run to lean.
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Post by keikara on Jun 10, 2015 15:18:54 GMT -5
Running good when cold and suffering when hot usually indicates you are too rich. Since it only happens at 4-5k RPMs, you should try lowering the needle by raising the clip on it, or removing washer spacers if used. Be sure to thoroughly inspect the diaphragm, though tears/holes in the diaphragm usually make it run to lean. Thanks I will try this. Don't know if the needle in the carb is adjustable, but I have needles from three other bad carbs that are adjustable just a matter of pulling the carb and switching it out. |
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Post by chromestarhustler on Jun 10, 2015 15:27:10 GMT -5
personally and this is just me, i am in the say climate as you, but way higher in elevation....106 seems small, i would be shimming the needle up, you might be to rich but with your symptoms i usually increase fuel and they go away, trail and error thou...good luck.
i have 6 to 8 scooters depending on the day, and i typically run, a drilled exhaust, tuned variator and 108 to 112 jet
i think your enricher is shutting off and then your losing that aux fuel source and slowing down.
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Post by JerryScript on Jun 10, 2015 15:35:20 GMT -5
I agree, if it gets worse moving it up,try the other way. Tuning is more an art than science unless you use EFI.
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Post by keikara on Jun 10, 2015 16:11:51 GMT -5
personally and this is just me, i am in the say climate as you, but way higher in elevation....106 seems small, i would be shimming the needle up, you might be to rich but with your symptoms i usually increase fuel and they go away, trail and error thou...good luck. i have 6 to 8 scooters depending on the day, and i typically run, a drilled exhaust, tuned variator and 108 to 112 jet i think your enricher is shutting off and then your losing that aux fuel source and slowing down. Yea I am in Phoenix AZ so it is about to start getting hot here, to me anything over 105 F. is hot LOL. The only upgrade to my scooter is a uni filter, everything else is stock, stock variator, and stock muffler. Also don't know if this would make a difference but on the center stand the scoot will rev from idle to redline with no bogging, but as soon as I go for a ride it will rev up to about 4k then bogs until just about the 5k and then will go all the way to 7k rpm with no problem, I can vary the throttle and anywhere from 5k and up when I twist the throttle I can feel it just pick up and go, but if I have to slow down to where the rpms drop below 5k it will bog until it is above the 5k again. |
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Post by geh3333 on Jun 11, 2015 14:27:10 GMT -5
I agree , but if it were me , I'd upjet instead of just raising the needle. 106 is small with a uni installed. I know you still have the stock exhaust , but installing the uni still let in more air. This is my whole point about these scoots " even stock bore" can take much more air and fuel then others think. You just install a uni and the engine is already screaming for more fuel. I'm not saying he should by a bigger carb. I'm just explaining how these scoots can gain from a bigger carb . of course you can jut keep up jetting your stock carb , but it will be more restrictive then a bigger carb. I think a 26mm carb would be just fine on a stock setup. Problem Is , I've never tried it , so I cannot varify that.
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Post by keikara on Jun 11, 2015 15:24:23 GMT -5
I agree , but if it were me , I'd upjet instead of just raising the needle. 106 is small with a uni installed. I know you still have the stock exhaust , but installing the uni still let in more air. This is my whole point about these scoots " even stock bore" can take much more air and fuel then others think. You just install a uni and the engine is already screaming for more fuel. I'm not saying he should by a bigger carb. I'm just explaining how these scoots can gain from a bigger carb . of course you can jut keep up jetting your stock carb , but it will be more restrictive then a bigger carb. I think a 26mm carb would be just fine on a stock setup. Problem Is , I've never tried it , so I cannot varify that. So do you think if I just up jet the main it could fix the bogging between 4-5k. If so I do have a few more main jets at home, think I have a 108 and a 110 at home. But it isn't running lean at WOT that is why I was thinking the pilot jet needed to be larger. Idle is fine at 1800 rpm, clutch stats to engage at 3k between 3-4k scooter will pull fine hits 4k falls on its face until 5k then will have no problems until I have to slowdown ad the rpms get below 5k. And I believe (will have to back and read) but I think they were saying to lower the needle as to lean it out some. |
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Post by geh3333 on Jun 11, 2015 15:33:16 GMT -5
If you suspect its the pilot, then def adjust the air fuel before changing the pilot. Did you tune the carb for highest idle rpms ?
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Post by geh3333 on Jun 11, 2015 15:45:26 GMT -5
If you suspect its the pilot, then def adjust the air fuel before changing the pilot. Did you tune the carb for highest idle rpms ? I don't think you need to lean it out at all. If you don't have any other pilot jets to test out. Idfirst adjust the carb , tune it for the highest idle rpm. If that doesn't work I'd replace the 106 with a 108 main. From what many say, the main jet kicks in pretty early in the throttle range. So if it were the pilot , I'd expect problems much earlier then 4000 rpms. If the main begins to kick in around 4-5k rpms then it is possibility the main is not letting in enough fuel. Stock main jets vary , I be heard some say 105 was their stock and I've even heard some say higher and lower . so I believe a 106 after letting in more air is kind of small. |
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Post by chromestarhustler on Jun 11, 2015 16:01:15 GMT -5
4-5 is kinda the transition point from the idle circuit to the main jet, raising/lowering the needle to see if it helps hurts isnt a bad plan...and wont effect WOT mix too much
most my stock and replacement carbs seem to come with a 108
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Post by keikara on Jun 11, 2015 16:46:18 GMT -5
My stock main in the carb was a 102 I believe, would have to look and see what the smallest main I have at home is, that's the one that came out of the carb. I think I will try to up jet the carb then retune, and if that fixes it than great. And yes when I first setup the carb with the 106 jet I did adjust to get the highest rpm out of it. So looks like I will be pulling my carb on Sunday and seeing what I have.
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Post by keikara on Jun 11, 2015 19:39:55 GMT -5
Just got home and yes the new carb I am using that was sent to me by the awesome dmartin95, had a 102 main in it stock. The additional jets that were sent to me as well were a 105, 106, and a 110. So I think I will try moving the needle first and if that doesn't work move it back down and then try the 110 jet.
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