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Tuning Question

762 views 4 replies 2 participants last post by  Bighomedog11  
#1 ·
I put a 110 main jet in and a 17.5 Pilot jet in on my Mikuni 125cc bike. I notice it will sometime bog when i rev the gears out and it would also bog sometimes when i am about to go full throttle. I try a 125 Main jet and it seemed like it got worse on the bogging on top end so i know that size jet is way too big. I am thinking my pilot is too small but i am not sure if that the problem. Could it be my pilot or could it be my mixture screw needs to be turned in some more? I also notice it doesnt take off as quick as it did when i had the 107.5 main jet. When i had the 107.5 main jet it would take off fast and everything but sometimes bog at top end so i thought i was lean and i put the 110 in and it doesnt bog as much but it bog when i rev out the gears.
 
#2 ·
Everyone on here has tried to help you, but you are still in the crap. So, it seems you haven't taken people's advice given. Do this, and report back, do this each step at a time, and write down what happened each time, and then you should be able to finally get this right. #1. Go UP on the idle jet to a 20. #2. Go down to a 107.5 main jet. #3. Go up to a 22.5 idle jet. #4. Go down to a 105 main jet.
All the advice we can give you here is based on what YOU tell us, so if it is still running like crap then I don't know what else.
 
#3 ·
yeah i know i been help a lot with this, I just dont wont to seize my engine because i have blow plenty of 2smokes Top ends.

Here a picture with the 107 main jet and the 17.5 pilot.. I think i might go back to this setup and just change the pilot i thought i was running too lean.. Tell me what you all think
 

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#4 ·
Don't waste your time trying to jet by reading plugs. This is only really any use for a motor that runs in the top 80% of it's rev range most of the time, a race engine. And you certainly can't use plug readings to set the idle mixture! This isn't a two stroke, unless you run it hard while no air passes the fins, it won't sieze. OK, one more time, do what I said in the earlier thread and report back.