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 New Mikuni bogging down at full throttle on 35 gtr 
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Post New Mikuni bogging down at full throttle on 35 gtr
Just installed new BPS mikuni carb kit on stock gtr 35. Starts, idles and accelerated great. Right at
full throttle the motor quits accelerating then bogs down and slows. If i let up on the accelerator it picks up and runs good. I'm wondering if anyone else had this issue. Is the main jet not rite for stock heads with 400 hours on them? I also have a Q muffler coming do yall think it might help.


Thu Aug 16, 2018 8:27 pm
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Post Re: New Mikuni bogging down at full throttle on 35 gtr

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Sun Aug 19, 2018 5:50 am
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Post Re: New Mikuni bogging down at full throttle on 35 gtr
Does it do it at the same rpm every time, or just any time you squeeze the throttle wide open?


Sun Aug 19, 2018 6:19 am
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Post Re: New Mikuni bogging down at full throttle on 35 gtr
If it’s a 42HSR I’ve been told it’s quite a bit much for stock heads. Sounds like you’re flooding the engine at WOT, but wait and Marcus, Russ, or Will can probably chime in and tell you exactly what jet to change to to make it better.


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Sun Aug 19, 2018 7:05 am
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Post Re: New Mikuni bogging down at full throttle on 35 gtr
What main jet are you running?

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Sun Aug 19, 2018 8:23 am
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Post Re: New Mikuni bogging down at full throttle on 35 gtr
Stock jet in it should be a 160. Yes asking a stock and well broke in motor to eat all that 42 mm is asking a lot. By the book I say you need a smaller main jet. Experience says you really need a good set of heads. It will be a completely different motor when u add the heads. Heads and a mikuni make a great motor.


Sun Aug 19, 2018 12:09 pm
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Post Re: New Mikuni bogging down at full throttle on 35 gtr
Here's how it cam be interpreted... Normally with a mikuni if you are running WOT and quickly back off to 7/8 throttle(still in the main jet) and you see the rpm rise.... you are too lean. (the motor gets rich for a split second when the throttle closes a tad bit).

But as I re read your post it sounds like you are backing off the gas enough to ride the needle and that tells me you are getting back into the range the motor wants to see.
Now when you have no porting, restrictions, and a small easy camshaft, you will see less signal to the carb. That normally requires a larger jet to achieve the correct AFR. With that being said, what jet is in the main circuit?

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Mon Aug 20, 2018 5:33 am
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