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blackiredi · May 28th, 2022, 07:51 PM

Hi All,

I just picked up an '08 250R with OEM carbs and an off brand aftermarket carbon can. I am trying to get it prepped for race weekend next week. It was bogging bad. So I rebuilt the carbs, replaced the plugs (man the bike was run lean) and have backed out the mix screws 3 full turns.

It now revs out really strong- no bog. But if I rev it hard and hold throttle at say 9000 rpm it dies off to 6000 or so as I holding the throttle in the same place. And the exhaust pops a lot.

My guess is it is still too lean, but my question is should I continue to back out the mixture screws or shim the needles? It seems like shimming the needles would be the right thing since it would give more fuel through the whole rev range?

Any help is appreciated.

Thanks

May 28th, 2022, 07:51 PM	#1
blackiredi ninjette.org member Name: Ben Location: Portland Join Date: May 2022 Motorcycle(s): '10 Ninja 250R (track), '20 Street Triple 765 (street), '12 CRF150R SM (racing) Posts: 55	Fueling help Hi All, I just picked up an '08 250R with OEM carbs and an off brand aftermarket carbon can. I am trying to get it prepped for race weekend next week. It was bogging bad. So I rebuilt the carbs, replaced the plugs (man the bike was run lean) and have backed out the mix screws 3 full turns. It now revs out really strong- no bog. But if I rev it hard and hold throttle at say 9000 rpm it dies off to 6000 or so as I holding the throttle in the same place. And the exhaust pops a lot. My guess is it is still too lean, but my question is should I continue to back out the mixture screws or shim the needles? It seems like shimming the needles would be the right thing since it would give more fuel through the whole rev range? Any help is appreciated. Thanks