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raga jetting?


jokerr
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just got a new raga 2010 250. does anyone know which jets are in as standard uk? bike came with a spare 120 main. i have a slight knock at higher rpm when covering ground so i am guessing that main jet needs upping. dont want to strip carb to find that its 120 or bigger. or what do you think? fuel screw out 4.5 turns. anyone go out further than that? dellorto phbl 26. cheers

Edited by jokerr
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just got a new raga 2010 250. does anyone know which jets are in as standard uk? bike came with a spare 120 main. i have a slight knock at higher rpm when covering ground so i am guessing that main jet needs upping. dont want to strip carb to find that its 120 or bigger. or what do you think? fuel screw out 4.5 turns. anyone go out further than that? dellorto phbl 26. cheers

A #120 in a PHBL should be slightly rich in most cases. To start with, I'd pull the carb and do a jetting map, recording what exactly is in your carb, rather than assuming and that way you would have an idea of where to go. If the knocking is at partial throttle (most of us rarely ride at full throttle), raising the needle might solve the problem.

The fuel screw is set by engine demand rather than a set amount (which is why the screw is adjustable). I set mine by warming the engine up and quickly open/close the throttle and adjust the screw in/out to get the best response (sometimes a 1/4 turn rich after that is somewhat better).

Jon

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many thanks jse. pulled main jet to find a 118 replaced with the 120, fuel screw now at a more sensible 3 turns out. 1st impressions are good, throttle is far crisper, i think the 120 suits our cold thick air here in scotland, will get a better idea at the weekend :thumbup:

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many thanks jse. pulled main jet to find a 118 replaced with the 120, fuel screw now at a more sensible 3 turns out. 1st impressions are good, throttle is far crisper, i think the 120 suits our cold thick air here in scotland, will get a better idea at the weekend :thumbup:

Each engine is a little different and although most bikes seem to be happy with a 116-118, yours may need a 120, especially in the area where you ride. If it runs a little rich in the mid-range on the 120, you can probably drop the needle down a little to clean it up.

Jon

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  • 2 weeks later...

A #120 in a PHBL should be slightly rich in most cases. To start with, I'd pull the carb and do a jetting map, recording what exactly is in your carb, rather than assuming and that way you would have an idea of where to go. If the knocking is at partial throttle (most of us rarely ride at full throttle), raising the needle might solve the problem.

The fuel screw is set by engine demand rather than a set amount (which is why the screw is adjustable). I set mine by warming the engine up and quickly open/close the throttle and adjust the screw in/out to get the best response (sometimes a 1/4 turn rich after that is somewhat better).

Jon

hi jon, thought i would let you know that your initial recomendation was the right one :thumbup: i put the 118 back in and lifted the needle 1 notch. much better knock gone. many thanks :icon_salut:

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