different main jet

[scottsgs]

Hi all,

Whatwould happen if I go from a 115 main jet to a 125? would it be too rich?.

Thanks,
Scott

P.S. It's a stock GS850G except for V&H 4-1 exhaust.

[chef1366]

Maybe..............
Is it lean now?
With the 4-1 I would guess a 122.5 or 120 might do ya. If you had a K&N flter in the box I'd go with a 125.
You know you are rich on the main if it runs better before warm than it does when it is fully warm at WOT.

[psyguy]

i run 115 and the plugs read ok

[snowgoose]

Like most carb mods its always a bit experimental, so you really need to assess where ur at now with the 115. i.e. plug read and chop at different RPM ranges will confirm rich, lean or in between. Prolly better to be slightly rich tho than lean keeping in mind that the main jet really only comes into play in the mid to upper rev range. Hence the importance of checkin plug colour immediately after flickin the kill switch at these ranges.

No point whackin in larger jets without a benefit, in fact could actually dampen your HP and increase your fuel consumption. You would then need to consider stage 3 kit with pods. Hope this helps.

[Steve]

115 is stock on the 850. On my son's bike, the PO had 120s in there. The manufacturer of the pipe is unknown. Carbs are not yet fully dialed in, but the 120s seem to be just fine.

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