concours
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- Dec 29, 2011
- Messages
- 8,551
worntorn said:LEN, I had it in my head that the factory fitted 260 mainjets to my Commando (mk3 850), however I was mistaken. 230s were fitted, according to both the Shop manual and the Riders manual. I see from an old Polk Cycle bill that the previous owner had them changed out to 260s, which work great on this engine.
280s are getting pretty large tho, a long way from standard issue, could be on the rich side at higher elevation.
If your carbs have drains on the bowls, then the main jets can be changed thru the drain holes. An 8 mm 1/4" drive deep socket will reach right up in there and do the trick.
It is possible your bike will pull better with smaller mainjets. When running too rich or too lean power drops off considerably.
Or you could just put a single Mikuni on there and make it into a Grampa bike! :mrgreen:
Glen
Remember that intake restriction will have a PROFOUND effect on jetting, so depending on which air filter(s) you choose to run, the jetting will change.