Bogging 500 Carb

"Dear Ralph" December 27, 1997 0
Dear Ralph, We seem to be having a problem with our Polaris 500 carbed machine as it bogs down rather often. After he rides...

Dear Ralph,
We seem to be having a problem with our Polaris 500 carbed machine as it bogs down rather often. After he rides for a while it seems to bog down very often. I have had the sled back to the dealer three times now and they’ve been adjusting the clutches, and the last time when I picked the sled up they said that they had adjusted the motor mounts. My son rode it for another 100 miles and he said that it is still bogging as much as it ever did. This son is 15 years old and has been riding since he was 8 years old and does have a fairly good understanding of the machine. My XLT Touring hasn’t had aby problems, and one of my other sons XCR SE has worked fine, but the 500 Carb has us wondering. I would appreciate any ideas or suggestions.

Patrick Maillett

My first reaction would be that the carbs are not synchronized, or the secondary clutch is ending up in too high of a gear ratio for the engine to pull the load, causing the bog. First, verify that the carbs are synchronized, then let’s get into the secondary clutch. Check the belt “ride-in”; the belt should be riding about 1/8″ above the top of the sheave of the secondary clutch. If it is lower than this, you are in “too tall of a gear” that could contribute to the problem. Check the belt deflection, as this could be what the dealer was tryiong to fix by adjusting the motor mounts. Place a straight edge across the top of the belt from one clutch to the other, and measure the amount of “flex” in the belt. The belt should be deflect about 1 1/4″ with 10 pounds of force. It is possible that the secondary could be too loose, allowing an upshift to occur at the wrong time. It would be a good idea to try a different Polaris red secondary spring in hole # 2, as springs do vary and the one in the sled could be weak compared to what it is supposed to be. Then again, it would be wise to verify the gearing in the chaincase – maybe someone has made changes to the gearing in an attempt to get more top end out of the sled before you got hold of it. Verify that the helix is a straight 36 degree, someone may have made changes here in an attempt to get stronger upshifting. It could also be something as simple as the secondary clutch being dirty, and not backshifting like it should. A good dis-assembly and cleaning should eliminate this. If the buttons are significantly worn the clutch would also act like it was in a taller gear.

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