1991 Polaris Indy 500

[jrambler]

Just bought a '91 Indy 500 for $500. Its in great shape with just 4000 miles. Sled starts easily and runs great. Only problem is that after it sits running for a few minutes, it drops to a low idle speed. It will idle there forever. The problem is when I try to pull away, the thing acts like it loaded up and won't go. I have to give the throttle a bunch of short taps and eventually it cleans itself out and revs up and works great again. While riding its very responsive.

I have thoroughly cleaned the carbs, new fuel, new plugs. After these things, it got better but still has this annoying hesitation.

I have been reading many posts about Mikuni carbs and synchronizing and jetting etc. I am looking for a link to an exploded view of a Mikuni carb. Most guys talk about the needle jets, various adjustments, but I'm not sure which is which.

Compression test was done and its 125/cylinder.

Any ideas?

Thanks

[sportnut]

This is just my experience with Polaris. Me and my brother both bought 2000 700xcsp new both machines would "load up" while warming up more so when it was warm out above zero. After about 300ft they would clean up and run flawless. Both machines went back to the dealer we thought the oil injection was pumping too much oil. They checked both machines and said they were where they should be. Both machines ran Polaris brand oil so searching for answers I talked to an Amsoil rep he ofcourse reccomended his oil . A bit sceptical but willing to try anything I switched the machine over to Amsoil "racing" formula . It worked !! My brother still run Polaris oil and both machines are getting close to 5000 miles neither has given us any grief mine just doesn't load up on warm up his does. Hope this helps!!!

[Matt]

I found the same thing. I bough a gallon of Polairis injection oil when I first bought the sled, and it seemed to run rich on oil, not to mention the smoke was pretty nasty.

[oldslednut]

That amsoil is good stuff i run it in my truck and sleds, what made me a believe in it was my kx500 dirtbike always fouled the plug, tired hotter plug just lasted longer, then one day i was at the track and a guy was mixing amsoil i talked to him about it and my troubles i was having with my kx500 well i drained my tank dry bought a gallon of mixed from him and i about pooped myself better power ran much much cleaner,, and not less than 3 weeks later i crashed that thing so hard ditch banging i ended in the hospital with a broken jaw, and i am glad i had a full face helmet on or **** i would probably not be here, so two things, dont be scared to run amsoil its good stuff, and always wear a helmet!! THANKS