Hey guys I know this isn't a snowmobile forum but I'm not a member of any and I just have a quick simple question for you. I just bought a 1990 Indy 500 really cheap but it really has a bog and doesn't even want to hardly move. It was just rebuilt a few years ago. I checked compression. Both cylinders are right on at 135. The guy told me the fuel lines and fuel pump was just replaced too. I haven't checked spark plugs yet but planning to do that next. Just curious if that's not it what are some other things to check. Thanks.

 

wow you into a whole much of 2 stroke things to check. depending on if the carb is clean and the float is set right and you have the right air screw setting and the right size jets for the temp. and the attiude your at. not to mention the p85 primary clutch(i think it is the 85 or maybe the 91) might be worn out and dier need or cleaning or a rebuild w/ weights and bushing. there is some good info for you to start with.

 

Yeah I was thinking about taking the carbs off and cleaning them out real good. Altitude and temp shouldn't be the issue since I bought from a guy in the same town I live and that's where the sled has been for at least the last several years as far as I know. I don't think it's the clutch either because it just seems that the engine is making the power to get the rpm's up. It's kind of hard to keep it running too. Well, I'll dig into it more tomorrow and see what I can find. Thanks for the reply.

 

I have lots of snowmobile back-ground and I would start with your main jet and pilot jets.......Check the carb bowl also and spray it with carb cleaner ...this is where the yellowish gum gas forms and can slowly break away causing it to plug-up the jets.............keep us up to date with this..........caper.............

 

Check belt condition and deflection,very important on this model.

 

I know the belt is almost new. This is a probably a dumb question but what do you mean by belt deflection?

 

its how the tight the belt is. if you put a staright edge across both clutches w/ the belt sitting where it belongs(at about 1/8" above the secondary clutch) you should not be able to push the belt down in the middle more then 1 1/4" + - to be good. if the sled is not running right then start w/ the carb. i would take it all apart so you can make sue you clean all the passages out not just the jets. the idle circuit is very important as well if it wont idle.

 

clean the carbs real good, check the choke plungers make sure there not sticking
(I had that happen to me on a sled) & make sure the plugs are not fouled.

 

Well here's what I found so far. One of the plugs was bad so I replaced both. After getting it running and the track up off the ground I noticed that it was idling high enough for the clutch to be engaged. Belt deflection is good and is sitting about 1/8 or so above secondary. I adjusted the idle down so the primary wasn't engaged. There still seems to be a lag right when I hit the throttle but as soon as it gets up to 4000-5000 or so it revs really fast like it should. Still haven't had a chance to clean the carbs out but that's my next project. Another question I have though is what rpm should it idle at and engage at? I mean for a stock machine. I know you can tune them however you want but I'm just curious what they should be at from the factory. I'm wondering if maybe the spring is worn out. I'm not even sure if they do wear out or just break when they go bad.

 

somebody can corect me if thisnt it but seems like it was 1250 rpm +-200 rpms.i still would clean and then sync the carbs to rule that out.