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Discussion Starter #1
I just got my first sled, 97 polaris ultra spx. the bottom end was just rebuilt and the top has good compression on all 3.
it starts fine and sparks on all 3, idles fine.
when I take it out to test it, I pin it it takes off really fast and will do 100mph no problem without letting off the throttle. but if I let off the throttle and try to punch it again it doesent get any power and only stays at around 6000rpm and somtimes looses speed. it will do this until i almost come to a complete stop then it will go to 100 again as long as I dont let off.
It doesnt really sound like its bogging. I cleaned the carbs and the plugs look good.
the oil throttle is turned up a bit (by the guy I bought it off because of the new bearings etc.)
also the exhaust leaks at the gasket on one cylender and its spitting out a little oil. could this be a problem?
I also checked the chokes and they seem fine.
any sugestions?:dunno:
 

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Does this happen only after a high speed run, or will it do the same after normal driving?
If it's like my ultra touring, there is an exhaust temp sensor on it, and if the exhaust temp is too high (like after an extended WOT run) it will do funny things to the engine to try and bring the temp down.

It also could be one of the carbs is icing up.
 

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Discussion Starter #4
it does it all the time. from a cruising speed ill try to get on it and it just wont get any power, but if im stopped or goinng really slow it goes good all the way to 100 unless i let off and give it gass again. i dont think the carb is icing up because i was testing it right out of my buddys shop and doing some runs in the field.
 

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you definatley have clutching issues check clean and service your clutchs check for broken springs worn helix, and worn out secondary pucks/rollers any motor can have all the power in the world but if your clutching isnt right you wont go anywhere!!! good luck
 

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Discussion Starter #6
Still new to sleds but if its clutches wouldn't it still rev high? Because when the problem happens it will only rev to about 6000 rpm then just decrease.
Thanks
 

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if your secondary is sticking open it will cause the engine to lag simple because there is to much belt deflection causeing the belt to slip!!! i had this problem when i did the clutching on my f7 i cleaned and tightened the secondary and the problem went away
 

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I agree. I have the same sled, and had the EXACT same problem last year. Serviced the clutches.........then HANG ON!!!!!!!
 

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yepper I agree with F7, check the clutches, also look at the belt, I worked on an XLT for a guy this fall that would not move from a dead stop, and when you did get it moving was real doggy, but the engine sounded fine, put his spare belt on and it ran like a spotted dog.
 

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Discussion Starter #11
bang on!
I took the clutches appart and found a grimey stickey mess cleaned them up really good and now my sled is running great!!!

thanks guys!
I feel way better and get to do my first snowmobile weekend this weekend.
thanks!!!
 
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