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Discussion Starter #1 (Edited)
I have a 1992 Yamaha Exciter 570. I was wondering if this sled should have the decompression cable? I thought I remember these sleds having this when they came out in the late 80's? I tried doing a compression test but I've read that you should have the throttle wide open is this correct because I'm only getting 90 psi on each cylinder but this sled had sat for 4 years and pulls over hard so I'm debating on rebuilding the motor. Any help would be greatly appreciated.
 

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90 lbs is low. I don't know if they had a decompression hole in those or not but I would doubt it on a 570. It's not until the 800's that they got serious about them. I would run it some first get it good and hot and then check the compression. It's probably even lower than 90. Also, after you do put some oil in one cylinder through the plug. About a teaspoon of injector oil works fine. Check the compression then. If better then you have worn rings. Do both sides like that and report back. A borescope can look in there too and see the condition of the piston and cyl walls. Lots of those work with cell phones now too from ebay.

Steve
 

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If you dont see a cable from the cyl then no
Try putting an oz of ATF in plug holes and work it over good to unstick the rings
Dont remove but pull up on belt till it goes into rear sheave (helps reduce drag on crankshaft)
After a few days of working rings loose, test again, 10 hard pulls with throttle wide open
 
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