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Discussion Starter · #1 ·
Working on a rhino 660 for a customer of mine. Came to me not running cuz they thought they broke timing chain. Found out it had stretched too far and jumped timing then fell off lower gear. I replaced timing chain, center valve that got bent and went a half size over on bore. Couldnt get it to pump any fuel so had to order a fuel pump as well. Finally got her running and its acting up. Other then being a half size overbore its completely stock. Seems like if it sits for awhile and cools off it will run "ok" untill it gets up into higher rpms, then just falls on its face and starts sputtering and backfiring alittle. Once it gets warm it wont run right at all. I've cleaned carb and its clean and all jets and passages are clean(used to work at RAGE ATV so I know how to properly clean a carb). It seems to be running super lean as I took duct tape and blocked off 3/4 of the snorkel tube off airbox and can get it to rev decent at idle and it will run alittle better for alittle longer when driving. I've played with the needle and going as rich as possible with clip and moving washers around seemed to only really make it worse, which makes no sense to me. I personally have a rhino and am gonna pull my carb off and swap it to his rhino to see but for some reason Im leaning towards stator or something else electrical. This has been a ongoing problem for a few weeks and is just getting worse. Forgot to mention that after i rebuilt motor it ran "ok" and then next day it started acting like it was hitting rev limiter but still ran "ok" and its just slowing getting worse, which is the reason im thinking stator. Any ideas????
 

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Discussion Starter · #3 ·
jets are stock, cant remember what they were but it had never been touched till I opened it up. I've tried screw from half turn to 3 and half turns and didnt really seem to affect it. Just seems like pilot is extremely lean and main is extremely lean now but its completely stock besides the half size bore
 

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Maybe the cam decompression pin is set up wrong... there was another guy on here with the same issue post rebuild, and it turns out his decompression setup was 180 degrees off (ie: little nub was out when the weights slung out).
 

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sometimes its a dumb lil simple thing we over looked, what sucks is u didnt hear it run b4 u tore it down to ,

do u need fatter jets maybe 55 pilot 152.5 main , bigger piston burning a hair more fuel maybe
 

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Discussion Starter · #14 ·
ya i wish it had ran or something cuz now i got a case of the owner saying it didnt do that before and just dont think thats possible. Its a side-job so wont be till in the morning that i can get back over there
 
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