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Discussion Starter · #1 ·
so yesterday me and a friend decided to give ridin a try again. went to a ATV/UTV park this time. we rode fairly hard for.. i would say maybe 4 hrs. took maybe 5 breaks and let everything cool back off. when i say riding hardish its -25mph most of the time but is mountainous riding. near the end of the ride i stopped to talk to him a second and it just died. no clue why and wouldnt start for all i tried. let it cool for 20mins because it was rather warm. then tried again to no luck. pressure out the exhaust seemed fine. checked the oil and it had none on the stick... when we started the ride it was almost full. the crankcase breather is blowing out oil. not a ton but its a drip drip. and when you get on it a bit it blows a fair amount out. we were able to get a Jeep to jump it off (it died tryna get it to start) and then it started right up. got it back to the trailer (it had blown oil all over the place when we got back. i shut it off and then we i went to load it it started fine again.. the motor was rebuild im gonna say i think 300 miles ago. i just added the HMF exhaust. the jetting is not 100% perfect but will run 63, doesnt bog on top end, has one place were it blubs a bit but i think it is on the rich side. is this a motor issue or jetting or what? thanks for any advise. edit my vent does not go inside the airbox. it is zip tied to the CVT exhaust tube.
 

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these motors make a ton of crankcase pressure as they have almost a 4" bore...if you don't vent the case and have a return it will puke all over,I run two vents on my 660 motors as the oem vent is thru a bearing on the countershaft and is only a 3/16" hole!!...way toooo small, I vent it and the intake valve cover to a 1/2" hose that runs uphill so it can back drain into the motor and then to an up hill filter/breather...so doing eliminates the crankcase pressure on these motors tremendously!....helps to stop leaks too from gaskets and seals....no crankcase pressure makes a happy motor...
 

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Discussion Starter · #3 ·
oh, so you think its just pressure in the case and no real issues? if thats the case then how do i go about making the vents i have better? i cant add new vents if i have to cut holes in it somehow
 

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these motors make a ton of crankcase pressure as they have almost a 4" bore...if you don't vent the case and have a return it will puke all over,I run two vents on my 660 motors as the oem vent is thru a bearing on the countershaft and is only a 3/16" hole!!...way toooo small, I vent it and the intake valve cover to a 1/2" hose that runs uphill so it can back drain into the motor and then to an up hill filter/breather...so doing eliminates the crankcase pressure on these motors tremendously!....helps to stop leaks too from gaskets and seals....no crankcase pressure makes a happy motor...
hello camshaw. been reading an old post about venting 660 motors. I would like to do the same. Do you have any pictures?
 

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hello camshaw. been reading an old post about venting 660 motors. I would like to do the same. Do you have any pictures?
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