Time to freshen up top end, have a few questions

[Puma]

I noticed oil some oil by the base of the cylinder where it meets the case, did some checking and found its spitting air from there and my compression is only 80psi (never checked it before, may have been this low the whole time). So its time to do the top end. I have no previous history on this quad so I have no idea if its ever been apart. It does start right up and runs decent but havent rode it since I noticed the leak.

First question: Once I tear it down check the cylinder and piston, if nothing is scored and if piston to wall clearance is fine (I do have the proper mics and bore gauges to measure this), would I be fine with a quick hone and new set of rings or is re-ringing a waste of time? I would rather do this and save for a big bore kit or send it off to Ken for a full port but thats just not in the budget at the moment.

Second question: If I need to bore it, Wiseco offers a top end kit with gaskets and wrist pin bearing, how is the quality of the gaskets in that kit? I have read here that certain base gaskets are known for leaking, not sure if this is one of them.

 

[Larry's Shee]

Any indication of leaks at head? Have you done leakdown test? As to your ??, yes. If you are well within service specs should be fine. If you are getting near limits and have cast piston you may be on thin ice. As to gaskets, had greenies on the shee , no problem, don't recall on blasty. Just finishing up the shee with weisco gaskets, they look good to me.

 

[blasterdemon7]

You sure you did the compression test correctly.? I would think at 80psi, it wouldn't even start. The factory Yamaha base gasket seems to be the best.

 

[super noober]

i wouldnt run anything except cometic EST gaskets personally but guys have good luck with oem also..

 

[blasterdemon7]

i wouldnt run anything except cometic EST gaskets personally but guys have good luck with oem also..

Heard that's a good one to.

 

[slickerthanyou]

I noticed oil some oil by the base of the cylinder where it meets the case, did some checking and found its spitting air from there and my compression is only 80psi (never checked it before, may have been this low the whole time). So its time to do the top end. I have no previous history on this quad so I have no idea if its ever been apart. It does start right up and runs decent but havent rode it since I noticed the leak.

First question: Once I tear it down check the cylinder and piston, if nothing is scored and if piston to wall clearance is fine (I do have the proper mics and bore gauges to measure this), would I be fine with a quick hone and new set of rings or is re-ringing a waste of time? I would rather do this and save for a big bore kit or send it off to Ken for a full port but thats just not in the budget at the moment.

Second question: If I need to bore it, Wiseco offers a top end kit with gaskets and wrist pin bearing, how is the quality of the gaskets in that kit? I have read here that certain base gaskets are known for leaking, not sure if this is one of them.

As stated if specs are all good and all looks good no reason not to re-ring, but for sure use an oem base gasket or cometic only! And leak test that bad boy when ya have it all together!

 

[Puma]

Thanks for the replies everyone!

No I havent done a leakdown test, but I definitly will when is goes back together. I found the leak by letting it idle and spraying soapy water around the base, definitly a large leak. But didnt check the head, seems dry around that. Confident I did the compression test correctly, held the throttle open and kicked it over about a dozen times and that was the highest point the gauge went to. Did the same thing a couple more times, same result.

 

[blasterbogger]

Slickerthanyou : I have a Namura base gasket dat im running right now and its doing just fine?