Rebuild....Ring job only or all the way?

[Chips2000]

A few months ago, both my 'Shees cyls checked out at 150 lbs. Since then there have been a number of trips to the dunes and trail riding. This last weekend my son borrowed it for a desert run of over 150mi in 2 days when the right K&N fell off after about 50 mi. He said he was following a desert rail, and does not know how long it had been off before he discovered it laying in the frame. The quad had not been running right even before it lost the filter (although, early in the trip, it had good top end), and it would not do over 60mph on pavement (for about 20 mi) on the way home.

 

I did a compression check tonght, and the right one was reading 120lbs, and the left 145+. This was with the engine cold. I am planning on a ring job, and the question I have is could the injested dust effect the bottom end bearings? Is there a way to test for that? The engine now has about 400mi on it since it was rebuilt in Jan. 05. Would you guys rebuild the whole engine again or just the top?

 

Thanks!

 

Chips2000

[racer]

all the way! when youre more than 10% off its time for a rebuild. you may get ur compression back with a set of rings, but those piston skirts may be laden with internal cracks and other stress risers. plus a bore job will make sure your cylinders arent ovalized.

[csrmel]

if you ingested enough sand into the engine so that you lost compression, you can bet you have some light to moderate scoring on the crank and rod bearings, wrist pin, and the actual crank its self.

 

i would split the cases and send the crank out to be examined, and go from there. i know it sucks, but doing it now is better than doing it later when a bearing falls apart and causes the rod to be blown out the case.

 

have the cylinder miced as well. theres reasonable odds you have some cylinder scratching.

[Chips2000]

Ok, thanks for the advice. At least I got though the duning season and had a blast with it, and now I have all summer to work with it.

 

It is kind of sad as I was thinking a month or so ago to get rid of the K&Ns and install the foam filters with carbon fiber tubes and mounting bracket.

 

Chips2000

[dajogejr]

I know it's real easy for one of us to tell you how to build/repair your motor, we don't have to look into your wallet...

In the case of mine...you could hear a pin drop or an echo...

 

 

I agree...new pistons, fresh bore, get the crank checked out. IF the crank turns up good, spend a bit of money on a MX/Dune port for a little more kick.

 

A new crank costs a little more than a decent port job. Hey...you're gonna have it down the far anyways...

 

Sorry to hear about the damage...best of luck on the rebuild...