OK, my 700 was burning coolant big time, and turning it over with the radiator cap off could get you splashed. It had been having an over heating problem, I bought it last fall because the previous owner was frustrated. I've been trying to get it up to snuff, replacing the rear axles, and now this.

So, I bought a new head gasket (and valve stem seals), took the thing apart. The old gasket's surface was flaking big time, but other than that I could not see an issue. Using a feeler gauge and straight edge, I could not get my smallest .0015 blade in anyhere on either the head or the cylinder, so I'm satisfied there's no warpage. Some cross hatching could be seen on the cylinder walls.

I cleaned everything up good, replaced the valve stem seals, and proceeded to reassemble. I did not have the "Primer-N" that the service manual calls for to lube the head bolts, but used motor oil to coat the threads and under the head of the bolt. Torqued them to 63 ft/lbs in the prescribed pattern - first to 30, then to 50, then to 63 (not loosening them, each time just going tighter).

When reassembled, the thing leaped to life, very gratifying! Took it down the driveway, and she started smoking white again. Brought it back to the barn, shut it off and swore a bit. A little while later, started it again, at idle it was fine. Under load, it starts to burn coolant again.

So, I clearly made things better, But.

1) Is the use of motor oil instead of the Primer-N an issue?
2) Is my technique faulty?
3) Is it worthwhile to try to retorque the head?
4) Do I get another head gasket?
5) Is there a better aftermarket head gasket?
6) Is it time to bring it to a machine shop?

This thing is sooo close to being perfect, I'm really getting ready for the summer, just about there.......

 

The motor oil should be fine , my Polaris service manual says to tork head to 35 lbs + or minus 4 lbs then turn an additional 90, 1/4 turn in sequence, might get another gasket and try again, thats a bummer.

 

Interesting your service manual says different. Here's what my manual says -




Before reassembly, clean the bolts and bolt holes with Primer N (PN 2870585) to remove any debris. This

will ensure proper sealing when installing bolts and new Loctite.

 

Is it possible that an oil seal or water pump seal failure could also cause it to burn?? I know mine was going thru coolant, and the seals went bad but no head gasket problems. I know usually if you are burning that much thru the exhaust it is the head gasket but I thought I would at least throw that out there...

 

i was wondering that too, or maybe a bad base gasket.

 

New seals on both crank and oil pump shafts, and new water pump mechanical seals. Base gasket is original, AFAIK.

 

Is the inside of your muffler and head pipe still coated with coolant from the previous head gasket being bad?may have to get your machine good and hot to burn all the coolant out of the exhaust .We have run into that before.

 

Good thought, but I think it's still the head gasket, it tends to bog a bit when the problem reappears.

Here's my plan of attack -

1) Try a retorque. I don't expect this to work, but what the heck.
2) I've ordered a new gasket in case that doesn't do the trick.
3) If 1 or 2 doesn't do it, Bar's Leak is gonna get a crack at it.

 

Final update:

I was installing the second new headgasket, and while thinking about it, I decided as long as I had the head off again, I'd take it to a machine shop (our local NAPA has one). $100 and 2 days later I got what looked like a brand-spanking new head, the machinist said it was about .008" out of flat (book says .004" limit), I guess my starightedge/feeler gauge technique leaves something to be desired.

Anyhoooooo, slapped everything back together and she roared to life, and everything seems fine. I haven't had it on a serious ride, but I've been zipping around my property for a few hours with no problems. I'm one happy camper!

 

Glad to see you got things worked out. It always seems like there is some kind of trial and error when working on my own stuff too.