Taken care of is the problem. It has been neglected for many years, I don't even know if my father did routine oil changes, air filter, valves etc. I do know the only time a belt would be changed was after it blew up...sigh...
I have Mobil 10w40 in there right now as the manual said 10w40 for a synthetic motor oil if polaris oil is not used.
Would setting the valve clearance to .008 or some similar modification resolve this?
And is there another ideal point in the cycle to check the compression besides TDC?

 

No on altering valve clearance and no,this is the standard way to check compression on this engine.

 

the compression came to 80psi dry and 102 wet. since a substantial difference i began teardown last night. the valves looked good, just alot of black buildup and after a couple of hours with wd40 sitting above the valves a little leaks through on the intake valves. any specific way to clean these up a bit if i get the valves open?
and for the cylinder. the skirt was scaring up the bore pretty good, progressively worse towards the bottom of the stroke. took it in and had some advice from a shop that bores engines and such, he suggested to bore it out and is also a wiseco dealer so hes ordering the piston and rings for it.
if the piston was slapping the wall this would also explain some of the knocking noise i previously posted about.
Hopefully tuesday night the moment of truth will come. till then the rusty exhaust has been buggin me so thats gona get cleaned up and re-painted
I really apreciate all the advise!! and a few questions if ya dont mind
the clutch/flywheel can be pushed in and out, there's just enough to move it back and forth and hear it clunk. How concerning is this, if at all?

once again very grateful for all the advice!!

 

If the crank shaft moves from side to side then I would be very concerned! Sounds like worn crank bearings and races causing the side to side slack. Like you said, this atv wasn't maintained very well. I think it would be best to tear it down,replace the bearings and inspect the rod. Like the manual says the crank bearing races should be firm with minimal side to side play and no up and down play on the crank shaft ends.I'd be concerned that it could cause excess wear on the new piston and bore by not running true in the cylinder.As far as the leaking valves, you can clean the face of the valves of carbon build up with a drill and a soft wire brush,but won't help the seat and inside of the valves. You need to remove the valves clean the excess carbon on the inside and around the valve seat area and lap the valves back in with a fine grade valve lapping compound.Usually not necessary to recut the valve seats unless they are really pitted. On assembly you need to install new valve guide seals. This is something I'd let the machine shop do unless you want to rent a valve spring compressor and lap them yourself.

 

more stress on the pistons exactly what ive been worried about. the connecting rod doesn't seem to move when i push or pull on it. however it does move side to side like the crankshaft, and when it push on the end of it there is some movement. bearing issue here also or normal play because there is a bearing?
Races, are those the spacers on the crankshaft?
should i worry about other bearings, (seals to?) or not so as they are under less stress and there isnt play up and down on the crank bearings.
i only ask before inspection as i was hoping to take this on a trip next thursday, (even if i have to just ride around the roads breaking it in) and id like to get everything on order and here in time.
reading in the manual theres alot of shims, sugestions for them?
thanks for the guidence!!

 

having the insight, how much would the valve servicing probably cost? would this be a dealership job?

and the bearings I am thininking about All *****, they are japanese bearings and, from work i have learned how much good japanese bearings can cost.

much grattitude, Winchest

 

Every shop is different as to prices. Just ask the machine shop what they'd charge on a valve job.We averaged about $15 per valve to remove,lap, replace valve seals. Some may be higher,others lower.Crank bearing are pretty tough that come with the 500 crank.Always replace crank seals!Most crank bearings I've found on the 500 are NSK,another good Japanese bearing. If done right there shouldn't be any side to side play to speak of when the cases are reassembled.If the rod is salvageable,this will save the trouble and expense of having to pull the counter balancer gear from the crank and a new rod kit installed..

 

thanks OPT,
the conecting rod is chewed up from the wrist pin, so a new one is being instaled by the shop. As for the valves, they will also get a lapping and new Moose seals. Hopefully all the time and money put into this rebuild will make the engine last for many years. which brings up a very controversial topic-break in. Whats the best way, or conbination of ways to ensure a happy engine down the road? all i can find is drive it like ya stole it, or, pretend the piston rings are glass and don't ever put to much stress on them.
There doesnt seem to be any preferance for break in oil either, sounds like the best way to go is the stock polaris PS-4 or just the same your currently running? is higher octane fuel beneficial?

for assembling the crankcase, the manual says to pull the crank through the left bearings, i would assume until the case seals. My crankshaft has some glazing on the left side, and i was sugested to use a kind of locktite meant for sealing the crank into the bearings, to ensure they dont come loose ( the crank FELL out of the left side when i took it apart, no preassure required)

sorry for all the questions ive been doin some reasearch as i want to be confident in what im doing. i have a week or two till i get to start reasembly.

once again very gratefull for the advise

 

I'd use 0w40 Mobil1 on break in oil. Manuals just state drive it at varying speeds for a couple hrs,no wide open throttle. Stay with 87 or 89 fuel. I had the two bearings installed on the clutch end of the crank shaft ,heated the cases and seated the crank and bearings in one motion. Heated the other case half up,installed the one bearing inside the case. Use Threebond,Yamabond around the cases when they cooled,then with a dead blow hammer installed the right case over the crank.Then criss cross the case bolts to proper torque.Every mechanic has his own way of doing things.. Not every one goes by the book.

 

Humpty-Dumpty finally was put all together tonight. with valves lapped, cylinder bored and honed to 92.5, wiseco pistion and rings, new bearings and seals all the way around on the crankcase and top end. shim measured for and installed. cases sealed up with Yamabond 4, and the cases were warmed up to allow the seated bearings to slip over the crank without any harsh pounding. As everything went together, i was very generous with my oil squirt bottle, coating it all for protection as it took a few days to assemble the whole engine.
Now that it is back in the frame and completely hooked up, oil and coolant were added, and it was fired up for the first time. vent hose was clamped for first 10 secs and them released, no hiss was audible. Oil level did not drop in the reservoir. the tanks bottom screen was cleaned on assembly, and all banjo bolts etc. are to torque specs. There is no oil in the oil filter either. after trying to get some down into the crank for the pump to circulate by filling up the oil filter, i started again, pinched vent hose, and also pinched for a second the oil return to the oil tank. still nothing and a Very noticeable/concerning ticking noise came from the engine, maybe not happy without oil circulating. pulled the drain plug on the engine and no oil in there for the sump to even circulate. next idea was the one way oil valve, it has an edge that is rubbed off a bit, as if the one side wanted to be a hex nut. once removed i left the switches off and pulled the starter, and a little burst of oil would shoot out of the oil valve hole.
is this valve enough to stop oil from getting to the crankcase and the oil filter?

spending close to 5 hours a night on it has me very frustrated that its still not working right. Compression was at 110 dry, or just an oil film from assembling. Really hoping somone has some thoughts on this one. thanks everybody!!!!