Found my oil leak - cylinder gasket
 

Finally found where my oil leak is coming from - see photo. Right at corner where cylinder gasket is. Pressure builds, air leaks out with oil, then pressure builds again. I want to check the torque on the bolts but can’t find them on this side where clutch cover is. Parts diagram show 2 bolts on other side.

Any idea where to look for the bolts? 1999 Magnum 500

2 of the 4 head bolts are on this side. Have to remove the rocker cover to access them.Not normally an area that would leak if torque sequence was followed correctly,but anythings possible. Trying to stop a leak now may be tough,but first thing is make sure the crank case in line filter and the hose isn't blocked and you can feel crank case pressure from the hose in the air box. Going back through the head bolt torque sequence many or may not help at this point,may take a new base gasket to solve it,but here goes from scratch:

Tighten the four larger bolts in a
crossing pattern evenly in the following steps. Mark
a line on the large bolts for a degree reference:
a. Tighten to 30 Nm (22 ft.-lb.).
b. Tighten to 70 Nm (51 ft .-lb.).
c. Loosen each of the four bolts exactly 180'
( 1/2 tum).
d. Loosen each of the four bolts again exactly
180' ( 1/2 tum) .
e. Tighten to 15 Nm ( 11 ft.-lb.).
f. Tighten each of the four bolts exactly 90' (1/4
turn).
g. Finally, tighten each of the four bolts exactly
90' (1/4 turn) more.
9. Tighten the two small 6 mm bolts *
to 8 Nm(71 in. lb.).

*There are two 6mm bolts visible(after you remove the cam sprocket cover) that tie the head to the cylinder and two 6mm bolts from the cylinder to the engine case.

Got it - thank you as always. Will save for a weekend project.

My 1998 sp 500 leaks some in the same area- great idea to check the crankcase vent, that will be on my list. I tried JB weld on the seam but must have missed the leaking area. I checked the valve lash earlier this year, but didn't check all those bolts then. I took the front rack, plastics, handlebar and gas tank off, which was a fair amount to get to the valve cover.
Is that the best way to check those bolts or is there a better way?
Thanks!

You don't have to go to all that trouble of removing all the plastic and tank. Just lift the rear of the tank enough to where you can get to the valve cover bolts. Once the valve cover is off the head bolts are easy to get to.

Huge relief! Thanks for the experienced help again! I hope either possibility of vent or bolts is the fix for the leak!

Appreciate it!

I followed all the steps, but still have the leak. It's very minor - should I just ignore it for now?

Can I replace the base gasket without pulling out the entire engine?

ENGINE
EH42PL/EH50PL Engine
Removal
The following components can be serviced or removed with the engine installed in the frame:
• PVT System
• Flywheel
• Alternator/Stator
• Starter Motor/Starter Drive
• Camshaft
Rocker Arms
Cam Chain and Sprockets
Cam Chain Tensioner and Guides
• Cylinder Head
• Cylinder
Piston/Rings

If it's just a small leak I'd just check oil level until you have a good time to work on it.. Plus by then you might want to check the piston/rings,valves for leakage,ect while you have it torn down.

Thanks again

Sorry if this is a dumb question - but can't I just pull the bottom cover off to get at the base gasket? Or do you have to tear down the entire engine from the top?

Nope,gotta go from the top down.. Get a manual before you start.Polaris ATV Service Manuals PDF Download

Thanks for the link OPT.

Ok - I’m tearing down the engine. Problem is that the cylinder won’t budge. Removed the 2 screws for the oil line, head bolts, and 2 screws on the flywheel side. What am I missing? Don’t want to break anything.

If you have the head removed along with the two 6mm bolts on the cylinder,it may take a little tapping with a dead blow hammer all around it to help jar it loose while you're pulling up on the cylinder. After being on 18 years the cylinder may take a little persuading.

What about applying a bit of heat?

Silly question, can it be tapped from the side of the head?

When separating head or cylinders, the gaskets tend to adhere to the adjoining parts and often require a certain amount of force. I always try to hit with firm, deadblows to reinforced areas and try not to hammer on the sidewalls to prevent any damage. Try hitting right beside where a bolt would be and should feel it start to loosen.
​​​​​​It would take a fair amount of heat on aluminum to do much and should not be required if all bolts are out. Its a bit of knowing and sensing how much force to apply to prevent damage and get the job done.

I bought a deadbolt hammer, and could not get it off. After so much pounding I ended up cracking the cylinder. Which is fine because I’m looking at a rebuild kit that includes a new cylinder. Still can’t get it off though.

That's too bad about your cylinder. I would suggest next time to check and recheck if things on motors are not moving after a couple firm taps before applying much more force. It's a learning process to get a sense of what force to apply to different materials.

Also, did you remove the cam hold down/caps, cam, chain and chain tensioner?

Isaiah

Entire head was removed with no problem. But cylinder won’t come off. I’m worried I now have to pull the entire engine out. Don’t have a flywheel puller - way too much $$$ for a one time job. Was trying to remove cylinder with engine in place. So hard to access all the places where I can hammer.

Did you download the manual I listed? If you didn't sounds like you didn't remove the 4 bolts INSIDE the cylinder water jacket along with the two 6mm bolts. Manual shows disassembly step by step with the bolts pictured. Good way to crack a cylinder if you didn't.

4. Remove the two 6 mm cylinder base bolts.
5. Loosen each of the four large cylinder base bolts 1/4 turn
at a time in a criss-cross pattern until loose and remove
bolts.
NOTE: The bolts are inside the water jacket.

Oh crap. Yes - I have the manual, but I missed the 4 bolts in the water jacket. For crying out loud - I’m cursing like a sailer. OPT - u saved the day again!
... back to work...

If you cracked the cylinder I didn't exactly save the day for you.. :rolleyes: Oh well you said you were planning on replacing it as a kit..

I don’t have the 12 point socket to remove it tonight, will buy one tomorrow. But I’m going to bed knowing how to solve the problem. Replacing the cylinder is a small price to pay compared to pulling the entire engine to then realize my mistake.

The kit I’m looking at has a new tensioner plus the cylinder. The chain slipped again - so I’m assuming it’s the tensioner. Timing was not off, but chain was lined up the way I had set it before.

If you're going to all that trouble order a new chain. Especially if the chain feels the least bit loose or the tensioner is all the way out.

That's what I was thinking too. Chains stretch over time and it would be easier to change it now than to go back and do it later.

Will do. Thanks again.

Can you remove the chain without having to pull the flywheel?

Nope gotta pull the flywheel. Not that big of a deal as you can rent a harmonic balancer puller at most auto parts houses for a small refundable deposit rather than buying one if you wish. Mark the stator plate and case with a pin punch even if you may have marks on it anyway. This makes sure you have stator timing correct when you reinstall it. Make sure the lower crank sprocket is tight. Left hand threads on the slotted nut holding it in place on the woodruff key so be careful.Just a simple tap with a punch and hammer to make sure. Look at the manual carefully as it shows how to time the chain up correctly with the plated links. Look at these pics that a member took when he timed his up. One plated link on the lower sprocket mark,two plated links on the two dots on the cam sprocket.https://atvconnection.com/forums/pol...ml#post3305250

I found a video on using the balance harmonica - is there a better way to hold the flywheel in place than a strap?

Puller is ok but you need an air impact or you won't get it off. Look at this video on a 700 engine in a dune buggy. Similar to the 500 and shows how snug flywheels are on these tapered shafts.Need that air impact. Look starting at the 2:45 mark.

That’s what I thought. Need another tool. Will have a good collection when I’m done.

Yup - torque wrench is the only way to get the flywheel nut off. Popped right off.

Back in business - just need to wait for the top end kit to arrive, along with some other parts like the chain. Need to finish the engine disassembly, and can then start to put it all back together again.

Hoping for no more surprises....

Always expect the unexpected. Read the manual slowly and follow each step.

Next challenge - flywheel won't come off. Broke the bolts on the tool. The rental place won't be happy. Now what?Attachment 28164

For one thing thread the bolts a little deeper into the flywheel without touching the stator. You can get a grade 8 8mm flange bolt at most hardware stores to replace the broken one.

I bought new high grade bolts, the one with the tool were low grade. Still not coming off - I'm worried about apply too much force and breaking something. Is a torque wrench ok to use?

While you have pressure on the flywheel,apply a little heat from a propane torch around the crank shaft area then use an air impact like shown in the video I posted. If you have enough pressure on the puller sometimes heat alone will cause a flywheel to pop right off. Plus looks like you have the flat piece on the puller. Remove it to where you have the tapered end of the puller bolt against the shaft.

Sorry - I meant impact wrench, not torque wrench. Will try this soon.

I assumed you meant impact wrench on post #33 too. You could wreck a torque wrench using it to unscrew nuts or bolts.