Sha35297

Thank you for the input. It does have a copper gasket in it that I had replaced the first time I tore it down. I could try replacing it again to be sure its not the issue. While its running I cannot see or feel any combustion coming from around that area though. I've had exhaust leaks before that did not sound like this. That's why it has me stumped so bad. I feel like I have tried all of the obvious things multiple times and have become sort of blind to being able to see past what I know I have already done. Was hoping a fresh set of eyes or thoughts on it would trigger something new. I am attempting to upload the video again a different way. The one I have already uploaded plays on my computer, but will not play from my mobile device on the website. video-1611872782.mp4

This is the header. I'm not seeing anything abnormal about it.

Just removed the rear crank case cover again. These are the pics of inside. I used a screwdriver to verify piston was at TDC. All marks are lined up.

Ok, With the Stethoscope it seems like the noise is loudest in the valve cover. What is strange to me is that I have replaced the whole top end with another one from a bike that I know runs good with no issues. So what would cause the same noise to be in the valves on both cylinder heads? Also, after listening better to the timing of the sound. It is in sync with the exhaust not the piston. I'm going to pull the crank case cover again and check the timing one more time and post pics of the inside to post.

Hello Mech, Thank your for responding. So, I did test ride before doing the repair and this particular sound was not there. The original noise was a rubbing sound on the rear crank case. After replacing timing chain that noise went away and this new sound appeared. Noise is not apparent at idle on cold start or when warmed up. It starts at about 1/4 throttle and speeds up and slows down with the rev of the engine. Seems to be at the speed of the piston, not speed of the valves. Piston Pin fit is good. I've tried using a screwdriver to pinpoint the location. Seems to be more prevalent on the exhaust side, but hard to tell if its crank case or top end. I bought a stethoscope to try to pinpoint the sound better. I'll update on that when I get back in the shop.

Hello, got this bike in to replace the jug and piston. Made the swap, crank looks good, no play in connecting rod. Put it all back together and then heard a rubbing noise in the rear crank case. Ordered a new timing chain and tensioner. Installed them and put it all back together. Fired it up and ran great on the work bench. Took it down and went for a ride and noticed the higher the rpms, the noisier it got. There was a tapping noise on the exhaust side of the valve cover. Removed valve cover. Checked valve clearances, all good. Checked the valve springs, the were a good bit out of tolerance. Installed brand new springs. Same noise. Decided to replace the whole cylinder head with one from a known good bike. Still the same noise. Decided to replace the camshaft with one from a known good bike. Still makes the noise. Replaced lift caps. No change. I’m at a loss on what could be causing this noise. It’s very loud and not normal by any means. Any suggestions would be appreciated. Video doesn’t really pick up the noise good, but it’s there. Thanks IMG_2225.MOV

So, I got this 07' Polaris Outlaw 90 in the shop to rebuild top end and transmission. Replaced all bearings and gears in the transmission. Replaced cylinder and piston with brand new parts. Put the engine back on the frame and fired it up. Started great, but had a taping sound in the lower crank case. pulled the flywheel cover off and found the flywheel was wobbling and hitting the stator. I then replaced the stator and flywheel with brand new parts. Timing is all set on the timing marks now, but when I turn it over it kicks back when it fires and ends up stripping the starter idler gear. I've replaced the starter gear once already and now have to replace it again. Is it possible that the timing marks on the flywheel are off or maybe this flywheel is not for this exact model? Thinking of advancing the timing to try it, but don't want to keep going through idler gears.

Hello, Just wanted to give an update. I found a couple broken teeth on one of the gears. Ordered a new one, had the correct part number, but was the wrong part. Found a used one on Ebay. Got it in over the weekend and installed it this morning. No more knocking sound. Simple fix I guess. Thanks for the help.

Mech, Thank you for the quick response. I will give it a good look over in the morning and update what I find. I didn’t even consider whims before this. Hopefully I can see some obvious wear and go from there.

It is very similar to the Polaris. When I attempt to replicate the noise by manually rotating the clutch with the crank cover off. I cannot hear the noise or see anything hitting. Here is a pic of what it looks like.

Customer brought in this bike for no response when put in gear. After getting into the transmission I found the main shaft for the clutch had been stripped where the gears mesh up and also the shaft for the gears had been broken in half. I replaced all broken parts and reassembled the transmission. Now it makes a knocking noise in low gear and in reverse. When in neutral it tries to roll reverse while making the same knocking noise. I’ve disassembled and reassembled it several times with the same result. Any ideas??