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Discussion Starter · #1 ·
Hi everyone,

I'm tackling some top end work this winter, so I figured I might as well start a thread on here to document my progress since I've gotten so much help from reading similar threads on this site.

First a little background: I bought this bike for $500 back in February of this year having never even so much as sat on a motorcycle. The PO said it just needed a carb cleaning & new battery to run, which actually turned out to be true! I spent the next 8 months doing a lot of work on it to get it running as best I could, getting my license, and riding as much as possible. I put about 1,200 miles on it over summer and spent god knows how many hours working on it. Although I have nothing to compare it to, I think it runs pretty well. No hesitating or backfiring. Usually fires up second or third kick from cold. I’ve had it up to 85 (indicated) a few times, though only very briefly because of the top end oiling issues I’ve read about. The only real issue is that it burns oil, and the compression readings are a little low (about 140 psi on both cylinders, & 165 with a squirt of oil in the spark plug hole). I had planned on doing the cam chain tensioner & rocker arm shaft recall work this winter since it was never done...so I figured I might as well replace the piston rings while I’m in there to see if that helps with the oil burning & low compression. This is my first time tearing into an engine so I’m pretty nervous, and I’ll be ****ting bricks when i go to start it up in a few months!

Here’s some pictures of my progress on the engine so far:

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Rocker arm surfaces seem pretty good?

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Cam looks good!

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Tensioner did have a crack in it, but getting replaced.

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Circle Auto part Metal Audio equipment

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Lots of carbon, and looks like maybe a head gasket leak at some point?

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I cleaned the carbon off of the pistons with some liquid gasket remover which I will post pictures of later. Also got some new OEM rings & dropped them off, along with the jug & pistons, at The Shop here in Milwaukee to have everything measured to make sure it's in spec & to hone the cylinders. I got a call from them yesterday & everything looks good so I will be picking that stuff up this weekend! Next step will be to check the valves for leaks with some acetone.

Thanks for reading! Any and all advice would be greatly appreciated along the way.
 

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Discussion Starter · #2 · (Edited)
Auto part Metal Wheel

Pistons cleaned up and back on.

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Jug back on! That was a lot easier than expected. I completely cleaned the cylinders & pistons with brake cleaner & put them together dry per the recommendation of Tim at The Shop.

Unfortunately both intake valves had a tiny leak, so I dropped off the head to have the seats re-cut & lapped. Looking forward to having this engine buttoned up!
 

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Discussion Starter · #4 ·
Progress!

Got the head back from The Shop. They cleaned up the valves, & re-cut & lapped the seats, so that's all good to go.
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I brought the rocker arm in question with me when I picked up the head & Tim said it looked like just a defect in the casting, which is common & nothing to worry about. Good news!

I was getting ready to install the head & I got paranoid about the oil passages in the upper crankcase cover being blocked, so I pulled the cylinder & both side covers to have a look. They ended up being clear, but it was worth it for the peace of mind. Plus it gave me a chance to clear out the centrifugal oil filter & oil pick-up screen while I was in there.
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Cylinder back on & head gasket sprayed with Permatex copper spray.
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Head installed & torqued down!
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Next step: install the cam. I did measure the side clearance with the cam in the head & it was about 0.25mm. Spec is 0.07 to 0.3mm, so I'm towards the upper end. I was going to replace the 1mm thrust washer that's currently on there with the 1.1mm washer, which would put me right in the middle, but I haven't been able to track one down, so I may just skip it.
 

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Discussion Starter · #6 ·
Aaaand now a setback. I realized the outer valve spring on the right side intake was upside down (you can see it in one of the pics above). Also the inner spring on the left side exhaust was upside down. Had to pull the head, which means I had to order another head gasket :( I'm pretty miffed, but I'm glad I noticed it.

Also, looking back at the pics from when I did the tear-down, it looks like both outer springs were upside down on the intake valves. That might explain why the intake valves developed leaks (valve float).
 

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Discussion Starter · #7 ·
Got my new head gasket today. I wasn't feeling too confident about the valve job after finding the upside down springs so I decided to do a quick acetone test before I put everything back together. Whaddya know, all four valves are leaking! Looks like I'll be giving The Shop a call tomorrow. Feeling pretty annoyed right now. Hoping I can get this done right, or get my money back.
 

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Well done on spotting the springs Mike, some models have paint on one end which makes it easier to spot.

I hope you get the leaking valves sorted, I know we usually still lap them in ourselves even after the machine shop has done them just to be on the safe side.

Irene
 

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Well done on spotting the springs Mike, some models have paint on one end which makes it easier to spot. I hope you get the leaking valves sorted, I know we usually still lap them in ourselves even after the machine shop has done them just to be on the safe side. Irene
How can you tell which side of the valve springs both inner and outer are the top side?
 
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