Here are some pics of my progress. Just by chance, does someone have a late badger they are parting out. I need that front suspension piece that was bent by the previous owner. I hammered it as best I could but it still seems to a little bit off. I actually used my sledgehammer and not the hammer seen

 

Bad news. Got the adapter for the Compression Tester and this is what I got.

Just above 30 lbs of compression. Looks like an engine rebuild in the near future.

 

I finally found some time to work on the Badger again. I was able to heat up and bend out most of the twist on the front frame part. I then welded a piece of metal to give it strength.

I reassembled and painted more parts. It is starting to look like a quad again

I was also able to unassemble the top end to see what my low compression was. Both rings were stuck, I pulled the piston off and have it soaking in PB-Blaster for now. The measurement of the jug is 47mm, so it's stock and never been bored. I am going to drop it off at the machine shop to get it honed to verify it's ok to just get some 47mm rings.

Just thought I would give an update to my project.

 

Some pics and some of the damaged jug. I tried to just hone it but that just brought out how really bad it is. Gotta bore it now.

 

more pics

 

You have me gripping my keyboard in suspense.

 

Subscribed. I'm working on a 1987ish YFM80. Looks like good spark but won't start. It checks 90 pounds compression. I can't even get it to pop with starting fluid. Keep us posted on the rebuild.

 

The minimum spec is 142psi, standard is 171psi.
Check the valve clearance first. I had no clearance at the intake valve, when i adjusted it it fired right up.

The clearance should be 0.003 - 0.005 in. on both valves when the engine is cold.

/henrik

 

I adjusted the valves. The intake was tight. The exhaust was about .001 or .002. I set them both at .005. At 90 lbs compression, wouldn't it try to run? It didn't smoke when it ran, just lost power then quit. Might be time for a top end. Thanks

 

Strange, it probably should make some sign of life i guess.
Put a small amount of engine oil (something like a half tablespoon or less) into the cylinder and take a compression test again. If the compression is higher that suggests that the piston rings are bad. If there is no change there is probably something going on with the top end/valves.

Check the cam chain so that is tightend as it should be so the timing is correct.

/henrik