Wednesday, June 17, 2009

A Broken Heart

OK, where do I begin? I borrowed a compression gauge from Autozone because I wanted to see if low compression was causing my idling problems. Nixon is also burning oil so I figured the rings were worn. I got reading of 130-135 psi in each cylinder. I was told it should be around 180 and anything below 150 warranted new rings. So, I figured I could ride it the rest of the summer and replace the rings and hone the cylinders this winter, since that means pulling the engine off of the bike. But first, I had to fix this pesky oil leak from the ignition housing.

I may get a bit technical here so if you don't care, just skip this part. I actually didn't know about all of these parts until I opened it up. I ordered a new gasket for ignition housing. When it arrived, I took the housing off, and discovered that the housing also acted as the bushing that the exhaust cam spins in. So I took the housing off and cleaned the mating surfaces and gave them a light sanding and cleaned them with some denatured alcohol. I spread a thin film of gasket glue on both surfaces and then put the gasket on the engine. I then put the ignition housing back on and sliding cam back in the bushing. But, it wouldn't go all the way back on. There was about an 1/8th of an inch gap between the housing and the head. Hmmmm. It was kind of tight when I pulled it off. I tapped on it a couple times to coxe it in. Nothing. I started turning the screws and the seemed to be closing the gap. They were kind of hard to turn, but as long as I kept going around the bolt pattern, the housing continued to go on. I finally got the housing all the way on and put the rest of the ignition parts back on.

Since I had take one of the valve clearance locking nuts off to get the housing off, I had to reset the valve clearance. This is where everything started to go wrong. I took the altnernator cover off so I could rotate the engine. Oil started gushing out. Normally, this doesn't happen. In fact, you have to have this cover off when you set the timing so only a little oil sprays out. But this time, it kept coming and coming. I had to scramble to catch it all and all I had was paper towels and plastic grocery bags. I seemed to have that under control and then noticed that one of the grocery bags had let the oil through and it was now all over the garage floor. Unfortunatley, my garage is carpeted with industrial carpet (don't ask) so the oil made quite a mess. After I had that as clean as I could get it, I went back to setting the valve clearance. I got the valve cover off and checked the valve clearance. There was A LOT of clearance. Hmmmmmm. I tried rotating the engine and it was very hard. And, I didn't see the valve move. Uh-oh. That's when I noticed it. I could see the end of the valve. I shouldn't be able to see that. The cam follower was supposed to be on in. Where was it? It was NEXT to it! Huh? I took the ignition parts off again and started to take the ignition housing off. I heard a loud pop and the cam follower popped up and sat partly on the valve. I took the housing off and the cam follower fell off next to the valve. I managed to get everything reassembled the way it was supposed to be and the housing went on all the way easily. But now the cam follower was only slightly sitting on the end of the valve and that's when I realized exactly what I had done.

I BENT THE VALVE! When I took the housing off, that allowed the cam to shift a little, and the cam follower fell off of the valve. I didn't see this because the valve cover was still on. When I put the housing back on, the cam follower got stuck between the valve and the cam bushing. When I forced the housing on, the bushing pushed the follower which pushed the valve to the side which bent it. Engines don't run with bent valves. I'm screwed.

So now, I have to take the engine off of the bike and take it apart and replace the valve, the valve guide and probably a bunch of other parts. Since I'll have it apart, I might as well redo the rings and cylinders. So, it looks like I won't be riding for awhile. I have no idea how long it will take to do all of this work. Oh well. I bought this bike so I could learn how to work on engines, so I guess now is my chance. I was just hoping to get a good riding season out of her first.

1 comment:

Christopher said...

That's tough. I feel your pain. I guess this is the good AND bad of having an old bike.

I wouldn't dare dig into a newer bike's engine, so I guess you can think of this as a blessing in disguise.

I did a full rebuild, new rings, cylinder hone, etc on my old bike, and got her running just in time for good weather. I got about 50 miles out of it, and all of a sudden, it's giving me trouble again.

Anyway, just know that there are folks out there that feel your pain. You seem to be a competent person, so you should be able to get it back together without too much trouble.

Keep an eye out for a parts bike or engine. It might be worth it.