I managed to get my '77 GL1000 out for a ride last week. Was riding along, beautiful day, when the engine just stalled like that. Luckily, traffic was low, so I had enough momentum to park the bike and was only 1 mile from my destination, so finished the trip on foot.
As I was walking, I was really wondering what could possibly have gone wrong; no idea at the time...I thought maybe the primary chain had snapped, but, how likely is that to happen? Then I thought it might be the timing belts, but I knew they were quite recent; turns out they only were 2 years old and had 5000 miles on them.
Cranked the engine in the garage and noticed that the points timing cam was moving, but not circularly, and certainly not all the way around. That's when I thought one of the belts had broken, but then why would there be L cam movement?
Once the belts were exposed, I noticed that many teeth had fallen off. There has been an oil leak inside the belts compartment for some time, but I didn't think it was that big of a deal and hadn't taken the time to fix it. Turns out the oil had weakened the belts, in particular the L one, and sheared off numerous teeth. The tooth-free section of the L belt was on the crank pulley and so the belt wasn't doing much.
New belts have been ordered and will be here soon. Meanwhile, I had a set of old belts from my parts bike, that I installed to see if I hopefully hadn't destroyed something in the messed-up timing that my engine suffered for a few short moments. I loosened the valve tappets completely on both sides, in order to turn the crank and cams to their appropriate positions to slip the new belts on.
Oddly, when I went to set valve tappet clearance, cyls 1 and 2 were normal and easy, but cyls 3 and 4 were impossible to slip the feeler gauge. I ended up bending the gauge in the process; that's how impossible it was. As a result, I "went by feel" and made the tappets look like the front cyl ones. I didn't check or adjust the timing after all this (I know, probably should've).
The bike started and ran, not great, but it did. The R side headers were warmer than L side. I guess if the timing was checked and set it would've run better.
Now, I'm seriously wondering why valve tappets were impossible to adjust for cyls 3 and 4... Hopefully I don't have to swap my parts bike's engine but if I have to, at least I have a spare. Thoughts? Thanks for reading and hope riding weather has arrived wherever you are. Here, it's going to be another wait; for the weather and aforementioned mechanical issues
individual Cylinder Pressure Leakdown Rate testing is more precise...
