FWIW, what you have circled in Red looks like maybe a chip is missing, but if I can see it correctly, it looks very minor and is not your problem.
I use to work at a Honda/Kawasaki dealer when I was young, and the mechanics were always asking for parts. It was in some ways a scatter shot approach to diagnosing a bike with problems. With the internet, you can do a lot more then the mechanics could do back in the early 1980s, but still it is nice to have an actual OEM part to compare with, especially when you are not a master mechanic with a decade of experience on the machine in front of you.
That being said, maybe visit the dealer. Ask to handle a part or speak with a mechanic? In my experience they would likely be helpful in dealing with someone that has a base of knowledge and is truly looking for help in solving something that is not an everyday situation. Just be sure to follow up with them after the bike is finally running.
Yeah, I guess I should have clarified it a little better. I was a bit disappointed when I got in there with the scope and found that everything looked somewhat normal. I’m pretty sure this means I’m going to have to go deeper, most likely pull the engine and split it. I’m definitely going to check a few other things first though, especially since I did find evidence of someone being in there before (or at least trying to get in there).
One of the heat shield bolts was a lot more challenging to get out than the others. I ended up resorting to clamping down on the clip nut with some vise grips in order to get it off. Evidently, someone had almost twisted it off trying to get that bolt out. The back part of the shield was mangled where the clip nut mounts, not sure if they ever got it off or just gave up.
Didn’t make any progress today, too many irons in the fire! I did get a cell pic of the chain/tensioner/guide setup though... looks good to me. Also picked up a hex drive socket to turn the engine with. Going to check the timing and the valves... why not!
As good as she looks in the garage... hoping she’ll be out soon!
Had some time today, so I did a few things on the bike. First, I pulled the fwd valve cover and did a crude check of the timing to make sure it wasn’t crazy off. From what I see, the cylinders are in time. When one is at TDC for compression stroke, the cam gear marks for the other cylinder are parallel with the ground.
I pulled the plugs next and checked the valves. They were very tight, couldn’t even get the low side of the tolerance feeler between them. I’ve read they come tight from the factory to keep noise down, that’s crazy because they’re just going to get tighter as the valves wear. I adjusted them all to the median of the specs.
Since I had the plugs out, I went ahead and did a compression test. Got a little over 100psi on both cylinders (battery’s weak again which didn’t help).
Turning the engine by hand, it moves easily and freely. No binding or rough sticking points. At first, I thought I heard a dragging/scrapping noise on the aft side, then I realized it was the belt/secondary. There’s definitely some noise coming from the secondary as I rotate it, not sure if it’s normal or not. Of course, that wouldn’t explain the filings in the oil.
100 psi sounded low, at least it is for chainsaws. But if they are both the same then you can likely check those off the suspect list.
Being able to turn the motor over by hand and not feeling any grabby or scrapping points is a big positive tell.
You have a real head scratcher on your hands. IMO, you are just going to have to go all in. The easy lead pipe indicator is not likely to present itself.
Curious how tight were the valves? What feeler gauge could you get in there? I had neighbors that had Polaris ATVs and they had awful starting problems, and to tight of valves was the culprit. Doesn't sound like that is your problem.
Next step it to pull the heads off, and hopefully you should be able to keep the motor in the chassis. With the heads off, figure out a way to monitor/measure the piston movement. By rotating the engine back and forth, you might be able to tell is there is any slop at the crank or pistons in connecting rods or if there is any variance from forward or aft cylinder.
One thing I noticed when working on it yesterday was the oil on the flywheel. Didn’t realize it was wet in the stator case. That has me thinking... I wonder if there’s something loose in there banging around and making metal. I remember reading somewhere that if the engine is turned the wrong direction with the crank, it can loosen the magneto or something like that... need to check that since it’s easy. That’s really where it seemed like the noise was coming from initially.
Really wish they would have put a better drain on the coolant system... draining it was a mess! I think it would have been better to remove the lower hose verse the lower water pump bolt that they call out in the service manual. 🙄
Oil looked clean, until we pulled the filter. Wow, it’s definitely making metal. I’m thinking it’s going to be the lower rod bearing on the aft cylinder... we’ll see.
For anyone that might need to pull an engine in the future, here’s some steps that I found in an old post. These are by no means detailed instructions, but they give a high level overview of the process and definitely helped. I‘ve changed/added to these, I think some things were different on the Gen 1’s that it was initially written for.
Take pics of everything before you start (and as you work), especially the wires on the right side of the engine/gearbox.
Disconnect the battery.
Pull both floor boards and the floorboard support on right side (requires rear master cyl and bracket removal).
Drain all engine/gearbox fluids (oil and coolant).
Unbolt rear prop shaft, cut the boot clamps (all 4) off of the front prop shaft.
Unbolt and remove the clutch including secondary and backing plate (requires a special tool for inner primary).
Loosen the boot clamps for the throttle body.
Remove the long shift rod.
Unbolt and remove the exhaust (penetrating oil is your friend here).
Unbolt the intake manifold from both cylinders (do not disconnect fuel lines or injectors, none of the fuel system is disconnected/removed from the bike).
Remove coolant hoses and vent tubes.
Unplug all the wires, there are a bunch and it takes a few minutes, but for the most part they only go one place for re-install.
The rectifier harness has to be pulled from the back, through all of its routing, all the way to the front (it stays with the engine when you pull it, do not cut the wires). It’s the grey plug with 3 yellow wires in it, the other rectifier plug stays put.
Unbolt the three motor mounts. One on the gearbox, one on the fwd cyl head, and one on the lower front of the engine.
Using a pry bar, move the engine enough to pull the throttle body out of its boot. Flip it up and out of the way onto the shifter assembly, the throttle cable does not have to be removed (electrical connectors must be removed to allow enough movement).
Using 2 pry bars, push the gearbox up and engine back to remove the front prop shaft.
Now, push engine/gearbox forward and drop the rear prop shaft.
Spin the whole assembly in the bike, gearbox to the left (like pictured above) and then slide it out of the bike to the right (you might want a helping hand, it’s a little heavy).