Honda CH80 - Hydrolock?

[Rideslikenacho]

So I have a CH80 thats basically been sitting on its side literally in the bushes for a while now. Was given to me a year ago like this and no idea how long its been since it actually ran. Now my son has shown interest in getting it running which is great. That said we took the plug out, and turned the motor over with a drill and there is spark which is good. However with the plug in, the motor won’t turn over. So I also removed the exhaust thinking it would turn over freely and kick oil out of the exhaust port with the plug in but won’t spin freely. It’s turning.. but not freely. Seems like its hydrolocked but would have thought with the exhaust off it would rotate faster. Any advice on this for a ch80?

Also when I took the oil dipstick out oil just poured out the hole so someone really must have overfilled it at some point.

[Meatball]

Probably water in the crankcase. Likely why it seems so full. Pull the drain plug and see what comes out. Water sinks to the bottom so if there is water in there…it will come out first. I rescued a Metropolitan sitting on its side in someone’s bushes for a few years. It had water in the case and the internals were too far gone. Crank, cylinder, valves were totally rusted. I was able to salvage the wheels, steering stem and a few other bits but the rest went to the scrapyard.

[Rideslikenacho]

Yeah the crank end on the belt side is rusted but still spins and has the gear on it. I don’t mind dropping the motor, splitting cases and replacing the crank if needed. The challenge is more around finding the parts. This one’s missing quite a bit on the belt side including left side case cover, airbox, and entire back left plastics. I’ll try draining and see what comes out, probably is water now that you say that. I got it mostly for the parts but hey if there’s a way to get it running even better. That and I have another running ch80 for reference so knowing which parts are missing will be easy.

[Rideslikenacho]

Drained all the oil and everything from the case, surprisingly it didn’t look horrible. Nor did it have excess oil in it. Still same results when turning the motor over, with plug out, it spins freely, plug in it doesn’t. I’ve also pulled the exhaust off. Starting ti think the exhaust valve is stuck.

[noiseguy]

Moved to tech help.

Valve could be stuck down, but that's an odd failure, and wouldn't depend on plug being in place. Valve timing could be off but If it was running when it was ditched on it's side, not likely.

Is the spark plug the right one for the bike? Too long, electrode hitting piston? I could see someone doing then, then deciding it "doesn't run."

[Rideslikenacho]

Moved to tech help.

Valve could be stuck down, but that's an odd failure, and wouldn't depend on plug being in place. Valve timing could be off but If it was running when it was ditched on it's side, not likely.

Is the spark plug the right one for the bike? Too long, electrode hitting piston? I could see someone doing then, then deciding it "doesn't run."

Hmm good question, I can check that though and see what someone put in there. If too long probably a nice hole in the top of the piston. It does that whole half spin of the crank then nothing, then half spin with the plug in. Which I guess could be the plug keeping it from rotating over.

[Rideslikenacho]

Also condition when I received it was non running so it could be timing too I suppose. I originally picked it up mainly for backup parts but its mostly intact.

[noiseguy]

The piston is probably fine, b/c it wouldn't have been able to kick over. You don't even need to pull head, just run a compression check.

And I would check the timing if there are any doubts, but I'll bet it's fine. If you had valve interference it wouldn't turn over with plug out either.

[Rideslikenacho]

Yeah I can check the plug and compression next.

Just odd that it only spins with the plug out. All that said I am also spinning it over with a drill which clearly someone else tried because there was a rusted 10mm socket stuck to it when I found it.

[Rideslikenacho]

Plug is an NGK CR7HSA

Compression tester in plug hole does same thing as having plug in, can’t spin it over fast enough.

[Meatball]

Crank bearing shot? You can sometimes turn a cooked bearing but not fast or easy. With plug in and you get compression…makes turning even tougher.

[Meatball]

I got it mostly for the parts

Resurrecting the dead isnt always successful. Sometimes you need to call it, dig a hole and toss it in. Move on to the next one. Every time I do this I disassemble completely to salvage every nut, bolt, washer, bushing, cables, plugs, harness, etc…someday you’ll need them.

[Rideslikenacho]

Yeah I’m at the point of just dropping the engine and taking it apart. Not opposed to splitting cases to swap the crank either. Problem is like the Spree though, parts like gaskets, crank, crank seals all that stuff are getting hard if not impossible to find.

[noiseguy]

Plug is an NGK CR7HSA

That's the correct plug for that engine. Not sure what issue is; it should turn over same with plug in and out aside from developing compression. Perhaps something with the valves, but you may just need to start tearing it down to find it.