Reading valve color

[e3steve]

Well, so I tried that starter motor sprocket again after reading your experience e3steve. This time I was able to turn the motor in both directions. It just took more force than I had originally applied (and a firm grip rather than just thumb and forefinger) to twist it. So, I'll wait to hear back before I start dismantling it.

nander

S'about right; good, firm grip (thankyou nurse!). I'd still check it out across a battery, though. Be aware of my precautionary notes in the previous post of earlier this week! If the (starter) gearbox isn't damaged it should be fine, as mechanically spinning a motor merely reverses its role and it becomes a dynamo.

Pull the gearbox off and inspect the gears' teeth. It's all good experience, too, to know how it works.

[nander]

The little gearbox came off the motor with relative ease. Everything looked okay inside and there was a good amount of grease in there. So, it doesn't look like the starter motor locked up -- or was damaged.

So here's where I think we are:

The screw on the back of the starter clutch worked itself loose. This induced a wobble in the sprocket attached to the starter clutch. For some reason, this caused the sprocket to bind up and the starter clutch to no longer allow it to freewheel in one direction. The chain to the starter was thus engaged and the engine was forced to drive the starter motor in reverse direction. This was too much of a load on the motor and caused what appeared to me at first to be a piston seizure.

This would also account for the resistance I felt when trying to kick the motor through a stroke.

What say we?

[e3steve]

Pretty logical distillation of the situation. And would explain the noise from the left side, as I previously suggested. How does the starter sprocket look now; does it appear to turn true?

[teazer]

Nander, sounds like you will be good to go when that valve is cleaned up and seated.

BTW, I was in our local auto machine shop today getting a set of barrels machined and took the opportunity to check out a pile of heads in teh shop. ALL of them had white exhaust valves and black intakes. Not just some but all of them. We all know that exhaust valves run hotter than intakes, but that was interesting.

Of course a random pile of car heads doesn't tell us what a CB77 head should look like, but it was interesting none the less. Our CB175 based motors all come apart with "white" exhausts but we run them hard.

So I wouldn't worry too much about the color as long as you take it out and it's not burned. Get it to seat properly and check valve clearances carefully and you should be OK.

[LOUD MOUSE]

Took ya a while but ya finally got to where I wanted to get for the problem. ............lm

The little gearbox came off the motor with relative ease. Everything looked okay inside and there was a good amount of grease in there. So, it doesn't look like the starter motor locked up -- or was damaged.

So here's where I think we are:

The screw on the back of the starter clutch worked itself loose. This induced a wobble in the sprocket attached to the starter clutch. For some reason, this caused the sprocket to bind up and the starter clutch to no longer allow it to freewheel in one direction. The chain to the starter was thus engaged and the engine was forced to drive the starter motor in reverse direction. This was too much of a load on the motor and caused what appeared to me at first to be a piston seizure.

This would also account for the resistance I felt when trying to kick the motor through a stroke.

What say we?

[e3steve]

Pretty logical distillation of the situation. And would explain the noise from the left side, as I previously suggested. How does the starter sprocket look now; does it appear to turn true?

Meaning the one on the crankshaft, not the little one on the starter itself.

[LOUD MOUSE]

The whole area there steve.
Not that common or that rare.
Screech/squeal lung engine down.
That was why I ask him to turn the rotor counter clockwise early in the game. ..............lm

Pretty logical distillation of the situation. And would explain the noise from the left side, as I previously suggested. How does the starter sprocket look now; does it appear to turn true?

Meaning the one on the crankshaft, not the little one on the starter itself.