750 TSCC Rebuild or Replace?

[Rich82GS750TZ]

Contacted Norm (Storm 64). I’m driving to OH tomorrow to get his engine. It needs a new head gasket so I’ll have to tear that one partially down anyway. But at least I know it runs and nothing broken. I’ll keep this thread going with pics and questions as I move forward.

Thank you all for your attention and sympathy.

[Redman]

As far as broken shards going thru engine, that would only be that broken portion of the rocker, right? and those contained in the cam cover, and can see any place where anything could have happened. And is the the cam chain guide the only casualty of that??

That is what case hardened steel looks like when fractured. The inner part looks more grainy that the outer .060” hardened surface.

Ah... I understand what you are saying. THat it did fail all at once on one occassion, and the outter part that is more hardened looks different than the internal portions.
That does make more sense, relative to all four of them failing all at about once from an over rev.

[Redman]

Contacted Norm (Storm 64). I’m driving to OH tomorrow to get his engine.. . . . . .
. . . ..

Aint Norm Great ! ?
Aint this forum great, because of guys like Norm ! ?

[GSXR7ED]

Norm is a good guy!

Ed

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[93Bandit]

Contacted Norm (Storm 64). I’m driving to OH tomorrow to get his engine. It needs a new head gasket so I’ll have to tear that one partially down anyway. But at least I know it runs and nothing broken. I’ll keep this thread going with pics and questions as I move forward.

Thank you all for your attention and sympathy.

The GSR is the best forum out there, and this is why. I've been on many many forums, and never have I been on one with more generous and helpful people, than on here.

[storm 64]

Oh boy, I have to clean the garage/shop, I have company coming over tomorrow! 😲 The engine doesn't look to bad. I sprayed it with grease before I put it into storage. Downside of that, it's a greasy mess. I should have it ready to just remove a couple of bolts and heav it out of the frame tomorrow.
Also, this engine is out of a 1980 750E 4 valve. It should be the same engine as Rich's 82 750T shouldn't it?

[Nessism]

Also, this engine is out of a 1980 750E 4 valve. It should be the same engine as Rich's 82 750T shouldn't it?

As far as I know it's the same.

Those engines have oiling issues. One of the few GS engine's that are not bulletproof. There is a fix that involves shimming the oil pressure relief valve. Details available in the archives. That said, don't think that's the cause of this engine failure.

[Rich82GS750TZ]

Checking parts fiches on partsoutlaw, the crankcase has the same part #. That tells that the frame mount holes are in the same place. That at least ensures me that I shouldn’t have any issues bolting it to the frame, and that I can use my case covers. Norm sent me some pics that show cross head screws on the case covers, I have bolts.

Cylinders are the same, as are base and head gaskets.

There are differences in the valve cover, and gasket, and head and head internals, cam shafts and whatnot. I don’t plan on swapping any internals from my 82 to the 80.

And Norm, you certainly don’t halve to clean on my account. I’m just happy to be getting a replacement engine so quickly and within driving distance.

[93Bandit]

So, if all 4 intake rockers broke, how on earth were you able to limp it home??? I would think if the rockers are broke, the intake valves wouldn't open and it wouldn't run?

[Rich82GS750TZ]

I didn’t limp it home. I wrote about 1/2 mile. Probably wasn’t quite that far. Didn’t measure it.

[zuluwiz]

You should put crime scene tape around that engine. Ok, the valve rockers appear to have stayed in the cam cover, but that adjustment screw went someplace after it ate the chain guide. You will need to find it and examine all the damage it did during it's tour of the engine. Hopefully not too bad. As I said earlier, a total teardown is probably a Good Idea, but it can wait until youve got the new engine installed and running. I think we know what youre going to be doing next winter.

[Rich82GS750TZ]

Yeah, that valve adjuster nut must have gone down the cam chain tunnel. I haven’t found it yet. You’re right, put Norm’s engine in so I have a bike to ride. Then totally tear down the original engine his winter.

[93Bandit]

I didn’t limp it home. I wrote about 1/2 mile. Probably wasn’t quite that far. Didn’t measure it.

Ah, gotcha. I must have misunderstood.

[TeamDar]

When the engine is over-revved the valve train floats. The rocker arms are not following the cam lobes smoothly anymore but are being hammered open and slammed closed. All of this causes wild harmonic vibrations which can loosen the valve adjusters and even cause the screws or nuts to back out. When an adjuster screw separates from the rocker, especially the ones closest to the cam chain tunnel, they frequently get drug down with the timing chain. When the screw gets jammed between the crankshaft sprocket and the chain the sprocket teeth jump the chain links throwing camshaft timing out of synchronization. The results can be bent valves or in this case the valve to piston interference was significant enough to break the rocker arms. I have personally found valve adjuster screws backed out on engines that the owners admitted to missing a gear and severely over-revving the motor. In one instance several screws/nuts had fallen out of the rocker arms. All but one screw was still laying in the head. The last screw was still in the crankshaft sprocket area and had cause the cam timing to jump time. All 8 of the intake valves were bent and required replacement. Dar

[GSXR7ED]

This is going to be intersting...an 8V/750E engine (1976-78) into a 1982 16V/750T.

I'm not saying it isn't going to work...I'm just amazed how these bikes can be interchangeable.

Spyder put an 1100E engine into his "T" but it was from the same year...1982.

Watching this thread with interest Rich!

Ed

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