Engine only rotates counter clockwise.

[padutch47]

Just purchased an 81 GL1100 with a "locked up " engine, or so said the owner. Since it had a pair of brand new Metzeler tires on it and the bike was pristine and CHEAP, (less than the value of the tires) I bought it figuring a worst case scenario would be an engine change and not much work to find out and, I had another good engine. As a retired Mercedes Benz tech, I'm a pretty good mechanic, but apparently not a great Honda mechanic. lol I've pulled the plugs, timing and valve covers, Flywheel plug and stator plug during the diagnosis process to determine just where the problem hides. Belt timing, valve adjustment, rockers and waterpump, all normal. Now here's what's puzzling me. Not being terribly familiar with this engine, I'm at a loss as to why I can rotate the engine without any interference although it does make a measured clicking noise much like a really large ratchet, but try to turn it clockwise and it will lock up just like a piston hitting a valve the minute I attempt to rotate the engine. I've drained the oil which was in pretty good condition and carefully checked it for any kind of metal residue and found none. ran a bore camera into each cylinder and they look outstanding and even made a futile attempt to insert the camera into the galley through both the oil fill hole and drain. I hate just giving up and replacing the engine just because I have one and I'm not smart enough to diagnose the problem. Any help would be greatly appreciated.

[Rambozo]

Have you inspected the starter? It has a one-way clutch and if the starter is locked up, maybe that is your issue? Just a guess.

[Rednaxs60]

Just a thought and you probably know this. The engine turns clockwise looking at it from the front of the engine. To turn the engine you should be using the rotor bolt at the rear left side of the engine - the rotor bolt could back off if you turn it the wrong way as if to remove the bolt. Not recommended to turn it CCW (looking at it from the front of the engine) except for a small amount. Using the rotor bolt, you go from the floor to the top of the engine to turn the engine CW - looking from the front of the engine you turn the rotor bolt CCW - tightening the rotor bolt, translates into turning the engine in the correct CW rotation.

Check the timing marks on the flywheel and timing belt camshaft pulleys and make sure these are correct.

Good luck.

[joecoolsuncle]

what they said. note.......do not pull the starter and then try to turn engine, bad things happen!

[padutch47]

Thanks to all but everything suggested has been checked with the exception of joecoolsuncle's post, "bad things happen" ... better explain because the starter had already been removed aod I'm sure the engine had already been rotated every way possible before I ever got it but if it had not been, I closed that deal! Guess you better explain the bad things and can they be rectified. lol

[WingAdmin]

Thanks to all but everything suggested has been checked with the exception of joecoolsuncle's post, "bad things happen" ... better explain because the starter had already been removed aod I'm sure the engine had already been rotated every way possible before I ever got it but if it had not been, I closed that deal! Guess you better explain the bad things and can they be rectified. lol

The starter may be removed, but the one-way sprag clutch is not part of the actual starter. The starter engages a chain, which connects to a sprag clutch at the rear of the engine. If that chain is bound up, or something is causing that clutch to bind, it will prevent the engine from rotating backward.

[padutch47]

Thank you Scott for both the schematic and the detailed explanation. Since the starter had already been taken out by the previous owner before I got it, I have only attempted to rotate it with the it removed. If I'm lucky, that's what's locking it up. Tomorrow's yet another day and I'll put the starter back in and see if that makes a difference. Fingers crossed! lol

[joecoolsuncle]

there have been reports of the starter driven chain falling inside the engine if rotated with starter removed. also, bench test the strter before installing. if the starter doesnt jump with force as it starts to spin, go ahead and rebuild it now.

[padutch47]

Thanks uncle, I'll check that.

[padutch47]

OK all, latest development in the "As the stomach turns" drama ... lol Tested the starter and it's actually seized tight! Think this is what the previous owner started out trying to find but the problem escaped him. Is it possible the starter clutch is seized and THAT's the actual problem resulting in a burnt up starter? The engine itself cannot be seized as I can, (rather I should or not) rotate the engine backwards with the starter out. With the starter IN however, everything is seized and nothing will even budge trying to crank it from the front crankshaft bolt either way. To quote Alice, "curiouser and curiouser" ...

[joecoolsuncle]

yep. starter can seize. the starter clutch can, but not likely. it usually fails the other way, it fails to engage.

[padutch47]

OK then, if we've all run out of best guesses on how to fix it I guess the next step it to pull the engine and strip the rear end off and look inside, huh?

[DenverWinger]

Can you find the chain with starter spocket still hanging in the opening where the starter is supposed to go?

Try rotating the engine in either direction, or rock the motion to see if the chain and sprocket show up. Do this with bike leaning on the side stand, if the chain and sprocket become visible in the hole where the starter goes you might be OK. On Sidestand, the chain and sprocket should be hanging right there, ready for you to insert the starter into the splines of the sprocket gear.

If you can't see a sprocket hanging loosely by a chain where the starter goes the chain is probably wound up inside the alternator case and the engine will need to come out to find out what happened to the chain and sprocket...........

[slickster]

Btw, I recently pulled the starter on my '80, it was full of grey/black dusty crud, cleaned it out, polished armature, replaced brushes, works great, good luck on hunt, let us know what you find

[padutch47]

No, chain and sprocket are hanging right where they should be. I've inserted the starter back into the sprocket and bolted it up but starter was sized and couldn't move engine in either direction. Removed starter again and could rotate engine CC again from front crankshaft bolt with a socket and again, it makes a loud clicking noise like the timed steady clicking of a ratchet, try to turn clockwise and it moves 1/2" and binds like it's hit something immovable. I'm leaning heavily on the chain binding into a gear or the starter clutch having come apart somehow but these are just a guess

[slickster]

Figure it out? Don't leave us hanging...

[padutch47]

LOL ... been really tied up with more pressing jobs and had to back burner this one for a while. Promise I will report my find as soon as I have time to pull the engine. Thanks for all the support from everyone though.
Jon

[Limpy45]

If you have a helper could they put something into the starter sprocket and hold it in place while you turn the engine over? That way the chain would not go wandering off by itself and possibly bind up the engine? The back cover will have to come off to check on the starter clutch and related parts. Good luck on this project!

[padutch47]

Thanks Limpy45. I've been planning to pull the engine for a more thorough inspection but with the onset of spring and impending summer it seems everyone on the planet wants something done to there bikes and golf carts which is what I do. Needless to say, mp personal projects have taken a back burner to cash paying work. In fact, there off the stove all together and about to be put up in the pantry! lol

[padutch47]

At long last, Found the time to pull engine and after cringing a lot determined it was an internal hemorrhage and need to be taken down. Upon splitting the case discovered the primary chain exploded, damaged several teeth on the primary chain drive gear and stripped all he inside teeth off the stator driven gear in the process. Since you can't buy a primary drive gear, I have to buy a crankshaft to make the repairs. This presents yet another problem since used crankshafts seldom come with rod & Main bearings, and when you look them up in the honda manual they address them as red, blue green or brown instead of standard, 3 over ect. I'd go full ham on this engine if I could just figure out how to determine what parts to order but alas ... I haven't a clue!

[Rambozo]

As I don't believe any bearings are available any more, it's kinda a moot point. The color coding for bearings is not the level of oversize for crank grinding during rebuilding. Most factories do select fit bearings based on the crank dimensions. They often do this for bores as well. The automation seems to have trouble hitting exact sizes when machining, so they just get it close then pull the parts that fit best. Good machine shops hit the numbers spot on, so this isn't done with aftermarket parts.
I seem to remember a topic about some other application that had bearings close enough to work. Be aware that you can polish the crank journals and hand scrape the bearings to get proper clearances. Also depending on your crank and the replacement, they may very well be close enough to reuse the bearings. Just be sure to measure the actual clearance, don't trust any bearing codes, they have been known to change year to year as needed. As long as you can keep it within the service limits you should be good to go.

[padutch47]

Thanks Rambozo, this info helps a bit but it's a mystery why a company as huge as Honda with the most dependable engines on the planet would do such a hit & miss job on something as critical as a crankshaft or piston! As for the bearings not being available, it's not exactly a moot point as NOS can be had at an absurd price, one half shell at a time, which again, is amazing to me! Having been a Mercedes tech 27 years I'm well versed in German precision engineering and this kind of "fly by the seat of your pants" fitting of what should be a precise fit is totally foreign to me. lol Again, thanks for the info and stay safe out there.

[padutch47]

By the way Rambozo, if the color codes do not indicate bearing size, what DO they represent? Inquiring minds want to know ... lol

[Rambozo]

Oh, they do represent bearing size, just not the large variations like first under, second under, etc. More like fine tuning amounts like .01mm. This is common practice among most manufacturers. Yes, even MBZ does this on some things. Honda uses colors, GM uses letters (take a look at the oil pan rail of most GM engines and you will see a letter stamped near each bore denoting it's size.) Most manufacturers don't provide the over and under sized parts for rebuilding, but some understand wear and do help out. For example, I remember MBZ has several rear main seals (4?) for some engines where the actual seal lip is offset differently to ride on a different spot on the crankshaft as grooves wore in it. I wish I could remember how they denoted the differences, but it's been too long.

This practice may be going away now that lots of machines do inprocess probing, tool wear compensation, and the like. I have been out of that field for quite a while, and time marches on.

[padutch47]

No one knows better than I about time marching on. Like you, I too have been out of the field for several years now and am rapidly approaching the end of my journey. lol Thanks again for the info.