1982 GS650GL. Loud banging sound. Possible valve problem.

[tom203]

Price bearing stuff before you go ebaying crankshaft- if you have had metal bits circulating around engine innards, lots of the plain bearings could be damaged, not just the one for rod #4

[recycled64]

There's always something like this, it's a crap shoot almost no matter what you choose-

http://www.ebay.com/itm/suzuki-gs650...076e0c&vxp=mtr

[recycled64]

Also, the crank I referred you to has the rotor attached, FWIW, same seller, different stock #

[JTGS850GL]

Hard to believe that your rod machined that crank journal surface so precisely. Are there visible signs of where on the side of the rod? If not, then it's more possible that it was machined by Suzuki originally. The metal shavings could be from another source or from the rod bearings themselves since the rod did have more play in it then expected. Don't ignore the possibility of the transmission rebuild being the source of the damage and metal. Inspect everything again.

Personally I would either pick up a complete engine or part out that bike and use the funds to get another good example easy fixer-upper. Lots of good usable parts on that one and many older Suzi's out there.

If you're determined to get this one running again, then clean and flush the entire engine case of any metal shavings before you proceed with the reassembly. New oil, new oil filter are manditory.

[JamesWhut?]

Price bearing stuff before you go ebaying crankshaft- if you have had metal bits circulating around engine innards, lots of the plain bearings could be damaged, not just the one for rod #4

+1 On this.

You have to assume ALL bearings are suspect and failed, plane and roller. This is a complete overhaul of the motor job. Not just a "pop in a new part and off you go". Everything, EVERYTHING, that is exposed to the oiling system needs to be meticulously cleaned, and then cleaned again. Bottom and top end.

Sucks that you just went thru to work of replacing the gearsets only now need to replace the crank (your cases are seeing a lot of daylight).

Path of least resistance/expense is to buy a complete used engine somewhere. Hopefully close by, and hopefully in better condition. Then resale the salvageable old parts to recoup your costs. The much more satisfying and interesting path is to overhaul the motor yourself. Than means; new crank (probably), all new plane bearing shells, new gaskets & seals, and you might as well do a ring job while you are at it.

[eil]

I'm using this bike as my motorcycle school.

Now that's an attitude I like! My 850GL is my motorcycle school, but so far she's been a much more lenient headmisstress.

[60ratrod]

Will, I'd pop that rod cap off and see what the damage is and see if it can be ground and polished back into service, but this will require some measuring calipers. And any good engine machine shop should be able to clean all parts of that motor for you. Otherwise a new crank IS in order and you still need to have the cases cleaned by a machine shop. I would also have the cylinders honed and some new rings fitted, and new bearings of the correct size ordered. Everyone is right when they say that now you assume ALL bearings have failed. Ihad a rod bearing spin on a 79 ranchero I had and drove it for so long that the crank was ccompletely toast and no machine work would have saved it, including all of the other journals. And the wheel thingies in the car world are the crank throw weights that balance the crank and keep it from tearing the motor apart. And the one in your photo looks too precise to have been done by the bad rod. The bad rod would have done more and that rod would either have snapped in half or been ground down

[William Groebe]

Great feedback, fellas. I am going to take my time thinking about what my next steps are.

This is the where I take the fork in the road.
Fix it, or f%$# it.

1 - I could try to fix my current engine, doing a lot more work, spending more money, but learning a lot more about the machine.
2 - I could buy a replacement engine. There is a salvage yard selling a 1982 GS650GL for $100, but then I'd have another whole bike, and I'm not in the ebay bike parts selling business, and my wife has only allotted me so much space in the garage.
3 - I could sell the bike for parts and buy another bike. I like this option the least. I've already done so much with this $300 bike, and would hate to "give up" on her.

I'm leaning towards getting deeper and trying to fix it. Take apart the crank, have the engine cleaned out and do whatever needs to be done. But I'm going to plan my steps, and I'm busy working all day and now watching the World Series at night. Looks like I'm a week out from really doing much with the bike. Maybe Saturday morning I can get a bit done. I"ll keep you all in the loop. And thanks again for all the great advice.

[60ratrod]

I like option 1 myself. And if you go with door number 2, keep what ever spares from the other bike and scrap/craigslist the rest, or put them here in the classifieds. It never hurts to have some spares. Parts go bad, as you are experiencing now, or you might wanna try something out and you can use the spare as the guinea pig! That's what I'm going to do with the other kz tank I have

[William Groebe]

I took the engine to my mechanic. Didn't get a lot of time to chat, but he says it's definitely a bad rod bearing. Apparently it's pretty common (for a mechaninc) to find bad rod bearings and usually he ends up replacing the bearing as well as the rod, depending on if the rod became damaged or not. I haven't had a chance to do any work on it and won't have time until the weekend. I'll let you know what I find once I pull the rod apart.

I also need to do some research on bearings and rods and figuring out what I have to measure to make sure the rod is ok, and to figure out what size bearing I need. Should I go ahead and replace all rod bearings while I'm in there? Back to the manual!

[barnbiketom]

I am concerned if the crank pin(s) are bad and worth grinding/polishing (resizing) and whether or not it
is economically better to buy another crank or engine

[JTGS850GL]

I'd vote for a replacement crank assembly or the complete engine.

[tom203]

I'd go for low mileage engine (or entire bike), beg for mercy/plead insanity from wife, part out the old one to recoup money. You've invested lots of time in this , but as song goes, best to know when to run away.

[recycled64]

You haven't posted in a while, don't tell me you got depressed and stopped! You da man! Would this help, maybe?

http://www.ebay.com/itm/suzuki-gs650gl-gs650l-gs650-gs650g-complete-engine-motor-parts-1981-1983-/311159688121?pt=Motorcycles_Parts_Accessories&hash=item4872900bb9&vxp=mtr

[tom203]

He needs something in his hemisphere! How about this critter?

http://sfbay.craigslist.org/nby/mcd/4714708519.html

$100 - I see plenty of good parts if pic is honest!