Weird engine noise, tapping. 1982 GS650GL

[Connie]

Have you fixed it?
everyone can put an engine together!
so when you check all the main and rod clearances what did you come up with.
i have seen engines with different size journals from the factory.
i have even seen reground cranks end up with the wrong size journal.
oiling problems can come from to much oil clearance letting oil to pass but not make it to the end with enough oil pressure
to lube and cool the last rod, main.
These engines don't have much oil pressure to start with.

[William Groebe]

I've been out of town for a couple weeks. Just got back and cracked the cases. It is the exact same problem as before. The bearings for rod #4 are worn down a bit allowing play between the rod and the crankshaft. The crankshaft journal where the rod sits is a little scuffed, but I measured it out and it isn't worn down so hopefully I don't need a new crankshaft. I shot each crankshaft bearing oil hole with air and shined a light down a side hole and can see the light when I look down each individual lower crankshaft bearing oil hole. There are no obstructions getting to the crankshaft. Plus all the crankshaft bearings are fine, which means they are getting oil. So, if the crankshaft bearings are getting enough oil to not wear down, what could be causing the #4 rod bearing to keep wearing down? This is my second crankshaft and it's having the same problem as the last one.

I am stumped at this point. A little depressed to be honest. I can take the cases to get cleaned out at a local machine shop, but again, since all the crankshaft bearings are fine it means oil is getting as far as the crankshaft, which makes me think it's not a problem with the cases. Oil is getting as far as the crankshaft, but enough oil isn't working it's way through the crankshaft to the #4 rod bearing.

The thing that keeps bothering me is that I had the bike running fine for a year before I changed the transmission. There were no problems with bearings before, and now I've had this same rod bearing wear down on two crankshafts. I'm thinking that maybe I need to lubricate this rod journal up real well after installing as it may be the last place oil gets to after starting the bike and perhaps it's been too dry on the last two installs and it just needs more lubrication to begin with. Could I lube it up with something special? Am I crazy? Help me regain my sanity.

[recycled64]

Out of the factory manual, Suzuki Moly Paste, part #99000-25140, recommended for your possible specific need, as well as other near-by functions.

[tkent02]

Do you know about this issue? Stolen from another thread....

For the sake of reassurance with your choice, it might help to look for a 650L with an engine # 122709 and later, with supposedly an improved crank and rod bearing setup, better materials and oil flow, which translates to early-mid production 82's, (I think) and also 83's. This info comes from the factory manual, page 26 of the '82 supplement pages.

I just heard abut it in another thread a few minutes ago, wonder if you may have mixed and matched parts that aren't playing well together?

[tom203]

"....which makes me think it's not a problem with the cases. Oil is getting as far as the crankshaft, but enough oil isn't working it's way through the crankshaft to the #4 rod bearing."

Have you been using the same oil pump (and pressure regulator) ? - maybe its output has dropped off and no oil is making the journey thru crank to #4 rod nearing. The lobs in oil pump can be checked for excessive clearance, but not sure if this would tell you enough about system running pressure which is rumored to be 50psi.

[JTGS850GL]

Might want to verify that the rod big end is round and in spec since you used the same rod with both cranks. The first crank failure may have damaged the rod on #4.

[uk gs nut]

+1, rod #4 big end is not round. Have it checked for size, then use it for a sinker next time your fishing !

[William Groebe]

Responding to a few of you out there.

JT850GL- I am using all new (to me) rods that came with a new (to me) crankshaft. When the first rod blew I replaced the entire crankshaft and rod set with a new (to me) crankshaft and rod set.

tkent02- Because I was worried about the replacement bearings wearing down I bought and installed all new bearings according to the Modifications table in the manual, page 309.

tom203- I am still using the original oil pump and regulator. I'm not sure how to check anything on them. I have not taken either of them apart.

[Grimly]

tom203- I am still using the original oil pump and regulator. I'm not sure how to check anything on them. I have not taken either of them apart.

That's a red flag.

[JTGS850GL]

That's a red flag.

Yes, with a completely different rotating assembly and having the same failure, I'd say it's oiling system dependent.

[tom203]

Can you tell how oil gets fed to #4 crank bearing and then to its rod bearing? I'm wondering if it could be an obstruction in crankcase itself (since you have different crank and its oil holes to rod seem clear). I can see a worn out oil pump or faulty regulator causing long term problems, but this problem in #4 rod bearing is showing up too quickly and why just #4? It's almost like no oil is getting to this crankshaft position.

[William Groebe]

Ok. So it's been a while. I'm finally back to figuring out what my next move is. To recap, after replacing the transmission on my bike last year and putting the engine back together the #4 rod bearings on the crankshaft wore down. I then took the engine back apart and replaced the crankshaft and rods with a replacement crankshaft and rod set, as well as installed all new bearings... yet the same problem happened again.

What I think: I didn't apply enough oil on the crankshaft and bearings during my first reassembly after the transmission replacement, so the bearings on rod#4 blew. During the second reassembly, after buying the replacement crankshaft I did put some oil on each bearing before installation, but the same problem happened again. Perhaps I should have applied moly paste to the new bearings, or when I put new oil in the bike there may still have been some metal dust from the worn bearing in the cases that the oil got thick and wouldn't travel smoothly throughout the crankshaft. Or perhaps I need a new oil pump.

What I'm going to do: I'm going to replace just the one set of bearings which blew on rod#4. I'm going to apply moly paste to all rod bearings during installation for extra lubrication. Also, when I put new oil in the bike I'm going to run it enough to get it warm, then drain the oil from the bike again, hopefully draining any remaining metal dust from the engine. Then I'll fill up the engine with oil and try again.

I looked into buying a new oil pump but the part is discontinued, so I'd have to buy a used one, of which I already have two (one from a parts bike). So instead I'm going to take apart the extra oil pump from the parts bike and check out it's innards. If I can take it apart easily enough and put it back together, I'll try opening up the original oil pump and check it for problems. Hopefully I can just clean it out, refurbish it, and replace it.

So, that's the plan. I'm going to have to wait a week or so for parts, then I'll be putting this baby back together... again.

[60ratrod]

Will,

you need to get all of those oil galleys and passages cleaned or it will happen again. perhaps a bit of the old three bond or some other sealant is blocking the galleys and passages. but this needs to happen or you will more than likely have to do it a 4th time.

[William Groebe]

Good call, 60ratrod. I have sprayed compressed air and can shine light through all the passages I can see leading up to the crankshaft, and I will spray air through the crankshaft as well. But does anybody know where I can find a map of the oil passages in the cases? I can pretty much follow them from the oil pump but it might help.

[recycled64]

In the factory service manual, pages 5-19 and 5-20, not easy to decipher, however-