replacement rod bearings with no oil holes? 1982 GS650GL

[Guest]

I am replacing all the crankshaft and rod bearings in my 1982 GS650GL and noticed that none of the bearings look like I expect them to.

They either have no oil hole where they should, have an extra oil hole, or have an oil groove where there shouldn't be one.

What I'm most concerned with are the new rod bearings which no longer have oil holes in them. All the rod bearings from my original crankshaft have oil holes in them, and the diagram on the ordering form show them with oil holes, and the crankshaft itself has oil passages in it to feed the rods. I spoke with Corey from PartsOutlaw.com and he called Suzuki for me but couldn't get confirmation as to why the parts were changed. Apparently some parts are modified over the years. Suzuki insists these are all the correct parts for my bike and should work in the bike just fine. I'm a little nervous about putting the rod bearings in without an oil hole. Corey said I could return them for no restocking fee if I want. That's pretty cool.

I've noticed a few other threads on this issue on the forum but none had a resolution. Anybody have a clue what I should do?
I'm thinking of returning them and checking on ebay for replacement parts with the original part number and if all else fails, I'll machine my own holes where necessary.

The new bearing is on the right, and the old one with the oil hole is on the left in the photo.


As far as my understanding six of the eight upper crankshaft bearings should have no oil grooves or holes. Whereas the the inner two upper bearings are the same as the lower bearings with both a groove and two holes. Again, just like in the diagram below.



But the upper crankshaft bearings I received have oil grooves. The original bearing is to the left while the two in plastic are new. I'm not as worried about these. So there's a little more oil distribution along the crank. Seems fine, but I'm no mechanic. Should I be worried?


And the one lower bearing I received so far has three holes, but the original bearing below it only has two. The new one is in plastic. Also seems like not a big deal, but I'm new at this and don't want to ruin my engine.



Any help is appreciated.

[tom203]

image.jpg"Suzuki insists these are all the correct parts for my bike and should work in the bike just fine."

Call me skeptical , particularly regarding rod bearings . The attached pic is how I recall a similar plain bearing engines - oil is first supplied to crank main bearings, then any excess from here is "flung" up those angled holes to feed rod bearings. The rod bearing is not as loaded as the crank, but it likely will last longer if it's floating on oil film as intended by engine designer who specified feed holes.
The three holes versus two stuff for lower crank bearing shouldn't be an issue. But it's not clear why upper crank bearing now needs the groove. At startup, crank is sitting on lower bearing, once oil pressure builds, it's no longer in contact with either the upper or lower bearing material.

refresh my memory.... Don't you have a total of three crankshafts?

[tom203]

I usually don't look at my Clymer manual, but this does have some tidbits regarding grooved and non grooved bearing inserts on crankshaft.

[William Groebe]

Here's a link to the service manual on BikeCliff's website. http://www.mtsac.edu/~cliff/storage/gs/GS650GManual.pdf
page 3-45 shows the rod bearings, and crankshaft bearings together.
page 3-57 shows the crankshaft bearings.

The only difference between the manual and what I found in my original bike is that the two top middle crankshaft bearings were the same as the bottom ones with the oil groove and hole, just as in the diagram from my post above. The grooved bearings with oil holes are the ones labeled 5. Plain bearings for 6, and 3 is for the rods and they are plain with oil holes. I may try calling Suzuki myself, but I was hoping someone on the forum would have replaced their bearings and found a solution for this problem.

And yes, I do have three crankshafts, and all three have oil holes in their rod bearings.

[tom203]

Bunch of cautions in clymer.... Like this tidbit....

"the oil hole in (rod ) bearing insert must be aligned with the oil hole in the connecting rod."
Plenty of other cautions regarding rods. Are these in that service manual? I never looked at it

[GregT]

The oil holes in the rod bearings simply spray oil up into the bores via the matching holes in the rod shoulder. Given it's going to spray out the sides of the rod anyway, it's not something I'd stress over. Some motors have this feature plenty don't.
Regarding the extra grooves and holes in the main bearing shells, I seem to remember this family of motors having some oiling problems and the solution was better oil circulation around the crank so as to get more to the big ends. This would certainly account for the grooved top shells and extra holes.
Again, not something I'd stress over.

[tom203]

The oil holes in the rod bearings simply spray oil up into the bores via the matching holes in the rod shoulder. Given it's going to spray out the sides of the rod anyway, ....

For oil to reach contact surface of bearing and rod (and do its hydrodynamic dance ) ,it must come out hole in bearing insert- relying on spray entering sides works ok on lawn mowers,scooters, etc. but is poor solution to high reving high power engine. The 650 shafties came with high pressure pump to ensure the crank and rods stay happy.

[Old guy]

This is my take if I'm reading correctly. The mains feed to the rod journals. The grooves in the main bearings become part of the pressurized oil system. In a half grooved system the rod journals will only recive oil when the oiling hole on the crank feeding the rod journals passes the grooved section. Going to a fully grooved creates 360* oiling for the rods.

The hole in the rod bearing is for an oiling hole in the rod (if it is there) is to provide a small brief spurt of oil to the cylinder wall or bottom of the piston, depending on the timing, only when the hole in the rod and bearing passes the oiling hole on the rod journal. Some oiling holes run the length of the rod to oil the pin.

going to a 360* main ensures constant oiling to the rods, greater pressure and flow, and the rod journals are probably slinging enough oil with that setup to negate the need for a skirt/piston/pin oiler.

If if there are enough failures, things change. This was probably what came out of those failures.

[William Groebe]

Old Guy,

I'm still fairly new to working on motorcycles so forgive me that I don't fully follow your last paragraph. "going to a 360* main ensures constant oiling to the rods, greater pressure and flow, and the rod journals are probably slinging enough oil with that setup to negate the need for a skirt/piston/pin oiler. " Are you recommending I do something, or are you saying that the bearings I have might be fine?

Also, there is an oil hole in the rod as shown in the pic below.

[Grimly]

Jeez, it's quite simple.
Oil-fed crankshafts are calculated with oil feeds to supply main bearings, and through internal crankshaft drillings to the big ends. Then from the big end, the small end of the rod might *not in all engines* have a longitudinal drilling to feed that with an oil supply.
If you look at the crank, bearing shells, big and small ends and rods themselves, you will see a pathway for the oil supply. Block any of the oil supply holes off at your peril, and beware of know-nothing advice from parts suppliers, most of whom have never stripped anything down in their lives.

[Old guy]

The hole on the main journal on the crank is the feed for the rod journal. That hole is supplied when the hole is passing over the grooved section of the main bearing. The holes in the main bearings let oil pass from the feed in the main caps/case to the bearing. With the old MAIN bearings, the rod journals would only be feeding oil for 180 degrees. With the new main bearings with a groove all the way around, the rod journal feed hole is always being fed. Hence 180 vs 360 degree bearings in reference to the rod journal being fed oil.

The holes in the old rod bearings were to squirt a small amount of oil at the bottom of the Pistons or cylinder walls. But only when lined up with the hole on the rod journal on the crank. How much good it actually does is debatable. My guess is with the switch to the 360* mains to constantly feed the rod bearings, there is enough oil slinging on the bottom of the Pistons and cylinder walls not to need the "squirter" built into the rod.

If it still concerns you, you can drill the bearing and chamfer the hole edges. But my guess is suzuki decided the oiling hole was no longer needed in the rod bearing with the change to the 360* mains.

Old Guy,

I'm still fairly new to working on motorcycles so forgive me that I don't fully follow your last paragraph. "going to a 360* main ensures constant oiling to the rods, greater pressure and flow, and the rod journals are probably slinging enough oil with that setup to negate the need for a skirt/piston/pin oiler. " Are you recommending I do something, or are you saying that the bearings I have might be fine?

Also, there is an oil hole in the rod as shown in the pic below.

[tom203]

I've rethought this without benefit of clymer's cautions . As long as oil gets to rod bearing ( which it will) , who cares where it goes next. It will be pushed out rod bearing sides and get thrown around by crank throws - lots will hit underside of pistons to cool/lubricate that area. The pic shows that the hole in rod is pretty small, so maybe suzuki figured it was overkill. So I'm joining the no hole needed crowd.
But I agree with grimly that most times you have to be real cautious with these changes.

[William Groebe]

I tried calling Suzuki to see if I could talk to someone, but their customer service guy told me they do not offer technical support to individuals, only to shops. And I already had Corey at Parts Outlaw call for me and talk with the tech guy who (though he didn't know why the part was changed) insisted it's the correct part and would work fine.

Once the rest of the crank bearings arrive I'm going to go ahead and finish the install assuming these bearings will all work fine. I could drill some holes, but I'm just as worried about ruining the bearings with my crappy machining skills as I am about them not being the right design.

[prays4u]

check out the Factory Manual pg. 311-312...seems like they updated the bearings

gerald

Sorry.. I meant the Supplemental Shop manual for the "Z" year model on pg.25 - 26

[William Groebe]

prays4u, you are a godsend.

I didn't see this section of the manual. Looking at these pages makes it clear that the new rod bearings no longer have oil holes. It doesn't explain why the holes were removed, or even mention the holes, but the picture shows that the bearings no longer have holes. Maybe the holes were what kept wearing down all my rod bearings.

I will install the new bearings without worry.