Engine bearing info?

[Bob S.]

Regarding a 1979 xs110 special with unknown history:

I found that the crank bearings (other than the two center bearings) have differing designations stamped on them.
Some have D8I while others have D8C.
Does anyone know the meaning of these designations.

Also, does anyone know of a source for crank & rod bearings that is cheaper than Yamaha (looks like such bearings would cost well over $200 at the dealer). Ditto for rings.

BTW, the crank journals look fine for further use, with no scoring that can be detected by feel.

[strom]

OK, crank bearings have different designations... dunno why, since all are the same xcept one (half).

I changed crank bearings on 78E, cost me bout 100$. Didn't change the rod bearings, since they seemed OK.

It's not the designations that are important... color is. On the side there are some color marks, so be sure you get a new set with the same color codes.

Crank and rod bearings may have different color designations. You can have green crank and yellow rod bearings... Check it!

I'd reccommend an original yamaha set. You can get them made, but since the color codes represent the hardening process, you should get the same. If the bearings are too soft, they can get hammered together and when they do, they seize and you're looking at buying a new crank, rods, bearings.... if the shavings don't ruin the rest of the engine first.
If the bearings are harder, the crank gets f**** up.
It happened to my kawa... not pretty, cheap nor quick to fix.

Check with the dealer what colors are avaliable, then check your bearings. Mine looked brown, but it was the closest color to yellow (orange.. don't remember). Seems age and wear affect this.

Color codes are on the SIDE of the bearings... look carefully, since they are only a few mm thick.

You might want to check the one half, that is different from the others... I forgot whether it was the same color as the rest or not.

Crank... you might check the color there too... there should be color dots there... give the info to yamaha dealer/service guys. Just to be on the safe side.

If you're planning on using the same bearings, don't mix em up. They're run in, so if you change them, be sure that you run em in properly... don't ask me how, but I'm gonna take it easy for a few kmiles.

Check if the crank has been repaired. My kawa crank was scraped off, so it was an option to hard chrome it and grind it down to original size... the only problem is, it's a 1k-3kmile fix. The faster the surface speed, the faster it's gonna brake.

If the crank was chromed, look for uneven brighter areas... and the magnet shouldn't stick (as good). If that's the case, get a new crank and bearings, engine... whatever's cheaper... or fix till it'll start and sell... and hope it doesn't seize on test ride.

BTW: When reinstalling the bearings, keep in mind the oil holes... I think these yamahas have the same bearings all around (-1), but my kawa didn't. Some had holes for oil lubrications, other didn't (the other side did).

Did I mention not to mix them... (when reinstalling old ones). It's easier than it seems.... take out only ONE AT A TIME.
Another thing... micrometers count here.... so if the engine's apart and you're not sure bout changing them.. do. Don't worry bout different D8x designations. If the surface is smooth as glass (to the eye too), it's OK. All the bottom ones have a spot in the middle. That's not a problem. When engine stops and oil draines, the crank rests there. No biggie.

Why did you pull the crank? Routine or....?

LP

[Bob S.]

Thanks for the advice which I understand completely.

I prepared to pull the crank from a spare engine, intending to install it in the engine that is currently in my bike. This is to maintain matching numbers. The crank in the bike engine moves side to side with only the alternator cover removed. I watched very carefully, thinking the rotor might be moving on the shaft, but this is not so. The original reason for looking into the alternator area was a substantial oil leak from the alternator cover when the engine was running. the leak was a steady and substantial stream. I suspect that the bearings are completely shot in the bike engine, and perhaps the rest of the motor is also shot. I will likely refresh the spare engine and install it in the bike even though I will not maintain matching numbers.

[xssiveone]

The crank in the bike engine moves side to side with only the alternator cover removed. I watched very carefully, thinking the rotor might be moving

There is one bearing that has a flange on it, can't remember which one off hand, but it shows it in the manual. This flange is to keep the crank from doing exactly what you describe, stop sideways movement.


As for a source, not where you are, but I bought bearings, both crank and rod, from Zanotti Motors in PA. http://www.zanottimotor.com/ Can't remember the price but didn't seem outlandish to me at the time.

[Ken Talbot]

I believe the different colours on the crankshaft and connecting rod bearing shells indicate shell thickness, not hardness. You put things together with a piece of plastigage, torque to spec, then take apart to check the plastigage and determine the clearance for that particular shell/crank combination. If things are too loose, you move up to a thicker shell. Too tight, and you move to a thinner shell. This is a trial and error process much like checking valve shims, only you can't use a regular feeler gauge to measure clearance.

[strom]

Originally posted by Ken Talbot
I believe the different colours on the crankshaft and connecting rod bearing shells indicate shell thickness, not hardness. You put things together with a piece of plastigage, torque to spec, then take apart to check the plastigage and determine the clearance for that particular shell/crank combination. If things are too loose, you move up to a thicker shell. Too tight, and you move to a thinner shell. This is a trial and error process much like checking valve shims, only you can't use a regular feeler gauge to measure clearance.

Seems like you do have some bearing selecton...
In that case, if you order the same color, nothing wrong, you can also measure diameters on the crank and order new bearings. You can also have the crank grinded to size. Have an expert do it, but be sure to give him all the info...
Seems like mine are alredy the thickest (thinnest crank), so not much I could do if a bearing went to valhalla.

If you're gonna use the crank from the second engine, use second engine bearings as well... and remember their position.
The simplest and cheapest solution. If the second engine didn't have crank problems that is.

xssiveone, u r right. That's the one bearing that's different (one half at least) that I wrote bout. (number 6 on the link above)

Be sure to get new crank oil seals (numbers 2 and 3). They sent me wrong left side one, now I have oil dripping from that area... gonna have to pull the engine again to replace it.

When dissasembling the engine... a useful bit of info: The crank and primary shaft stay in upper half of the crankcase... might be confusing if you don't know that.

LP

[xssiveone]

Be sure to get new crank oil seals (numbers 2 and 3). They sent me wrong left side one, now I have oil dripping from that area... gonna have to pull the engine again to replace it.

Yep, BTDT. Ordered new seals because I couldn't source them locally with the flange on them. Zanotti sent me one with a flange, and one without as it was discontinued. Can't remember off hand which one it was. The one without the flange is just a standard seal so if you can't get one from the dealer, a bearing supply house should be able to order one for you.

When dissasembling the engine... a useful bit of info: The crank and primary shaft stay in upper half of the crankcase... might be confusing if you don't know that.

Never had the pleasure of taking it apart. When I bought it, I carried it into the garage one box at a time. Frames repainted and assembled, engine is reassembled and installed... hopefully this winter will see me get to the rest of the stuff.

[strom]

Never had the pleasure of taking it apart. When I bought it, I carried it into the garage one box at a time. Frames repainted and assembled, engine is reassembled and installed... hopefully this winter will see me get to the rest of the stuff. [/B]

Me too... well, most of the engine was together... almost.

LP

[sixtysix]

You talked about a steady stream of oil, isn't there a rubber plug in there? Under the alternator cover, held in by the cover. Somebody had there cover loose or something and took off and this plug popped out and they had a steady stream of oil. I sent them a spare out of a junked motor. Check to make sure this plug is in first. I am going from memory here.........

[Bob S.]

Yes, I first checked the plug and put in a new oring, thinking I had aced one. But, that was not the problem. BTW, I misspoke earlier. The crank moves front-to-back and up-down. This is why I suspect major bearing damage and likely dead engine.

[strom]

Originally posted by Bob S.
Yes, I first checked the plug and put in a new oring, thinking I had aced one. But, that was not the problem. BTW, I misspoke earlier. The crank moves front-to-back and up-down. This is why I suspect major bearing damage and likely dead engine.

eeeek... is it even worth dismantling the engine?
I mean... if you're lucky pistons and cyls are OK, transmission maybe... if you have a spare engine, make that one run.

Another option is, that all the bearings were taken out for whatever reason.

Eh, well... dig in and tell us what you find.

PS: I have a set of crankshaft bearings (no rod bearings), I think they have yellow designation... well, had (looks brown now). I replaced them just in case, so they should work. If you're desperate I could send them your way. But if you're into fixing this bike, do it right.

LP

[Bob S.]

Spare engine has worn bearings, crank has slight scoring, engine likely shot. Engine in bike has the crank that wiggles, engine likely, shot. I'm out of the 1100 business. Add for a parts bike going in the classifieds, then on to ebay. Thanks for all your comments.
Bob

[Bill__Woods]

were do you live Bob? I could use some xs1100 parts, if you are getting out of the business, as you put it!

[Bob S.]

Alpharetta, Georgia-a suburb of Atlanta.

[strom]

Don't give up... u've got lotsa spares and stuff... dig in and tell what's missing.

LP