Crank & Conrod bearings

[79XS11F]

Opinions ... Can I change out the crank and conrod bearings by just using the correct color code replacements without the pre replacement and after replacement clearance testing? If plasti-gage tests were to indicate that the correct color replacements were a little tight what happens then? ...
Rob

[79XS11F]

Bump ...

[trbig]

I didn't use the plastigauge on mine, and I think that most don't. If there is really questionable/odd/ or just plain weird wear on any of the old bearings, I would use it. If they are fairly uniform and it wasn't knocking before and you're just "Freshening up" the engine, I wouldn't mess with it personally... but it's your call.


Tod

[79XS11F]

Originally posted by trbig
I didn't use the plastigauge on mine, and I think that most don't. If there is really questionable/odd/ or just plain weird wear on any of the old bearings, I would use it. If they are fairly uniform and it wasn't knocking before and you're just "Freshening up" the engine, I wouldn't mess with it personally... but it's your call.


Tod

That's it for sure Tod. I have the bearings and the engine is already on the bench so I was thinking I might as well change them out for the sake of doing it while the engine is on the bench. This is the Hop-Up engine so the entire top end is freshly broken in with about 500 miles on it.
I was thinking if I do the lower end now I will pretty much have a "new" engine that would not require any major work for as long I'm alive. That's is based on having 3 bikes to put mileage on every year.
So when you say you wouldn't mess with it do you mean at all, or just skip the measuring and remeasuring part?

Rob

[mro]

If plasti-gage tests were to indicate that the correct color replacements were a little tight what happens then? ...

Checking right after installing new ones might read on the tight side...
Assembly lube/oil/bearing may need engine spun before checking.
Have rebuilt a couple lower ends. Did not check em. All still going good. Have also rebuilt industrial 4 cylinder engines. Never did check them either if crank/rods were still in spec..

Latest engine working on, CG-13 Nissan.
Had head done by a shop. Came back from head shop with a broken cam.
Sure hope I don't have to eat that one
Cam cost more than profit on the whole job


mro

[79XS11F]

The engine came to me with about 25000 miles on it which is not a lot but I have no idea how well the engine was maintained and or used for those miles. I'm just thinking that if I do them, and they are properly, I will not have to re & re this engine in the future.
I think I will go ahead and do them. There doesn't appear to be any real risk so long as they are not too tight in the end but the engine will require a break in in any case.
I guessing that the correct bearing inserts are sized to return the clearances to factory specs unless the pins themselves are worn.
Thanks guys.

[somesuch]

I would check, but then again, I tend to overdo things. Miking the crank is really fast and you don't need any special gauges, just a micrometer, so I would do that. Plastigage is cheap, and doing the con rods is very fast as well......so I would do that. (some engine rod bolts are not supposed to be torqued multiple times, but I don't think XS1100 is one of them) Main bearings are quick to do as long as everything is on the bench, clean and ready to go, since you just drop the crank and tighten the main bolts.....so I would do that too And that should leave you with a "new" bottom end after you replace the starter clutch, trans bearings/shift forks/undercut the gears, and maybe I am forgetting a thing or two


Do it, and you will never have to worry about having to work on that motor again!


--Nick

[79XS11F]

Thanks Nick. I am ready to remove the stator rotor now and that's the last thing to do before I split the cases.
I will not be changing out the tany bearings or shift forks, or doing the gear dog "fix" on this engine.
I had her apart last year and unless something has changed those parts were all in excellent condition. The crank and con bearings were however not checked and I didn't have bearing on hand at that time. If the stator rotor does not present any removal difficulty (fingers crossed) I should have this engine completely back together by tomorrow afternoon. Then I can park it in the corner of the garage and get to work on the frame work for this bike.
Rob

[trbig]

What I was saying, is if I had the bearings I would swap them, but unless there was a weird vibration or knocking in the motor before, just put the correct bearings in and go with it. But to be truthfull... the plastigauge is fairly cheap, and I haven't looked in the book, but I am assuming you just have to slap the bottom half of the case on and torque those main crank journal bolts down and pull them back off... not ALL the bolts? Seems like it may take a whole 5-10 minutes to check??


Tod

[79XS11F]

Yeah there was no unusual vibration or knock and I already have the bearings. This engine has a complete unassembled top end so flipping the engine around on the bench is not a quick and easy task. I wanted to keep it straight forward and easy. On that note I already have the stator rotor off and the upper case bolts out and after a short break I will flip this puppy over and do the bottom bolts.
Rob

[John]

While you have it apart I would recommend replacing the crankshaft end seals while it is apart. Much easier on the bench than in the frame.

[79XS11F]

I hear yeah John and they are new from 500 miles ago. I did them with the 1179 kit rebuild. The only reason I didn't do the crank and con bearings that time was that I didn't have them on hand and ran out of time and dollars were tight after the 1179 kit and machine shop work.
I now have the cases apart and see that all main journal numbers on the case are 4s and so are the con rods.
The clymer manual however has the location of the groups of numbers on the crank counter balancer reversed so I will have to confirm that to the factory manual.
Rob

[trbig]

If you're looking down at the engine from the rear, the numbers will (Should) be on the crank lobe on the right as you are seeing it... which is actually the left lobe since the engine is flipped over.


Tod

[79XS11F]

yeah that's where the numbers are ... a group of 4 and a group of 5 but in the manual their location on the left counter balancer is reversed as compared to the factory manual.
I'm watching hockey this evening so tomorrow morning I will do out the bearing and start putting her back together unless I decide to put a quick coat of paint on her.
Rob

[AlanB]

Hi Guys,

Strange how things happen together; I typed a reply to a similar thread yesterday for the UK site; it has a couple of links to previous threads included......

TRY THIS!

Hope this all crosses the pond OK........

AlanB