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Discussion Starter · #1 ·
Some might remember my project on restoring a 12R. Well, the time has come to start putting it back together.
I took all this time to get a replacement crankcase, which is here and has been measured, looks great. Have most of the parts, need to place an order with partzilla for bearings and a bunch of other stuff, and the assembly shall begin.
Yesterday I stripped the rest of the parts from the old lower crank and the starter clutch from the upper crank. All is ready there.
Now, the new crankcase has this funny white crust in places, it loos like that calcium buildup you get in a teapot. It is present in the ends of the lower case and here and there throughout in a few spots. It is not exactly corrosion, cause once scraped off, the metal under it is pristine.
It is a pita to remove! I have been religiously scraping it off for three days, yet keep flinging a flake here or there. Solvent does not touch it, I did take it to a solvent cleaner.
Any ideas? I am going to call around to see if a shop here has a large ultrasonic bath but if not, I guess the best I can do is scrape. Tries water, does not do anything.
Is it some oil additive residue?
 

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Discussion Starter · #2 ·
Ok, no takers. I will figure it out.
Another question, this time regarding the main bearings.
My new crankcase came in with undersized bores (which is great). I miked them all, and they all are 1.5747" give or take 0.0001. The case is marked with "O" for all bores, which is a match for the measurements.
The crankshaft mains are 1.4561", which is "no mark", or minimum OD.
According to the book, I need black inserts. However, when I do the math it appears that with black inserts the oil clearances will be 0.022-0.024mm, which is under the min spec of 0.031mm, and well under the spec of 0.051mm (0.002") that I found recommended by spencercycles, who seem to have a web reputation for knowing their engine rebuilding.
Looks like I should go with brown inserts. Of course one can plastigage them and go with another size if the ones tried are wrong, but no store has them in stock, so it is shipping them back and forth from an online source, which drags out and adds cost.
I would much prefer to go with the right size the first time.
Below is the table of calculated clearances from the measurement of the bore, minus the measurement of the main journal, minus the average thickness of the colored insert (1.478 for brown; 1.483 for black; 1.488 for blue).
What would you do?
P.S. Hubz, if you chime in please don't put in the A-B-C doodley doo matrix at the factory suggestion, these data here are actual measurements :eek:hno:
 

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before we get into what shells to order, how many times have you done this? are all the parts fully warmed up to room temp? your body heat can really play havoc if youre trying to measure cold parts. (never again!! lol)
not trying to be a dick, just getting some background info first :thumbup:
 

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Discussion Starter · #6 ·
Measured in the garage at about 50-60F. I did not touch any of the measured devices with my body parts.
I have seen threads before going about the importance of nanometers when holding the crankshaft in one's hand. With tolerances allowed from 0.03 to 0.063 mm, I would think the temperature expansion from 55F to 75F is not a critical factor but I can be wrong of course. I also saw a response from spencercycles about un-importance of people obsessing over this.
Point is, it was measured in a reasonable temperature. Crankcase and crankshaft both were in the garage for days and were temperature stable.
 

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Discussion Starter · #7 ·
Glad to see you're ready to start buttoning it up. Good luck with it Paul, looking forward to hearing about your first ride!
:) Thanks Rundog, I can't believe there will be a moment when I get to hit the start button on it. Let alone it actually starting :puzzled: :lol:
Weather has been nice and I am riding my VX800. Getting distracted, too. Believe it or not, I just about have walked off my bike this AM without putting it on the side stand. It rudely reminded me about this by using my leg as a landing cushion :banghead:
 

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I would do the looser clearance. i had a bad experience with a cold garage and measuring stuff, always do it on the kitchen table now after everything is up to temp
 

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Discussion Starter · #9 ·
I would do the looser clearance. i had a bad experience with a cold garage and measuring stuff, always do it on the kitchen table now after everything is up to temp
I am leaning that way. Brown is the one for looser tolerance, with #5 being black. If my measurements are off (unlikely; crank was also measured by Falicon and my own measurements are +0.0001" from that) then I will have to send them back after plastigaging.
I also read people (spencercycle for one) saying plastigage is a waste of time, just measure (as I did) and assemble. I have used it before and plan to this time. What's the thinking here on this?
P.S. I can bring it in overnight to measure just to confirm. Would be an interesting experiment, if nothing else.
 

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i dont use plastigauge. guys with way more experience and knowledge taught me to measure everything when i was learning how to rebuild my first motor.
 

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Discussion Starter · #11 · (Edited)
I called Spencer and Muzzy. Both said, measure well, both said, they don't use plastigage. Both said, use the loosest bearings available.
I suppose this answers my original question, especially since the measurement indicates that the loosest is the one I should use to get even the minimal clearance.
I am inclined to use the brown on all except #5 (see table above) and black on #5 to keep the clearances as close to each other as I can. Have a feeling it is not a good idea to have one of the clearances larger than others.

P.S. I am discovering more and more interesting details. Like, the 2000 and 2001 bearing shells are not the same part numbers ??? Well I guess I will have a good knowledge of this once I am done :headscratch:
 

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I believe the new main bearing part number is just a super session IIRC...? some of the rod bearings will have different size tangs though. in a pinch ive just reshaped the tang on an oddball bearing that had the proper clearance. 13 000km on that motor last summer :)

try to keep uniform clearance. mic the shells, pair similar sizes
 

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Discussion Starter · #13 ·
I went straight to the service manual, and what I am seeing there makes no sense.
The smallest crank main diameter allowed is 36.984 mm.
The largest main bore diameter allowed is 40.016 mm.
This leaves 3.-16 / 2 = 1.516 mm for the insert + oil gap.
The thinnest main insert is actually 1.490 mm (my above table is wrong, I did it using the con rod bearing thickness by mistake).
This means that the oil gap, for the most worn out crankshaft and the loosest fitting crankcase, is 0.026 mm ??? this is under the minimum factory spec.

This means that black or blue inserts would never, ever be needed.
Something is fishy here. I am not sure what to think of it all. They must be accounting for some kind of deformation in the manual, otherwise from summing up the dimensions, it is impossible to get the oil clearance specified.
 

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I went straight to the service manual, and what I am seeing there makes no sense.
The smallest crank main diameter allowed is 36.984 mm.
The largest main bore diameter allowed is 40.016 mm.
This leaves 3.-16 / 2 = 1.516 mm for the insert + oil gap.
The thinnest main insert is actually 1.490 mm (my above table is wrong, I did it using the con rod bearing thickness by mistake).
This means that the oil gap, for the most worn out crankshaft and the loosest fitting crankcase, is 0.026 mm ??? this is under the minimum factory spec.

This means that black or blue inserts would never, ever be needed.
Something is fishy here. I am not sure what to think of it all. They must be accounting for some kind of deformation in the manual, otherwise from summing up the dimensions, it is impossible to get the oil clearance specified.
40.016mm - 36.984mm - 1.490mm - 1.490mm = .052mm clearance.

the 1.516mm represents 1/2 of the circle.
cmg
 

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Discussion Starter · #15 · (Edited)
So the clearance is not the gap between the bearing and crankshaft, but the sum of them on both sides?
In other words, which is correct:

clearance = bore diameter - journal diameter, or
clearance = bore radius - journal radius ?

I guess I have never really thought about it. For the couple of rebuilds I did before, I simply bought the over-sized bearings as specified with the honed crankshaft.

If clearance is the diameter difference, it all adds up, and the original conclusion remains, I need 4 browns and 1 black.
 

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Discussion Starter · #17 ·
I figured it out. I was off a factor of two. At the risk of stating the obvious, the clearance is on one side of the crank, laying in the inserts, so it is the difference in diameters. I was dividing it by 2 one extra time, so couldn't get the right number. Thanks CMG for setting me straight.
 

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Times like this you wish you had a Kwak design engineer standing / sitting beside you....you keep giving him beers and he keeps telling you how to rebuild your motor. Seems to me you are spot on with your approach to doing the job but simply lack of understanding on how it all goes together, this guy behind you would make perfect sense and you would be sorted :).....sadly they are not easy to get hold of :(.
Your doing a grand job and you have bigger balls than most of us on here tackling this job....I can feel the tension building up when you come to press the starter button for this first time lol.
 

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Times like this you wish you had a Kwak design engineer standing / sitting beside you....you keep giving him beers and he keeps telling you how to rebuild your motor. Seems to me you are spot on with your approach to doing the job but simply lack of understanding on how it all goes together, this guy behind you would make perfect sense and you would be sorted :).....sadly they are not easy to get hold of :(.
Your doing a grand job and you have bigger balls than most of us on here tackling this job....I can feel the tension building up when you come to press the starter button for this first time lol.
along with $50,000 worth of the right tools!:crazyloco:

good job Paul...just pass'n along the help i have received.
cmg
 

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Discussion Starter · #20 ·
Another order just been placed, 51 parts, $397. As soon as I hit Submit I realized that I forgot to add the valve cover gasket :( Maybe I will do what others here did and goop mine up with silicone. Some deadbeat didn't send me on from E-bay that I paid for, but at least refunded my money...
Once these parts are in, the Great Assembly shall begin. I am taking tons of photos and will probably post a DIY of this for the benefit of some poor soul in the future.
 
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