first time rebuilding tranny, need pointers

[AlisoBob]

#640 and #680 is what they used.....

Honda didnt design the cases to be apart 4x times...

Whose they? Ive used the sleeve stuff before with no issues....

Me, Rob, my friend Pat, and another friend Bernie.

I think it was more to do with WHY the race spun in the first place, rather than a failure of the bond. Finding the CAUSE is the most important part of any repair, not just swapping out the pieces.

[CR500R7]

Finding the CAUSE is the most important part of any repair, not just swapping out the pieces.

110% correct.

[seanmx57]

http://eastcoastgearsupply.com/i-129994 ... ainer.html

Honda didnt design the cases to be apart 4x times...

So are you saying that spiltting the cases causes bearings to spin? What other causes could there be?

I assume that the tranny shafts are a slip fit not a press fit in the bearings

[AlisoBob]

When Honda assembles the motor, I'm pretty sure the cases are hot, everything is perfectly aligned, and they have this really cool tool that draws the cases together, not squeezes them together.

Anytime you split them without the proper tools ( A steering wheel puller is not the proper tool by the way) you run the risk of distrubing the bearing bore. Even with the proper tools, the bearings are only going to go in and out so many times before the bore gets compromised anyways.

Roosty has the right tools, and proceedures.... he can shine some light on this when he gets back from Canmore.

[seanmx57]

I think I figured out the "other" reason when I wasn't trying to figure it out. when the bearing getts gritty/worn or semi siezed creating drag the outter race has inerta being put on it that doesn't normally occur.

That honda method sounds interesting. Bob how do you know thngs like that? R U a mechanical engineer or something similar?

How in the hell would you get cases apart without a puller?

[thestuz]

im pretty sure honda would have the right jigs to put their engines together.they would have it pretty well sorted after all these years of engine building. not just a bunch of monkeys with rubber mallets and blow torches.but i think as long as you dismantle and reassemble the engines propperly, you should get ten case splittings out of them. unless as mentioned, you let the bearings get rough causing inertia etc.

[AlisoBob]

ten

No way...

[Rosco-Peeko]

Hey Sean, I may still have some laying around. I used the same stuff on my old cases. The surface prep has to be as clean as you can get it, no oil or dirt. I'd clean up the bearing bore then use rubbing alcohol for a final wipe down.

You will have to move quickly, that stuff sets very quickly. Then I would let it cure fully for 24 hours to open air and without being introduced to any oil.

I just looked I do have some--Loctite 620. You're welcomed to it if you want it. Its more or less a liquid shim or retaining compound. It did not work on my application, crank bearing....the bore and crank were so worn out it was mere wishful thinking. Plus the force is substantially more.

All of you bearings should be have to be pressed in. You mainshaft and countershaft are slip fit. Now that I think about it, that same bearing you're having problems with is prone to being loose. I think I built a motor a few years ago and used the 620 to lock it in...

Good luck!

[seanmx57]

well the motor has been apart several times but only changed main bearings till now.

I'm totally at a loss as to why splitting cases with slip fit bearing/shafts wears out the cases.
I'm a mere mortal when it comes to building motors, maybe the motor gods will shine down with an explanation. I'm more than curious now.

I can see wearing out the hole where the bearing lives by changing them a few times.

[Rosco-Peeko]

well the motor has been apart several times but only changed main bearings till now.

I'm totally at a loss as to why splitting cases with slip fit bearing/shafts wears out the cases.
I'm a mere mortal when it comes to building motors, maybe the motor gods will shine down with an explanation. I'm more than curious now.

I can see wearing out the hole where the bearing lives by changing them a few times.

Picture this....the bearing is already loose in its bore. It will continue to loosen up the tolerances a bit till the case is trashed and it starts wearing on your counter and main shafts...then the gears. Somewhat of a domino affect over time.

I am going to say....if your in there...it would be best to church it all up at once. Bearings will wear on the active surfaces over time. Add some dirt or metal fillings and your wear will be accelerated...then comes the pitting and galling...then the bearings will want to try to rotate in its bore.

Its not the point of changin bearings....thats preventive maint. It the "not" changing bearings that sneaks up on people. If you put you index finger on the inner race and rotate it...it should rotate smoothly to the touch (light finger pressure)...you should hear NO grinding (like its dirty) or have any hints of difficulty/hesitation rotating it...if you do...change it.

New bearings should last quite a while if ALL tolerances are met...such as the case of my old 89 motor....crank was slip fit as were the crank bearings. That was a no win situation...I had to replace the crank, cases and bearings to bring everything back into spec. That thing shook like elvis....my hands would go numb after 10 minutes.

[AlisoBob]

I'm more than curious now.

Your pushing and pulling hardened steel, in and out of cast aluminum, sometimes at an angle.

The steel is winning every time.

[seanmx57]

I'm more than curious now.

Your pushing and pulling hardened steel, in and out of cast aluminum, sometimes at an angle.

The steel is winning every time.

Sure that would be true if the bearings had been changed. with the shafts a slip fit and not having changed any bearings I still do not understand how splitting cases wears them and the bearing holes out.

I could see if I was low on oil once, ran it out of oil or only changed it every few years how it would lunch bearings.

[AlisoBob]

Your crank falls out of the bearings when you split it?

[seanmx57]

Oh, ok crankwise I see your point. I'm tunnel visioned on the tranny stuff. Using the freezer and oven certainly help things going together.

side note, my 3 and 5 year old love your avatar bob, the eyes especially

[thestuz]

i hear bobs point, and rosco is right about the preventative maintainance on the bearings. i think if you heat up the cases with a heat gun upon separation, then use the frozen bearing/heated cases on assembly then you can get quite a few rebuilds done on a set of cases.
my cases have been apart at least three times that i know of, possibly more depending what the previous owner did. the loosest bearing was actually the shift drum bearing on the rhs case.

[Rosco-Peeko]

I have thought about this over the course of a day. My cases are new...essentially. I think that bearing is supposed to be a slip fit Counter-shaft right bearing/idler gear.

The past few motors I have done, that bearing was loose, while everything else was tight in the bores. Can you look at the case......its there any galling (metal transfer) or obvious wear...shiney or dulled areas or does it still have the clean machined surface?

Lemme know what you have....I can still send you the 620....its no big deal.

[seanmx57]

Looks like it has spin marks in the case. I'll get the magnifying glass out. The bearing definitely has spin marks, duh, I guess I don't need to check the case, the bearing ain't supposed to spin that I know. I got a mock up spare case I'll compare to that.

I gotta get some pics of the gears up. stinkin satellite Internet sucks when it's raining. It seems like it rains for 2 days every time a storm comes in New England.

[nmdesertrider]

My 85 cases has been apart more times than and old whores legs- if you do it right you wont have any problems.

[Rosco-Peeko]

Alright, I'll get the 620 out to you early this week.

[seanmx57]

here is a few pics of the gears. Those buggers are tricky to take pics of. I only took pics of 2 of the 4 but I think you will get the jist of it. I'm not sure if they need replacing or not.

[Roostius_Maximus]

them r junk

[Roostius_Maximus]

usually when those have rounded edges the others they drive didnt survive either, heres a drawing, not in assembly order, but by gear order.

seldom is 4th bitched and the fork from 3rd is stil good, it might not show burning on the pads, but it can have a spot closer to the pin where the gear rubbed it.

[nmdesertrider]

use them till they stop shifting

[seanmx57]

Adam, so from what's I'm seeing, you are saying that they have to be square, no rounding is acceptable?

[seanmx57]

I got out some feeler gauges. The rounding on the gears in question varies from apoximately .025 to .035 deep from the top edge of the gear dog toward the gear.

So how does one make a decision between a gear that is worn but usable and one that needs replacing???????

Adam said they are junk but they were shifting fine %99 of the time, the shift forks do not have any measurable wear on the pads.

What are the reasons it will go into a false neutral on an upshift from 3'rd to 4'th or 4'th to 5'th?

The manual is very vauge about gear inspection.