Montreal Manchild with an '81 Honda CB750K
- Thread starter Jimbonaut
- Start date
Oh and totally sorted the front wheel bearings out today - me and Jimmy channelled our inner monk and got all soft and gentle with the bearing puller - little tug and got 'em spinning. Get you some of that
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ChroniclyQuickly
The itch
You're lucky you even got them out. I couldn't get both bearings replaced at a freakin Honda dealer shop, they didn't have the tool. They were able to change one of them.
Does sound like too tight tho in my experience. The other thing and pray it is not the case, could just be defective parts which can happen with a few thousandths of an inch off. Unfortunately, most parts available for these bikes are no longer made by the manufacturer or anyone who cares about quality control for that matter. I have a box FULL of "DOHC CB750" parts that came unusable. I've been burnt literally half the time, my fabrication skills are getting pretty good thanks to all the non functional crap I keep buying. Just had to modify my frame last night for "CB750" crash bars that are "designed" for my bike. So hopefully, you were able to make those bearings work? I hope they're good.
Pay more, spend less is my new motto. I'm buying highly vetted parts now that cost more but have saved me money on not buying them twice, like my controls and master cylinder for the brake which I bought 3 times actually.
Does sound like too tight tho in my experience. The other thing and pray it is not the case, could just be defective parts which can happen with a few thousandths of an inch off. Unfortunately, most parts available for these bikes are no longer made by the manufacturer or anyone who cares about quality control for that matter. I have a box FULL of "DOHC CB750" parts that came unusable. I've been burnt literally half the time, my fabrication skills are getting pretty good thanks to all the non functional crap I keep buying. Just had to modify my frame last night for "CB750" crash bars that are "designed" for my bike. So hopefully, you were able to make those bearings work? I hope they're good.
Pay more, spend less is my new motto. I'm buying highly vetted parts now that cost more but have saved me money on not buying them twice, like my controls and master cylinder for the brake which I bought 3 times actually.
With wheel assemblies, as with many other similar parts of your bike, it is important to understand the nature of the mechanical assembly and how it works to avoid difficulties. The hub assembly would seem to be a very simple bunch of components - and it is - but getting it correctly assembled (on purpose) seems to send some people into a tail spin, so here is a tour.
The idea behind how our hubs are engineered is to make the front axle, the inner bearing races, and any spacers or extra bits like a speedo drive, function as a structural element of the suspension. Imagine assembling all these parts by themselves. For the front, you'd have the two fork lowers, the outside spacers, the inner bearing races and the center spacer all bolted together by the axle. Assembled loosely, you have a wobbly mess, but clamped tightly, you have a very strong and rigid connection between the two fork lowers. The larger the axle diameter (and hence, the larger inner races and spacers) the stronger and more rigid this assembly will be. which is why high performance applications have large hollow axles. This is the intent of the basic design. The wheel itself simply spins on the ball bearings located on this structure.
So when assembling the bearings into the hub, the distance between the bearings you are trying to achieve is not the space machined into the hub, but the distance the spacer that goes between the bearings locates them apart. If you were to leave the center spacer out, you could drive the bearings completely home on both sides, but then when you put the rest of the assembly together and tightened the axle you would be placing great axial pressure on the bearings causing them to fail very quickly while losing most of the structural stiffness of the assembly. The bearing seats in the hub are machined a tiny bit deeper than needed to make sure the spacer is what determines the bearing spacing and not the hub. If the spacer were even a little bit too short, the hub would hold the bearings too far apart and you would have axial compression again on the bearings leading to failure.
Proper assembly is simple. Press one bearing all the way into its seat until it hits bottom. Slide the axle in, and from the other side slide on the center spacer followed by the other bearing. This will aid tremendously in aligning up the other bearing for pressing it in. You can use the axle itself to press in the bearing if you round up enough spacers and washers and simply tighten the nut down until the center races clamp down on the center spacer. Then take the axle back out. When properly assembled, the center spacer should be a "tight slip fit" between the two center bearing races. If you end up going to far as in your case (which is not hard to do), striking the center bearing race on the opposite side will move the other bearing back out to the perfect spot. Technically, this of course is a very evil way to treat your new bearings, but in real life the impact needed will move the offending outer race with no ill effects.
So since the bearings are the only moving parts, they are the only thing that need lubrication, right? While that is true, I always coat EVERYTHING with a film of grease. While they don't move against one another, given time they will corrode and sometimes can be nearly impossible to disassemble, so a little protection is a good idea!
The idea behind how our hubs are engineered is to make the front axle, the inner bearing races, and any spacers or extra bits like a speedo drive, function as a structural element of the suspension. Imagine assembling all these parts by themselves. For the front, you'd have the two fork lowers, the outside spacers, the inner bearing races and the center spacer all bolted together by the axle. Assembled loosely, you have a wobbly mess, but clamped tightly, you have a very strong and rigid connection between the two fork lowers. The larger the axle diameter (and hence, the larger inner races and spacers) the stronger and more rigid this assembly will be. which is why high performance applications have large hollow axles. This is the intent of the basic design. The wheel itself simply spins on the ball bearings located on this structure.
So when assembling the bearings into the hub, the distance between the bearings you are trying to achieve is not the space machined into the hub, but the distance the spacer that goes between the bearings locates them apart. If you were to leave the center spacer out, you could drive the bearings completely home on both sides, but then when you put the rest of the assembly together and tightened the axle you would be placing great axial pressure on the bearings causing them to fail very quickly while losing most of the structural stiffness of the assembly. The bearing seats in the hub are machined a tiny bit deeper than needed to make sure the spacer is what determines the bearing spacing and not the hub. If the spacer were even a little bit too short, the hub would hold the bearings too far apart and you would have axial compression again on the bearings leading to failure.
Proper assembly is simple. Press one bearing all the way into its seat until it hits bottom. Slide the axle in, and from the other side slide on the center spacer followed by the other bearing. This will aid tremendously in aligning up the other bearing for pressing it in. You can use the axle itself to press in the bearing if you round up enough spacers and washers and simply tighten the nut down until the center races clamp down on the center spacer. Then take the axle back out. When properly assembled, the center spacer should be a "tight slip fit" between the two center bearing races. If you end up going to far as in your case (which is not hard to do), striking the center bearing race on the opposite side will move the other bearing back out to the perfect spot. Technically, this of course is a very evil way to treat your new bearings, but in real life the impact needed will move the offending outer race with no ill effects.
So since the bearings are the only moving parts, they are the only thing that need lubrication, right? While that is true, I always coat EVERYTHING with a film of grease. While they don't move against one another, given time they will corrode and sometimes can be nearly impossible to disassemble, so a little protection is a good idea!
As always gents, thanks a million. Mobius really appreciate the in-depth and invaluable info - next time I do a wheel bearing I'll be following your steps to a t. Everything I'm doing on this bike is pretty much for the first time, learning so much, both by trial and error and from this forum. I had no idea that the spacer determined the bearing position - I thought once both bearings were fully seated then it was job done. Not so - seating them fully ends up being too tight. Now I know for next time, and I'll be remembering the assembly steps next time. Thanks again =)
Yeah Chronically, lucky. My man in the local shop had a bearing puller - with a gentle pull we freed up one of the bearings and now both spin freely. Lesson learned. And I agree with you - buy once and buy well. At least as much as possible. Have to say though, the bearings I bought were cheap as chips (from All Balls), but here's hoping they'll do the job.
This afternoon I worked on the front brake caliper. Was about to rebuild it with the kit I just received (new piston, rubber boots etc) but decided I should strip the paint off first as that's the look I'm going with. Sprayed a bunch of carb cleaner on it to work on the paint, then got busy with a fudged tool on the dremel -
- they came out pretty good. Gave them a final good going over with wire wool to give them a brushed finish. Question - does aluminium oxidize? And if so should I clear coat the caliper? Or will it stay looking like it does now?
Cold here in MTL - minus 14C. Went skating for three hours this morning, now working on some beer. It's been a great Saturday.
Yeah Chronically, lucky. My man in the local shop had a bearing puller - with a gentle pull we freed up one of the bearings and now both spin freely. Lesson learned. And I agree with you - buy once and buy well. At least as much as possible. Have to say though, the bearings I bought were cheap as chips (from All Balls), but here's hoping they'll do the job.
This afternoon I worked on the front brake caliper. Was about to rebuild it with the kit I just received (new piston, rubber boots etc) but decided I should strip the paint off first as that's the look I'm going with. Sprayed a bunch of carb cleaner on it to work on the paint, then got busy with a fudged tool on the dremel -
- they came out pretty good. Gave them a final good going over with wire wool to give them a brushed finish. Question - does aluminium oxidize? And if so should I clear coat the caliper? Or will it stay looking like it does now?
Cold here in MTL - minus 14C. Went skating for three hours this morning, now working on some beer. It's been a great Saturday.
The Jimbonaut said:
Yes. A hard polish slows the process but doesn't prevent oxidation. Wax will also work, but still has a life. A clear coat is the ticket.
Shark hide huh, I'll see if I can find some, thanks for the tip. You're in New Brunswick? How's winter treating you - things are looking frosty here and I'm down with that. No biking, but skating for all I'm worth. And getting filthy in the shed, love the winter =)
No skiing here yet either, but I live right across from a big lake which takes care of my daily skate. Your avatar - that's a leg X-ray? You sidelined for a while?
Cleaned up the callipers a bit more today, I'm giving them a brushed finish which looks great at the moment but I'm definitely going to be looking into the clear coat. Looked for Shark Hide - none here but there are a few Canada-based marine shops that carry it. I'll see if they have it in aerosol.
I'll check out the aluminium epoxy paint as well Hillsy - just googled it but didn't get a specific product return - I'll keep looking.
Another question - I'm going to be cutting the front fender, and I'm guessing it's made of steel? Hope so, as I want to give it a brushed finish too.
Have a great evening fellas,
- J
Cleaned up the callipers a bit more today, I'm giving them a brushed finish which looks great at the moment but I'm definitely going to be looking into the clear coat. Looked for Shark Hide - none here but there are a few Canada-based marine shops that carry it. I'll see if they have it in aerosol.
I'll check out the aluminium epoxy paint as well Hillsy - just googled it but didn't get a specific product return - I'll keep looking.
Another question - I'm going to be cutting the front fender, and I'm guessing it's made of steel? Hope so, as I want to give it a brushed finish too.
Have a great evening fellas,
- J
Maritime
Over 10,000 Posts
Shark hide is a paste I believe, so not likely to be aerosol. I am still recovering from a deer hitting me on my GL, got a new hip and a shit ton of Ti in my lower leg. Had to regrow 2 inches of bone and was in a bed for six months so still rebuilding the muscles in my leg now that the bone is healed. But I rebuilt the GL and road it on the Cabot trail on my 1 year anniversary of getting hit so that was good. Your CB is coming along keep at her.
The voice of experience indeed! I'm learning by my mistakes but learning before I make them rocks way harder. I'm planning to cut them just after the eyelet that keeps the brake line in position (or maybe it's the speedo, don't remember) - I'll tee it up and see how that looks with potential water trajectory. Good call Hillsy, thanks man
CarbsAndCylinders
Careful With That Axe Eugene
If that fender is in nice shape, then you could sell it and get a lighter fibreglass one and paint to match the rest of the tins.
Maritime said:
Mother of God, you ok man? That's a hell of a spill, I'm sorry to hear that. Sounds like the worst of it is behind you, and I wish you well for the rest of your recovery. This past summer a buddy of mine in ON rode his V Star into the back of a truck that pulled out in front of him, broke his back and shattered his foot. Had him on major painkillers, a turtle shell and some pretty major reconstruction in his foot - he's back up and running now, albeit gingerly. Tango career on hold for the foreseeable though.
Wishing you well mate, and very glad to hear you're back in the saddle. Take it easy out there 8)
Maritime
Over 10,000 Posts
Thanks man, it sucked for sure but I am at about 70% recovered. I can walk with and without a cane now and can ride, drive my manual car etc. and I am supposed to be able to ski again so winters won't suck as bad. Not sure I will be able to skate though, it's pretty hard to get my foot in some boots because the ankle is solid. Cheers
Damn border - whoever came up with horizontal sucks. Slam that thing vertical right down the middle, all the way down. Canadians! Fancy some freakin' sub-arctic snowshoe action? Not a problem - head up north! Canadians! Tired of all that hypothermia? No problem! Head down to Miami, Ontario, where it's ragtops down and cuba libres on the beach all the way!
Me and the wife got into x country skiing a while back, didn't do much last year as the snow was awful but hoping to get out there this year for some. Hope you get some ski time in - the winters are totally doable as long as you can snap into some gear and make the most of it. I'll have a skate for you mate.
Me and the wife got into x country skiing a while back, didn't do much last year as the snow was awful but hoping to get out there this year for some. Hope you get some ski time in - the winters are totally doable as long as you can snap into some gear and make the most of it. I'll have a skate for you mate.
