Topic: swingarm needle bearing setup -on the cheap???

[Alan F.]

I was thinking about my swingarm bushings, they're old and probably need to be replaced, I know there are members here that offer very good bushings at good pricing, there are a few needle-bearing kits from Z1 (a great company) and OBB (if I dare ever buy from them...) but they're pricey for what they are.  I took a look on Service Honda at the swingarm pivot of my 92 NH750, here's the diagram.

does anyone think it would be simple enough to put a kit together for sohc 750's with parts like these?  I deal with a great bearing shop at work that can source anything I'm likely to need except the spacers and sleeves...which I can fab at home with suitable precision.

I figure with my swingarm bushings removed, I could just make a few measurements and go from there... right?

[HondaMan]

My only comments about switching to needle bearings:

All of the accel/decel and aft braking foces pass through this important bearing in this frame setup, so make sure it is robust. When selecting tolerances, multiply all fitments by 18 to see how far this will let the rear axle wiggle back and forth (e.g., .005" tolerance x 18" length = .09", or about 3/32" of slop). This makes for discomfort in cornering, while you chase the wiggle around.

1. Start with a slight (0.0005") interference fit, as the arm's bearing tube is not round anymore after about 25,000 miles. Or, bore yours round again, then select the bearings accordingly. Otherwise, the needle cage will have to distort oval as it goes in, and you will likely find it tough to insert the shaft collar afterward (maybe insert the collar first?). The distorted system may wear itself together, but it will never be 100% contact: so make sure the bearings can take the load. (e.g., it should carry at least a 5000 lb load so a 50% contact will leave you with 2500 lb capability to cover shock loads.)
2. Make sure the setup has a way to get lube into it: some needle setups do not.
3. Make sure there are seals on it that work: some do not. Small dirt eats needle bearings like Pac-Man.
4. Finally, make sure the new setup lets the collar clamp TIGHTLY to the frame's insides, or it will be very loose, indeed!

Overall, the brass bushings are the better design selection for this frame.

[jonbuoy]

I got a needle bearing kit from Z1 - came with a new shaft, needle rollers for the pivot and also needle rollers for the end "float", the shaft needle bearings were standard off the shelf items.  I took them to a few bearing shops before I fitted them - they all agreed that the end float bearings were custom made or at least not standard bearings.   

[Alan F.]

Thank you both for exactly the answers I was hoping for....without anyone asking me, "why do you want to do that?" or worse.   
I'll search back for HondaMan's brass bushing posts, you offer the kit if I'm not mistaken....I'll read all about it and educate myself before I ask. 


There are two kinds of people in the world, those who understand the binary system...and those who do not.   

[OldSchool_IsCool]

There are two kinds of people in the world, those who understand the binary system...and those who do not.   

Actually, it's 10 kinds of people    And remember, there's no place like 127.0.0.1

[754]

Remember if you make any parts of a needle assembly, that contacts the needles as a wear surface it will have to be properly heat treated.

I was thinking that taperd rollers, ie timkens would work well, but you may have to weld collars on swingarm ends and machine.. but at least you have good control over preload and slop.. works well on a certain other brand..

[Terry in Australia]

Ok, I'll be the one to ask, "why"? I've just finished replacing the needle roller bearings and shaft in my Suzuki GS1000, (180 bucks for genuine parts, thank you very much.......... Ka-Ching!) the PO had them replaced only 5 or 6 years ago (bike hadn't been ridden for last 5 years before I bought it) but he used a steam cleaner/pressure washer to clean his bike and so the old bearings were literally just a pile of brown, shapeless rust, and the arm was virtually seized.

Like you discovered, my bearing shop couldn't match them with any commonly available bearing. Interestingly, in my copy of Petersens "Great bikes of the 70's" under "performance mods" they recommend converting Suzuki's GS750 from needle roller bearings to bronze, or even Teflon bushings.

I installed a needle roller bearing kit in my CB750F2, they are probably still around on EBay for around $70.00 for the kit, including a new shaft. I kind of wish I didn't now, seeing first hand how fragile they are if not kept dry, clean, and well greased. I guess from my perspective, good bronze bushes are cheaper, tougher, and less susceptible to accidental destruction if not regularly maintained. Just my $0.02. Cheers, Terry.

[ev0lution7]

i can vouch for HONDAMAN my bronze bushing he installed have been a god send i LOVE THEM!!!!!!!!!!!!!!!!!!!!!! the cb750 no longer handles like a pig on stiltz it handles like a sport bike SHOULD be for the sake of argument go ride a rubber mount harley then ride a cb750 (stock) harley (even for a rubber mount) feels titer

[Steve F]

FWIW.....I made a set of bushings out of DELRIN and have put on "several thousand" miles since.  I checked the swingarm this fall for side play, and couldn't detect any.  When I pressed the bushings in, I had to go back through with an expanding adjustable reamer to re-size them to the shaft.  After it was all assembled and greased up, there was just enough of an interference fit that the swingarm would take a few seconds to drop (no wheel or brakes on the swingarm).  At first, I was concerned that the DELRIN would crack or something like that, but so far, I can't complain.
Terry,
You mentioned using TEFLON for making bushings........that stuff is like hard butter and squishes.  I've made GEARS out of delrin, and holds up better than nylon too.  Oilite bronze would have been the next choice if the DELRIN didn't work out.

[HondaMan]

FWIW.....I made a set of bushings out of DELRIN and have put on "several thousand" miles since.  I checked the swingarm this fall for side play, and couldn't detect any.  When I pressed the bushings in, I had to go back through with an expanding adjustable reamer to re-size them to the shaft.  After it was all assembled and greased up, there was just enough of an interference fit that the swingarm would take a few seconds to drop (no wheel or brakes on the swingarm).  At first, I was concerned that the DELRIN would crack or something like that, but so far, I can't complain.
Terry,
You mentioned using TEFLON for making bushings........that stuff is like hard butter and squishes.  I've made GEARS out of delrin, and holds up better than nylon too.  Oilite bronze would have been the next choice if the DELRIN didn't work out.

I use the 841 Oilite Bronze for the built-in oiling "backup" if someone forgets to grease them for a while, and for their incredible strength, compared to most materials. It takes shock loads very well, which almost no other bearing can do, except maybe an oversized tapered roller type. For racing apps, there's also a 9000 series bronze I've used (a dream to turn on the lathe!), and I have some of that in my 750 now, as an experiment. It's not self-lubing, though, so scheduled maintenance is a must with it.

[Steve F]

Yeah, I like the oilite for it's porous properties and the ability to prevent seizing. Nice stuff to turn to very tight tolerances.
Never tried the 9000 bronze, you have any links to data on the stuff?

[ev0lution7]

hondaman doesnt charge that much....
dont hesitate just send him your swing arm and shut up and ride!

[Terry in Australia]

Terry,
You mentioned using TEFLON for making bushings........that stuff is like hard butter and squishes.  I've made GEARS out of delrin, and holds up better than nylon too.  Oilite bronze would have been the next choice if the DELRIN didn't work out.

G'Day Steve, yeah mate, I was surprised to see that too, I've never tried Teflon for swingarm bushes and don't think I ever will, I was just quoting from "The Good Book", ha ha! Cheers, Terry.

[Alan F.]

I guess from my perspective, good bronze bushes are cheaper, tougher, and less susceptible to accidental destruction if not regularly maintained. Just my $0.02. Cheers, Terry. 

ev0lution7  hondaman doesnt charge that much....
dont hesitate just send him your swing arm and shut up and ride!

 

Yup, this one's gonna be a daily ride so I believe I will go this route.  Thanks for all the input Gents.

HondaMan how's your schedule look for after the holidays?

[HondaMan]

Yeah, I like the oilite for it's porous properties and the ability to prevent seizing. Nice stuff to turn to very tight tolerances.
Never tried the 9000 bronze, you have any links to data on the stuff?

A good online place, where I buy my 'raw' metals, is MSC. Check them out at mscdirect.com. The old term "9000 bronze" is now called "SAE 660", so you can search for that. The former term "Oilite" is now called "SAE 841" bronze today. It all changed with the country's switch to ISO naming, I think, but I grew up with the older terminology.

[HondaMan]

I guess from my perspective, good bronze bushes are cheaper, tougher, and less susceptible to accidental destruction if not regularly maintained. Just my $0.02. Cheers, Terry. 

ev0lution7  hondaman doesnt charge that much....
dont hesitate just send him your swing arm and shut up and ride!

 

Yup, this one's gonna be a daily ride so I believe I will go this route.  Thanks for all the input Gents.

HondaMan how's your schedule look for after the holidays?

I'm working over one for Jay (Jay's Performance, but forgot his online name at the moment  ) right now. I suspect my next opportunity after that would be right after Christmas, because of Christmas stuff and my being 'behind' over my wife's broken leg. She's starting to walk (and cook!) again some, so I'll soon have more time available. Certainly after New Year, I should be in good shape to work on some more lathe projects. I have to work on weekends in the garage, to allow the little heater to warm it up to usable temps (40 degrees, at least), which takes about 2-3 hours. Otherwise, the tolerances don't work out right, and I'm not happy with the end result. I might be too picky, but with a Lifetime Warranty, I really don't want to do it over because I went too fast or too cold!

The cost ranges from $88 for a simple refit, if the collar can be saved (ground down or polished round), to about a max of around $180 if everything is torn up (new new collar, end caps, felt washers, etc.) and the shock bushings are also replaced. I'm stingy, so the shipping is on you, too.    My "take" at the end is about $12 for the simple jobs, as I kickback part of it to SOHC4 to help them pay their bills for all of us.

It's really just a good reason to go work on my lathe. 

[Bouncer]

I guess from my perspective, good bronze bushes are cheaper, tougher, and less susceptible to accidental destruction if not regularly maintained. Just my $0.02. Cheers, Terry. 

ev0lution7  hondaman doesnt charge that much....
dont hesitate just send him your swing arm and shut up and ride!

 

Yup, this one's gonna be a daily ride so I believe I will go this route.  Thanks for all the input Gents.

HondaMan how's your schedule look for after the holidays?

I'm working over one for Jay (Jay's Performance, but forgot his online name at the moment  ) right now. I suspect my next opportunity after that would be right after Christmas, because of Christmas stuff and my being 'behind' over my wife's broken leg. She's starting to walk (and cook!) again some, so I'll soon have more time available. Cetainly after New Year, I should be in good shape to work on some more lathe projects. I have to work on weekends in the garage, to allow the little heater to warm it up to usable temps (40 degrees, at least), which takes about 2-3 hours. Otherwise, the tolerances don't work out right, and I'm not happy with the end result. I might be too picky, but with a Lifetime Warranty, I really don't want to do it over because I went too fast or too cold!

The cost ranges from $88 for a simple refit, if the collar can be saved (ground down or polished round), to about a max of around $180 if everything is torn up (new new collar, end caps, felt washers, etc.) and the shock bushings are also replaced. I'm stingy, so the shipping is on you, too.    My "take" at the end is about $12 for the simple jobs, as I kickback part of it to SOHC4 to help them pay their bills for all of us.

It's really just a good reason to go work on my lathe. 

I know we already talked about you doing my swingarm for me and after new year will probably be the time I will be sending it out to you. I had another question though...sorry I ask too many questions

I know you asked to powdercoat AFTER you install the bearings. Is there any risk involved in the temperature of the oven? I would hate to ruin your nice job on the swingarm by heat from the powdercoating.

[HondaMan]

I can't imagine that a powdercoat temperature would affect anything in the bushings. But, you might mention to the powdercoater that they need to plug the ends of the tube before painting or heating. The paint is very thick, and the end caps won't fit in after painting unless the paint is ground back out. Also, if they were to spray the paint into the hole, it can seal the surface of the bushing, preventing lube, and might reduce the I.D.

At least one rider solved it this way: he made wooden dowels (1" diameter) about 1/2" long, with 5/16" holes in them, and pushed them into the tube ends, up to the face of the bushings (about .200" recessed), then he installed a piece of allthread rod through and a couple of nuts to keep it in place while they painted. You could also use some of those plastic or vinyl cap plugs, pushed into the holes.

The swingarm tube is 1.044" diameter (when new), so a 1" dowel and a wrap of masking tape should work just about perfectly to make a seal. 

[Bouncer]

I can't imagine that a powdercoat temperature would affect anything in the bushings. But, you might mention to the powdercoater that they need to plug the ends of the tube before painting or heating. The paint is very thick, and the end caps won't fit in after painting unless the paint is ground back out. Also, if they were to spray the paint into the hole, it can seal the surface of the bushing, preventing lube, and might reduce the I.D.

At least one rider solved it this way: he made wooden dowels (1" diameter) about 1/2" long, with 5/16" holes in them, and pushed them into the tube ends, up to the face of the bushings (about .200" recessed), then he installed a piece of allthread rod through and a couple of nuts to keep it in place while they painted. You could also use some of those plastic or vinyl cap plugs, pushed into the holes.

The swingarm tube is 1.044" diameter (when new), so a 1" dowel and a wrap of masking tape should work just about perfectly to make a seal. 

Excellent information thank you sir.

[Steve F]

Yeah, I like the oilite for it's porous properties and the ability to prevent seizing. Nice stuff to turn to very tight tolerances.
Never tried the 9000 bronze, you have any links to data on the stuff?

A good online place, where I buy my 'raw' metals, is MSC. Check them out at mscdirect.com. The old term "9000 bronze" is now called "SAE 660", so you can search for that. The former term "Oilite" is now called "SAE 841" bronze today. It all changed with the country's switch to ISO naming, I think, but I grew up with the older terminology.

Thanks for that info.....we buy quite alot of items from MSC, but metals isn't one of them.

[crazypj]

I guess from my perspective, good bronze bushes are cheaper, tougher, and less susceptible to accidental destruction if not regularly maintained. Just my $0.02. Cheers, Terry. 

ev0lution7  hondaman doesnt charge that much....
dont hesitate just send him your swing arm and shut up and ride!

 

Yup, this one's gonna be a daily ride so I believe I will go this route.  Thanks for all the input Gents.

HondaMan how's your schedule look for after the holidays?

As a Rickman thread turned up few days ago, I'll add what little I know. (FWIW)
 When Rickman were developing frames fro inline 4's they tried all types of bearings and found bronze gave best support over widest area (didn't specify type of bronze though  )  Needle bearings were lower friction but tended to wear faster because of smaller contact area
The frames were originally hard nickle plated because it cracks when flexed, where plating cracked was a problem so they stiffened up frames in flex area's.

[Markcb750]

My experience with applying needle roller bearings in a small angular movement applications, like the swingarm, is that corrosion due to vibration (commonly called fretting) will occur.  This is exasperated by the fact that the grease is not well distributed by the rollers rotated through fractional rotations. 



I replaced my swing arm bushings with Oilite bronze, The hard part was communication with the machinist, he did not quite grasp how important the relationship between the length of the stationary pivot pin and the (swing arm + two thrust washers) IS.  In the end he let me use his measuring equipment to final size the system for near zero clearance in both directions.  I final sized the bronze with a brake cylinder hone.

The hole deal cost me $117 including the brake cylinder hone.

[754]

I cant see oilite lasting more than 1/2 as long as 660... if it is oiled.. if you are too lazy to oil, use oilite.

The 660 should have grease grooves though.

[Markcb750]

I never found a significant life difference between Oilite an hard bronze, both last for decades in low velocity applications.

My guess is most swingarm bushings fail because of contamination due to lack of sealing grease.

 

[Soos]

Needle bearings are evil.....

If you use one way clutch needle bearings it's not so bad, reduces rocking grooves by forcing bearing to move in 1 direction only.
Still a PITA to keep enough dirt out.


In practice I have seen plain bearings do things longer than I thought they could.
Especially on heavy equipment.
Most of those failures I have repaired(non motorcycle) involved either mis-alignment or lube failure over a extended period.
Cheap, easily made, and if taken care of from the beginning, then they will outlast you.


When was the last time anyone actually lubed their swingarm bushings?

I do, but I had a necessity to make custom bushings to adapt a new swingarm onto my bike(longer). Lengthened the surface area the bearings support by about 75% compared to stock, and out of better material as well.
About every 3 oil changes I lube it up and wipe the excess off. Keeps fresh grease in the bearing surfaces regularly, pumping a bit out to keep broken down grease from poorly lubing the bearing, contributing to early failure.
But being I made them, I REALLY don't want to have to make a new set in 10 years.
Reaming the holes... no problem, reaming them perfectly aligned from one bore to the other? Thats the trick.



l8r