Topic: DELRIN swingarm bushings

[HondaMan]

The Delrin 100 is about 2850 PSI strength, while the Delrin 500 is about 3300 PSI strength. These values are about the same as the original Zamac (composite metal-plastic powder) material Honda used in the K0 and K1 bikes. This was abandoned in the K2 (around June of 1972 or so) to become phenolic material (about 4500-5000 PSI), which remained until the end of 750 production.

In the 1990s, Honda changed the replacement bushings to be steel powdered composite. This makes the bushing-collar interface steel-on-steel, which is impossible to lube well: these usually rust together after just a few years and eat each other up.

Oilite bronze, even the cheapest version, is over 10,000 PSI strength, and comes with impregnated turbine oils that come to the surface if someone forgot to grease the arm and the bearing starts getting hot: this is an ideal bushing material for these bikes. Oilite (the inventors) make even harder versions of their 841 material: this is what I use on my Lifetime Warranty swingarm rebuilds.

During the 1980s, several aftermarket companies brought out SAE660 bronze and series 9000 bronze bushings for these bikes: this lasts a long time, too, if kept lubed (I went 80,000+ miles on mine). They are in the 6k to 9k PSI range of strength, which is almost as strong as the pivot collar itself. They are sensitive to lack of lube, though.

[Pinhead]

The Delrin 100 is about 2850 PSI strength, while the Delrin 500 is about 3300 PSI strength. These values are about the same as the original Zamac (composite metal-plastic powder) material Honda used in the K0 and K1 bikes. This was abandoned in the K2 (around June of 1972 or so) to become phenolic material (about 4500-5000 PSI), which remained until the end of 750 production.

In the 1990s, Honda changed the replacement bushings to be steel powdered composite. This makes the bushing-collar interface steel-on-steel, which is impossible to lube well: these usually rust together after just a few years and eat each other up.

Oilite bronze, even the cheapest version, is over 10,000 PSI strength, and comes with impregnated turbine oils that come to the surface if someone forgot to grease the arm and the bearing starts getting hot: this is an ideal bushing material for these bikes. Oilite (the inventors) make even harder versions of their 841 material: this is what I use on my Lifetime Warranty swingarm rebuilds.

During the 1980s, several aftermarket companies brought out SAE660 bronze and series 9000 bronze bushings for these bikes: this lasts a long time, too, if kept lubed (I went 80,000+ miles on mine). They are in the 6k to 9k PSI range of strength, which is almost as strong as the pivot collar itself. They are sensitive to lack of lube, though.

One comment concerning the use of lube on the oillite bearings. NEVER grease them. Grease will clog the pores and render the oil capacity of the bushing itself useless. Heavy oil can be used.

Before I install them in a machine at work, I further saturate them. Simply grab the bushings with two fingers covering one end with your thumb. Fill bushing with oil to the brim, cover it with your finger and squeeze. You'll see oil come "through" the bushing. Wipe off the excess with a rag and install. I've found that this procedure makes them last MUCH longer in a low lubrication environment.

[HondaMan]

The Delrin 100 is about 2850 PSI strength, while the Delrin 500 is about 3300 PSI strength. These values are about the same as the original Zamac (composite metal-plastic powder) material Honda used in the K0 and K1 bikes. This was abandoned in the K2 (around June of 1972 or so) to become phenolic material (about 4500-5000 PSI), which remained until the end of 750 production.

In the 1990s, Honda changed the replacement bushings to be steel powdered composite. This makes the bushing-collar interface steel-on-steel, which is impossible to lube well: these usually rust together after just a few years and eat each other up.

Oilite bronze, even the cheapest version, is over 10,000 PSI strength, and comes with impregnated turbine oils that come to the surface if someone forgot to grease the arm and the bearing starts getting hot: this is an ideal bushing material for these bikes. Oilite (the inventors) make even harder versions of their 841 material: this is what I use on my Lifetime Warranty swingarm rebuilds.

During the 1980s, several aftermarket companies brought out SAE660 bronze and series 9000 bronze bushings for these bikes: this lasts a long time, too, if kept lubed (I went 80,000+ miles on mine). They are in the 6k to 9k PSI range of strength, which is almost as strong as the pivot collar itself. They are sensitive to lack of lube, though.

One comment concerning the use of lube on the oillite bearings. NEVER grease them. Grease will clog the pores and render the oil capacity of the bushing itself useless. Heavy oil can be used.

Before I install them in a machine at work, I further saturate them. Simply grab the bushings with two fingers covering one end with your thumb. Fill bushing with oil to the brim, cover it with your finger and squeeze. You'll see oil come "through" the bushing. Wipe off the excess with a rag and install. I've found that this procedure makes them last MUCH longer in a low lubrication environment.

The use of grease on Oilite is very common, but in slow-moving, high-pressure applications: the reason for using Oilite in those applications is to allow the oil to keep the grease liquified if the temperatures rise and the grease is hard. It's a "backup lube" mechanism in those instances. The engineers at Oilite were very helpful about this when I contacted them about this upgrade for these old swingarms.

If the Oilite bearing is supplying support in a faster-moving application (like a speeding shaft, or fan, for instance), then you're absolutely right: oil should be used and not grease.

[cycleman]

Why not just upgrade the swing arm to needle bearings?  There is a kit out there to do this. A little more money than the bushing route, but not a lot.

[mystic_1]

Why not just upgrade the swing arm to needle bearings?  There is a kit out there to do this. A little more money than the bushing route, but not a lot.

There are a variety of reasons why some prefer bushings to bearings in this application.  Bushings are simpler, can tolerate higher loads, and wear more evenly in situations like this where there's little movement.

mystic_1

[MCRider]

Why not just upgrade the swing arm to needle bearings?  There is a kit out there to do this. A little more money than the bushing route, but not a lot.

There are a variety of reasons why some prefer bushings to bearings in this application.  Bushings are simpler, can tolerate higher loads, and wear more evenly in situations like this where there's little movement.

mystic_1

When I first heard of the needle bearing kits years ago i thought they would be neat. But since then I've learned as Mystic says they aren't  really stronger, and they are susceptible to rusting up. The real upgrade is bronze bushing in my mind, with hondaMans attn to the grease pathways.  IMO

[Terry in Australia]

I installed one of those needle roller bearing kits in my F2 when I restored it, thinking that it'd be neat, but since then I've pulled a couple of Suzuki GS1000 swingarms apart (they were fitted with needle roller bearings from new) and I was horrified at the condition they were in, they were damaged way beyond servicable limits, and had to be replaced at a cost of $150.00 (they're not a standard size, so you gotta buy them from Suzuki) along with the pivot tube, all because the grease had been washed out over the years, and the bearings were just black rusted scrap.

I converted the second one to bronze bushes and machined down the pivot tube to suit, all up it cost me 20 bucks, and will probably last forever. I also replaced all the needle roller bearing pivots on my neighbors Suzuki RM250 motocross bike's rear suspension with bronze bushes, and it works fine, for a fraction of the cost. BMW use adjustable tapered roller bearings for their swingarms and they are the "ants pants", but impracticle unless you're building a whole new frame. Cheers, Terry.  

[Soos]

Why not just upgrade the swing arm to needle bearings?  There is a kit out there to do this. A little more money than the bushing route, but not a lot.

There are a variety of reasons why some prefer bushings to bearings in this application.  Bushings are simpler, can tolerate higher loads, and wear more evenly in situations like this where there's little movement.

mystic_1

When I first heard of the needle bearing kits years ago i thought they would be neat. But since then I've learned as Mystic says they aren't  really stronger, and they are susceptible to rusting up. The real upgrade is bronze bushing in my mind, with hondaMans attn to the grease pathways.  IMO

As Terry also stated nedle bearings are.....ok IF  maintained properly.
I have seen needle bearings eat into hardened shafts in commercial applications.


If there is no full revolutions of the needle bearings (only partial revolutions as the swingarms do) you can't really fully use the potential of needle bearings.
They are nice. I've used them in a few personal project applications.
When given the ability to get a few full rev's out of them, and lubed properly, they are GREAT.



But for swingarms.... my money is on the bronze bushings for accessibility to material and longevity.




l8r

[HondaMan]

Why not just upgrade the swing arm to needle bearings?  There is a kit out there to do this. A little more money than the bushing route, but not a lot.

There are a variety of reasons why some prefer bushings to bearings in this application.  Bushings are simpler, can tolerate higher loads, and wear more evenly in situations like this where there's little movement.

mystic_1

When I first heard of the needle bearing kits years ago i thought they would be neat. But since then I've learned as Mystic says they aren't  really stronger, and they are susceptible to rusting up. The real upgrade is bronze bushing in my mind, with hondaMans attn to the grease pathways.  IMO

As Terry also stated nedle bearings are.....ok IF  maintained properly.
I have seen needle bearings eat into hardened shafts in commercial applications.


If there is no full revolutions of the needle bearings (only partial revolutions as the swingarms do) you can't really fully use the potential of needle bearings.
They are nice. I've used them in a few personal project applications.
When given the ability to get a few full rev's out of them, and lubed properly, they are GREAT.



But for swingarms.... my money is on the bronze bushings for accessibility to material and longevity.




l8r

Roger that on the needle bearings: the Engineering manuals for those bearings state unequivocally that they are "not to be applied to reciprocating systems", meaning that if they don't rotate all the way around, they cannot spread the load nor lube. When Kawi first introduced these on their mid-70's bikes, they came with 4 needle cages on each shaft (two at each end) which are impossible to change out, let alone get apart, after about 20,000 miles (witness KZ650 and 750). The needles and cages get so distorted that the assembly slowly eats itself, it seems. Greasing slows it down, but again, the Engineering manuals point to "moderate pressure oil flow" as a proper lube for them, not grease.

Maybe the 750, with it's dry sump system, could reroute some of the returning oil to the tank through the swingarm? 

[tbpmusic]

Maybe the 750, with it's dry sump system, could reroute some of the returning oil to the tank through the swingarm? 

I think I had to work on one of those once !!

[HondaMan]

Maybe the 750, with it's dry sump system, could reroute some of the returning oil to the tank through the swingarm? 

I think I had to work on one of those once !!

In chopper circles, one popular Triumph mod was to route the oil return through the frame tubing instead of using visible hoses. A few of them actually worked: most leaked.

But then, they WERE Trumpets, which I think came from the factory with a big 2 quart pan that fit underneath the vertically-seamed cases while parked. 

[mk2jettavr6]

I have used DELRIN bushings on my turbo vw track car for years! I made some shiftkits for vws in a small quanity and sold them on a popular forum about 6 years ago and out of the 50 kits ive sold i never had 1 request for replacement bushings or any failures!