Reaming swing arm bushes

I ran into a problem doing my swing arm bushings.
It turns out that when the spindle is inserted through one side it is offset into the other side to the point that it binds up.
It can be tapped into the other bush but takes a wrench to turn it. Not good.
Bwolfie, Brent, suggested I have to ream them which is what Phil Radford from Fair Spares suggested too.

Has anyone here had to do this and if so where and what kind of reamer do I get.
I had been looking at reamers online but am waiting for someone who has done this to direct me to the the right kind, length or reamer.
The weekend is tomorrow and I want to put this puppy together. Help please

I'm not sure it's something you want to do by hand. You might have to make a trip to San Jose or to Rabers if they will do it. If you'll pay for the flight, I'll do it for you. It's 40 deg. here tonight.

You might find a local shop that could do it. It's not magic. I may be wrong, again.

Good luck.

Dave
69S

DogT said:

I'm not sure it's something you want to do by hand. You might have to make a trip to San Jose or to Rabers if they will do it. If you'll pay for the flight, I'll do it for you. It's 40 deg. here tonight.

You might find a local shop that could do it. It's not magic. I may be wrong, again.

Good luck.

Dave
69S

Click to expand...

You're killing me Dog. It can't be brain surgery. I am talking a couple of thousands to be removed. I just want to hear from someone who has done this.
I can pick up a hand reamer for about $36 + shipping. It would be nice to have this in my tool box.

' Line Rear ' , like Camshaft Bushes , the Reamer must go through both .As In the bl;ades / cutters be the length across the outside of the S/Arm bushes , Plus.

This is a topic that was pretty popular on the mc-chassis list a few years back. The most popular solutions were based on using a piloted reamer, the kind used to ream king pin bushings on cars. Other schemes involved ways to set the swing arm up in a mill and bore the bushings in line, or using a honing machine with long enough stones to hone both bushings at once. The difference here is that all those methods were based on starting with an undersized bushing. You are starting with bushings that are already the right size, but in a bent swinging arm. When you ream the bushings in line, their bores will no longer be round throughout their length, but will be oval for at least part of the bushing length.

Having said all that, I've done it two ways, and both worked. When I made my own swing arm, I used some simple jigs on the mill to be able to bore one side, and then turn the swing arm over and bore the other side, and end up with them both in line.

I'm almost embarrassed about the other method, but only almost. I had a stock swing arm that was pretty much like yours sounds, and used a triangular machinists scraper to carefully add clearance where needed. That's a real hack solution, and I don't recommend it, but it worked. After a bit of scraping, the swing arm could be pivoted with little effort, but there was no free play. The bike handled just fine afterwards, noticeably better than it did with the worn out original bushings.

Another alternative would be to remove the bushings, turn a bar to just fit the swingarm bores, and use heat from a torch to bend the ends until the bar will go through both, letting it cool with the bar in place. I've not done that, but it should work.

Ken

Ken

Yes on of the standard adjustable reamers is not going to make a nice job, unless you can make up an extension. Now if you have a lathe, and the reamer is long enough, can you make up a bush to go between the reamer shaft and the other swing arm bush. That should get the bush bores parallel?

Cheers Richard.

P.S how tight is the swing arm axle pin. I made an oversize pin and reamed out the cradle hole and original bushes to suit. And added extra fasteners in the cradle to attach the pin. Works for me!'

I wonder how this differs from when the bikes were built new. The swingarms would probably have twist and alignment issues. And when the spindle was installed, it would bind in the second bushing, just like described here. Then what? A big hammer and a drift? The binding bush and spindle would wear in. And most folks at the time wouldn't know the difference. I'm not recommending this, just wondering how the issue was dealt in the factory. What do you think?

Stephen Hill

http://www.motorcycleframeman.com/

If the spindle fits in each mounted bushing individually then the swingarm is probably bent. How much closer could he get?

Stephen Hill said:

I wonder how this differs from when the bikes were built new. The swingarms would probably have twist and alignment issues. And when the spindle was installed, it would bind in the second bushing, just like described here. Then what? A big hammer and a drift? The binding bush and spindle would wear in. And most folks at the time wouldn't know the difference. I'm not recommending this, just wondering how the issue was dealt in the factory. What do you think?

Stephen Hill

Click to expand...

Couldn't have said it any better. I can drift it into the other bush and using a 7" box wrench make it turn. I have a bolt screwed in with a 1/2" head on it. It's turns with one hand so in comparison to the length of the swing arm it would feel tight and support it's own weight. It is by no means locked up so I figured if I got this reamer and removed a couple of thousands it would be ok. There I go thinking agian.

rpatton said:

http://www.motorcycleframeman.com/

If the spindle fits in each mounted bushing individually then the swingarm is probably bent. How much closer could he get?

Click to expand...

I like the link. Since I live only 30 minutes away I'll call them tomorrow.
I still have the tranny to work on so I still have time.

I can drift it into the other bush and using a 7" box wrench make it turn.

Click to expand...

It sounds so close it might be OK ? Why not bolt it in and see how it feels ?

Cash

Mine binds, & has done for a few years now. Just resprayed mine & looked at putting a new spindle & bushes in it, but as there was no play, left the originals in it. Looked at adjustable reamers on the internet & were all too short.
In situ, without the shockers on, the swinging arm will stay in any position you leave it, but seems to work fine.

As all you experts are aware reaming oilite bushes will result in smeared over and bloked pores

splatt said:

As all you experts are aware reaming oilite bushes will result in smeared over and bloked pores

Click to expand...

Not sure about reaming, but I do know from experience that turning and boring oilite bushes in mill and lathe with carbide inserts is normal practice, and does not damage them. You do need to use sharp tools. I've not tried reaming them, but IIRC you can do it as long as you use a sharp reamer.

Ken

This forum doesn't have the facility to apply 'reputation' points but I wish it did for Ken's first post. His second explanation sounds like a thoroughly sensible real-world answer.

We're talking about mass-produced motorcycles that suffered from poor quality control and which were in the main, bought by ride-to-work motorcyclists who dealt with maintenance at the weekends and had to have everything back together again for monday morning without any access to a machine shop.

A bearing scraper is not very often called for these days but in any text dating from prior to 1950, it appears as often as a spark plug spanner. I'd feel that there is nothing much to lose by easing the bushes where they're binding and seeing how it offers up. It's what 'fettling' is alll about.

Flo said:

Mine binds, & has done for a few years now. Just resprayed mine & looked at putting a new spindle & bushes in it, but as there was no play, left the originals in it. Looked at adjustable reamers on the internet & were all too short.
In situ, without the shockers on, the swinging arm will stay in any position you leave it, but seems to work fine.

Click to expand...

Thats the dampening for the worn out girling isn't it???

probably find the eye would move easily with the right size bar in it, I reckon they welded them up with the bush eyes as one tube and cut the middle out , because the inside welds are all machined back

rpatton said:

http://www.motorcycleframeman.com/

If the spindle fits in each mounted bushing individually then the swingarm is probably bent. How much closer could he get?

Click to expand...

And the winner is Bob!!!! You nailed it right on the head Bob.
I took the swing are to "The Frame Man" in Sacramento today and he looked at it and showed me that it was indeed bent. As you can see from the picture it must have been layed down at one time before I bought it 30 some odd years ago. He said it was repairable to like new and I should have it back in about a week.
He also said for me to bring in the frame to have it checked too. He does an alignment check for free.
The guy's name is Pat. The nicest guy's around. he also said if he can't fix it or it breaks while trying to fix it then it's free. What have I got to lose.
He also said it won't be more than $115. A used one runs around $225 from a number of sources I've found and a new one is close to $500.
I just want to thank Bob for the link to these guy's. They've been doing this for over 30 years. I hope it all works out.
Now to strip the bike down to the bare frame. that'll give a chance to see what the iso rubbers look like at least.

Look at the 2 rods that are thru the bushes and where the axle goes and how they are twisted.
Never occurred to me that's how to check for staightness without a jig.

Glad you got it sorted. Keep us posted.

Dave
69S

I've heard Pat is very good at what he does. If you take your frame to him, you might want to ask him if he wants the cradle and iso's too.
At the bottom of this link Vern Feuston had my frame on his table a long time ago. He lists the dimensions.

http://www.nortonownersclub.org/support ... el-offsets

Yeah, I want Pat to look at my frame but before I rip it all down to bare I'll ask him what He'll need still on the bike.
This has gotta cost me a bit but it will feel great to ride a bike which is true and in line and tight.
The weather has just been great here. I wish it would rain so I don't feel like I am missing riding time.

Well, I got my frame and swing arm back from the Frame Man today. That's the actual name of the business, in Sacramento.
I posted earlier about the "hump" in the back bone and a few people replied that it was normal and that they all have it.
Pat at the frame shop said it wasn't normal and that it should be straight.
Mine is now straight. They have done lots of Nortons and have the factory specs and jigs to set it right.
My bike, before I bought it 25 some odd years ago, had been layed down.
The fram was a 1/4" off to the left, the rear loop was also pushed to one side and the rake was all wrong due to the humped spine.
The swing arm which is what started this thread was twisted and that is why the spindle wouldn't go in straight.
Well, it goes in fine now and when sat down on my granite counter it doesn't rock anymore.

I have a lot of painting and polishing to do now. The trans is going to be completely rebuilt as soon as my parts arrive from RGM, new front and rear sprockets and chain, Clutch center and discs, isos redone, new Dave Taylor head steady and forks redone.
Whats left is the master cyl upgrade.

This going to a tight straight running machine.
Funny thing is, it really seemed to handle great even with the twisted swing arm and frame.