Topic: Bronze bushings - might have made mushrooms out of them

[Tim.]

So I gleefully pounded the crap out of my bronze bushings a couple weeks back (ok ok, I didn't pound them, they were frozen and I didn't have much trouble getting them into place) and at the time my stock swingarm sleeve didn't fit.  Blinded by my obvious infallibility I assumed the stock sleeve and non-stock bushings were a bad match.

To further my belief that I could not possibly have caused this problem, Mikesxs (yes my XS650) sells a new sleeve with one of the selling points being that the old sleeve might not fit the new bushings and that this one would.  So, a month later my new sleeve arrives.

You can guess the punchline.  Obviously I distorted the bushings when I put them into the swingarm.  So now I'm stuck with a) ordering new bushings, waiting a month for the shipment to arrive, paying someone to press them in properly and hoping that works or b) honing out the bushings to match correct the problem.

Anyone encounter this?  I'm going to take the swingarm to a machine shop to let them mic it and compare to the sleeve.  Hopefully they can hone it out to make it a true cylinder again and match the sleeve, but I'm not holding my breath.

[754]

No big wupp!!

 Do you know sleeve size.. Might be as simple a running a reamer through... or using an expanding reamer. You likely only have a burr at point of entry where you hit it..

Too bad you are not close.. a sixpack or two and you would be done..

[Tim.]

Yeah, I'm hoping it's that quick and simple.  Its 22mm I think.

[Tim.]

What tool would I want for this job?  Just called a reamer?  Might be a good excuse to buy something

[754]

Expanding reamer

KBC tools has cheap ones.. slow work but you can fit piston pins with one if need be..

[bistromath]

I used a small 3-stone brake hone. Worked like a charm, but be gentle and use plenty of cutting fluid and clean the hell out of it when you're done.

[HITMAN]

Although having a cheap arbor press is nice, pressed in some bushings only to find they collapsed enough to be too tight. 

Luckily with a Harbor Freight nearby, I bought a set of reams that proved to be nice to have around.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=38577

[754]

Tintin, keep in mind I was assuming your bushings are concentric, that is od &id turned in one operation, then the reamer will work well. If the bushings are off, then you could have trouble.

Expandable reamer can also be seered a bit if you have a slight misalignment.


Brake hone tends to follow easiest route and the stones can rock, be careful with it as it can remove material where you dont want it removed and it can bell mouth the bushing.. in short ruin a real nice long lasting fit.

[754]

 Like ebay #110198190730

Reamers like the middle ones with 6 straight blades.

22mm sounds like the od of your bushings??

Reamers cut in very small increments, cut hard it will dig in.

[dusterdude]

i bought an expandable reamer from wt tools,wttool.com,when i put new pistons in my panhead.worked real good.

[Jerry Rxman Griffin aka MuthaF'er]

I was browsing through the odd ball parts cabinets in the hardware section at Lowe's this afternoon. Never know what you're going to find or need. Bronze bushings! Large sizes too. Unfortunately SAE and not metric.   

[Jinxracing]

tintin, if you don't have the means to hold and index a reamer dead-center to the hole you're trying to ream, you could pretty easily end up in a bind. It'll cut, but I think you'll probably end up having problems with the hole going out of round and ending up oversized due to the inevitable misalignment with anything but the most precise setup. For example, the tailstock on my lathe will ride a few thous high if a piece of swarf gets caught underneath it. That slight misalignment will cause a reamer held in the tailstock to cut an oversized hole. I can only imagine how that problem would be magnified if I were trying to run a reamer precisely through a hole with a handheld drill motor (which is what I'm assuming you'll be doing...please forgive me if I'm wrong ).

My suggestion would be to investigate something that 754 mentioned earlier...the possibility of a burr on the inside lip that might prevent the sleeve from going through. If in fact it's an obstruction on the inner edge where you were pounding and the majority of the inner "meat" of the bushing is still round I'd carefully attack the inner edge with a VERY fine file (#4 cut Swiss jeweler's half-round for example) and just try to take down the raised edge. If done carefully you might get away with it without touching the majority of the internal surface.

On the other hand, if your bushings are in fact distorted and out-of-round, having a machine shop bore and ream them in situ will probably cost quite a bit more than a new set of bushings. You could also buy some Oilite bronze bushing stock and an appropriate-sized reamer (probably about $30 for both) and I'm sure one of us here on the forum that owns a lathe would be willing to help you out by making a new set of bushings for you. I'd be happy to help if you could provide the exact dimensions.

Good luck!

[Lumbee]

...just my 2 cents...when you insert those bushings it really should be done with a press...hydrolic or arbor.  I put some new bronze (or was it brass) bushings on a 750 swing arm, and started out by trying to whack them in with a mallet.  Luckly I realized that this wasn't the right way to do it before I mauled them up.  An arbor press made short work of the job.  A press fit means that bushing is actually .0002 oversize.  You need constant even pressure to press them in, and the bushing needs to be square to the hole its being pressed into.  Without an press, none of these prerequisites are met.

[754]

To get a good fit Bushings are often pressed in & THEN sized. Pretty common practice.

I was talking about using expanding reamers which are usually turned by hand with a big tap handle, slow cutting in minute amounts.. with care can produce very precice fits. They can also be used with a pilot to center on your other bore, but I use them a lot without pilots. You can correct slight misaligment by steering them a bit at times but to do this you may have to use a slightly smaller shaft or mandrel to do so.

 It is just plain old fitting and assembly work, its done all the time..

[Tim.]

Well I'm going to take the bits to a local machine shop today to see what we're up against.  If they're out of round and not able to be easily bored to fit, I'll make some choices from that point on.

[Terry in Australia]

Like I mentioned in your Yammy 650 thread and bistromath mentioned above, the 2 or 3 stone expanding MC hone is the way to go Tinny, cheap and much less aggressive than an expanding reamer.

I've done it on my CB750K3 when I machined up new bronze bushes for it, and even though it's slow, you won't bugger them up as you'll have plenty of time to check on your progress along the way. Cheers, Terry.

[754]

I maimtain that a hone with stones that can swivel is not a good coice as  you cannout prevent it from cutting areasother than the burr and risk bell mouthing. Also not steerable for slight alignment change.

The hone will work, but will not provide as good a fit if bore isburred from install.

Fixed hone.. whole different story.

[Terry in Australia]

Well it's the same design as an engine cylinder hone mate, so why would it not work? A fixed hone, on the other had, would be more susceptible to buggering it, due to the fact that you can't hold an electric drill perfectly still, so there's no room for error.   

[754]

A lot of people realize that honing a cylinder does not produce the straightest bore, use a boring bar first, then finish hone. You are then honing a cylindrical bore and you try to follow that.

Now if the swingarm bush is just shrunk then the hone may do it nicely..if you dont run off the ends a few times, but you will  have no feel. If the bush is shroomed at the install end, then part of the hone will ride on the high part, and the other end is cutting clearance, where it may not be needed. So the bushing can end with less contact than desired.

If you had a tight fit on the assembly but could just get the shaft thru with light force with a hammer, the difference between that and being able to twirl the shaft with fingers would be about 5 cuts with the reamer, it cuts slow but precisely.. and it des not remove material merely by touching againstit, bronze is tough and resists cutting..

The next thing that happens is you ream one bush and the shaft is just sliding  through, when it get to the inner end of the other it stop. You look at it and notice that it is off to the side very slightly! How are you going to correct that with a hone?? You dont, just keep honing away till it fits, then the shaft is riding on a few high spots, a fe month later it is loose.. again.With the expanding reamer you can lean a bit one way or the other tochange direction slightly.

Another question begs to be asked.. if you are running a closefitting bronze bush, should it have a spiral track for lube??

[D-Ral]

I know this is an old thread, but I'm going to add to it. I got impatient using threaded rod trying to press in my bronze bushings. I had a hard time keeping the first one straight in the cylinder. So I pounded it in, and ended up mushrooming the bush. I slid the collar in from the opposite end and realized the bush was ballooned only at the end it was whacked. I pressed the other side in properly, and took some fine grit sandpaper and used my finger to lightly remove the lip from the affected bushing until the collar could slide in. I took it back out, greased everything, an checked for play with the bolt through the collar. Didn't feel any, but we will find out when I rebuild the bike. I don't know if sanding is bad.  I cleaned it up well, and the bushing still felt smooth. I had already screwed it up, so I figure i had nothing to lose. If I can ride it as is this summer, great. If it's a little jiggly, which I assume it will be, I'll replace the bushings AND the collar next time and I'll invest in the proper tools. Like patience. Don't do what I do!

[Terry in Australia]

Ha ha, well it might be an old thread, but it's timely for me mate, so thanks for that, I'm going to install some bronze swingarm bushes tomorrow, they're in the freezer now and I'd considered tapping them in, but now I think I'll find some threaded rod and do it properly. Cheers, Terry.

[D-Ral]

Ha, I'm glad. I'll let you know if my attempt works out for me.

[Bootlegger56]

I thought hones were for the imparting a surface finish and not sizing?  But I have been wrong many times before.  Probably this time too!  I like the threaded rod/freezer method but that's cause I don't have a press!

[Terry in Australia]

I used the hone because the bushes were too tight once they'd been installed and I couldn't think of a better method to make it work at the time mate, it was pretty slow going, but the result was good, and they're still in the bike now, so no biggie.

I've got a press here, but I've buggered things in it when they've moved slightly under pressure before, so the threaded rod method will do the job today. I'm going to machine up a couple of "top hat" shaped inserts with the same OD as the swingarm pivot tube that will go inside and protect the ends of each bush as it's pulled in, so hopefully there'll be little chance of damage. Cheers, Terry.

[Roach Carver]

I've used threaded rod with washers and had no trouble at all.