Garage Night: New video - all about swingarm bearings

We've done another episode of our web video show about working on
bikes.

This time it's removing, replacing and maintaining swingarm bearings.

http://www.garagenight.tv/replacing-swingarm-bearings/

Looking forward to discussion - the merits of freezing/heating etc.

All the best,
Waz from Garage Night TV

 

You had me thinking you were serious...I can never take a budweiser
drinker serious. ;^)

 

In communiqué

Too late for me !

I managed the relay and control arms on the SO YZ250, though I had to
use a hacksaw, sharp implements and a lump hammer to get the totally
rusted remains of full complement needle roller bearing outer shells
out. Not having a FOAD vice I used a length of threaded rod, nuts,
sockets and natty bearing driver discs to get the new ones in. As these
small castings would go in the oven I used heat and had the new bearings
in the freezer. I reckon it helped. In fact, I re-heated them when it
became obstinate to good effect - differential expansion works.

I had to take the swinging arm to an expert with a press though as the
brute force approach wasn't shifting the old bearings.

Good video though.



--
+-------------------------------------------------------------------+
| Pete Fisher at Home: |
| Voxan Roadster Yamaha WR250Z/Supermoto "Old Gimmer's Hillclimber" |
| Gilera GFR * 2 Moto Morini 2C/375 Morini 350 "Forgotten Error" |
+-------------------------------------------------------------------+

 

I buy whatever's cheapest (within limits). Can you take a budget-
conscious beer drinker seriously?

 

I realise this bloke has a funny foreign accent, but was he even
speaking English?

"roller bearing"

"caged bearing"[1]

wtf?

[1] I thought this might have been a reference to Bern at first, but
realised that although I had know idea what the bloke was saying, it
wasn't in German, I was pretty sure of that.

 

Another good vid.

A good tip for needle bearings is to have a magnetic tray
underneath when you extract whatever it is - any needles
falling out stick in the tray rather than making a break
for freedom under the workbench.

I've successfully used the bearing-in-freezer routine (they
were left in for a couple of days) to make it easier to
push them in on an interference fit. You'll never get them
to drop in (certainly nothing motorbike size!) but it does
help to get them in. They'll retain the cold for a good 5-10
minutes, so taking them out one at a time will be fine.

I'm surprised about the comment on anodising - you've obviously
not used the right anodisers! Anything can be re-anodised,
but you have to make considerations for anything non-alu -
steel buses or insert will get eaten away during acid
(type 2/3) anodising. What is better? It's personal choice
and availability of decent tradesmen to do a good job. Cost
would be roughly the same as a decent powdercoat. I think I'd
have gone with powder coat on the swingarm too.

 

snip>

I wouldn't use heat or freezing on a needle roller bearing because
there isn't enough surface area to make it worth the effort.

I agree about having a magnetic tray to catch rollers that want to
take a holiday because the little bastards always make a break for
freedom and you only find that one when you're about to go for a test
ride.

 

I decided that the effort was worth it, if only psychologically, and
time wasn't of the essence.

--
+-------------------------------------------------------------------+
| Pete Fisher at Home: |
| Voxan Roadster Yamaha WR250Z/Supermoto "Old Gimmer's Hillclimber" |
| Gilera GFR * 2 Moto Morini 2C/375 Morini 350 "Forgotten Error" |
+-------------------------------------------------------------------+

 

I must admit that I've not had the experience of needle bearings,
but the sealed bearings that I've used on swingarms, wheels,
ride height adjusters and the like have all benefited from being
left in the freezer for a few days.

Of course, the biggest tip about bearings is to take the old
one to a decent bearing sales/distributor and to get them to
supply a new one based on the bearing number and not your bike
make/model, as it will 99.99% of the time be a fuckload cheaper,
and usually of much better quality too.

 

Hi Antony,

In my view, if it's going to be worth re-anodising something you need
to be able to bring the metal back up to the finish of the original
pre-anodising surface.

I think if the anodising has 'gone off' like mine had it's likely you
won't be able to restore the metal well enough to make it worth re-
anodising, and if you tried you'd be disappointed with the results.

In my case it definitely wouldn't have been possible to polish the
swingarm back to something that looked good enough to anodise - hence
powdercoating. Let's see how it stands up to rocks, sticks and ruts!

The clincher, though, was that the arms of the swingarm are box
section extruded or whatever, while what i'd call the 'girdle' at the
front is cast. So you'd get differing results when anodised. I believe
cast alloy doesn't anodise that great??

Best,
Waz

 

A good dip in a warm caustic soda bath will remove the existing
anodising, at which point you're left with the bare metal, so
any issue with the anodising itself will be gone at this point.
You shouldn't need more than 10 minutes in the dip to completely
strip any anodising.

The trouble with anodising is that it is only a 25 micron or
so coating, which is grown onto the original metal surface.
Any nicks, cuts or scuffs will effectively stay in the metal,
so after stripping the prep is vital to get rid of anything you
don't want to still be there after anodising. This is the time
killer, as you really want the best surface finish here to give
you the best looking results; not much different to paint prep
really!

Once prepped you can re-anodise, and this just grows a new
oxide coating onto the bare metal. After sealing (and optional
colouring) you'll have a brand new anodised layer which should
be tougher than powder coat.

I've had the frame on the race bike (a Ducati 600SS with a
620SSie engine fitted by me) powder coated and was less than
impressed with the results. Three years later and the surface
has already dulled, sections worn away (my fault for using
ratchet straps through the frame!) and generally looking scruffy.
Obviously it being a race bike means it gets a lot more abuse
than usual, but it still doesn't inspire confidence.

It depends more on the composition of the alloy than it does
the formation method, but you normally find that extruded is
indeed made up of a different composition than cast, which is
where the differences come in. Having said that, any decent
anodiser will be able to compensate their setup and should be
able to achieve a good result no matter what.

Home anodising isn't that hard - I've done small bit and pieces
with no more than a few plastic tubs, an old car battery, an alu
plate as the cathode, some alu wire, a 2 quid bottle of caustic
to clean parts first and an 8 quid bottle of sulphuric acid ("One
Shot drain cleaner") from B&Q mixed with distilled water as
the anodising solution. You can buy anodising dyes off ebay for
a tenner a bottle (makes 1L) so for a very small amount of money
you can be doing your own parts at home ... maybe you should
give it a try as a future video? ;-)

A good guide here, if you're interested...
http://www.focuser.com/atm/anodize/anodize.html

 

Very true. Luckily for me it was head bearings for the SS frame
and they match a rear wheel kit on a Fiat Punto or something,
coming in at a bargain £7 or so the pair.

 

If it's a bearing sitting in an aluminum housing heat definitely
helps. Throw a housing in a low temperature oven and it makes
removal of bearings much easier, sometimes allowing them to
just drop out.

Seems as if cooling both would work against you though.

 

I'm not saying heat *won't* work at all because (obviously) it does
help but I'd try the bearing at room temperature first and see how
things progressed. It's probably more important to make yourself a
nice little assembly tool so you know you're fitting the bearing
square then either draw it in or knock it in steadily.

The best thing about that type of bearing is that if you **** things
up and get it stuck they're easy to smash out with a hammer and
chisel. Apparently.

 

I saw that One Shot cleaner stuff and was sizing it up for anodising!
Is it pure sulphuric? I thought there might have been other shite in
it that would cause problems.

Did you use desmut with nitric in your home anodising set-up, or not
worry about it?

What I really want to know is how to recoat the bespoke steel bolts,
axles, spacers etc on my bike in that original yellow finish, which I
think is some kind of zinc plating.

Waz

 

More likely that coating was cadmium .

 

I don't need to watch the video to agree with the merits of heating/freezing
to help remove/install bearings. Do it regularly, the biggest consideration
is the types of metals and temperatures involved.

 

sheesh, I said nothing about buying it... I cook with it not drink it!
(makes great beer bread)

Remember SMILE! 8^) Makes everyone wonder where you hid the limburger
on their bike.

 

It's 91% so a lot better than most battery acids you can buy,
and a damn sight cheaper too. The other 9% is probably a stabiliser
and a bit of colour too, as it comes out purple. Once bubbling it
goes clear. You want to get it down to around 15-18% sulphuric
so for the whole 1L bottle you're talking between 4-4.5L of
distilled water. You can use a battery acid tester (dropper)
to check the acidity, but measuring works well enough for me.

Here's a pic of my little setup, a 10L box (I think) with a
nice thick piece of alu plate running across the bottom, hooked
up to an old battery!
http://img140.imageshack.us/img140/8634/img0431l.jpg
bubbling away:
http://img401.imageshack.us/img401/1773/img0432wk.jpg
bubbles died down - almost done
http://img526.imageshack.us/img526/8103/img0433ew.jpg

I've not needed to yet, and didn't really bother because it's
not that easy to get hold of nitric. Maybe I should do a bit more
research and find a cheap supplier. I just use a lot of distilled
water to keep things clean both before and after anodising.

The original (yellow/gold) finish to Ducati nuts and bolts
is cadmium plating which has then been passivated, known
as "cad & pas". It's quite tricky to get done now (here
in the UK) as, much like real chrome, you need to be licenced
to do it, but have a Google and you may be able to find somewhere
close to you to get it done.

Personally, I just replace with stainless and be done with it!

 

Snag, any advice on how to strip and recoat the bolts with zinc
chromate?