Doms CB550F1 project

[Oddjob]

Look at the back of the arm, on the inside edge near where the cain adjusters are welded on there is a small vent hole drilled into the arm. Clean the hole as it normally gets partially blocked with rust flakes. A small straw or something similar inserted in hole and jiggled whilst shaking the arm will allow the rust to drop out
.

[DomP]

Look at the back of the arm, on the inside edge near where the cain adjusters are welded on there is a small vent hole drilled into the arm. Clean the hole as it normally gets partially blocked with rust flakes. A small straw or something similar inserted in hole and jiggled whilst shaking the arm will allow the rust to drop out
.

I thought there should be a venting hole, must have been powdercoated over, I'll have a look.

[DomP]

Look at the back of the arm, on the inside edge near where the cain adjusters are welded on there is a small vent hole drilled into the arm. Clean the hole as it normally gets partially blocked with rust flakes. A small straw or something similar inserted in hole and jiggled whilst shaking the arm will allow the rust to drop out
.

None on mine Ken, doesn't look like they've been painted over at there's no evidence.  The most rattly but is the pressed bracing plate that has no vent hole either so I will just drill my own and flush it out

[DomP]

All cb550 swingarms on Ebay are missing drainage/vent holes, would it be sensible to drill a 3-4mm hole so I can flush the crap out and put cavity wax in?

[Oddjob]

The CB500 swinging arm certainly has them and it's essentially the same arm.

[DomP]

The CB500 swinging arm certainly has them and it's essentially the same arm.

Shall I just pop a couple of holes on each side, wouldn't at the lowest point on the underside be the best place to allow condensation to drain out?

[Oddjob]

I'll take a pic of the 500 arm, it may be that the hole is there but so blocked and painted over that you can't see it.

[Oddjob]

https://www.ebay.co.uk/itm/314995246801?hash=item49572e06d1:g:zqgAAOSwQbNlZh7B&amdata=enc%3AAQAIAAAAwF%2FweM8O98kTru5%2B7Nwb27qwvYviYl8ad9Dns%2BNX51SArPK5SE7uqP3hqHbnaoTDgXe7XzDOEkBq2mfrUK0oVubNz6HFMD7B%2Fl%2Feqj46nppPTpMOA4W%2B4sL1%2Btku9%2FVgjxJYIAVBiB2L3j81ompIjRQij2P4wzIa84aVY6KlWlmrzwkPzGPoTIrRuvJI%2BTiroeQo%2BLd9uXh2a601T%2FsllI%2FtbpRzugJYVswV2zEDXmBOzmFIdYkd50dvescZrKT35w%3D%3D%7Ctkp%3ABk9SR8a83IqGYw

7th pic, you can see the hole.

[DomP]

I'll go out and wire brush it to see if it's there,  why would they put it there and not at the lowest point to allow draining?  Water will pool in the bottoms on those

[Laverda Dave]

I'll go other and wire brush it to see if it's there,  why would they put it there and not at the lowest point to allow draining?  Water will pool in the bottoms on those

It could be because if they put the hole in the bottom it could potentially allow water to find it's way in especially when you consider this is directly behind the rear wheel and subjected to the spray thrown off the rear tyre.

[Oddjob]

I'd do the hole where Honda put it on the 500 Dom, I'm using the same hole to fill both sides with Waxoyl after it's been powder coated, then allowing it to drain out afterwards just leaving the layer of wax behind. Do that every few years and it should outlast me

[taysidedragon]

I'll go other and wire brush it to see if it's there,  why would they put it there and not at the lowest point to allow draining?  Water will pool in the bottoms on those

Any holes in frames or swingarms are often there to allow the escape of hot gasses during welding. It reduces distortion  I believe.

[Laverda Dave]

I'll go other and wire brush it to see if it's there,  why would they put it there and not at the lowest point to allow draining?  Water will pool in the bottoms on those

Any holes in frames or swingarms are often there to allow the escape of hot gasses during welding. It reduces distortion  I believe.

Rickman put holes in their frames for the same reason Garath. It was also to allow the nickel solution to drain during the plating process otherwise the frame would rot from the inside out.

[Oddjob]

The problem though is that the swinging arm, because Honda didn't use seam welding but spot welding which allows moisture to form inside the tubes, this then rusts the tubes from the inside out, hence why you can hear rust flakes tinkling around inside, the holes allow you to get rid of those and also to put something down the tubes to stop any future rot.

[Laverda Dave]

Did Honda put holes in all their frames Ken because I haven't seen any on the 400 frame or was it just the 500/550’s?