'29 bitser racer...

[barry.swanson]

[quote="brett.hayhurst"...that bloke with the torch is worth a few cartons !!
Brett[/quote]

...shame he only works for C.Ash, pretty good rate though...works from home, don't tell the IRD

[nevhunter]

The late 20's gearbox mount plate is pathetic. Totally inadequate for the job. If you have an original bike and ride it gently and carefully that is fine but most of them have suffered over time and are obviously a problem. You could fabricate a heavier one and replace it with that. Having just one weak attach at the top is not good. Nev

[barry.swanson]

.... and the doorstop.

...sacrilege but it works very well.

[barry.swanson]

The late 20's gearbox mount plate is pathetic.... Having just one weak attach at the top is not good. Nev

...yes Nev, I have a couple of of hollow cases that have had the stay attachment lug broken off , I have given some thought to the inadequate bracing for the top of the box, and how it might be improved, but it's not as easy to improve as the bottom...
If it behalves the same as the the B31, the box will get forced rearward, so the 2 little bolts that hold the poor old top bracing bracket are being subjected to a damaging stretching force rather than a less damaging compression force... would appreciate hearing from anyone who has some thoughts as to how this could be done.

[nevhunter]

The rear chain always pulls as the torque is multiplied by both the gear ratios and the sprocket ratios . There is not a lot of twist as the chain runs are close together . Shock loads making it want to move around cause the cracks eventually. Really the only way around this is to have the engine and gearbox unitary as everything has done eventually
. New Imperial had it in 1930. The American super X had it in 1925. Peugeot had it in their twin OHC 4 V racer in 1913. The original SQ4( had the design been completed as proposed), would have had it in 1931 . Nev

[barry.swanson]

...its taken about 3 years to get this lot together, shipped it off to Hamilton yesterday for plating...found it a bit of a traumatic thing to, a little like a parent farewelling a child I imagine, every piece is precious, some are fragile, some I've spent hours over, some would be hard to replace, some like the seat springs are rough and it will be interesting to see what can be done with them...

[chris.vredenbregt]

I know the feeling Barry,I went to the chromer a few years ago and I asked him do you ever loose things in the proces and he told me,YES,but we make a picture of every item to know what we are looking for if something is missing.
I was not convinced and not happy,but fortunately everything showed up after the plating ....chris(good luck Barry)

[adrie.degraaff]

Never crome old springs they will break.

[john.deeth]

...frame bracing, brake pivot and rebuilt gearbox platform.
Spent most of today, a wet Sunday fortunately, with a file in my hand getting the platform level...my mate with his bloody gas torch again Adrie
I was concerned the gearbox might move so added a lump of steel to each end of the platform through which a couple of bolts will be screwed.
It might seem a bit excessive but with "Burt" the B31 that I race, having the gearbox move is a pain in the bum. I often come in after a few laps to find the primary chain has tightened up, it's one of the issues I'll try and get to this winter.
When I got my " bits of Ariel", I got 4 frames, all 4 gearbox platforms had either some serious cracks or gone completely , hard to believe the person that designed the frame couldn't forsee the huge strain he was expecting the platform to take, both the torque of the drive train and the flex of the frame, hopefully with the piece of tube I've added behind it and lots of lovely bronze in every joint, she'll be right now.

G'Day Barry,
My fathers idea has been to TIG weld the underneath side of the gearbox platform to the two frame rails. There is a gap of a few mm's between the rails and the platform. We run three fillets of weld on each side of the platform for a bit of extra strength and peace of mind.
Cheers,
John.

[barry.swanson]

[quote="john.deeth
My fathers idea has been to TIG weld the underneath side of the gearbox platform to the two frame rails. There is a gap of a few mm's between the rails and the platform. We run three fillets of weld on each side of the platform for a bit of extra strength and peace of mind.
Cheers,
John.[/quote]

evening john, yes it's a weakness alright...as you can see from the picture on the previous page, there's lots of brassing, underneath as well like you speak of.
That cross-tube should help also....unfortunately the guy that does my work dosn't do TIG.