Bitza...

[trickytree]

Been collecting bits for another project for a while and made a start at last. Got a well butchered A7 rigid frame...has been chopped (badly) in a previous life and the back end was widened to take a 5x16 wheel so first job was to put that right.



 Got some 4x2 box section and made up a bit of a jig. The headstock is machined all the way through and luckily I had some mild steel the right size. Frame is obviously upside down as its only the drive side hardtail tubes that needed replacing.


I was a bit concerned that the tubes had been slugged close to the lugs making life difficult...need'nt have worried, no slugs fitted..just butt welded!




Axle plates fixed in correct possision



New frame tubes bent and in place. As I'm a bit low on gas I have just tacked the slugs at the momment.



Frame was all over the place and took a fair bit of heating and bending to get it something like.

[andy2565]

what sort of bike are you making,did you use seamed or seamless tube,i have got a big reconstruction to do on a 1920's sunbeam frame,and always interested to see simple jigs,a flat track twin would be nice !

[trickytree]

Looks wise, pure hotrod...something like this...



I use seamless tubing from Ringwood Precision (there on ebay)...good folk to deal with, they have good stocks and will sell in small quantities unlike many steel stockholders.

[andy2565]

oh yes ,a board racer,nice one ! i just wondered about the tube because the chap who does my grasstrack engines,was a works grasstrack rider for bsa and his thoughts are that seamed tube is stronger,due to the fact that the thickness of the steel is constant when rolled,but the seamless can vary and have weak spots,and interested to learn that when a bsa frame was put together in a jig,with the lugs in position with brazing foil in between the lug and tube then drilled ,and pegged and placed in an oven/furnace which welds it all at once.
i was interested because i was going to convert a later swinging arm to the earlier type,when blasted you can actually see the pegs,but i wouldnt heat the lug to remove incase of weakening the frame.

[iansoady]

I believe that the brazing makes the steel tube in the lugs "hot short" ie becomes brittle when it's heated.

[trickytree]

Finished welding the frame frame tubes in. Fitted the cases and gearbox to check the mounting holes all line up, which they do.



Started messing around with the rear wheel, its a plunger item and needed a fair bit of bodging. Spindle plates on the frame had been altered to accept a 20mm spindle. I only had one spare spindle knocking around and as luck would have it it was 20mm so that fitted in one side no problem once the end was turned down to pass through the stub axle. The stub axle needed to be 22mm (7/8") but I didnt want to open up the frame that much so I filed .020" off the top and bottom of the frame and milled the same from each flat on the stub axle. Turned up some new bearing spacers as the new spindle is smaller than the original one and thats as far as I got. The brake plate had some rivets that were fouling the frame so I ground those off and welded them up....also welded a plate into the redundent anchor slot so will have to sort out a torque arm...might use the silencer mounting lug, not sure yet. Need to pick up some new sprockets, wheel bearings and rear wheel nuts to finish off.

[trickytree]

Had another play with this one this afteroon. I was wandering around Newark autojumble last Sunday when I came across some girder blades and bought them on a whim as the price was right (very right in fact). The chap didnt know what they were off (he sold car bits normally) but were with a load of NOS BSA stuff he had come across, mudguards, tool boxs etc. I wasnt convinced they were Beeza  because of the tapered tubes and have since identified them as Norton/Webb. Wandering around a guy said he had some yokes in the van...these were BSA so I snaffled those up aswell.

Obviously matching the two is not going to be straight forward so I had a mock up session to see what it looked like...and I liked it very much so have decided to keep 'em.



Rear tyre is to small, Its all I had to mock up with and I'm not sure if I will use the 8" front but the general layout is there. Its only when I wheeled it outside for a propper look that I realised the rear has a slight stretch to it, about 2-1/4" infact...I never noticed it on the workbench. Im not bothered about it as such (being a 6 foot fat git) but what bothers me is when I repaired the frame the tubes had not been slugged, just butt welded. Thing is, I have stripped all the paint and was sure the right hand tubes had not been modified...and even in the daylight I cant see where the hardtail has been extended.   Will have to look into this further.

Would still like to try and get the rolling chassis sorted before I get started on the engine, but these old parts dont always come up when you want them. Mind you I also have a swinging arm A10 frame to play with now

[muskrat]

You will need to put some fins on the barrels  . Looking good. Clever git.
Cheers

[tombeau]

Is the A65 head and rockerbox just there to help with the mock up or are you fitting it to the A10 engine?
Looking good.
Cheers,
Iain

[trickytree]

Is the A65 head and rockerbox just there to help with the mock up or are you fitting it to the A10 engine?.......

Will be using the A65 head and making a one off set of barrels....A10 at the bottom morphing into A65 at the top.

Infact I managed to pick up a radiused side and face cutter just the other day. I just want to get the rolling chassis done before I start on the engine as I only have a single garage so need to be able to move things around to get away from flying swarf!