New member and Bantam build

Thank you Edward.

Like I said -- such experimenting is not recommended.

Can be painful -- but its like the little Jack Horner who stuck his finger in the pie story -- I just had to do it...  

PS -- see how that web has been drawn -- that is what I mean by being WRONG. With the flexing of the upper (tank) tube, relative the down tube, that web buckles and exténds. After a few thousand of these reversals (like several race meetings) the web fails and it is usually the down tube that breaks just under the bottom of the web...s although I have been told of the upper tube failing. The welding should always be along the neutral-axis (centre-line) as when looking at the side view as here and of course have a thinner plate either side, instead of one in the middle

Cheers!

Last bit -- we all hope!

Point about welding or brazing the clip-on bar to the clamping (Cuff) tube. With welding relatively thin steel there´s a chance of more deformation or lumps forming on the inside of the Cuff than with brazing. i.e. If the melt goes through to the inside of the cuff -- even if just a small bump -- the cuff with work loose. If the weld melt is not formed by part of the cuff it will be a thin attachment. Sort of suggests brazing to be the better choice.

Sorry Boardtracker the case Dan made looks stronger by the moment but never fear -- keep at it -- your clip-ons will probably be alright.


Cheers!

I think it needs to be added that what John calls webs (I call them gussets !) should have a good radius tapering down the tube. A sudden change in section is a stress point.

Dan, "so the bore would be whatever it is plus 20 thou" The problem is that I don't know the original bore size and if this barrel has been re bored before.
I thought I would just get the new piston diameter and add on how many thou clearance it should have and then get the barrel bored to that size.

John,
Yes I do find great satisfaction out of making parts for my projects and not having to pay others to do it.
I don't think I will be doing any geometry modifications on my bike. It looks like you have been there and done that already! Interesting that a few degrees difference makes a huge difference in handling though.

Board track racing was phased out at around 1917 because to many people were killed. In one race 4 spectators were killed including 2 children as well as 10 others being injured! The only thing which is similar now is racing around concrete bicycle velodromes which i do with my twin villiers contraption. This is still very fun as there are lots of other villiers powered bikes to race.

Are you talking about if the melt goes through to the inside of the cuff and is not filed off?

i think the clue would be in the piston you have bought , i.e if you've got a 63mm +20 piston the bore would be 63mm+20thou as the clearance is already on the piston and worked out for you .

Good one Ned -- a tucking fillet in the nickers!

Gusset must be the right word but Web sounded right for where the reinforcement plate sits wrongly between the tubes like a ducks-foot web. When I was an apprentice we cut and filed:  "Male & Female fits..." and I´m still trying to find out more about the subject....

Uh oh! better stop or someone will splatt this ....

Interesting thing about frames is the history where lugged frames were rejected and all-welded tube frames took over. I´ve seen several fail at where the tube enters the lug ... We could get into a lot of other stuff about this and stress-raisers on here, Ned but  The Lads are on about bores now....

Ned! Perhaps us two old farts might be described as such....

Cheers!

JayBee,

I have started building my lightweight seat. I am doing the tail section first, then I will make the seat base.

I started of with a flat bit of 1/16 sheet roughly cut to size.



And then I took it outside onto the grass (I don't have a sandbag) and started hitting it. I was going around the edges with the shrinker quite often.



After about 10 minutes of taking all my anger out on this bit of alloy, it started to get into the shape that I wanted.



After 5 minutes in the English wheel it was smoothing all the dents out. The surface finish is still very wobbly and dented because the camera does to good of a job of hiding rough finishes! More shrinking done around the edges here to pull it all in.



Now I had got all the major dents out and I was just trying to get the shape where i wanted and tightening up all the curves.



And the last picture, after The final passes through the english wheel it looked like this. I just need to file it up and trim it to size.

Neato BT....

About 5 or more years back I saw a replica Royal Enfield  GP5 seat and mudguard for sale at 3.50 pounds. Probably be a fiver by now.  The back of the seat looked a bit like the shape you have made.

It was the original motto of the Bantam Racing Club, and a book was written by the 5th or 6th Chairman of the club, Roy Bacon,  "Racing On The Cheap" which showed a lot of the essentials in frame, cycle parts and engine preparation.  It might be a good idea to try and find a copy... I only borrowed the one I used. It was certainly a good guide regards the early Bantam frames which had several `weak´areas.

Keep at it.

Cheers!

Thanks John,
3.50 pounds! What was wrong with it?
A quick google search of that book has come up with nothing but I would love to have a read of it. Does anyone else on this forum have a copy or a file on the internet they could direct me to?

I made the seat base today. It is a piece of 2mm thick aluminium that I put through the wheel a couple of times to get some shape into it.



I then roughly trimmed it to shape and tacked the tail section on.



I trimmed it down and folded a safety edge right around it and then it was time for a mock up.





Had a quick sit on it, it all feels good but I will be cutting out some tank scallops to get my knees closer in.

Thanks -- & Hi BeeTee....

Actually recalling it now the RE GP5 component was in fibreglass. Whether the original was in fibreglass I don´t know but obviously with the cost of metals today what you are doing is akin to gold-mining.... When you are my age you´ll be able to say to your grand-kids that you were probably the last of a species who could make things WITHOUT the aid of a computer. They will be putting up the 3-D picture of what they want, on the computer, and a load of robots will whack it together.

Its refreshing to see a young fellow as yourself doing such skilled work. There seems a lack of such and a lot of people would retaliate that it´s all unnecessary because you can get whatever-it-is you want at e-Bay for next-to-nothing. Bullshine is what I say to that -- there is great satisfation in making things (whoops! I´ve already said that).

With the help of my Dad I built a model steam engine at age 8 and at ten, made one myself. I could solder nipples onto clutch and brake cables at around nine -- long before I knew what a real nipple was...etc ... etc... When I started my apprenticeship I got ribbed (`mobbed´is today´s definition) by the older blokes and had to quieten down as to what I could do....

But on here you are under orders. That is to show-&-tell what you are doinga and show some of the equipment you have there at your disposal....

I look forward to seeing some more....

Cheers!
JayBee.

What a talented young man you are, and are the envy of many, me included.
Could you post some pics of the finished project and notes of what you have done to achieve what appears to be a very impressive build .
Pete

Hi all, after being sort of stalled on this project for a while i have finally made some proper progress on the racer!

first i have spoked up my rear wheel with stainless steel spokes that i got locally.





This rim isn't to flash as it has been in a crash at some stage i reckon so i am on the lookout for a new rim that i can paint and re-spoke into the hub.

I have also made up the front and rear seat mount brackets out of steel bar and bolted the seat on so this is what the bike looks like at the moment.







It is good being able to sit on a solid seat so now i can carry on with the foot pegs and the tank scallops.

Cheers, Boardtracker

Well done BoardTracker!

For you MODERNs: Another bit of boring, sloppy and nauseating Nostalgia:-

I was a temporary mechanic for Sam Flack in Epping, Essex in the early sixties and a wrecked Tiger Cub came in with front forks and front wheel written off. Sam and his regular mechanic straightaway said they´d have to send the front hub, new rim & spokes off to a wheel builder and I said, "No, I shall rebuild the wheel." Sam said it would take too long, I retaliated that he ring the wheel-builder, find out how much it would cost and I´d do it for less at the hourly rate he was paying me. My cost was 2/3rds of the wheel-builder´s cost so I suppose Sam & his regular mechanic were right....

Point is about such jobs, even if we are trained artisans, we tend to take the easy way out. All it needs -- as wheel-building, I mean -- is a degree of patience and the right attitude. Including that Tiger Cub wheel I did 4 wheels for two Bantam racers and the two wheels of my 1927 Triumph I rode in Vintage events.

Nothing to do with cost: it is the satisfaction of DIY (doing it yourself) which I see is something BoardTracker obviously enjoys.

Tell us more,


Cheers!

JayBee.....

Wow, 3 years have gone by since i properly worked on the bantam. I have not been idle though with a few other quite big projects taking up all my time, a couple of penny farthings and a small light aircraft were the main things.  I am determined to finish the racer before i start on anything else from now on.
So where were we, shortly after my last post 3 years ago i finished getting the top end of the motor together. I managed to find a big fin/head 125 barrel that i had re bored for a new piston. The motor ran well and i had a ride on it up the road and back.

I dug it out of the shed a couple of weeks ago and got it running, it fired right up with some fresh gas so all is well in that department. I have been doing a bit of work on it so here are some pics.

First job has been sorting out the tank. To get the front of the seat to fair into the tank i made a little fill in piece and welded it in.


After finalizing the knee cut outs i took the tank outside and ground out all the old horrible filler, i then got in there with a dolly and tapped all the dents out and now the tank is completely smooth and wont require any filler. I gave it a good sand with an orbital sander and that sorted all the light surface rust out.


Template for the fill in pieces


Should work pretty good


I made up a transfer pipe and some fittings for that and the new fuel tap and easy flowed them on

I have also finished the seat off, its now ready for paint and upholstery

Template


Cut out and fitted


Welded in and filed up.







Cheers, Louis

As always your craftmanship is first class.
The video of the Mynah was superb, pity my PPL is out of date !

Just seen the earlier post picture of the Grimeca Ducati, a good one, have same on my 185, it works well on a lightweight Bantie.
You might find it stresses the forks a bit though.
You may have heard on the NZCMRR grapevine that I have acquired a huge collection of spares, so I may have some inheritance that might help the cause.
( The Captain had a USA twin CPL too! )

So lots to do before Pukie 2018

I go along with the comment -- really good looking workmanship.

I have a vision in my mind of boardtracking being inside on polished boards with bikes broadsiding on very short circuits ....?

Must be fun ...

But with a Bantam?

Cheers!

JayBee....

Cheers John(s), Yes it is a shame about your PPL, you might have to get it back up to speed.... I am having second thoughts about that brake drum now, more to come on that later. No I hadint heard about the spares aqqusition, sounds good though.

Some more progress on the bantam....

I have got the tank scallops finished and the tank welded up and fuel tight (hopefully!)

tacked in


welded and faired up





have also got the rear brake linkage sorted out

I cut the peddle out of some 4130, should be strong enough haha  



Turning up the pivot


Tigged the bush onto the peddle


Tapping out the original rear footpeg mount 7/16 unf fof my pegs to screw into


The whole assembly

As the bike stands...









The bike is pretty much ready for stripping down and painting now, i just need to cut of a few unneeded  mounts and cut out the center stand mount
One last detail i haven't decided about yet is the front brake, i am quite keen on making a twin bantam front drum hub, ive seen period pictures somewhere of these before but i cant seem to find them anymore. Does anyone have some pics of this arrangement?

It seems to be coming together very nicely. I like the way you have fitted the rear brake pedal - very neat and practical. I wouldn't advise making a twin drum brake from D1 Bantam parts. It would be a lot of work for very little benefit. You have made a lovely job of fitting knee cutaways in the tank, but have you considered doing something similar to provide clearance for the handlebars on full lock?

If I might make a suggestion, your posts will be easier to read on this forum if you were to re-size your photographs so that they don't expand the page unreasonably. Pics of 500kb to 1mb are plenty big enough.

Looking forward to seeing the finished bike. It promises to be very individual and interesting.

All the best,

John C.

Hello John, Thank you for your comments. The reason i am wanting to do a twin front brake as i believe it was a period mod done in the early days of bantam racing and an early racer is what i am trying to create. I made up and welded on a new steering lock stop as it was missing on my frame. with this stop the bars dont come close to the tank at full lock. It shouldn't take to much to put one together anyway (famous last words haha)
Louis

The Bantam is finally finished! Here are the pics. I think i have achieved my intention of a period correct racer. The twin drum front brake worked out well and it seems to pull up quite well, much better than my friends standard bike so i would defiantly recommend doing it if you wanted a bit more stopping power.
























Cheers, Louis

Congratulations on a lovely period machine. Did you form the 'megaphone' yourself or were you lucky enough to get one to fit the pipe dia?
Jim