Wednesday, 29 September 2010

Airfix kit with no instructions and with some pieces missing!

The plan was to dry assemble everything, so that i knew what went where, what fitted what needed doing to what etc before any paint or powder coating was applied to anything. this meant that the build may take a little longer but that when final assembly came along everything would fit as i'd already fitted it once before.
first things first preserve the frame.
as picked up from the M6 it was in bare metal with its bronze brazed joints loud and proud. There was plenty of flux visible so as soon as it landed in the garage i took out the plumbers  Yorkshire Pad and gave the frame a good rub down to clear the flux and and slight surface corrosion.
this gave me a chance to give the frame a close inspection and a good coat of looking at. first impressions were that the brazing was first class and that the joints were all well made with no lugs in sight. the headstock was long ( circa 150mm) and wide (52mm) compared to my previous cub and bantam frames and that at the rear upper shock mounts the bike seemed quite wide about 40mm wider than both cub and BSA yet narrower at seat/ tank junction than both by about 10mm. 
the rear shock position seemed more 'laid down than both the other bikes and the 'engine room'  significantly shallower than both bikes ( at least 25mm) overall the impression was of a strong frame with robust proportions that coupled with the T45 tubing would make it up to the job of supporting my svelte like 100kg frame!
I'd hoped that removing the motor from one bike it would drop cleanly into the other and initially this seemed to hold true withe the engine complete with carb lifting cleanly into the frame of the James/FB. the reduced height was immediately confirmed but was adequate with no immediate issues. the front engine mount was perfect the bolt went straight in, and the middle/lower seemed to do the same , unfortunately the rear was approximately 5mm out and the engine mount would require re drilling also concernedly the mount was 3 mm too wide on the near side of the bike and 4 mm too wide on the off side.checking the lower/ middle mount I found that although the bolt holes were perfectly in line the off side Mount was approximately 8mm too wide.
the lower mount was easiest to solve by maching a spacer from 5/8 inch aluminium rod/ bar. the rear mount is more complex as it is also the mount for the clutch cable and silencer.
on to the biggest looking issue was the size of the headstock it was about 25mm longer than either of my existing bikes and thus seemingly too long for either of my bolts on the.other bikes. setting that aside it was massive internally compared to the other bikes the cub and BSA both having and id of circa 42mm the james/fb was 47mm. Alan had recommended a bearing size of 47x25x10 sadly that was never going to fly as both my head bolts are imperial sized 3/4 inch which comes out at 19mm give or take. 

Tuesday, 28 September 2010

nuts and bolts

For ease of maintenance in the garage and especially 'in the field' I want to have as uniform as possible fasteners. I want where possible to reduce the number of tools required , both in the garage and  in the pocket whilst competing.
I have chosen to go for A2 grade Stainless steel, metric ,button headed bolts, washers and nyloc nuts where ever possible.
Button headed so that I don't need two 12 mm spanners just one and an Allen key, so that the head has the lowest and smoothest profile yet the largest contact area and A2 stainless steel for corrosion resistance ( the more durable in A4 was excessive in spec. ( sea water) and cost!)(+ 30%)  and finally metric as it is the most commonly available size.
Finding all the fasteners required for the frame set proved relatively simple locally at and even the counter sunk screw for the GasGas chain tensioner proved no problem via
As for length of fasteners each has been machined to an optimum length to leave a complete thread outstanding from the nyloc nut when the fastener is secured.
The most complex bolts to source have been the three engine mounts, although drilling out the frame to a metric 10mm was not an issue, I felt that drilling out the cast alloy mounts on the engine  cases was perhaps taking a risk and one that carried little or no value so I stuck with the ioriginal sized fasteners.
After several days looking i found in the UK who specialise in imperial sizes for classic cars, they have something of most threads although some  are now in limited supply as traditional automotive threads are been discontinued even in the US.  There are in fact many stockists in the USA but import duties and fees proved prohibitive.
So 3/8 inch bolts and nuts were obtained eventually but unfortunately were not /are not available in Stainless steel in the correct lengths of circa 90 -100 mm so zinc plate and traditional hex heads  it is.

Sunday, 26 September 2010

Meet you on the corner!

Having searched high and low for a contact no for Alan Wright 'Classic Dirtbike' and Trials Central both came up trumps. Amazingly I got through to him straight away and a deal was done over the phone for a frame swinging arm. spindle, bash plate and brake pedal the only catch was he was going to the Isle of man the next day for the two day trial so my only chance to get the thing relatively quickly meant meeting up in a service station en route!  long story short.. we finally met on a roundabout! and I took delivery of a new frame etc. in the first week of September. I had an ambitious plan to move everything from the Banvill across to the new frame and be riding the new bike in the Yorkshire Classic Trial the first week in October..   oh how quickly optimism fades!!

A germ of an idea

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Matthew and I had been up in Scotland for the Pre65 and SSDT at the beggining of the year and in the West End car-park Alan Wright had amongst all his other stuff some Pre65 bits including a James/ FB frame set and other associated bits. I checked them out at the time just out of curiosity, as a year or two earlier (2006 to be exact!) i had snapped his bike at the Pre65 minus paint/powder coating. See the photos alongside.

Monday, 20 September 2010

New Dawn!

On the Banvill, YCMC  November 16th 2009..
The time has come to freshen up the 'Banville' and sort out some of its inherent issues.
The engine and forks are great ( 37a and Mazzochis inside 'cub' legs) However the frame is too short ( wheelbase is approx 48.5 inches) the foot pegs are too high and the rear shocks are under sprung ( it has circa 2 inches of sag when i sit on the thing and most riding conditions have the springs almost fully compressed!)

Having checked out the dimensions on my Beta Rev3 to try to have a similar riding position I can see that some drastic chopping / fabricating of the Bantam's modded frame would be required and then re powder coating the whole lot. The swinging arm spindle is supported by bronze bushes which although recently replaced and still as new, this frame is possibly at the extent of its life in my hands.

So armed with a drawing board, pencil, tape measure, micrometer, credit card and an exhaustive trawl of the Internet for inspiration I have decided to build a James /Francis Barnett replica.

The FB concept holds more attraction to me as 'everyone' has a James (must be a red thing) and FB were regarded in the 40's and 50's as being a a well engineered bike. However the adoption of the AMC unit for power in the late fifties meant that as trials bikes in the early 60's they were unfashionable and simply useless! 1962 though had the 'works' using the 32a/37a motor. At the end of the day the only difference was the tank badge and frame colour red vs Ardent Green..