Monday, 4 October 2010

The man that can..

One of the essentials of pre 65 trialling is knowing someone who knows whats what what works and what doesn't. I 'm fortunate to have one on my doorstep, the other is knowing a 'man who can 'so that when your muse tells you to head off in one direction you have someone to hand who can make stuff ( well is essential, quickly is good, cheaply is fantastic!)
Access to a decent lathe and knowing how to use it, an industrial pillar drill and a stock -pile of various metals in sheet, rod and tube are all strong qualifications so step forward my father.
Normally happily making model steam engines ( stationary, rail and marine) or sailing or running them, he can usually be persuaded to produce some fantastic pieces of bespoke metalwork such as bushes, spacers and tube etc. all to your specific requirements. Over the years we have found that rather than working to drawings and measurements it is much more accurate to build to fit. Especially so on sthings like swinging arm bushes where the present dimensions may be far from what they were originally. and where two formally identical round holes are no longerround nor identical.

So to the depths of the Lake District I travelled armed with a box of aluminium sheet and rod plus the bike as it stood so that we could 'make to fit' . Hopefully at the end of the day iIwould have pre load spacers for the forks, spacers for the rear spindle, an original pre 65 rear brake plate that fitted the Sherco 17mm spindle and various other spacers.

In the space of a couple of hours we had the rear spacers turned on the lathe and drilled out for the 17mm spindle and they fitted first time! We made up mock ups with 22mm copper tube to get the right lengths so that the wheel was centred and the chain ran true then replicated them in alloy. The off side was simple as it is single piece and on the chain side we cut two pieces so that they and the brake back plate made up the required distance and bingo..
The brake back plate soon became the owner of a 17.5mm hole.

i have earlier said that the forks ran great and they do but they do 'sometimes' have a tendency to drop a quarter of an inch upon putting weight on them. I believe that this was because i was using an old valve type spring in each one as a preload spacer. Springs being what they are I suspect that they moved a little and became unseated so we made up a couple of 'top hats from alloy to do the job instead and popped them in.. As near as dammit the same sag and suspension movement so we'll try them ( movement of the old valve springs was approx 5mm over their 35mm length so we opted for 32.5mm long spacers as a mid point)

I think i also mentioned earlier that some of the brackets were 5 - 10 mm too wide so we made some tube to use as spacers rather than packing the gaps with washers.. I ended up with 8,10mm and 3/8 of an inch i/d tubes with an o/d of 15mm.

a nice days pottering and a decent lunch thrown in!

Saturday, 2 October 2010

Shopping list..

Well firstly some photos from my design board of what it is I'm building, most of the bikes I've photographed myself at Yorkshire Classic trials or at the Pre65 SSDT. the style I am trying to recreate is best exampled by the top bike. Mine will almost certainly though have white plastic guards front and rear as well as an alloy tank with a white crescent.

Just to even things up a bit after posting the last update I realised i'd missed a few suppliers out.. so best pop them in to create a fair view of whats been bought.. no expenditure figures until the end so that in best 'Grand Designs' fashion I can boast of only using 80% of my contingency fund!

Anyway more bearings via ebay from EBR, 18mm with 13mm shank drill bit via ebay from Uk Drills ( this for a fantastic piece of bespoke metal work and fabrication from the countries leading steam boat engineer! more to follow in a special piece soon) rubber washers from Naoutlet All these suppliers delivered within 48 hours of making a Paypal payment.

Finally the only personIi've done face to face business with the brilliant Andy at Pennine Trialsport although not specifically into pre65 or twin shocks he has a fantastic background knowledge and is more than happy to root through his parts bins for something off the peg! the bike now sports a GasGas chain tensioner and an aluminium  Sherco rear spindle that weighs a third of the originally proposed steel one. all thanks to Andys' perseverance.( and they fit first time with no modification!) to complete the theme i'm searching for something from the other three manufacturers that will also fit the bike. ( Beta, Scorpa, Montesa)

The rear spindle did give us our first 'proper' engineering problem/ solutions and when I have a moment I'll go a little further but it did involve a 180 mile round trip and a day out in the Lake District..

Photos..well I've taken loads on my new Nikon all I have to do now is get the pooter and camera to speak to each other, so when they come they will probably all come at once..

How much is scrap aluminium worth?

The postman and UPS have been busy and have dropped off a load more bits and bobs for the bike including spherical bearings for the shock lower mountings, imperial bolts for the engine mounts, rubber washers to mount the rear mudguards and a  rear brake pedal.

I spent a couple of hours head scratching trying to work out how to fit the brake pedal, but as it was built for the frame buy the frame builder and 'bolts straight on..' I assumed that it would .. however the bolts used are larger than the mounting, the arm fouls the sub frame, the mounting fouls the footrest mount, the total movement is only 12mm and the actuating arm is about 60 - 75 mm too short.. so it probably wont see the light of day..

On the other hand small stuff arrives by the bucket and is 100% correct just as ordered. Big shout  out to Namrick for thier imperial nuts/bolts and Simply Bearings for the spherical bearings ( they have a handy calculator on thier site which tells you what size bearings are available, you tell it what sort you want and one of the dimensions and it does the rest) still not quite as impressive as the man at Rochdale Bearings who armed with a well thumbed reference book found the right mix of imperial and metric sizes for the steerer bolt.

So the engine/ box came out and the bolts were machined to length, half the head of the lower mount has to be machined off so that it can clear the chain case. I opened up the engine mounting holes on the rear mount as they were slightly adrift of where they should have been. opening them up to 12mm sorted that out. The engine protector ( a piece of bent bar that protects the front of the chain case) fitted spot on via the front engine mounts.

Then out with the file and Dremel to fabricate an alloy bracket that holds the clutch adjusting screw, the exhaust mounting and with a little thought serves also as the lower mounting point for the rear mudguard! starting off looking a little agricultural within 4 hours it looks smart but importantly is functional and easily adjusted etc. the only downside is that the floor of the garage the workbench and I are all covered in about a hundred weight of alloy filings. Time for the sweeping brush!