500 K cafe racer conversion - build thread

[Ewan 500 K1]

Forks all done and dusted: new oil seals, new oil seal retaining clips, new dust covers , 165cc of 15w fork oil in each, repolished. That'll be me for a while till I can get hold of a steering lock key so that I can get the steering lock out ready for frame, swing arm, stand and lower triple T powder coated. Many many thanks to all who have provided advice and comment so far

[Ewan 500 K1]

After much gnashing of teeth my Dual Disc calipers all set up now , 0.06 inch clearance between both fixed pads and their discs and a freely rotating wheel. This was the most trying part of the build I have done so far .. as I didn't originally realise that the caliper arms I have were not identical, that the mudguard bracket is non standard and that I have a narrow 500 hub on 550 forks.

The right hand side needed no modifications such as shims or filing ... just the simple addition of a caliper arm, a caliper pin, a caliper pin bracket and a caliper. On this side the mudguard bracket is sandwiched between the caliper pivot pin bracket and the fork. All that was need was a few washers on the spring adjuster screw to give the spring some compression (see photo)

On the left hand side all that was needed was to file down the leading edge of the pivot pin bracket.

 ... not that this reflects the fact that it took me all day trying different combinations of pivot arms, pivot pin brackets and mudguard bracket placement. Full agony is exposed in my other thread at :

http://www.sohc.co.uk/index.php?topic=5571.msg27634#msg27634

Thanks go to BryanJ and Oddjob for sharing the pain

[Ewan 500 K1]

.. and just as I finished getting my dual discs set up right a man in a van arrived with my new Hagon rear shocks. These are a special build at 361mm between centres (standard are 315mm) , needed longer ones as clearnace at the back wheel has reduced due to insertion of the plate in the rear hoop to hold the battery and electrics .

Later edit; Not sure what effect this will have on the bike's geometery and in particular on the front end rake and trail, but will calculate the effects once I have the bike togeather and see if I need to do any front end mods (should have done this before I took it to bits again ... but didnt realise the potential issue) One thing in my favour is that the bent sterring stem woul have recuced rake and trail , so running with a straight triple T and longer rear shocks might make me end up in the same place as when running with the bent triple T and stancard rear shocks .. we'll see)

[UK Pete]

Do they charge more for special build shocks?
pete

[Ewan 500 K1]

Model number 31012CSS , Custom Shocks. I paid £195 delivered Pete, got them from Bike Revival at http://www.bike-revival.co.uk/page1.html   I think was an extra £15 for the custom build

[Ewan 500 K1]

having cleaned the frame ready for powder coating I found some cracks and corrosion under one of the rear footrest mounts. Also the cafe bars hit the tank on full lock, so thinking that the steering stop on the lower head stock needs to be a bit wider

[Ewan 500 K1]

Now not sure what effect the longer rear shocks will have will have on the bike's geometery and in particular on the front end rake and trail and thus handling. Folk on the US site have been raising concerns about effect on handling and particularly about the potential for rear end twithches and tank slappers.
I will now  calculate the effects on the rake &  trail once I have the bike togeather and see if I need to do any front end mods (should have done this before I took it to bits again ... but didnt realise the potential issue)
One thing in my favour is that the bent steering stem that has been on the bike for at least 17 years would have reduced rake and trail. I now have a new and straight sterring stem, so running with this and longer rear shocks might make me end up in the same place as when running with the bent triple T and standard rear shocks .. we'll see)
Alternative solutions posed if effect on trail is significant are:
a) rework the bike to remove the battery tray from the rear hoop to allow more clearance for the tyre . This would mean undoing the frame mods and electrical work already done ... not keen on that.
b) get longer frnt fork stanchions to counterbalance the lifted rear end
c) get a triple T / top yolk set with a greater offset than the standard to counteract the shortening effect of longer rear shocks on the rake an trail
d) get a steering damper

Views welcome !

Must get to bed ... been up all night reading about bike geometry, trail and rake which was all new to me 

[Ewan 500 K1]

Put everything back on the frame today to compare the original front end rake and trail with the rake and trail impacts of the new longer rear shocks. I was intending just to put the essentials back on to do this, but ended up putting everything back on .... as I'm swithering between black and silver for the frame. A few pics to follow

[Ewan 500 K1]

With the old shocks and the old bent steering stem. First in sliver frame , then in black frame.  Gone off the silver , think I'll stick with black

[Ewan 500 K1]

new longer rear shocks in black frame and silver frame

[Ewan 500 K1]

dont like the rear mudguard anymore ....

[Ewan 500 K1]

some random photos

[matthewmosse]

I'd get a few miles in and see if things need to be altered, a diffrent steering stem / tripple tree arrangement could then be looked at or longer forks. In the 70's there were extenders that  screwed into the top of the forks to make them longer but I think that would be pants as a long term solution, might be worth trying if a cheap set were to be found to see if they helped if the geometry proved problematical. I'd try it as is as often forseen problems fail to materialise - I have had all manner of advise about the way my 500/4 sidecar wouldn't handle at all well, but I like the thing as it is and havn't even re attatched the steering damper when it broke a mounting.

[Ewan 500 K1]

I'd get a few miles in and see if things need to be altered, a diffrent steering stem / tripple tree arrangement could then be looked at or longer forks. In the 70's there were extenders that  screwed into the top of the forks to make them longer but I think that would be pants as a long term solution, might be worth trying if a cheap set were to be found to see if they helped if the geometry proved problematical. I'd try it as is as often forseen problems fail to materialise - I have had all manner of advise about the way my 500/4 sidecar wouldn't handle at all well, but I like the thing as it is and havn't even re attatched the steering damper when it broke a mounting.

cheers for that , really heartening ... unlike the state to which I'm being pulled apart across the pond .  I quite fancy doing all the measurements for working out rake & trail stuff anyway... as a learning experience if nowt else . One day of holidays left to play before its back to grindstone for a while

[Ewan 500 K1]

so .. the speedo cable rubs against the new disc. High tech fencing wire speedo wire restraint fabiricated and installed