Triumph Chop

Build Diary

Just getting organised and ready to start as its raining outside and I cant fix the old mans car. The bike is now ready to start work on in a clear part of the garage. And here are some retro exhaust clamp/cooling fin things that a good friend Ian Summerfield let me have for a bargain price. Very period parts methinks, not sure if they will work with the look or not yet but lets hope so!

With the car pc finally done to a stage that its working I spent a few hours doing a relentless clearing of the garage and then started on the chop dismantling so I could get a better idea of what I was working with. surprisingly the whole thing came apart very easily and I had it stripped and the engine out in about 4 hours! spread over one evening and one morning though.

After getting it all apart I now have a big list of things i need to source and replace or repair. obviously a large amount of parts need re-chroming and some of the brackets and gubbins that were welded on need removing and re-welding. all of the wiring was ripped out as it consisted of mainly twin core house flex eek. I wheeled it outside this morning for a few piks as just a roller, looks a bit different. And finally two piks of the new front drum that will be laced into a 19" rim when i can find one, the drum is a nice twin leading shoe from a cb250k and should look and work better than the nasty little one that was on there

A day full of unwelcome surprises inside the BSA A10 gearbox. it came apart easily but the time sat in the container with minimal oil inside it has let the old tin worm do its magic. The selector cam is well rotted with the hard face peeling off half of it and some of the gears looking a little worn. Luckily I've managed to source another selector cam off ebay. I will have to live with the gears and hope they are ok for now, along with new seals and a gasket set.

The strip down started on a much better note today with the engine coming apart nice and easy. The heads innards look great and on removal the pistons are brand new nice shiny +30 thou ones and the barrels look like they have just been re-bored too. However after removing the barrels a dirty secret has been revealed. look at the pictures to see the dents in the connecting rod and around the crank case and camshaft lobe cut outs. Then the crank case halves were proving a pain in the arse to separate, at first I couldn't get one of the screws out between the two barrel cut-outs as the head on one was mashed right in. eventually with much hammering with a punch it started to rotate and I managed to remove it. Then the primary drive side bearing wouldn't release its relentless grip on the crankshaft so I couldn't split the cases. lots of bashing later and it came out. I need to get hold of a tool to remove the crankshaft pinion gear so I can then change the main bearings. the crank bearing journals look ok so I'm hoping I can get away with new big end shells, new small end shells and then polishing the dents out of the con rods and balancing them.

After a bit of pondering I tried to just remove the gear by supporting the crank case on two blocks of wood and knocking the crankshaft through it. The blighter only took two sharp taps from a raw hide mallet.

While I'm waiting for new bearings and such to turn up I decided to make a start on polishing up some of the engine parts. I started by using a file to remove all the casting marks and big scratches and dents. Then 240 wet and dry and slowly working up to 1500 wet and dry. These stages took about 5-6 hours of work!! then I gave it 30 minutes on the buffer and its looking pretty good.

Whilst waiting for the new big and small end shells to turn up I thought it time to get cracking on making these con rods a little more usable. First things first to take five mins out and knock up a tool on the lathe to press out the old ones! this sits snugly inside the bush as well as pressing on it and stops it scuffing up the rod or damaging the bush. not important when removing the old bush but I can use this to push the new bushes in to. After removing the bushes I scraped the rods to remove all of the dings, dents and big scratches. I then used 150 grade to 1500 grade wet and dry to smooth them out and remove any stress raisers. Finally I gave them a good buffing up on the polisher and then a quick clean with some fine metal polish to remove remaining wax and crud as my polisher isn't really up to the job. The rods will soon be balanced end to end at work on the rather delicate scales
.

Another few bits going on at the same time. A bonnie head from a nice chap on eBay for a steal at £120 with rocker boxes and its not long been refurbed with what looks like new valves, seats and guides! should add a few more ponies and allow the twin Amal concentrics to breath a bit better. The wheel as it should look roughly with the spokes slapped on it. The spokes are long so I need to get them rolled lower as you cant use a die apparently. Finally a pik of the new timing side engine cover with its T140 type main oil feel seal. Should help keep the oil pressure high even when the engine gets hot and be more reliable than the bronze bush.

Another little work in progress whilst I've had the gearbox apart for polishing and new bearings. Along with the new selector plate I thought it would be nice to convert the spring locator to a roller bearing one, as claimed was used on works goldstars? Should make a marked improvement in gear change smoothness and lightness and reduce wear on the camplate of this old BSA gearbox. not actually sure what the box was from but presume it to be A7/A10 or goldstar. Anyways I started with a length of silver steel and turned it down to 13mm which happens to fit nicely up the hole for the spring tension adjuster, I then turned the second smaller OD to fit into the spring tensioner snugly. I bored a hole of suitable diameter for the spring to fit up and with a small drill tool it right through to the front face. This allows air to escape from behind the plunger when its compressed!

With the lack of a mill at home I resorted to drilling a 6mm hole through the end of the plunger and cutting out a slot up to it with a hacksaw. Then much careful filing resulted in a reasonably parallel 8mm slot for the bearing to sit in. Before signing off the plunger I drilled a 5mm hole through the sides of the slot and then opened one out to 6 and tapped the other one M6.

The final task was to make a spindle for the needle roller bearing which incidentally is an 6x10x8mm one I got off eBay and was the smallest I could find. I turned up a 6mm spindle for it to run on and put an M6 thread on the very end. Then cut it to length and chamfered the end and put a slot for a flat blade screwdriver so I could tighten it into the hole in the plunger.

With it all ready to rock I decided to try and harden it a bit to improve its life span. As the bar I used was silver steel it was perfect for this job. NOTE: you can't harden mild steel by heating and quenching as it doesn't have enough carbon in it to start with. I heated the plunger and the spindle up until they went cherry red and then quenched them in a tub of water. This makes them very hard and brittle. Then after cleaning the light scale off with some wet and dry paper I heated them up to a straw colour and quenched them again. This removes some of the hardness and toughens them a bit. The spindle I only reheated to a mild yellow so it should be hard enough to take the wear of the bearing. Final assembly was made with a little studlock to hopefully stop the spindle coming undone. A few piks below and one of it ready for some action.

Before clearing the lathe up I decided to have a go at making my own alloy clutch pressure plate. I started with an old bit of ally angle plate from work that used to be a door stop. I hacksawed it up into a semi round shape to make it easier on the lathe. then drilled an eight mm hold in the centre and fixed it to spindle and then turned it in the lathe. Took longer than expected as the lathe is a little worn and loose and its hard to stop it digging in. That may be my next project when the bikes done to give the lathe a complete overhaul.

To put the spring cup holes and some lightening ones into the pressure plate I decided to use the rotary table at work on the old Bridgeport which is considerably knackered but it did a stellar job considering how hot the work head got and the noises it was making! First I made a Morse taper size 3 adapter on the lathe to sit snugly in the centre of the rotary table. This was bored out to allow me to fit a bit of threaded silver steel through it and lock it in with some washers. I then held the pressure plate down onto some key steel to stop me milling the table away ;). As the pressure plates accuracy only has to be to a few thou I used the non threaded bit of silver steel to centre the table and job to the work head of the mill, by moving the bed until the 8mm spindle would fit into an 8mm collet. I then offset the front slide by half the distance between the hole centres on the 4spring clutch hub as it was easier to measure than a 3 hole PCD. Then I pumped 3 3/4 holes into it with a slot drill and another 3 which I elongated a bit to remove more material and maybe make it look nicer? seemed to do the trick anyway.

Still waiting on barrels so thought id get cracking on getting the gearbox together so I don't loose any of its bits! First pik shows the comparison between the old cam plate and the new one. A bit cleaner!

First I polished all of the outer casings which incidentally took bloody aaaages! I then slapped in two new bearings for good measure and a new outer seal. The new bearing was a sealed type so I popped the seal out of the inner side of it to allow the oil to get to it. The pressed it in and fitted the new outer seal and clip ring. After fitting the bearing using a humungous socket set I had it was ready for assembly. Luckily I did a dry run as I couldn't get it to run freely in neutral without binding up. Turns out the input shaft is located against the small bearing by a gear on the outside so without that fitted it wasn't pulled tight into the bearing. tapped it into position and bingo all working. Also when doing the dry run I noticed the lay shaft had a lot of side to side play. On consulting the drawing in the haynes it would seem I was missing a thrust washer, this must have been missing when I tool the gearbox apart as I kept the shafts assembled. Luckily I had a bit of Phosphor Bronze kicking around I could use to turn up a new one. A short time later I had it assembled with new gaskets and a smidgen of Hylomar. A few more bits polished tomorrow and ill have the kick start cover on.

With the speedo taking its drive from the Honda front drum I thought it would be better to remove the worm drive from inside the BSA gearbox as it was mashed up a bit. When done I was left with a 16mm ish hole that needed to be plugged. Lacking any aluminium to block the hole up other than a 3" bit of stock I definitely was NOT going to turn down to 16mm I thought sod it ill turn up the old bush that came out of the hole. I put two grooves in it for some O-rings to seal it and tapped a thread down the hole 1/4UNC as I had a nice stainless set screw I could use. Hopefully this will stop the oil leaking out the front too as it was leaking from the speedo drive here when I stripped the box down. As an extra precaution lots of Hylomar was used ;). cant do much more with the gearbox until Dan drops the new hydraulic to cable cylinder round then I can setup where I want the arm positioned for the clutch actuator.

While I'm still searching for pistons I thought id check the engine over. Oh dear the inlet camshaft is fooked. some good flats on it. Two new camshafts and some new bushes are in order methinks. Camshaft pinion gears come off really easy with the right tool! Undo the nuts with a 9/16 Whitworth spanner and a rag wedged into the idler gear and shock it to loosen, remembering its a left hand thread. The removal tool screws on and pops the gears off super easily. Also found in a box of spares from Bert two 3 key idler gears, they have lightening holes in which I wasn't going for however they will do for free!