The 1975 Silver Smoke was purchased from a friend in Horsham who was finding the restoration process too daunting. As I'd already owned a '75 Daytona Orange since new, I had a collection of bits, contacts and experience to help me finish the job. The picture below shows the 2 together on the night it arrived from Victoria on a trailer behind my car. Dark outside + no flash on the mobile phone camera = lousy photo.
The page that follows gives a brief outline, in words and pictures, of the restoration process to date.
I
didn't take any pictures as I dismantled the bike. It didn't take a long time
and involved creating a lot of ordered storage space to put things so they'd be
safe and easy to get to when needed again. The cylinders had already been honed
and had new rings fitted in Horsham, but there were oil leaks and signs of
neglect around the motor, so a strip down, at least partial, was demanded.
The oil seals on the crankshaft, camshaft and tacho drive were replaced. The timing cover gasket was also replaced. The timing gears, tensioner and chain were in remarkably good condition so were left alone.
The crankshaft and big ends were perfect, as is generally the case in these older BMs. My orange one has over 300 000 km under its belt and the crank is still fine. This one has only done 86000 km.
While the clutch and flywheel were out, I took the opportunity to de-glaze the clutch friction and pressure plates.
At the other end of the motor, the alternator was glad of a cleanup and spider removal programme.
Camchain, sprockets and tensioner are all in A! condition. The alternator housed a decent spider population before cleaning.
New crankshaft, camshaft and tacho drive oil seals and a timing cover gasket were fitted at this stage. Although it looks complete, there are no pistons or valve gear fitted yet, the barrels are just there to keep the dirt out.
The heads were soda ash blasted to clean them up and a gentle valve grind
ensured a good seal. All indications were that they had been sealing fine before
dismantling but a polish while they were off seemed like a good idea. Valve
guides were in excellent condition with no noticeable side play and the valves
themselves were terrific.
The frame was being bead blasted and powder coated while this was going on. When it arrived I fitted the engine back into the frame. I kept the frame on the ground while I did this as it was easier to manoeuvre the engine around on the sump without having to support its weight as I lined up the mounting points. It also avoided scratches to the new paintwork.
Pistons with new rings are fitted and the newly honed barrels slide on. Base gaskets have been given a smear of Silastic as this seems to be a reliable fix for the oil weep problems of the non-o-ring barrels of the 1975 engines. Heads were put back on but not fitted with valve rockers or push rods at this stage as I wanted to keep the valves shut until I was ready to get the motor running.
Valve gear has been fitted, along with all new gaskets. The rocker arm adjusters have been slackened off totally so that none of the valves is open.
The flywheel, clutch assembly and gearbox were refitted next. Fitting the gearbox is not especially difficult if the clutch is properly aligned - failure to do this properly will mean the gearbox input shaft won't fit into a misaligned clutch and the clutch spring is too strong to allow any movement without the gearbox and clutch actuator in place.
Time to lift the frame and engine onto the centre stand. The rear sub frame has been fitted as has the battery holder. Without the forks, the front end is supported on a stand. Forks are full of crud, composed of old oil and decomposed bumper stops. Damper valves have stuck closed, explaining why they were rock hard.
Once cleaned out and refilled with new oil, the forks were refitted. The head bearings were greased and new seals, bumper stops and crush - washers were fitted. The forks now work smoothly.
The next job was to dismantle the final drive as it had an oil weep from the main oil seal.
Other than the seal, this was in great condition. A new seal and gasket have made it oil tight once again.
Time to refit the top fork bridge and headlight. This is fiddly because the wires to the front indicators run through the headlight mounts and the whole lot, including indicator mounts, has to be added as a unit. Easy if you have three hands! The fairing brackets and steering damper are also best fitted at this point.
I also began re-wiring, sitting the main loom in place to check that everything was in the right spot.
Getting the wiring done was the most difficult part of the whole restoration as so many connections had to be checked and re-checked before everything finally worked as it was meant to. A new right handlebar switch set was fitted as the original starter switch was not working. Cost for the switch was about the same as a week on the Gold Coast, but at least it was readily available. Not bad for a 34 year old bike!
The wheels were in good condition apart from the spokes. These were the original steel items and the chrome had flaked off and rust appeared on most of them. I bought new stainless steel spokes from Germany and had the wheels re-laced by GC Motorcycles in Adelaide.
The brake master cylinder was pitted, so it was re-sleeved with a stainless steel liner and a new seal kit was fitted. The kit came from the UK and the sleeve was made and fitted by PBR at Norwood. All up cost was around $150, but ABS on Richmond Rd, Richmond can do a similar repair job using Toyota seals for around the same price.
The bike is now almost ride ready. It has not been started, although turns over on the starter motor and holds good oil pressure. The rear shocks still need replacement and I am waiting for the fairing and front mudguard to come back from the painter (scratches and stone chips). The complete new exhaust system really looks the part - it made such a huge difference to the bike's appearance when compared to the rusty, dirty original setup.
The original polished alloy indicators had been replaced with painted alloy
units. These had been powder coated and took a huge amount of time to polish up
again. I thought about buying a set of alloy blinkers until I checked the price.
Better to spend 4 or 5 hours in the shed than pay $300 for new ones. The
polishing mop brought them up to a mirror shine eventually, so it was worth the
effort.
I tried to start it this week (May 3rd) but it seems new carburettor float valves and seats are needed. Petrol began weeping from around the float bowl on the right carby as soon as the fuel was turned on. More bits from the UK.
A $40 kit will stop the fuel dripping from the overflow on the carbs. A new steering damper was ordered at the same time, so it will look pretty tidy when finished - might be a bit reluctant to part with it after all this work.
23rd May
The mudguard, fairing and carburettor parts have arrived. A new steering damper has been fitted and once the new needle valves and seats are in, the motor should fire up. It certainly looks sweet, with only wheel bearings and shock absorbers needed to finish it off. I'll ride it next week and have it up for sale once the new engine parts are bedded in and the heads are re-tensioned. Should be a bit of a novelty having 2 R90Ss out together.
June 7th
Well, the hard bits are finished but now the devil is in the detail. I've got fuel, a nice fat spark and lots of compression BUT ...... the ignition timing makes no sense. On static timing it appears to be around 600 too far advanced but there's only 250 of adjustment on the points backing plate. I suspect I've either made a mistake with the wiring or my measurement of TDC is wrong. The cam timing hasn't been altered since it was last runing sweetly, so it has to be something straightforward. There's a bit of a spit and pop when I try to start it, so I'll spend the holiday Monday working it out and should have it running on Monday night.
June 20th
Never assume anything!!! IF the flywheel was installed so that the timing marks lined up with TDC, then I could use them as planned, however, the flywheel fits on in any position, so unless you deliberately check that the paint marks on the crankshaft and flywheel are aligned, the timing marks could be irrelevant. I had a 1 in 5 chance of getting it right with 5 crankshaft bolts. At least I now know why the timimg appeared so wrong. The engine did start but runs like a wooly goat. New fuel and some carburettor adjustments have made a big improvement, but there is still a little more to be done. There's also smoke from the left cylinder, so the barrel is going to have to come off to see what the cause of that is. There is also a bad earth connection to the instrument housing.
Having said all that, it starts very easily. A new tinted screen is coming from Eagle Screens in WA and I have reconditioned the rear shocks so they now look the part.
June 27th
Aahhh. The silly little things we do! The oil scraper ring was working perfectly, what a pity it was put in upside down and scraping all that oil INTO the combustion chamber rather than the crankcase! All of 2 minutes to refit the ring, but a few hours' work to get the barrel off and back on again. At least it is easily fixed. The worst of it was that I broke the ring when refitting it so will have to wait for a complete new set to arrive from the UK. The screen arrived but did not fit! It was returned and I was promised a replacement asap.
July 15th
At last, all the required bits have arrived from various parts of the world and found their way into or onto the BM. The engine now runs sweetly and cleanly and there is a sparkling new tinted screen atop the fairing. Just the wheel bearings to replace and it's ready for sale or riding. The wheels go down to Ron Lienert tomorrow for bearings - that's a job beyond my skills. While they're being done I'll take to the rest of the bike with the polish.
August 3rd
More or less complete, I took the bike over to Horsham on a trailer to show the original owner. We rode it about 10km for a shake down and it behaved beautifully - no odd noises or oil leaks. The handling is very nice and the forks and brakes have settled in very sweetly. The new exhaust has a slightly louder note than the original - that means you can actually hear it.
It did hit a duck though and wound up covered in blood and feathers. The duck fared much worse - the BM was back to perfect after a wash and polish. It is now ready for sale.
I took it down to Regency Park for an inspection by Motor Vehicles and will have it registered on Historic plates ready for this weekend.
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