Triumph Bonneville

This bike was built over a 4 or 5 year period, I'd hate to think what it would have cost had I farmed out the work. Never quite finished her though, was going to install some Borani rims, an electrolytic capacitor in place of the battery, alloy guards, a breadbox tank and rear sets. Also on the wish list was a Morgo oil pump, a Joe Hunt magneto and Mikuni carbs, but big dollars for this lot.


The first picture is of the engine from the last build,

the second is as bought around 1991,

third picture is of the first build around 92/93 I think, which included metallic charcoal paint and most of the mods listed below, minus a few of the shiny bits including polished crankcase. Used as a daily work hack whilst in Katherine, and

fourth picture is after the final major build around 95/96 which included jet black paint and a few more shiny bits. Also used as a daily work hack down south

After stripping the front end I polished the lower sliders and hubs and removed all casting marks and blemishes from the callipers with a file and emery. The wheels were re spoked with S/S spokes and a new alloy bracket made for the speedo along with S/S brackets for the headlight, the tacho was binned. The headlight and mudguard were retained in original form.


I removed the air cleaner tabs from the oil tank down tube on the frame, transferred the frame number to the headstock and filled in all welded areas with filler. The alloy oil filler cap and bottom blanking plate were then polished and oil supply tubes re routed.


The seat was binned and I hand formed a new seat base from aluminium, shaped some foam, sewed a new cover using patterned vinyl on top, smooth vinyl on the side with black piping between. New hinges and lock were fashioned from S/S. A little while after the pictures were taken I added a chrome strip around the base of the seat, made a big difference..


The entire electrical harness was binned along with the triple zenner pack, rectifier, battery cradle, side covers, coil bracket and air filter/heatsink assembly. I fashioned a new coil bracket from 3mm alloy sheet which also double as a heat sink on which I mounted a single zenner from an earlier model, a 35 amp Tandy bridge rectifier and a master switch, I then rewired the entire system.. Ignition switching was supplied by a simple rocker switch on the left side panel. I replaced the battery cradle with a hand beaten steel cradle, replaced the side covers with hand beaten alloy covers and mounted them via three grommets on each cover. I machined 6 positive stop alloy T nuts to engage the grommets and threaded rods mounted on the battery carrier and rear down tubes. I replaced the tail light with a hand beaten sheet metal item and mounted it to the rear guard via two grommets and two positive stop alloy T nuts.


Rear wheel was disassembled, hub polished and respoked with S/S spokes. Brake calliper had blemishes and casting marks removed with file and emery. The alloy calliper mount was polished and a couple of S/S wheel spacers replaced the originals. Swinging arm spacers were also replaced with S/S spacers machined up on my lathe. Both master cylinders were binned and I machined up two new S/S master cylinders with matching pistons. The front reservoir was retained whilst for the rear I machined up a long thin alloy reservoir from 35mm stock and threaded it and cap with acme threads. I also made a new alloy master cylinder bracket along with S/S push rod. The rear guard was shortened by 100mm, reshaped and remounted along with a new hand beaten alloy chain guard.


The engine was stripped and the lower half assembled without internals for a grind around all joints, all covers were then lapped in by hand and the entire assembly, including crankcase halves, was polished along with both concentric carbs and rocker covers and inspection caps. I purchased a new barrel and pistons, polished the crowns along with combustion chamber and valve heads and gave the ports a polish. The original pressed steel pushrod tubes were binned and a couple of S/S pushrod tubes machined up along with some new longer S/S barrel nuts. The gearbox cam plate was reshaped to rid the box of a false neutral and an air cleaner was hand beaten from alloy sheet which also served as a carb coupler. After reassembly pipes were replaced with 1/¾” drag pipes into which I fitted a couple of circumference baffles. Once up and running I re jetted the carbs and experimented with different cam timings until I was happy with performance. The original pointless ignition setup was retained. I purchased a Norton oil filter housing gave it a polish and mounted it to the right, front down tube via a floor polisher handle clamp which I reshaped and polished. An after market oil cooler was then plumbed in and mounted next to the oil filter.


Before reassembly I painted the frame, tank, side covers, tail light, callipers and a few other cycle parts in Jet black followed by a couple of coats of clear


Of course there were a million other mods I made, but I just can’t remember them. In this trim the bike was pretty quick, started first kick every time and aside from a broken earth lead, never let me down. It was louder than a shed full of Harleys, amazingly I rode past the Katherine Police Station quite often and was never stopped . When I moved south I had to install a couple of mufflers to please southern law - bugger. And would you it believe it, after all that attention to detail - it leaked from a small section of the crankcase joint just in front of the sump plug - bugger.


All work was done by myself: mechanicals, polishing, paint, upholstery, electrical, wheel building, etc, nothing was farmed out. After the final build I entered the bike in the Darwin European Bike Show around 98/99 where it won ‘Best Triumph‘. After that it was disassembled and sat in boxes for a couple of years before I sold it - bugger!

I'm in love!

Nice Bonnie, shame you had to sell it though. And at least it would have sounded heaps better than a Hardly Ferguson !

My brother in law is a Ducati guy. His current rides are '73 750 SS (like the Green Frame) and a '74 750 GT. But he has had various other bevel Dukes, eg 900ss, early 750 GT, another 750 SS and even a 860 GT. Nothing like a decent V Twin through a set of Contis. An awesome sound.

A 74 750SS and this, a 1966 BSA Spifire, mmmmmmmmm.

After all that you disassembled it and put it in boxes? Then sold it.?
Well it is a free world I guess.

Things are not always as they sound: I was in the defence force, defence personnel move every two to three years. When moving everything gets put in boxes to prevent damage, I just never got around to unpacking it - life happens.