Reverb Motorcycles CB750 Bad Dog
By Ross Sharp - 03 Nov 16
Some folk see motorcycles as inanimate objects that serve a purpose of moving a bag of flash from A to B. Then there are those at the other extreme who talk to their bikes and bestow more attention upon them than they would their own offspring. I reckon I'm somewhere in the middle, swaying towards the talking (swearing) side when the shit hits the fan. Mark from Reverb Motorcycles who built this handsome steed dances from one side to the other, loving the nostalgic story of a potential donor bike, but then hating it's retrograde recalcitrance that thwarts the potential of actually making a decent living out of building custom bikes. We don't blame the donor for the latter, that's Mark's fault, as you'll see. The CB750 DOHC you see here was built in 1979 and put on a boat bound for Canada where it spent a few years before an owner rode south to the far more agreeable climate of California. Three and a bit decades and less than 20,000 miles later and one of Mark's friends popped it on a boat once again, headed for England. It arrived in such good order that Mark decided to spend the sunny summer enjoying it's original design and function, belting along the country lanes that surround his East Sussex workshop. Then the summer ended, the rain came and a man arrived at the workshop clutching a photo of a custom CB. Momentarily Mark had dollar signs in his eyes before remembering how much effort the last Reverb build was and that this customer was standing here for the same reason - he wanted bike of a similar standard. If you've seen one of these seventies and eighties Hondas up close you'll know that there's now point faffing around, you have to chuck the engine in a corner for a while and set to the frame with a grinder. The factory welding was pretty bad and there were tabs and ugly bits strewn all over the place. Suffice to say that Mark spent enough time so that once back from the powder coaters the frame looked like it'd been freshly fabricated from scratch, with a neatly looped subframe. There's no argument about CBs looking great with a flat, bratted-out seat but for the crossover café style the kick-up that incorporates the shock mounts is a nice touch here, complete with frenched-in brass tail light. Mark's upholsterer has done a lovely job on the saddle and avoided trying to make a seamless tank-to-seat interface. Seeing the bolt that holds the tank down is something us rose-tinted nostalgists appreciate. Customers always seem to like a completely bare rear triangle which creates a headache for all but the super tidy. Mark fabbed a small battery box and suspended it beneath the swingarm pivot and ran a fresh loom from there up to the minimalist cockpit. A Motogadget speedo and singular idiot light is the dash. A starter button has been craftily spliced into the brass headstock nut. (see, told you Mark was a perfectionist) The speedo was grafted into an old brass wick lamp. In fact there's a fair bit of brass on the bike including used bullet caps. The customer liked the patinated, raw metal look a wanted a finish that would age with organically with time.
All of this aesthetic effort would be wasted without a decent mechanical going-over. If you've got mate with a single or twin cam CB750 who's pulled the airbox off you'll be familiar with either their moaning or the sound of their engine attempting to fuel properly. These motors are a ballache to setup on stock carbs and wise chaps like Mark reach for the Keihin catalogue and order a fresh set of CRs. Unfortunately before Mark's wisdom could be rewarded Sod turned up with his stupid bag of laws.
Whilst running the engine on the bench cylinder number 3 decided it didn't want to play anymore. It's not totally clear how but either the ignition failed or the stock carb got carried away with itself and dumped a load of fuel into the combustion chamber. Suffice to say, the thing hydrauliced giving the piston nowhere to go. The conrod capitulated and turned banana shaped, promptly followed by said piston which smashed its way into the crankcase, snapping the skirt of the cylinder liner in the process.
Bang, grumble, rattle, bang, bang, tickle, pfffft. That's the sound of Mark's profit margin going up in smoke.
The engine was stripped back to the crank and all new bearings, seals and gaskets were replaced along with pistons, , rods, rings, liners - the whole shooting match. Mark took this on the chin and made sure the customer's enjoyment of the bike took precedence over his wallet, and social life. Not sure if this is why the bike has been named Bad Dog, but it'd be a fair guess.
Once back together stubby filtered velocity stacks were fitted to the new Keihins and the bike taken to the rollers for a proper setup session. It sounds flipping spectacular with an induction roar emanating from just above the stunted exhaust. The 4-into-1 culminates in a short, single baffle. But how many decibels that can suppress is debatable, in a good way. If it's any consolation Mark the motor certainly looks nice from the outside.
The eagle eyed among you might be frustrated that I've taken this long to mention perhaps the most significant mods. Yes, the suspension isn't the normal CB parts bin special. A GL1000, yup Honda Goldwing, gave up its front end for the project. The wider triple clamps and burlier forks not only perform better on a more spirited ride but look more stout. The twin drilled GL discs and calipers look spot on and negate the need for a USD fork, which would have spoiled the classical styling.
The rear end has also been swapped. Honda's big boy six-banger CBX1000 features a more accomplished setup with giant rear disc brake, replacing the CB's outdated drum. Being the later, Comstar sporting model from '79 the CB did leave the factory with large, cast peg and control hangers. These have been modified to accept a tidy pair of rearsets, positioned nearly in line with the back axle, the owner is long, 6'4" to be precise and needed stretching out to avoid the knees in the chin crouch.
These photos were taken right after the bike rolled off the bench, but it doesn't look like this now that mother nature has added her touch to the project. The brass accents, aluminium engine cases, the clipons, and steel fuel tank have all been painstakingly satin polished by Mark but the customer specifically didn't want this hard work to be sealed in by lacquer. Natural ageing has started already but hopefully the customer has kept away from Mark's workshop to avoid the "do you know how long that took me" conversation.
The reason Mark isn't swimming in pound notes and driving to work in a Lambo is because he's a flipping perfectionist and honourable gent, preferring to spend all night making sure a part fits just so, rather than making do. Which is great news, for everyone else. The customer gets a great bike, we get great pictures and hopefully you all have another dose of motivation for your own project. Thanks Mark.
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