We’re excited to bring you this stunning CB550 cafe racer built by Linden Spencer of Doncaster, UK. This, to us, is the perfect cafe build: clean, tight, with components that help the bike handle, accelerate, and brake better than it ever did stock. Rarely do we get such detailed insight into a build, so we will let Linden take it from here.
In the Builder’s Words
Started with a £200 ebay bike , came as a bare frame 7 boxes of bits 4 wheels a new seat and a decent Motad exhaust (lots of this was sold back on ebay as we did not need it for the build).
Bought by my son, Andrew, after he saw an image on Google of the Cognito Moto CB550 built by Devin Henriques in America…with the comment that’s just how I would want one!
Andrew thought it a shame my tools were being neglected after we stopped racing cars 4 years ago, so this ‘project’ seemed like a good plan to get me back in the garage…..must admit it’s been a joy to do.
Spent a while trawling through the parts needed from America:
Cognito Moto for front hub to fit GSXR forks with a spoked wheel (bought his complete wheel to suit), suitable headstock bearing kit, CNC machined headstock with integrated Motogadget speedo, Tardotzi rear sets, extended rear dampers, exhaust end can, Sun alloy rims and the K&N filters.
Steve Carpenter, ‘Carpy’, exhaust which is a Yoshimura copy essentially, ceramic coated for an easy life, re-painted the manifolds on the race car so many times it became a pain.
Dime City for the seat, had this shortened locally as it was about 3” too long for the look we wanted.
The build started with having to gather all the bits to make a complete engine, including buying an engine in one piece for £50. This allowed me to strip one and see how it all went together…was a useful source of a few missing bits as well (plenty of pictures of the internals and the re-build of the bottom end).
Had the crankcases, head and barrel vapour blasted locally to give the bare alloy look we now have. Crankcases not painted or coated, just used a spray of WD40 regularly. The barrel and head along with the carbs bodies (once cleaned, bought an ultrasonic bath to help) were treated to satin heat paint bought at Newark auto jumble, seems to be holding up very well.
Did a bit of gas flowing on the head just to tidy it up a bit (the old racing addiction is still there…..) and had the seats re-cut along with a couple of thou off the head to clean it more than boost compression.
Thanks to Jonathan at Stanwood Engineering for that…..he built our car race engines previously .
I fitted new gear shaft bearings, oil seals, primary and cam chain as a matter of course. Cranks and mains were good to go again as were the pistons with new rings and a hone. Thanks to David Silvers for all the bits needed.
Once engine was done and safely out of the way under a cover, I started to look for a set of GSXR forks. Soon found some via ebay at Sherburn in Elmet bike breakers, £500 later and we had a complete front end…bargain.
Next up was the frame mods needed to clean up the back end and support the new seat. Cut of the old frame and started with the new seat dimension’s which were vital in working out lengths widths and angles for the frame tubes. Made a new front and rear mount for the tank, a CB500T tank bought of the vapour blaster after we dropped the cases of for cleaning. I just happen to mention we needed a tank but there were a bit thin on the ground. He said I have 2 if you want one. Oh yes.
Once the rear frame mods were done I turned to making a tray for the electrics, rear light unit / number plate mount and the battery, all these needed to fit under the seat for that ‘clean look’ took a bit of trial and error but it all worked out. The seat is secured with hidden cap bolts reassessed into the new frame cross tubes with Rivnut’s in the seat base.
I thought it wise to build the loom next and make sure it all fitted before coating, just in case I needed anything adding, turned out I did with a few washers cut down to allow the wiring for the starter and generator to be hidden / secured behind the down tube and newly installed dirt plate (the one with the Honda logo laser cut into it between the rear wheel and the carbs…keeps the road dirt of the engine and carbs). Biggest challenge with the old Honda loom was to make it work with the GSXR switch gear, and to squeeze the new connectors into the 5” headlamp. Thankfully it all did with a bit of jiggery pokey…only thing wrong when I eventually switched it on with power was the neutral and oil pressure warning lights (LED’s) were the wrong way round. Simple fix.
The battery is under the seta hump and I used a Antigravity 3 cell unit, as big as the proverbial fag packet and weighs about the same. It will run and start the bike, no issues to date.
I did pinch an idea from Steve Carpenters parts list, the exhaust supplier in America. He list’s a 7” headlamp with integrated LED indicator units, but as mine was 2” smaller I had to find some units to fit. Spiyda Designs at Stoubridge came to the rescue and made 2 units to my dimension fit alongside the halo LED’s already in the headlamp. I moved the left and right hand LED’s and re-fitted them alongside the upper and lower ones to give a bit more wattage to the side light. This cleared enough space for the indicator units to be fitted…bingo indicators in the headlamp Not strictly to VOSA standards in terms of spacing, but they are cool and I get asked lots about them.
Final bit on the frame before having in powder coated satin black, was to make a new steering lock stop that doubles as a mount for the GSXR steering damper.
Engine mating to frame came next and that ‘wow’ moment that spurs you on to add more bits. Soon had the forks in, the swinging arm on (with new Bronze bushes fitted) and the front wheel in.
Had to wait for the rear wheel as the hub and Sun rear rim were away for building with Central Wheel Components at Birmingham.
Messed about fitting headlamp, clip- on’s wiring loom and the rear sets in the meantime.
Once I had the rear wheel I need to fathom out how to mount the speedo magnetic trigger, needs to be mounted on / in ally so after much head scratching and sketched of what I thought would work I had an idea to drill out the brake back plate near the brake reaction rod mount to allow the pick up to be bolted on (the wires feed up the brake reaction rod I Made with rose jointed end, thus keeping them hidden) The magnet to trigger it is glued inside a alloy cap bolt which is in turn threaded into the drake drum flange, fully adjustable air gap and it works spot on.
The next ‘wow’ moment came when we trial fitted the newly painted tank, courtesy of Dream Machine Nottingham, not cheap but it is worth it. Now it looked nearly done, just the exhaust to fit and bleed the brakes. Had a small clearance issue with the fuel tap to carb top and I made the error of taking too much material off the tap and so it leaked. Back to ebay and as luck would have it there was a bare body for the tap on sale…bought and fixed within 3 days.
Time to start it, connected a slave battery just in case I flattened the lithium one fitted (no suitable charger if I did) usual plugs out to get oil pressure, then re-fit and see if it goes bang…It did but only on 2 cylinders, quick lead swap and we had all 4 up and running, once warm it was clear the jetting was wrong for the new none standard exhaust and air filter set up. Would not rev much beyond 4000 and would not idle for long before cutting out.
Arranged a session at Torque Tune Boughton with Russ where the jets were increase to 110 and the needles lifted 2 notches, oh the noise from that can at full chat on his dyno. Don’t know if it was his skill or best educated guess but the power graph looked spot on, 45BHP at the rear wheel….not bad for a 40 year old bike that gave 50BHP at the flywheel when new. There is a bit of fine tweaking still to do with the needles I thinks as it is magic when given full twist of the throttle, but is a bit ‘fluffy’ when trying to cruise. It’s well know these carbs were a bit fiddly when taken out of the standard set up.
The bike has now been to a few meets where it has attracted a lot of interest and loads of praise. It’s real fun to ride, handles a dream but is , shall we say, uncomfortable for longer trips…my wrists aren’t up to it anymore!
Andrew is now looking for another project for me, this one has converted him from modern sports bikes to cool classics, his R6 is gathering dust in the garage…possibly a 500 triple Kawasaki or an old school BMW boxer? The spanners will not be allowed to rust!
(Editor’s Note: our vote goes to a Kawa Triple!)
One more thing to note: Linden and Andrew were able to buy “1977 CB” from the DVLA, and that’s the license plate now on the bike. Lots of people think it’s a show plate until they ride out onto the public highway 😉