Wednesday 28 October 2009

Drew's "BIG" project

Back in the days when colour had yet to be invented and dinosaurs needed a way to impress girls and get to school (c1977), Mr Honda decided, for one reason or another, to produce a moped which looked like a proper bike and didn't stink like a Flymo (not you Garry, I'm sure you smell great). Out of the Big H factory popped the mighty CB50J. A 49cc OHC 4-speed bristling with almost some horsepower, a disc brake and a chrome megga. The British version also arrived with a neat little single seat conversion, (possibly due to our 'no passengers for 16year-olds' rule) and it looked pretty good. It was also tiny- you'd trip over it thinking it was still 20ft awayLuckily my Big Bruv bought one of these off a friend who, given his future maintenance record, failed to destroy it. As almost everything a younger sibling receives is hand-me-down, I was well chuffed when, having finally made it to the pimply age of 16, Big Bruv sold me the 'Ped for £10 more than he paid for it.Off came the standard air filter and on with the S+B with chrome end cap which unleashed an immeasurable amount of horsepower but sounded ace. The front disc was cable operated and was not bad if you tested it immediately having adjusted it (again), but soon became ok-ish when the car in front jumped on the brakes. Change the oil every 1000 miles and the odd new plug and it absolutely never broke down. It always started first kick, even in any of the worst motorcycle- unfriendly weather. And after I crashed it. Twice. The headlamp and battery were poor- applying the brakes unfortunately meant half the electricity destined for the bulb at the front came out of the one at the back, rendering the rider virtually blind approaching a tightening bend in the dark. To teach it a lesson, I crashed it into a field. I happily spent the next two-and-a-half years chugging around North Norfolk, to and from work and to sixth-form where I successfully failed to impress any girls on the ever reliable 50J. Then I finished building my GSX250, and so endeth the life of The 'Ped. Until...... I couldn't bring myself to get rid of it (Gibbo's rule- never sell a bike) so it sat in boxes in my shed for 16years. I got bored. I looked in the boxes. I was no longer bored. I want a cafe racer, I thought. Hmmmm. Hacksaw and welder out, let's get started. First things first, I made some (very high) rear-set footrest hangers, using the remains of a bike my mate used to reshape a Rover 25. Thanks Keallo. Made a cable operating mechanism for the rear brake as wherever I moved the linkage meant going over bumps would apply or release the brake. Don't fancy that much. Removed the rubber swingarm bearings (thanks Mr Honda) by intricately burning them out with a blowtorch and sent the whole lot off to the outlaw Andy Wales for grit-blasting. Once it was back, on with the black Smoothrite. NEVER follow the instructions, it went on like black water and promptly ran off like black water. Once that was sorted, time to plonk all the bits back together. It was nice having a project so small I could build it on my bench.
Had the forks re-chromed by A M Philpot, a friendly helpful bunch of folks, new headrace bearings, rear shocks and new rear rim (Dave Silver is a good source of new old Honda stock). Hagon sent me some beautiful shiny new spokes and I sent the rear hub and brake plate off to Gibbo and Son Eng. Co. where junior Gibbo worked his blast- tank magic. New wheel bearings (luckily NOT rubber, thanks Mr Honda) in and time for some knitting. Never laced a wheel before, so I used the still assembled front as a pattern- piece of cake. This is easy, dunno what all the fuss is about. Front hub off to Gibbo, lovely clean front hub back from Gibbo, assemble. Eh, what's going on? Why can't I make this one work. Five attempts later, the front is a wheel at last. Purely because the rear hub was wide enough meant I could unwittingly start in the wrong place and still complete it. Top tip- start with the spokes on the inside of the flanges or get someone else to do it... Wheels on, ace- bars on, one big white-faced tacho and time to scoot it around outside and laugh at its complete lack of size. Neat
Engine time. 49cc is never going to excite anyone so the original reliable engine retired to a shelf. E-Bay lightened my wallet but sent me a 'good, rebuilt' XR80 engine (identical crankcases so will fit in 50J frame). Apparently, a 'good, rebuilt' engine needs a new cam chain, cam sprocket, piston, rings, exhaust valve, cam chain guide. Glad I looked inside.... Incidentally the 50J engine was rated at a max of 2-2.5bhp, the XR80 a more healthy 7.5-9bhp. At the very least, power will be tripled so 40mph could become 69mph..... Oh bloody 'ell, better sort the brakes- it'll need a good front one more than Gibbo needs cake. Rear drum was fine, so down to Burto's for a hydraulic caliper and master cylinder. After much rummaging, said bits were found. I need to mount the shiny little caliper somehow- the original was in front of the fork leg, but as that looks not all that tidy and will slow down the steering (????) I'll put it where it should be. Oh dear, nowt to bolt it to. Except one original mount and a vastly over strong mudguard mounting point. They'll do. Off to Gibbo's (again- the coffee is pretty good here) with a lump of aluminium and a cardboard template. 5 hours later and having reduced a lovely great piece of metal to lots of chippings and a bracket, I bid farewell to Mr G's Swarf Emporium and do another 1 1/2 hrs on my lathe making more of what look like Metal Mickey's pubes.
The finished bracket looks ok, fits well and is very solid. It ought to, it took long enough. That's about as far as Project Ped has travelled so far, lots of other niff-naff and nonsense to complete but hopefully it'll be coming out to play in spring 2010. If you want an genuine original Honda 49cc racer, there's currently a 90mph 1963 CR110 (4-valve DOHC 8.5bhp @ 14000rpm) for sale on t'internet for a measly £37605. Sorry if you've fallen into a coma through boredom, but Adi made me type all this- he's standing behind me with a large stick as I type. Keep it rubber-side-down.

1 comment:

filthyritch said...

So that's where you've been you herbert!! Yes I remember the damp ol' days of, "How much money you got?"
"87p!"
"Great that'll get us to the coast!"
Yep the price of petrol was sensible then! Good work dude we'll be inspecting the 50J later.