PROJECT RICKUKI
Steve Cooper is back with Rick!
How time flies! Yes, it’s been a year at least since CMM caught up with Project Rickuki and despite an apparent lack of visual activity, things are actually making progress.
The truth to the ongoing engine rebuild is as simple as it is brutal; a lack of time, appropriate skills set and workshop resources mean I have to engage professional input to progress the motor’s rebirth. Some might argue that because the powerplant is just a simple two-stroke I should be rolling up my sleeves and getting stuck in. However, for the same reason most of us are unlikely to ever re-machine the valve seats of a Kawasaki Z1 cylinder head or rebuild the pressed up crank of a Suzuki GS1000, I’m in the hands of skilled, highly proficient experts. And, crucially, these guys have access to the appropriate kit and, more importantly, the
skills to use it. You might just recall from the last missive in this faltering and occasional series that we were looking at installing a Nova Transmission T500 CR Kit Type B close-ratio gear set and that I was wincing at the likely cost? Well, I emptied out the Biking Piggy Bank and sent the resultant and very posh looking cogs over to Rob Pemberton at SPA Motorcycles, only to hear some rather perturbing news: when the main and lay shafts were popped out of the lower engine case in order to play ‘Swap Your Cogs’ a worrying fault was picked up.
As you can see from the picture of the Nova kit, it’s not every gear that needs replacing and a fair number of Hamamatsu’s finest are retained and re-used… or not if it’s Project Rickuki. Close up, critical examination of the surface of the original cogs revealed evidence that the case hardening was about to fail or was on its last legs. Bloody annoying to be honest as when we’d given the gearbox’s contents a look over before we’d concluded the giblets just looked used. This only goes to prove the old adage ‘measure twice, cut once’. Rob P took a second opinion from next door neighbours – Race Techniques – who build everything from rally cars to TT race bikes and they concurred: some of the cogs were at the limit of their lifespan. Expletives were obviously then showered upon the bike, the gearbox, the project as a whole and the stupid notion that we were close to sorting the thing out, but this is the hard truth of working on old bikes.
Sometime later, but the same week, things had simmered down a little and common sense took hold. If Project Rickuki is ever to turn a wheel in anger then it needs a viable transmission, and despite not budgeting for new cogs something had to be done. We could either buy a used transmission from a breaker or speak to Nova who can make pretty much every cog ever needed in a T500. The first option was potentially cheaper, but we might just end up with something as bad (or even worse) as we’d already got and have to repeat the scenario ad nausea. Alternatively, I could just bite the bullet and buy what we needed from Nova… which we did.
Now, apologies if I’m guilty of labouring a point here, but this is the very nature of project motorcycles – they do not automatically or reliably follow the owner’s or builder’s intention. Forget your modern-day project planning, don’t even think of running a financial forecasting spreadsheet, and never set timelines because it simply will not work.
Old bikes, and especially those that have been abused by others, will always cost more than you expected. Suck it up, take a deep breath, resign yourself to the inevitable and move on. Or, alternatively, don’t take on someone else’s abandoned project…simples!
Now I’m chained to a life of penury the project moves on and the gearbox was finally, inexorably, relentlessly reborn and needless to say it will be forever filled
with the most expensive, technically advanced motorcycle gear oil there is.
Elsewhere there’s more money being shelled out for other, mission critical, parts. By opting to run the engine as a water-cooled unit we’ve engineered ourselves a couple of issues. Namely the engine’s cylinder studs are too short, the main sleeve bolts are too short and the auxiliary head bolts are too long on their tops. I could bore you incessantly with the minutiae of the challenges, but life is too short and CMM’S readers doubtless have better things to do with their time. A previous owner had obviously mugged up a dummy fixing of the correct length using some DIY studding so this was used as a pattern. Long story short, 8 x 10mm diameter studs 131mm long, threaded M10 x 1.25 for 20mm were commissioned to be made out of EN16T steel, and I was pleasantly surprised they ‘only’ cost me £56. ebay divvied up some appropriate nuts and the auxiliary bolts were suitably machined to fit. If anyone needs genuine T500 cylinder studs, I’m your man!
Last time, our man that can, Rob, had begun to look at the T500’s various passageways and given then a preparatory look-see with his porting tools. His professional opinion was that the porting was decidedly on the cautious side of conservative and there was a lot of latent potential that could be unleashed. However, what I don’t want is a missile with wafer-thin power band; the Rickuki will be a road bike not a track-day machine.
Whilst getting stuck in, Rob had also commented that the T500’s flow dynamics were variously compromised by both the location of the exhaust ports out on the external corners of the cylinders and the inlet ports that are traditionally orientated on the centre line. This odd arrangement effectively compromises the flow of the incoming fuel/air mixture and the ejection of the exhaust gases. The racing TR500S had their exhaust ports in the centre so there’s no argument for the road bike’s set up, they are simply poorly situated, but we have to live with what we have. To add to the mix this strange arrangement also means the transfer ports are, in effect, twisted around both the central axis and that damnably silly exhaust port.
The entire arrangement has made the resultant massaging of steel and cast aluminium emphatically longer winded than it might otherwise have been, but we’re there or close to it. Despite being atypical in location, the transfer ports were pronounced as being fundamentally fit for purpose and have only received a gentle tickle. The inlet ports have been dramatically re-worked, but we’ve retained the cast-in bifurcating alloy spar, which assists in flow dynamics. As might be expected, it’s the quirky exhaust port that’s swallowed up the lion’s share of the work. It’s been raised by several millimetres and substantially modified in order to speed up gas flow and take out some of the pronounced internal curve.
Now I’d like to think that we might now be able to nail the engine back together and put it to one side but, as we know, life’s not that simple when it comes to old bikes. We’ve been looking long and hard at the options for a modern ignition system and have been hovering between various options.
Ultimately we’ve decided to go for a GT500 generator cunningly patched into a specific Zeeltrontic programmable black box. And none of this should be an issue as we have GT500 crankcases, BUT some clever soul has converted them to run the earlier T500 rotor and stator! A look at the crankcases shows three hexagonal bosses to mount the older system and, of course, we have T500 rotor on the end of the crank. How did we miss that one? If we knew I’d not be writing the last paragraph – arse biscuits! I can see another large financial layout galloping towards me at breakneck speed!