MY Thruxton r-sc

Surly said:

Brilliant Phil !! Very tidily done. Is the blower,intercooler, etc, a kit ? And where you say " one extra tooth on final drive cog ", are you talking gearbox or rear wheel, as these bikes tend to come overgeared anyway ? We are lowering the gearing on my sons Black as it's obviously way overgeared, and though it pulls 6th okay, I'd assume this is done for fuel mileage tests and more importantly to pass emissions,noise and so on ? … cheers

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Surly said:

P/S .. how's about pictures of the other side (can't call it "drive" anymore .. haha) .. or is that where it becomes untidy ? … hahahaha ! Interested, as with the coolers, etc, onboard these days it's becoming harder to run pipework in a tidy fashion !

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Phil J said:

Most of it was bought as a bespoke kit, from tts performance of Silverstone. They buy the rotrex supercharger then manufacture all the welded plumbing, the intercooler, a bespoke replacement timing casing that is milled from a solid billet of aircraft quality aluminium. They also sourced the Scorpion downpipes, flat top forged pistons and the Commander5 ECU. This was then shipped to myself for fitting. I don't have the skills to do the work myself, so a very experienced bike mechanic, Royston Edwards of REPs motorcycles in Rogiet, South Wales, stripped my standard bike to bits and then rebuilt it with all the new parts. I sourced the bespoke injectors separately, from Roke Motors of Amsterdam, because we found that the standard triumph injectors weren't quite up to the task when we gave the supercharged motor handful of throttle, producing flat spots in the acceleration. All sorted perfectly with the new injectors though. In terms of the final drive sprocket, this is the sprocket connected to the front end of the chain driving the rear wheel. You are quite correct that the original engine power meant that 6th gear felt a little like overdrive and the motor wouldn't normally pull that all the way into the redline. With the supercharged motor, both torque and horsepower are increased by circa 50%, so the motor eagerly red-lines in every gear. The extra tooth on the front sprocket has given just about perfect gearing, married to the increased torque and horsepower.

Fuel consumption has remained very similar to before; the engine is even more efficient at normal engine revs, due to being supercharged, but will guzzle fuel at a much higher rate when ridden hard. To be honest, it's difficult to give it the full bean she for long on most roads, so overall I seem to get good economy from the bike. I haven't measured it accurately, it's not my main worry, but it seems to return about 55mpg overall. Hopefully I've answered everything, when all this COVID-19 stuff is resolved, get in touch and come to South Wales to see and listen to it in the flesh; maybe a little run up through Mid Wales could be on the cards.

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Phil J said:

Most of it was bought as a bespoke kit, from tts performance of Silverstone. They buy the rotrex supercharger then manufacture all the welded plumbing, the intercooler, a bespoke replacement timing casing that is milled from a solid billet of aircraft quality aluminium. They also sourced the Scorpion downpipes, flat top forged pistons and the Commander5 ECU. This was then shipped to myself for fitting. I don't have the skills to do the work myself, so a very experienced bike mechanic, Royston Edwards of REPs motorcycles in Rogiet, South Wales, stripped my standard bike to bits and then rebuilt it with all the new parts. I sourced the bespoke injectors separately, from Roke Motors of Amsterdam, because we found that the standard triumph injectors weren't quite up to the task when we gave the supercharged motor handful of throttle, producing flat spots in the acceleration. All sorted perfectly with the new injectors though. In terms of the final drive sprocket, this is the sprocket connected to the front end of the chain driving the rear wheel. You are quite correct that the original engine power meant that 6th gear felt a little like overdrive and the motor wouldn't normally pull that all the way into the redline. With the supercharged motor, both torque and horsepower are increased by circa 50%, so the motor eagerly red-lines in every gear. The extra tooth on the front sprocket has given just about perfect gearing, married to the increased torque and horsepower.

Fuel consumption has remained very similar to before; the engine is even more efficient at normal engine revs, due to being supercharged, but will guzzle fuel at a much higher rate when ridden hard. To be honest, it's difficult to give it the full bean she for long on most roads, so overall I seem to get good economy from the bike. I haven't measured it accurately, it's not my main worry, but it seems to return about 55mpg overall. Hopefully I've answered everything, when all this COVID-19 stuff is resolved, get in touch and come to South Wales to see and listen to it in the flesh; maybe a little run up through Mid Wales could be on the cards.

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Surly said:

Lovely stuff … answered perfectly thanks ! Excellent to see someone doing it differently, rather than just the bolt on stuff. As these bikes get a little older (and cheaper) we can start hacking them about like the old Bonnies,etc. Wish I could show you the 750 Bonnie I supercharged a few years back, the small blowers off jap cars are perfect for bikes, and as they have their own sump there's no need to plumb in oil feeds. Belt driven off the crank with an ARD mag for sparks so no need for alternator ..aaahh ! Have you altered the cam timing to suit the blower ? It's reasonably simple with OHC if you mill the drive sprocket bolt holes into slots and degree the cams to suit … just a thought. When I win Lotto you'll be hearing from us .. haha. I'd love to as my first kids grandmother was true blue Welsh, the next ones was Scottish, mine were Irish, and the new (ish) mummy-bears lot were Shetland Islanders. She's always wanted to do the Grand Tour, but never worked out how to stop having kids ?? Bloody left-footers,eh ? Seriously .. if we ever get the chance …. we'll bring the lot (how big's your house ?)

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Surly said:

aaaahhhhh … hey Phil ,you never know … mummy-bear reckons if I sold everything off (excepting the Legend of course .. she loves it) and said nowt to the rest of them, we could do it in style !! … hmmm ? Yeah .. Isle of Man, forgot that .. we could send her off to The Shetlands for a couple of weeks to appreciate the horizontal rain .. haha !! Christ, I need to come into todays world … wanna hot 'em up ? .. play with the computer. I mentioned cam timing changing as in the dark ages we'd do that to keep more of the charge working for longer, though the blowthrough does help to keep the exhaust valves slightly cooler. When we raced japanese 1000's at the speedway a bit of cam timing change (along with lotsa compression, etc) made the things pull like a twin out of the corners, on carbs of course. Now the young buggers run lotsa compression,injection and computers !!!!!! The top guys are all running around 200 odd hp. It all seems too easy .. and expensive .. so I'll stick to the old ways thanks .. more fun !

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Dewcati said:

Beautiful bike... how fast will she go ?

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Dewcati said:

Beautiful bike... how fast will she go ?

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Phil J said:

Haven't run out of revs in top yet, but with the revised gearing 70mph is 3,500revs and recent use suggests she'll easily pull through the 7k redline in top, so I guess 140 to 145mph is easily achievable; if I can hold onto the bars tight enough.

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