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About uniflow

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    New Zealand

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  1. uniflow

    300RR vs 300 xc-w tpi impressions

    I build autogyros, and engines to suit. For flying where reliability does matter, I use an old EA81 Subaru block as the basis for the power plant, it used to use a carburetor and points. I throw the points and carburetor away in favor of the much more reliable Link EFI system and transistorized ignition. Would not fly without it. The worry of a pump failure? dual pumps but in 20 years not had one fail yet. I wouldnt get too concerned about your trail bike EFI possibly failing, you are not going to fall out of the sky. Actually thats a false statement, autogyros glide, they dont fall.
  2. uniflow

    300RR vs 300 xc-w tpi impressions

    Pitty Yamaha didn't take the TPI when it was handed to them. Then you would have absolute reliability. KTM is just trying to be too cheap perhaps. Power CDI knows about the KTM ecu and it's short falls. Just step back a moment and think how a carburetor works. Little bowl of fuel sloshing around waiting to be sucked up through little brass holes, relying on a piss small pressure change. Floats wallowing around in this pool of petrol, opening occasionaly to dribble more fluid in, technology from before last century. ­čść Time for real fuel control, Electronic Fuel Injection controlled by an ECU, it will only get better. ECU can do stuff a carbuertor will never be able to do, no matter how 'smart'.
  3. uniflow

    250xc vs 250xcw vs 200xc vs 200xcw

    No it doesn't, where do you get that from? My YZ250 TPI same top end as a carburetored one. But feels slower due to power curve being smoother, I'm faster on the TPI than the carb bike but it feels slower, lap times do not lie. Carburetors patented before last century, little bowl of petrol sloshing around waiting to be sucked up by passing air creating a vacuum through little brass holes, time to move on and get some real control over the fueling.
  4. uniflow

    300RR vs 300 xc-w tpi impressions

    Says to me the market doesn't know what it wants. Small manufactures supplying to a small market for carbutetors, yes. Carburetors are a thing of the past, time we put them to bed. Change to EFI and they could be big manufacturers. KTM are doing well with TPI even with their problems.
  5. uniflow

    300RR vs 300 xc-w tpi impressions

    make no mistake, fourstroke injection is easy compared to twostroke, much more difficult, otherwise it would have been out long ago.
  6. uniflow

    300RR vs 300 xc-w tpi impressions

    sherco, beta, gas gas etc saying they don't need efi yet. Just says to me they don't have a worthwhile system developed. If you did you could trounce the market. KTMs TPI is a good start but they seem to have dropped the ball a bit, perhaps trying to be too cheap. TPI technology can be used by any manufacturer, just they should do it properly. If there was an EFI system that offered performance gains in the twostroke and fuel efficiency, you would have no competition, they would sell out, isn't that what every manufacturer dreams of. TM, clearly not silly.
  7. uniflow

    How much would you pay for a 2020 kx125?

    You've got an old engine design matched to a frame that was not made for it, a mismatch. Twostroke engine design has come a long way since Kawasaki stopped making 125s .For 2020 you need a fresh approach. Even with the newest YZ 125, Yamaha should be ashamed in regurgitating the 'same old'. I guess if we are silly enough to keep buying them, effectively encouraging them I guess.
  8. uniflow

    How much would you pay for a 2020 kx125?

    Anyway, I wouldn't expect a 2020 bike to still have a carburetor, patented before last century, when there is so much better available now. There, I've just turned it into carburetor v EFI. ­čść
  9. uniflow

    How much would you pay for a 2020 kx125?

    Well then, how much would you pay for this one of a kind Kawasaki 350. First off road twostroke to have electronic Transfer Port Injection, first off road twostroke to have variable rotary valve HOUSING fitted, full of modern technical stuff but its a one off orphan. Modern (young) guys hate it cause its an old piece of shit (opinion generally dished out at trail rides etc) and the old guys hate it cause its been bastardised and not original. Unless there is something special about the bike i.e. factory development bike or part of a small high end production run or something like that, its priceless / worthless. Never mind, I love my 350, its well suited to our Kiwi trail rides. And no, I wouldn't own anything less than a 175cc, at any price.
  10. I remember VMX years ago, riding my 360 DT , hotted up, plenty of power. Mate of mine kept insisting I ride his XR200. Not interested, too small and a fourstroke also, too gutless. End of the day I softened and had a ride, couldn't belive how easy it was. No throttle control required just on to stop always. More time to just concentrate on controlling the bike, hated that experiance­čść, an eye opener.
  11. Redrider, here is whats inside the piston, titanium capscrews and 7074 gudgin pin caps. Gudgin pin is 1/3 less weight, whole setup is lighter than standard Wiseco of 60mm dia. Outside is not down to size yet.
  12. yes, off topic. This 'mod' is actually a whole new engine with some new concepts. Idea was to have a high power, wide torque curve, but twostroke light weight. 360cc so light weight has blown out. Should have made it as a 175, light and powerfull, next engine.
  13. yeah, but we are all not Chis Birch aye redrider144 , finally finished the kick starter housing for the 360 TPI. This housing also encorperates a counter rotating bob weight and an experimental system to sample read crank case pressure, a small mechanical device. The whole housing is a bolt on over the flywheel. A bit wider than I hoped for but too bad I'll address that on the next engine, the 175. And now to extract the kick start leaver from this piece of 7075 plate.
  14. Crappy rider or not, I believe the weight of the modern 250 / 300 etc are getting out of hand. All this add on stuff, Estart etc.
  15. Don't under estimate a light bike. I agree I'm not so keen on a 125, but 175 is a different story. The YZ bottom end is not suitable for taking out to 175cc, not enough room in the crank case to get much out past 58 stroke (safely). A decient twostroke needs to be at least square bore and stroke, port time / area, and off road applications seem better over square. Like I said say 60 bore x 64 stroke would be ideal. Combined with the minimalistics of a 125 size bike, you could not help but to have a giant killer on your hands. Now (now some will thing I'm going off the deep end here) combine with rotary valve top end performance and you are likely to have around 50 crankshaft HP. Possibly more if you want to shorten rebuild times, 50 would be a safe limit. Pistons? build your own, lump on the head is so I can finish machining to size and do the cut aways for the transfers. A real twostroke performance engine will have the exhaust eye ports spread right around to the center of the bore. This causes problems when the exhaust port can communicate with the transfer at part stroke through the pin, so most run gudgin plugs. With this design no gudgin hole to cause problems at all. ,