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Messages - Uniflow

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271
Vintage Two Strokes / Vintage Yamaha 360, Woods Riding!
« on: September 10, 2012, 01:06:09 AM »
Yes I'll start a new thread. Some quick answers. Yes runs well now. idles smooth, starts well when the day is hot or engine is hot. Ethanol won't vaporize well when cold so I use a little petrol squirt bottle to start from cold, first kick usually. Injection timing is critical around transfer opening. Injection can be staged to minimize fuel loss out the exhaust, at least a lower engine speeds. Throttle uses a TPS. Crankcase pressure is sampled by a small valve connected to the crankcase, is only reads pressure ( or vacume ) when the injectors are on. So far only "seat of the pants" tuning. Yes rotary valve case moves with RPM ( this is a very good feature for a rotary valve engine). The "new" engine will be a made up unit ( for the YZF ) . I'm also doing a "converstion" for a YZ250 T for the local Yamaha shop. I think it will be too dear to sell as a kit, but lets just see if it works first.  Yes I have access to a dyno but they cost so I've decided to get it tuned as close as I can first.

272
Vintage Two Strokes / Vintage Yamaha 360, Woods Riding!
« on: September 09, 2012, 10:56:51 PM »
Sorry for taking over the thread, after all it was about the RT2 360 trail riding. It's just good to see there are still twostroke people out there. Seems to have gone all fourstroke here in NZ. Just a few old fools like me still flying the twostroke flage. With the new computers available now it's possible to make the twostroke something it never was. It's got nothing to do with technology, if I can do it to this old 350 any manufacturer could, it just seems the big guy's aren't interested.

273
Vintage Two Strokes / Vintage Yamaha 360, Woods Riding!
« on: September 09, 2012, 09:34:45 PM »
The problem is because it's an old bike no one takes the technology in it that seriously and is hard to use the engine and ride fast, even in a straight line. I've just purchased a YZF 250 to take the engine out and replace it with a rotary valve EFI water cooled twostroke. Should handle a bit better.

274
Vintage Two Strokes / Vintage Yamaha 360, Woods Riding!
« on: September 09, 2012, 09:21:10 PM »
Yes modified a bit. I'm using it as a test hack to learn about EFI on twostrokes. I have a spare standard ish engine for offical racing. I'm injecting into the crankcase at the back transfer port. The Kawasaki has an air cavity, suitable for fitting two Bosch injectors and a pressure regulator. Pump is under the engine, you can just see it with mud all over it from the weekend just gone. Link controller is under the seat with a Ignitec ignition beside it. Ignitec runs the servo that powers the vairable rotary valve housing, you can see the drive cables behind the throttle body. This gives a rotary valve timing from 55 to 80 degrees ATDC. More top end power than a reed engine with the flexability of the reed engine. But more complicated! The engine is way too much for the frame and shocks, but it's just a test hack.

275
Vintage Two Strokes / Vintage Yamaha 360, Woods Riding!
« on: September 09, 2012, 09:09:10 PM »

276
Vintage Two Strokes / Vintage Yamaha 360, Woods Riding!
« on: September 09, 2012, 09:06:27 PM »

277
Vintage Two Strokes / Vintage Yamaha 360, Woods Riding!
« on: September 09, 2012, 10:24:07 AM »
This what's housed behind the air cleaner. Throttle body is from when it was mechanical fuel injection.

278
Vintage Two Strokes / Vintage Yamaha 360, Woods Riding!
« on: September 09, 2012, 10:14:47 AM »

279
Vintage Two Strokes / Vintage Yamaha 360, Woods Riding!
« on: September 09, 2012, 08:30:55 AM »
Out riding on Sunday, Taupo Berm Buster trail ride. A bit of tuning. Runs on E90, 90% ethanol and 10% petrol.

280
Vintage Two Strokes / Vintage Yamaha 360, Woods Riding!
« on: September 09, 2012, 08:26:30 AM »

281
Vintage Two Strokes / Vintage Yamaha 360, Woods Riding!
« on: September 09, 2012, 08:03:18 AM »

282
General Two Stroke Talk / Cycle World Two Stroke article
« on: September 09, 2012, 12:22:35 AM »
Why wait, do it yourselves, the technology is already out there. I use a Link Atom computer on my MX twostroke. Rear transfer port injection, by staging the injection, fuel wastage is reduced, more power, wider power spread. Enough oil deposit on the transfer runs down to the crankcase to service the bigend. It's been running for about eight months now. Yes there has been may issues.

283
Vintage Two Strokes / Vintage Yamaha 360, Woods Riding!
« on: September 07, 2012, 07:54:25 PM »
Yes it's a bit wide and awkward for trail rides but it's used mostly for VMX, pre 75 open class. Hole in the side gives more power, cool air. Air cleaner has a sock over it replaced every race. Pipe is a reworked  ( rewelded ) FMF unit. Rotary valve engines can still deliver startling performance with a bit of "modern" stuff inside. There is not a lot of original Kawasaki inside.

284
Vintage Two Strokes / Vintage Yamaha 360, Woods Riding!
« on: September 07, 2012, 09:08:59 AM »

285
Vintage Two Strokes / Vintage Yamaha 360, Woods Riding!
« on: September 07, 2012, 09:01:51 AM »

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