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Author Topic: Vintage Yamaha 360, Woods Riding!  (Read 9605 times)

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Offline gpnewhouse7

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Vintage Yamaha 360, Woods Riding!
« Reply #15 on: September 08, 2012, 11:44:34 AM »
Uniflow have you got any close up pics of that engine, Iv never seen a rotary valve smoker before, how does it work? I love the older bikes for reasons like this, they just used to have so many cool, totally different ideas on them but now you can take a look at any of the big motocross brands adult bikes and they're all the same (pretty much).

I read a book about John Britain a few years ago and that guy built some amazing bikes, anyone who is even slightly into the design of bikes should look at the bikes he made.

I don't see where the engineers of today get all this following the crowd behaviour from, if any of them raced the bikes that they make they'd know that you can't pass someone by following them. TM shouldn't be making updated blue Honda cr`s, a company of that size should be instead just going out and finding new ways of doing things.

Look at what Yamaha did when they introduced the monoshock, or look at how John Britain`s bikes did with their crazy suspension setup.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline SachsGS

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Vintage Yamaha 360, Woods Riding!
« Reply #16 on: September 08, 2012, 03:28:19 PM »
Right here in North America Bombardier built disc (rotary) valve Can Am motorcycles in the 70's and early 80's.

Innovation follows money and in these modern times offroad motorcycles are not very profitable so manufacturers don't stray too far from the beaten path.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline Uniflow

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Vintage Yamaha 360, Woods Riding!
« Reply #17 on: September 09, 2012, 08:03:18 AM »
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline Uniflow

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Vintage Yamaha 360, Woods Riding!
« Reply #18 on: September 09, 2012, 08:26:30 AM »
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline Uniflow

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Vintage Yamaha 360, Woods Riding!
« Reply #19 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.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline Uniflow

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Vintage Yamaha 360, Woods Riding!
« Reply #20 on: September 09, 2012, 10:14:47 AM »
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline Uniflow

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Vintage Yamaha 360, Woods Riding!
« Reply #21 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.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline gpnewhouse7

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Vintage Yamaha 360, Woods Riding!
« Reply #22 on: September 09, 2012, 10:41:51 AM »
Did most of this come standard on the bike or have you modified it? That old kawi of yours seems to have more modern tech than most modern bikes have.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline Uniflow

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Vintage Yamaha 360, Woods Riding!
« Reply #23 on: September 09, 2012, 09:06:27 PM »
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline Uniflow

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Vintage Yamaha 360, Woods Riding!
« Reply #24 on: September 09, 2012, 09:09:10 PM »
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline Uniflow

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Vintage Yamaha 360, Woods Riding!
« Reply #25 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.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline Uniflow

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Vintage Yamaha 360, Woods Riding!
« Reply #26 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.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline citabjockey

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Vintage Yamaha 360, Woods Riding!
« Reply #27 on: September 09, 2012, 09:53:46 PM »
Uniflow:

Comment 1: this is just so cool! Great to see such a testbed under real development now! Thanks!

Comment 2: you need to start a dedicated thread on this bike (and maybe another on the YZ250 as you dig into it).

Now for the specifics -- :-)

How is it running?  does it start easy? idle? give good plug color for mixture at most (all?) rpms and throttle settings? Do the injectors pump based on thottle position or on manifold (i.e. crankcase) pressure?

You have a servo to rotate the rotary valve's "stationary" plate according to a rpm curve?

do you run O2 sensors? Engine and ambient temps?

Can you keep the front end down on this thing at all?  ;-)

have you put this frankenstein on a dyno? Do you have access to one?

What is this rotary valve water cooled EFI engine you mention for your YZ250?

Thanks again for posting.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
Yamaha CT3, RT3, MX125, SC500, Toy Prius, Diesel F250 (it all balances out)

Offline Uniflow

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Vintage Yamaha 360, Woods Riding!
« Reply #28 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.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline gpnewhouse7

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Vintage Yamaha 360, Woods Riding!
« Reply #29 on: September 09, 2012, 11:23:57 PM »
I should of known you were from New Zealand when you did all that modifying to such an old bike. You NEED to start a thread on that thing.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »