Bye bye 2 strokes!

[Fortuna]

A 2 stroke 250 will produce more power than a 4 stroke 250 of equal research. This is due to the fact that the 2 stroke fires twice as many same CC's per revolution.
A 250 2 stroke twin is theoretically the same firing power as a 500 4 stroke 4 cylinder.

[Nath]

[Fortuna]

Putting valves in a 2 stroke would make it even more inefficient.

[Kickstart]

[Vin]

Awwee nuts I go away for a couple of days and miss a 4 v 2 stroke thread.
As far as I am concerned you can blah on about the relative merits of each but as a pound for pound good laugh 2 strokes rule. Oh and I love the smell.
Vin
P.S. Kickstart I am glad you mentioned the 2 stroke fiestas nobody I tell about that ever believes me. mmm a fiesta with spannies

[fuzz]

[Kickstart]

[lilredmachine]

Interesting little motor:

https://www.siscom.net/~louisekramer/
____________________
Bikes: too many, too much for one man to maintain anyway.

[Kickstart]

Hi

Interesting design. Suspect it would work rather better with more cylinders. Suspect that if you could get direct fuel injection working on it (should be easy with the revs he is talking about) then it could be simplified. But then it would be close to a conventional 2 stroke using a stepped piston (which would enable a 2 stroke to run on petrol, rather than petrol and oil), but with some extra drag from running a 2nd crank.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[veeeffarr]

Slightly O/T

But you'd think a 2 stroke would be more reliable than a 4 due to the simplicity of the engine? Or is this countered by the fact it produces way more power and is not 'wet' like a 4 stroke?

[lilredmachine]

More to do with the fact that it fires twice as often, so twice the wear.
____________________
Bikes: too many, too much for one man to maintain anyway.

[fuzz]

Valve timing is a problem with 2 strokes. Disc valves over reed valves offer more scope for induction, but the exhaust port is timed by the piston. Even power valves cant solve that.
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Bikes: '99 NSR125R, '00 SV650S, K1 GSX-R600, '97 CB500, K3 SV1000S, '16 VFR800

[Kickstart]

Hi

More heat to get rid of, but main problem is the poor lubrication bits will received, along with extra ring wear from having to go over gaping ports.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Kickstart]

[fuzz]

Is that the one with camless valves?

Just found this while searching for the above:

[Kickstart]

Hi

The Lotus 2 stroke engine they developed (quite a few years ago now) was not turbocharged, but used a machanically operated valve on the exhaust port to time it more indepenently of the piston position.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[fuzz]

I wondered whether you meant this https://waw.wardsauto.com/ar/auto_look_ma_no_4/index.htm but now I think it only applies to 4 strokes
____________________
https://www.bikepics.com/members/fuzzbcf/
Bikes: '99 NSR125R, '00 SV650S, K1 GSX-R600, '97 CB500, K3 SV1000S, '16 VFR800

[Fortuna]

[Kickstart]

Hi

Well, that would work for such a valve on a 2 stroke.

The could be fun. Mix in these virtually infinitly variable valve timing options, stick on the Saab system which allows variable compression ratios, one of the systems giving a variable inlet tract length (MV have such a system) and then all you need is some way to alter the exhaust length (Ferrari are already partly there). Power all over the place.

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[bish777]

[stinkwheel]

Ah no. This one was wierd, paralell twin with 180 degree crank. Instead of the fuel going from under the piston then through the transfer port to land up above the piston, the induction was under one piston in the traditional way then as it went down it forced the fuel through a transfer port into the opposite combustion chamber.

Picture may explain it better (only shows one 'half' of the porting).
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[NSR-Rulez]

I think that everythings a bit odd here, as to learn on a bike you are restricted to a certain bhp, or power to weight ratio, so all the fazing out of 2t bikes will end up in more people going out and buying bigger bikes.

And whats stopping people from buying old 2t machines when they are stopped being made, absolutly nothing unless the law changes.


NSR-Rulez
____________________
Past: 1985 Suzuki GS 125 + 2002 Honda NSR 125 R-2 + Ford Fusion
Present: Honda CBR 600 RR-5 + Suzuki SV650S-K4 + Mitsubishi FTO GPX

[AnaalBleacher]

Out of all of you anit 2 stroke how many of you have ridden an Rs125 or Mito or Kr1s or even the RD's???
You cant beat the fun of them...especially when ive been out cornering johnny fireblade on my Rs125 tut tut
2 strokes just need a little more TLC than 4 strokes I have found but then thats half the fun!

[Chiz]

Check out this months bike magazine, that has a 2 Vs 4 Stroke article. I read somewhere else that a 2 stroke car was built recently by some EU people. Basically a 4 stroke bottom end with 2 stroke top end and direct injection. Very clean, very powerful for size.

Personally: I like the idea of 2 strokes, power:cc and being a bit different from everybody else but the reality is a bit different. I have to warm my bike up for at least 5 mins before i can go anwhere while my mate on his bandit sits their waiting. Plus good 2 stroke oil costs a bomb. When i pass my test (March 3rd) i'll get a 4 stroke, im bored of waiting for my bike to warm up...

[NSR-Rulez]