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Author Topic: When would the Japs catch up with 2T, if ever?  (Read 914 times)

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Offline katana

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Re: When would the Japs catch up with 2T, if ever?
« Reply #20 on: April 17, 2020, 03:08:08 pm »
Just referencing to marine 2t diesels again.  Air injection is where the revolution lies.  Imagine no transfer port, no 2t oil and fuel injection economy on a 2t performance scale.  Hell, throw in short skirt lightweight pistons with 12000rpm.  Even dream away those easy to damage expansion pipes that won't be needed anymore.
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Online BuRP

Re: When would the Japs catch up with 2T, if ever?
« Reply #21 on: April 17, 2020, 03:11:14 pm »
Direct injection is the real difficult one to master on 2Ts?

Yip, especially when high power (means high revolutions meaning excruciatingly little time!) is chased!
Bimota failed, KTM, due to their (Patented I believe?) TPI, gets it right now... but there's yyeeaarrss of development inbetween these two.
TPI injects fuel droplets into a high velocity gasflow, the best place to do this!
Yammie may do this directly into the closed-off cylinder of outboard engines but one has to use very high fuel pressures to attempt - attempt yes, success is not guaranteed - complete atomizing of the fuel... and likely they will try to attempt some gas-swirl in the cylinder (I don't know if they do but this would be beneficial) to ensure better mixing as well as evaporation of the fuel droplets - which still will be droplets, never mind how high-pressure you inject the fuel!
Difficult indeed, and such will complicate a 'simple' 2stroke engine quite a bit, ditto its price!
But, that still leaves the main advantage of this engine: high power for little weight >>>>> that's for bikes then, plus (but to a lesser degree) outboard engines, not at all for cars.
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Online BuRP

Re: When would the Japs catch up with 2T, if ever?
« Reply #22 on: April 17, 2020, 03:12:38 pm »
Hell, throw in short skirt lightweight pistons

 :lol8:
Lol lol lol!
No, you forget a few basics  :P

Here's a hint: a 2stroke's piston skirt has a minimum height of Stroke - Transfer Port Height  ;)
« Last Edit: April 17, 2020, 03:16:36 pm by BuRP »
Sparta MC50, 46 other 50cc's, Garelli Tiger Cross, Jawa 250, Kreidler RS (plated), Kawasaki S1 250/3, S2 350/3, H1 500/3, H2 750/3, Suzuki GT380/3 - 10 year gap - KDX200, BMW 1150GS Adventure, Honda CBR600RR, Honda XR650R 2007 & 2003, Honda CRF230, Yamaha BWS100, BMW F800GS Adventure, Husqvarna 701 Enduro 2018, KTM 790 Adv R 2019, KTM 2020 XC-W TPI 300 Six Days, KTM 2014 500 EXC-W Six Days, KTM 790 Adv R Rally 2020, KTM 890 Adv R Rally 2021
 

Offline TheBear

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Re: When would the Japs catch up with 2T, if ever?
« Reply #23 on: April 17, 2020, 03:13:16 pm »
The Japanese actually hate 2T imo…. they lead the way in MotoGP away from the 2T era with Honda being the main protagonist in this arena....

When you are sold a 4stroke, instead of a 2stroke, you are also buying a lot of parts extra from the OEM. Afterwards your 4stroke is also bound to earn the OEM much more in maintenance and parts.

It gives the manufacturer license to sell you a 2stroke, and then go like; "Hey, you've got to also buy this camshaft, chain, tensioner, 4 valves, springs, seals, cotters and ugly sound along with the bike" :eek7:

One of the main drives behind the 4stroke rush, from an economical and business perspective.

If true, they did not succeed much, making them so incredibly reliable.
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Offline katana

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Re: When would the Japs catch up with 2T, if ever?
« Reply #24 on: April 17, 2020, 03:17:30 pm »
Hell, throw in short skirt lightweight pistons

 :lol8:
Lol lol lol!
No, you forget a few basics  :P

Here's a hint: a 2stroke's piston skirt has a minimum height of Stroke - Transfer Port Height  ;)
Very enlightening.  Care to elaborate?  We are talking of the possibilities, no?
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Offline katana

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Re: When would the Japs catch up with 2T, if ever?
« Reply #25 on: April 17, 2020, 03:18:36 pm »
Hell, throw in short skirt lightweight pistons

 :lol8:
Lol lol lol!
No, you forget a few basics  :P

Here's a hint: a 2stroke's piston skirt has a minimum height of Stroke - Transfer Port Height  ;)
Thank you for the edit.  Did you even read my post.  Any understanding of 2t diesel tech?
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Offline katana

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Re: When would the Japs catch up with 2T, if ever?
« Reply #26 on: April 17, 2020, 03:20:26 pm »
https://auto.howstuffworks.com/diesel-two-stroke1.htm @BuRP

Use a little imagination and think if the tech could be used in a small bike engine.
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Online BuRP

Re: When would the Japs catch up with 2T, if ever?
« Reply #27 on: April 17, 2020, 03:23:24 pm »
Even dream away those easy to damage expansion pipes that won't be needed anymore.

No, didn't even read this bit..... do you actually know how&why a 2stoke makes so much power?
The exhaust is a LARGE contributor, is is simply crucial for making power!
No, not on diesels, but their reciprocating mass (the crosshead, split conrods etc) rule out making high power relatively speaking (Hp/L), so let's stick to bike-2stokes here  ;)

Got a 2stoke plastic?
Take off the exhaust then run it!
It will run, but zero power!
And yes, loadsa noise, Plapp Plapp Palapp...  :P
« Last Edit: April 17, 2020, 03:24:35 pm by BuRP »
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Offline katana

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Re: When would the Japs catch up with 2T, if ever?
« Reply #28 on: April 17, 2020, 03:29:10 pm »
Even dream away those easy to damage expansion pipes that won't be needed anymore.

No, didn't even read this bit..... do you actually know how&why a 2stoke makes so much power?
The exhaust is a LARGE contributor, is is simply crucial for making power!
No, not on diesels, but their reciprocating mass (the crosshead, split conrods etc) rule out making high power relatively speaking (Hp/L), so let's stick to bike-2stokes here  ;)

Got a 2stoke plastic?
Take off the exhaust then run it!
It will run, but zero power!
And yes, loadsa noise, Plapp Plapp Palapp...  :P
If you could do all the exhaust function mechanically the pipe would be unnecessary.  That said, I will bow out of this conversation.  I was hoping to find someone with imagination to bounce ideas with.
If you want to haul ass, you gotta mix gas.
 

Online BuRP

Re: When would the Japs catch up with 2T, if ever?
« Reply #29 on: April 17, 2020, 03:33:13 pm »
Any understanding of 2t diesel tech?

Yes - awesome for humongously sized engines, and totally irrelevant for small ones.
You do know that those things rev to what, 700 rpm max in ships?
Yeah, a fairly high efficiency, but VERY low power per litre  ;)

Google Ryger engine, a better idea I think....
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Offline katana

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Re: When would the Japs catch up with 2T, if ever?
« Reply #30 on: April 17, 2020, 03:41:48 pm »
Any understanding of 2t diesel tech?

Yes - awesome for humongously sized engines, and totally irrelevant for small ones.
You do know that those things rev to what, 700 rpm max in ships?
Yeah, a fairly high efficiency, but VERY low power per litre  ;)

Google Ryger engine, a better idea I think....


Did I say build a ship size enduro bike?  Do you have any idea of the size and weight of a ship engine piston?   :imaposer:
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Offline 2StrokeDan

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Re: When would the Japs catch up with 2T, if ever?
« Reply #31 on: April 17, 2020, 04:54:50 pm »
Itoh's 1993 Honda NSR500 had electronic fuel injection, but Honda reckoned that on a race bike it made too little difference to be worth the effort.

So, yes, the Japanese applied F.I. some 27 years before the Europeans.

The fact that all their 4strokes are F.I. tells me they are not interested in further enhancing the 2strokes.

Fuckin' Yamaha, they're the ones that got me hooked on 2strokes....... :thumleft:
 

Offline Bill the Bong

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Re: When would the Japs catch up with 2T, if ever?
« Reply #32 on: April 17, 2020, 05:12:40 pm »
Before somebody tells me as well that I have no imagination:  I see no need for FI in any form in a 2T.  The need only arose because the newer generation doesn't have a clue how to jet a 2T.  Or was not willing to spend 5 min to change a main jet when the season change.
 
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Offline 2StrokeDan

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Re: When would the Japs catch up with 2T, if ever?
« Reply #33 on: April 17, 2020, 05:26:21 pm »
Before somebody tells me as well that I have no imagination:  I see no need for FI in any form in a 2T.  The need only arose because the newer generation doesn't have a clue how to jet a 2T.  Or was not willing to spend 5 min to change a main jet when the season change.

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Offline Welsh

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Re: When would the Japs catch up with 2T, if ever?
« Reply #34 on: April 17, 2020, 07:10:00 pm »
Never mind 2 strokes, I don't see much new tech from the Japanese on bikes full stop, unless you are an electronic display worshiper?  :sip:
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Re: When would the Japs catch up with 2T, if ever?
« Reply #35 on: April 18, 2020, 09:59:16 am »
Do you have any idea of the size and weight of a ship engine piston?

Yes - I've stood and sat on them whilst fixing their cracks.... with this stuff, watch the video clip:
https://www.metalockengineering.com/en/typical-repairs/metal-stitching/
Cast iron pistons yes, hence my remark of being a bit too heavy for a bike  :lol8:
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Re: When would the Japs catch up with 2T, if ever?
« Reply #36 on: April 18, 2020, 10:04:12 am »
Do you have any idea of the size and weight of a ship engine piston?

Yes - I've stood and sat on them whilst fixing their cracks.... with this stuff, watch the video clip:
https://www.metalockengineering.com/en/typical-repairs/metal-stitching/
Cast iron pistons yes, hence my remark of being a bit too heavy for a bike  :lol8:
I used to use a company in Booysens area in Jo,burg in the 1980’s to do that type of stuff on castings. 👍😎
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Offline jaybiker

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Re: When would the Japs catch up with 2T, if ever?
« Reply #37 on: April 18, 2020, 11:07:50 am »
Diesel type 2 strokes with short skirt pistons won't work. A long skirt piston is required to keep the inlet ports covered on the upper part of the stroke to prevent air being blown into the crankcase.

Add on the necessary valves, camshaft and the supercharger and the advantage of lightness and simplicity is gone. Your bike might as well be a 4 stroke.
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Re: When would the Japs catch up with 2T, if ever?
« Reply #38 on: April 18, 2020, 11:42:47 am »
Cant see anyone bothering with 2T anymore as electric will be the future. Bike sales worldwide is down as well, can only hook millenials with an ipad dash and green safe bikes
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Offline 2StrokeDan

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Re: When would the Japs catch up with 2T, if ever?
« Reply #39 on: April 18, 2020, 02:26:59 pm »
Diesel type 2 strokes with short skirt pistons won't work. A long skirt piston is required to keep the inlet ports covered on the upper part of the stroke to prevent air being blown into the crankcase.

Add on the necessary valves, camshaft and the supercharger and the advantage of lightness and simplicity is gone. Your bike might as well be a 4 stroke.

This is the big problem in my opinion, the complexity. I think that TPI, as currently run on the KTM/Husky's, is the ultimate in 2stroke development.

Even direct injection demands a very high-pressure pump in the system.