Messages

1

General Two Stroke Talk / TRIBORON!!!!!!

« on: May 13, 2013, 08:43:48 PM »

Thanks, I do ride (a 250sx) too you know

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General Two Stroke Talk / TRIBORON!!!!!!

« on: May 12, 2013, 11:36:52 PM »

A stable solution of boric acid nano particles seems to be the thing about Triboron.
See patent, in English: http://www.faqs.org/patents/app/20120108475

Found a mix of rave reviews and healthy skepticism on a couple of Swedish forums.
Looks like possibly a good oil to me, but would not expect any miracles.

3

General Two Stroke Talk / KTM 2 stroke fuel injection

« on: April 03, 2013, 08:34:22 PM »

Video? Yes please

On another note, Arctic cat have an interesting variation on the FI/DI theme in it's new 600 twostroke.
http://www.arcticinsider.com/Article/Tech-Insight-Inside-the-new-Arctic-Cat-600-C-TEC2-Engine
Plenty of cooling of the small end there.

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General Two Stroke Talk / Re: HGT Fuel Injection kit on our YZ 144 Project.

« on: October 12, 2011, 03:02:19 PM »

Sachs, without the pipe you end up with less air in the combustion chamber, basically what MikeD94 just wrote.
Less air - less fire - less power.

Getting eager to hear an update from Charles on the FI project

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General Two Stroke Talk / Re: HGT Fuel Injection kit on our YZ 144 Project.

« on: October 11, 2011, 11:09:53 PM »

If you are injecting into the combustion chamber after the exhaust port is closed (in theory anyway),why would you need an expansion chamber exhaust?

Because you inject fuel only, -cant get much of a fire without air.

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General Two Stroke Talk / Re: HGT Fuel Injection kit on our YZ 144 Project.

« on: October 10, 2011, 11:50:13 PM »

Theoretically a Direct Injection equipped 2T would not require an expansion chamber but this is still an issue with a FI 2T.MRHP, when you refer to the pipe heating up and "Altering the scavenging pulses" is this due to the pipe physically enlarging?

I've ridden many 2T dirt bikes where the jetting changes with clouds blowing over.I'd rather move in the direction of FI.

A bit of topic, but I just cant resist this DI not needing a pipe stuff

A DI two-stroke needs a tuned exhaust just as much as a two-stroke with a carb, if you want to make serious power per displacement that is.
You can always do away with the pipe and add displacement to achieve the same power as the smaller piped engine (much like the four-stroke handicap in Pro MX ), and you will get similar results regardless of DI, FI or carb.

Normally when you talk about pipe temperature and tuning, you are referring to the temperature of the gas inside the pipe. -The speed of sound increase with increasing temperature. I.e. a hot pipe would be tuned for a higher rpm than a cold one of the same dimensions.
The effect of thermal expansion of the metal very small in comparison.

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General Two Stroke Talk / Re: Facebook page

« on: September 19, 2011, 03:42:00 AM »

Done!

8

Photos & Videos / Re: 250A and 450A wins on ktm250 videos

« on: September 05, 2011, 02:00:52 AM »

I think you may need to re read the article, the stock bike made 50  hp, the pipe didnt add any hp to this peak, however it allowed it to make 7 hp more

MXA page 66 says in stock trim the KTM peaks at 50hp @ 8400rpm.

Pro Circuit pipe adds 1/2 hp @ 8500rpm and 5 1/4 @ 9000rpm and "an amazing 7 horses more at 9500rpm" ( I think they meant a total of 7hp).

The Pro Circuit pipe makes more power even though the rpms are higher but in stock trim it only makes 50hp peak as in no more power at any rpm. The article also stated that just adding the Pro Circuit silencer would give you 2 more horse from 8600rpm to 10,000rpm. I interpret that to mean it makes more power not just moving the powerband around?

Not sure I understand your response?

I would provide links for both MXA articles but they seem to be magazine only as I could not find them online at MXA.
    

My take on that quote is that the PC pipe added 1/2hp peak, i.e. 50.5hp total.
Now, widening the the peak of the power-curve is a really good thing too..

Need to check the video when I get home

9

General Two Stroke Talk / Re: Proof of what we say, if all manufacturers made 2 strokes.

« on: August 23, 2011, 08:49:35 AM »

2) with no unburnt fuel and air escaping out the pipe will there still be a need for an expansion chamber?

2) with no unburnt fuel and air escaping out the pipe will there still be a need for an expansion chamber?
Yes.

10

General Two Stroke Talk / Re: Proof of what we say, if all manufacturers made 2 strokes.

« on: August 22, 2011, 07:31:54 AM »

I agree with 2T in that if DI makes it to bikes the last we will see is a 125.
If we do get DI it will start with relatively low reving large capacity off road bikes first.

For once, I have to disagree with you. I think we will see it on the SMALLER engines first. The Lawn and Garden industries will be hit hardest with any change in the emissions laws as the marine and motorcycle industries have adapted to 4$ or DI already. 2T motorcycles in the first world countries are a very small percentage and would not put up much of a fight if they were legislated away. However, in the third world (or more PC: Developing Nations), the small bore 2T is the predominant form of transportation and a large contributor to the emissions pollution. That is where DI will have the biggest effect.

For the two-stroke in the developing nations, it's already there. -Google "Envirofit two-stroke". Otherwise I agree with the quote from TMKIWI above.

Yes, there are engineering challenges, but nothing that can't be overcome. Only the cost/desire limit it.

2TInstitute: You answered your own question.

On the other hand Ski-Doo seems to have solved that part of the puzzle as well with their E-tech's.

I don't think 2TI want to be linked to that quote, if for noting else, my less than perfect English

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General Two Stroke Talk / Re: Proof of what we say, if all manufacturers made 2 strokes.

« on: August 22, 2011, 01:43:38 AM »

... without a complicated big end/main bearing oiling/cooling system...

It doesn't have to be complicate. It just has to be wet. Oiling the mains has nothing to do with the emissions. It's just another part of the process because of the scavenging effect.

Cars, boats, and other engines are using EFI and DFI. Only cost and people unwilling to change are holding back the 2T Motorcycle.

I don't think your grasping the concept of what fuel does in the crankcase.

Why not explain then

-a lot of cooling, mainly of the big end bearing.

On the other hand Ski-Doo seems to have solved that part of the puzzle as well with their E-tech's.

12

General Two Stroke Talk / Re: Proof of what we say, if all manufacturers made 2 strokes.

« on: August 17, 2011, 08:33:55 AM »

TMKIWI - that's why Evinrude didnt consult you when they were designing their oversquare DI engine. But i admit, i should have said DI's are no longer "fully" dependant on port timing. When the injector releases its spray into the combustion chamber is now at the discretion of the engineer, not the piston

I'll try again...

That injector injects fuel (and depending on injector type, a tiny bit of air to help atomize the fuel) into the combustion chamber, but in order to burn that fuel you need a lot of air, and that air is delivered the same way as it is in a normal carbed two-stroke.  Any improvement in the power spread (due to DI) will be a result of improved engine management.

Now, drastically reduced emissions and reduced fuel consumption aint bad either...

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General Two Stroke Talk / Re: Proof of what we say, if all manufacturers made 2 strokes.

« on: August 16, 2011, 03:05:39 PM »

<snip>
And THAT is the beauty of direct injection. Because now, 2 strokes can be oversquare!! They no longer need to depend on port timing like conventional 2 strokes.
<snip>

Could you please explain how DI could accomplish such a thing?
-It is, after all only another way of delivering fuel, not air, into the combustion chamber.

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General Two Stroke Talk / Re: Rumor KTM 2 stroke SX getting linkage. And I was just getting on board w/o

« on: May 06, 2011, 01:47:26 PM »

To clarify, I read 2 stroke SX models to get linkage, exc models to remain pds.  

Got that, but found it interesting that they developed a whole new PDS frame from the 350EXC. -350SX has linkage..

15

General Two Stroke Talk / Re: Rumours,Rumours!

« on: May 06, 2011, 03:41:41 AM »

The way i understand it, is the difficulty in getting the necessary information to the computer, how do you monitor the fuel air mixture and prevent a lean situation. I'm thinking the usual sensors wouldn't cut it ie lambda probe or air flow meter. I'm thinking it would be very hard to manage, especially with the more variable throttle input and direct drive nature of dirtbikes.

Food for thought: What information does the carb have access to?