Two-strokes set to continue at MX Nationals in 2015 (not VMX)

[Nathan S]

Noise isn't a new pollutant the four strokes have just perfected it.

The manufacturers are the ones to blame.

Even right from the word go the 4 strokes were louder.  When they were first introduced a standard 4 stroke was 102 DBA and the 2 stroke was 98 DBA.

Even now they cheat.  They retard the spark in neutral so when you do a noise test it is quieter than when it is running on the track. It is time to get serious.  Make the manufacturers make them quieter and make the riders run the standard mufflers, for two and four stroke.  The so called performance exhausts that are sold in Australia just make more noise.

Also the sound from four strokes carries further than two strokes.  Fog horns put out a lower note for a reason because it carries further.

There's also the fact that low/bass sounds have more energy in them, so they travel further.
It's the same as when you hear a car stereo - you hear the "doof doof doof" way before you hear any of the higher notes.

The real answer is a mix of trackside and off-site noise testing. Off-site noise testing measures when the noise is actually an issue for nearby residents, trackside identifies which bike(s) are creating the problem.

[Lozza]

Only real 2T engine development now is with superkarts.  Check out Modena engines or Roland Holzer on fb

    There is a lot of progress  in 2t outboard motors  as far as emission and fuel injection goes...

    The stig

Snowmobiles as well it's refining what is already existing engines with electronics though. Karts have some real innovations whats not been done before along with the Freetech 50 Cup

[SUZUKI311]

Even though the Yamaha is basically a 2005 design, Errol Willis still managed to qualify at regularly in the top half a dozen at this years MX Nationals on board one. This year the class was so deep in talent, that pretty much where you started you finished, and Errol had several good finishes on board the YZ. From a friend who ran the KTM

[SUZUKI311]

Whoops, wrong button. From a friend who ran the CHOICE KTM lites team for a few years, he told me that he was told by a VERY reliable source, KTM have had a fuel injected version of a 2 stroke EXC for some time now, working out the bugs etc.

[evo550]

The chairman of KTM has openly spoken about them in a interview I read recently.
He described it as being dearer, heavier, far more complex with high maintenance and in it's current form the bike could not be rebuilt by the average punter. Basically all of the things that make 2t's appealing have been lost, so until they can do injection and retain all the 2t advantages ( or they are regulated to) the injection will sit on the shelf.

[80-85 husky]

husky were at the sharp end of developing an injected 2oie and the hot poop was 2015 for a 350cc injected 2/ putting out close to 500 cc power in a very useable range. maybe why kato snapped them up to keep the lid on that!

[KTM47]

While I'm sure a Yamaha could be made competitive against the current KTM and Huskys the change WEM is making would not permit modifications to do so.  Maybe the Yamahas will need some leeway or maybe Yamaha would introduce a up graded race kit that could be approved.

It is interesting I watched the MX of Nations last night on Eurosport.

1st France
2nd Belgium
3rd USA
4th GB  (same points as USA)

AUS were around 7th I not sure if they stayed there.  Reedy crashed at start final moto.

Anyway the 250 4/-s were up with the 450s at the starts.  I wonder how competitive a 300 2/- would be.

 

[KTM47]

Australia finished 14th.  Both Reed and Moss didn't finish final moto.

[bigk]

Fuel injection etc may be ok for closed course competitions where you car & lap top are close by but not on a trail/enduro bike. My 2t enduro is fast, smooth, extremely civilized & very easy to ride (not swapping for a 4t anytime soon). It is reliable & piss easy to work on, not sure what benefits FI could give it. As a new bike dealer I remember a few "glitches" with the first lot of FI four strokes & guys having to leave them in the bush or ride home @ 5kph in limp mode. The resulting phone call was never pleasant & the importers basically said that's how it is, suck it up.
K

[KTM47]

That is the price you pay for technology.

I think keep the two strokes simple, that is what makes them great.

[Lozza]

I very much doubt KTM has an injected 300. Most adventure bikes now are injected with good reliablity and they were mapped badly and erratic when first released but that's in the past.

To show how bad the rules are written it makes no reference to what models this applies to,one could fit a 2000 model engine (they haven't changed that much) and say it was as modified back in the day.   

[KTM47]

The proposed restrictions to my knowledge are for the Aust MX Championships only.  I'm sure the wording that has been released will be refined more.  The wording that has been released I think has come from WEM.

I watched the final round of the MX Nationals on the weekend on Speed.  The 2 strokes were better in the sand.  I haven't been able to compare lap times against the 450s.  But that may not mean much because the better riders are in the MX1 class.

[MaxPower]

If the answer is in the past 4 pages and I missed it I apologize, in these restrictions, are the 250 2 strokes to retain the stock ignition? Not that there are many options to switch them ,there are a few. It could be looked at as riders will have to look in other areas to gain power

[KTM47]

At the Conondale Cup just run yesterday, Yamaha rider Jay Wilson rode a 2015 YZ 250 2/- in the Open All Powers and a YZ 250F in the 250 class.  He said he did it to prove that the 250 2/- should be in the 450 class.

Kirk Gibbs was 1 to 2 secs and lap faster than Jay on the 250 2/- , but wasn't really pushed also, he won.  Jay was second on the 250 2/- and battling with 450s and therefore pushing hard.

Jay also easily won the 250 class on the 4/-, but was never pushed and was 1 to 2 seconds slower than the 250 2/-.

My conclusion from this.  While a 250 2/- is marginally better than the 4/- it isn't a match for the 450 4/-.  I think all three bikes could probably lap at a similar lap time, but the 250 & 450 4/-s could probably maintain the lap times better.

Just another note there were more 250 2/-s in the 250 classes than 4/-s.

I think to force the 250 2/-s out of the 250 class and into the 450 class would be a bad move.  I think the more riders move to 2/-s the better.

There was also a 125 class.

[Nathan S]

I very much doubt KTM has an injected 300. Most adventure bikes now are injected with good reliablity and they were mapped badly and erratic when first released but that's in the past.

Various reports from KTM say that they have a direct injected 2T that is pretty much ready to go, but it makes the whole bike as heavy and complex (and presumably as unreliable) as a 4T, so there's little point.