Anorak
OK makes more sense, but using the same logic it could be suggested that one could ban racing and mechanical failures etc. I would suggest far more people have been injured as a result of a bike spilling it guts an the race track though. Anyway not the place here to argue the merits esp as it's a done deal... but i now see the point. If potentially one life is saved, $400= great dealOriginally Posted by Bert
Kinky is using a feather. Perverted is using the whole chicken
Hardcore Biker
So tz350. Did you find the pumper carb better than an conventional bike carb
Forum whore
No better or worse, I used it because it is smaller and it can be bolted hard up against the motor in any orientation, so its easier to fit in and get a shorter inlet tract length.
Forum whore
I would be for it.Nope.
24-2-5 Fuel: See 10-17-1 Alcohol based fuel or fuel additives are prohibited.
Stupid rule. Why not change it to "only commercially available pump fuels may be used for this class". Would keep the cost down and the lead out!
Av Gas with 2T oil costs Team ESE about $100 a 20 L tin and we get through lots of them, a high octane pump fuel at half the price sounds appealing.
I asked Billy about any proposed fuel rule changes, and this was his reply.
" ... rulechanges outside of those based on safety have been submitted for 2013/14, The only change to the fuel rule, Was to allow the use of Ethanol based fuels with a maximum of 10% Ethanol content, Cheers Billy"
So just a remit, not a rule change yet.
Last edited by TZ350; 22nd May 2013 at 08:07. Reason: Added Billys reply.
Forum whore
Make your engine thermally sound (could be difficult with an aircooler), provide for sufficient (that is: lots of) blowdown angle area, and for effective squish, and lower the compression ratio.
Does 9:1 sound ridiculous? After I managed to convice a friend to change from 14:1 to 9:1 he reported a more reliable, easier to ride bike that was less sensitive to ignition issues and made more power.
Then you can drop the avgas and use pump fuel with a better energy content (more power), a better flame speed (cooler running engine) and a better price (more dow available for after-race celebrations).
Forum whore
Would it be sound to use an 02 sensor? Injecting at the back port and timing right you will spill air out the exhaust, not fuel air, so your sensor will say to the computer more fuel required when it will not be required.
Make your own rules, use E85 ( or make your own E90 ), bugger MNZ they still have their head in the sand.
And you can dip into the same drum for your after race celebrations ( before the petrol oil mix! )
TZ I have your ball valve ( both halves now ) made, I think it's ended up better than mine!
Forum whore
Avgas will kill any O2-sensor; pump fuel mixed with two-stroke oil will in theory do the same, but if you take care to heat the sensor to working temperature before starting the engine, and provided the sensor is not too close to the cylinder so it won't be hit by washed-through mixture, the sensor will last a long time.
I can hardly imagine that with the right injection timing you can avoid fuel entering the exhaust, certainly not over the entire rev range.
In order to make real power, the pipe needs to receive and subsequently push back about 40% of the cylinder capacity and I do not think you can separate air and fuel to such a degree that no fuel will enter the pipe. But in order to keep the sensor clean it will have to be fitted well away from the cylinder anyway.
At the end of the day it all depends on how the injection system is instructed to handle the various sensor signals.
Forum whore
No, I am talking about low speed, bottom third throttle. I don't think an 02 sensor in a twostroke is a very useful tool.
I'm only guessing.
No8 Wire Extraordinaire
Nothing wrong with using Av, heck at the rate a bucket sips it a 20l container lasts at least 3-4 meetings.
Presumably 2 stroke oil isn't a fuel additive?
Don't you look at my accountant.
He's the only one I've got.
No8 Wire Extraordinaire
Gibgab blubber. ok now you're blowing my tiny mindyes it does sound ridiculous, but I'm prepared to listen, although seriously have to sort out the first sentence which is difficult with these old engines. My poor 50 is very hard to get decent blowdown area & can't triple port it due to water jacket, still considering options there.
Don't you look at my accountant.
He's the only one I've got.
No8 Wire Extraordinaire
S'funny I was just thinking about Derek & his accident this morning before I'd read this, just one of those random things, I was thinking about my old bathroom which he had done the lino, but I got to thinking about how it must have affected his family. High speed collision is a cruel thing. I'm not sure many people would willingly run out of gas & whether a $400 fine would make them remember to fill up. May alter weight saving gamblers I suppose.
Don't you look at my accountant.
He's the only one I've got.
Was worth a crack
Yes there is. Avgas is expensive, hard to get (compared to pump fuel) and it contains lead. Lead is a particular nasty we can all do without exposure to.Nothing wrong with using Av
Presumably 2 stroke oil isn't a fuel additive?
Regarding "additive" well a common defintion would be "A substance added in small amounts to something else to improve, strengthen, or otherwise alter it".
Like I said stupid rule, it could be tidied up quite nicely with my proposal but it seems it never made it through to MNZ.
Forum whore
I don't know about that, Neil. Under those circumstances maybe you can inject so well-timed that no fuel will make in into the pipe. But then you could also instruct the injection system to expect more O2 under the circumstances.
I agree that an O2 sensor is not the best tool for governing the injection, but I have found it quite helpful on the test bench. You just have to keep reminding yourself that it does not say lean or rich; it only says 'I see more O2 or less O2'.
Maybe I've told this before but it can't hurt to do it again: during a test bench run the O2 sensor said 'lean' or so I interpreted it at the time. So I fitted a bigger main jet, whereupon the sensor said: 'now it's even leaner!'
What really happened was: during the first run the mixture was so rich that the engine misfired slightly, sending unused oxygen into the exhaust. And after I fitted that bigger jet, of course the misfiring became even worse.
Weekend cruiser
24-2-5 Fuel: See 10-17-1
Alcohol based fuel or fuel additives are prohibited.
Stupid rule. Why not change it to "only commercially available pump fuels may be used for this class". Would keep the cost down and the lead out!
AvGas is a "commercially available pump fuel" - available at the pump at most airfields !!! And contains lead. This argument has been presented at a protest , and prevailed.
Was worth a crack
Hadn't considered that
OK so the wording won't lock out Avgas, which will keep some happy anyways, but it will get rid of the silly alcohol and additive nonsense.
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