500cc GP bike with todays `tech`

BarryMachine said:

Did you never ride an old 750 2 stroke? ..... they were pretty attrocious

Seemed that jump in cc of only 250 turned them from sewing machine to rotary hoe ..... thats about the comparison I remember. The 750's never revved out smoothly and to anywhere near as high a revs. perhaps too much rotational mass ...... maybe there was a peak there too?

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Owned an H2 back in the 70's, worst handling bike i have ever ridden, but ....... it would get your heart pumping. The damn thing had an on off switch, and if you were not ready when the switch went on, you were off.

povol said:

Owned an H2 back in the 70's, worst handling bike i have ever ridden, but ....... it would get your heart pumping. The damn thing had an on off switch, and if you were not ready when the switch went on, you were off.

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The crankshaft always seemed wider than the engine was long to me



The stocker I found pretty sedate, its when folk did things to them that they got crazy, and they never seemed to be balanced in any way



One day many moons ago,I had the oddest oportunity and rode an old kriedler 50cc GP bike, then a fairly modded H2 ......... now if you could get that H2 engine hooked up with the Kriedlers 24 speed box ...... you might be onto something





Ah blue smokes ....... they came in so many shapes sizes, manners, states of tune, Still to this day one of my favourite ever bikes is a KTM200 EXC .......... just so perfect a transport vehicle. But I have also ridden many 4 strokes that impress even in days of yore. And I would have to say that 4 strokes are still getting better faster.



Mind you one of the best/most memorable engined vehicles I have ever seen was a go kart with an old 650 single long stroke royal enfield engine, seemed to thump out a beat about once every few minutes but it still sprayed rooster tails of dirt everywhere ....... odd vehicle to watch.

You can always buy a Rotax E-Tec and chuck it in your favourite 250GP chassis... 600cc, fuel injected, water cooled, 129HP+ in a mild state of tune.



Or the 700 or the 800... ...., Rotax will probably have a 1000 twin out in 2012.



Programmable ECU, a pair of cooking pipes and you're laughing - hysterically maybe, but laughing nonetheless

povol said:

Owned an H2 back in the 70's, worst handling bike i have ever ridden, but ....... it would get your heart pumping. The damn thing had an on off switch, and if you were not ready when the switch went on, you were off.

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Known locally as The Flying Coathanger for it's structural qualities



worked remarkably well as an instant enema, IIRC...



I rode all those 70's Kwaka 2Ts - (250, 350, 500, 750) and they were all nasty - too much power for the brakes, too little frame for both. Fun though... especially passing your RD-mounted mates - it certainly showed the power of disc-valved motors over reed valves.

BarryMachine said:

I know you are saying you disagree but then you go on to say the same ......

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I didn't - I disagreed with you - you said they didn't rev out, you said nothing about tractability - they are totally different. Peak RPM on TZs was nearly three times that of four strokes of the era, the RGs about 2.5 times (different era). If your two-stroke didn't rev out, it was because it was set up wrong. With much, much less reciprocating mass and a system that fires every time the piston comes close to the cylinder head, they revved like a schoolboy finding the joys of masturbation for the first time.



I also didn't say the TZ wasn't tractable, just that the RG was more so, but it's all relative - both of them would try and separate your wrists from your arms if you were incautious but nothing like the big-block Suzuki or Kwaka 4Ts, even when on the pipe.



Different strokes for different folks... while I love the power an 1100cc Suzuki engine can deliver, I would rather have a two-stroke for a mountain or seaside blast where the road gets tight.



All moot now - I own a BMW 1200-4, so I sit in one gear and worry about whether my wife is getting blown around too much

BarryMachine said:

The 750's never revved out smoothly

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If you don't read the "smoothly" it would sound very different



So are you saying that a 750 revved out as much as a 500 too? Cos I do disagree with that, as was another of my points.

We'd definitely have some newer, cleaner 2 stroke technology but the bikes would be less spectacular by far than todays motogp bikes

BarryMachine said:

I know you are saying you disagree but then you go on to say the same ......



When I say rev out smoothly I guess it could be said as tractability.



I am aware of the beastiness of the TZ ..... I even rode a dirt version ......... it was stupid

There was absolutely no rhyme or reason to it ......... except the fun factor

Also rode a somewhat worked 750 triple Kwaka ........ it was plain crazy.





I would have to say they had the torque over the 500 though when I think of it .... still they were nothing on modern bikes.

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Damn, if i stayed around reading stuff like this and google'ing a .... load of it, I would probably learn a ton.



I head from that Kawa 750 2T, i also heard is was almost un-ridable. That's about what i know from 750 2strokes

If GP had stayed 500cc 4-strokes, it would probably be defunct by now. Honda would have built and eventually perfected the NR500. It would have run the tables, and the sport would have been changed. Fans would have walked away both during the beat down by Honda, and after the rules changes. Banning oval pistons was bad enough, imo.

mylexicon said:

If GP had stayed 500cc 4-strokes, it would probably be defunct by now. Honda would have built and eventually perfected the NR500. It would have run the tables, and the sport would have been changed. Fans would have walked away both during the beat down by Honda, and after the rules changes. .

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Not if Hondas rider was prone to silly theatrical displays after each win. Quite possibly the sport would have grown to epic proportions and centered itself around that rider whilst his fans would his celebrate his GOAT status, all the while being completely ignorant of his mechanical advantages

Its true that generally the 2 strokes reached their 'performance' limit in 500 form, and that a lot of the technology today concentrates on emission control for these motors rather than outright power (though it is a side effect). Evinrude built the E-tec for cleaner running and people still build/develop them today for applications where weight savings due to less mechanical parts are paramount. Also a lightly stressed 2 stroke goes on forever due to their simplicity.

Zootalaws said:

You can always buy a Rotax E-Tec and chuck it in your favourite 250GP chassis... 600cc, fuel injected, water cooled, 129HP+ in a mild state of tune.



Or the 700 or the 800... ...., Rotax will probably have a 1000 twin out in 2012.



Programmable ECU, a pair of cooking pipes and you're laughing - hysterically maybe, but laughing nonetheless

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Are these Rotax 2 strokes or four strokes you are talking of? Cos Rotax make a lovely 1098? 4 stroke V twin.



Also I was lent a seadoo a few years back and under the hood was a Rotax 1500cc? supercharged 4 stroke pumped out about 255 HP I think. Hard to tell cos the actual boat is so big these days. Not like the old stand up minimal jetski's with about a 750 triple 2 stroke. We fitted a few performance bits to one of those and it was a fun machine.

BarryMachine said:

Two strokes were at the end of their development.



They would not need as invasive electronics as they were relatively well mannered to ride.



You can't have launch control anyway and it was mainly to help the rampant power of the 4 strokes.



I'm pretty perplexed as to why the myth of the "amazing" two strokes persists.

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I agree the 500cc two stroke engine had reached it's peak since the new four stroke engines right away were reaching speeds 10mph faster around the tracks. I don't agree that they were well mannered to ride watch any interview of GP riders including Vale they will all say it was ferocious and very difficult to handle compared to the four stroke bikes. I think with the same electronics the 500cc bikes would be limited too much and would in turn be much slower than they already were compared to the four stroke bikes. I won't deny two stroke engines make massive amounts of power for their displacement but, they seem to have reached a definite performance peak.



Just my $.02.....

Zootalaws said:

Fun though... especially passing your RD-mounted mates - it certainly showed the power of disc-valved motors over reed valves.

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Vintage Kawi 2T twins had disk valves, the triples had piston port engines. Where would you feed the disk for the center jug???

AaronG87 said:

I agree the 500cc two stroke engine had reached it's peak since the new four stroke engines right away were reaching speeds 10mph faster around the tracks. I don't agree that they were well mannered to ride watch any interview of GP riders including Vale they will all say it was ferocious and very difficult to handle compared to the four stroke bikes. I think with the same electronics the 500cc bikes would be limited too much and would in turn be much slower than they already were compared to the four stroke bikes. I won't deny two stroke engines make massive amounts of power for their displacement but, they seem to have reached a definite performance peak.



Just my $.02.....

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So is this a comparison of 500cc 2T with 500cc 4T or is 4T given a big displacement advantage to achieve that 10MPH difference?



I am no expert on road racing stuff but for offroad/MX, the 4T is given upwards of a 100% displacement head start over 2T these days. This is really too bad in that for a amateur or privateer it is much less $$$ to maintain a 2T bike over a 4T with all those silly parts flying around. I can do a topend rebuild on my smokers for less than $300 (these are single cylinder engines of course - YMMV) when a modern 4T MX bike will be upwards of $1500. The manufacturers love this because owners that could tackle simple 2T mechanical work are buffaloed by the valve gear and take their bikes to the shop much more often than before. If racing was cheaper we would have more racers. THAT there is a very large incentive for 2T engines once again.



I hope (probably a futile hope) that someone will start building production 2T bikes again -- and make them as available and clean as 4T (read DI engines) so I can have a modern bike with only 3 major moving engine parts.



Just MY $0.02...

valvesr4wimps said:

So is this a comparison of 500cc 2T with 500cc 4T or is 4T given a big displacement advantage to achieve that 10MPH difference?



I am no expert on road racing stuff but for offroad/MX, the 4T is given upwards of a 100% displacement head start over 2T these days. This is really too bad in that for a amateur or privateer it is much less $$$ to maintain a 2T bike over a 4T with all those silly parts flying around. I can do a topend rebuild on my smokers for less than $300 (these are single cylinder engines of course - YMMV) when a modern 4T MX bike will be upwards of $1500. The manufacturers love this because owners that could tackle simple 2T mechanical work are buffaloed by the valve gear and take their bikes to the shop much more often than before. If racing was cheaper we would have more racers. THAT there is a very large incentive for 2T engines once again.



I hope (probably a futile hope) that someone will start building production 2T bikes again -- and make them as available and clean as 4T (read DI engines) so I can have a modern bike with only 3 major moving engine parts.



Just MY $0.02...

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me and you are gonna be mates smokers ftw.... i think DI is the step forward when i get time there is a guy on youtube who has fitted DI kit to a 2stroke banshee, from the vid it looks like it goes well to .



i agree with you on maintenance i can rebuild a 2-stoke blindfolded and thats not a joke but 4-strokes meh...



even tho im not a fan of ktm's im sure they are pretty close to bringing the a DI smoker to market.



i will never own a 4 stroke..... that first start on a cold morning smell is enough to keep me focused on a smoker

jazkat said:

me and you are gonna be mates

smokers ftw.... i think DI is the step forward

when i get time there is a guy on youtube who has fitted DI kit to a 2stroke banshee, from the vid it looks like it goes well to

.



i agree with you on maintenance i can rebuild a 2-stoke blindfolded and thats not a joke but 4-strokes meh...



even tho im not a fan of ktm's im sure they are pretty close to bringing the a DI smoker to market.



i will never own a 4 stroke..... that first start on a cold morning smell is enough to keep me focused on a smoker

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Amen brothers...