All Right , I'll play your silly game .

With all the wonderous contrivances available now , could someone get a 100 Hp 750 to stay together AND retain the Tourque Characteristics that made these so competitive . :?:

Wots the TOURQUE CURVE available compared to curret XR 750s :?: :?:

Would need a bit of aluminum Everywhere , Even Magnesium , if permissable . looks like the oppositions hottin up .

Of course , thered be the small matter of a dollar or two , to cover the costs . Riders are a dime a dozen , but ones with balls & brains in equal prportions scarcer .




OOPS ; http://www.motorcycledaily.com/2016/08/ ... pectators/

Looks like old Massey furgeson's come up with something new , too . Looks a bit better than the street bike , at least .



aparently the Japs are nipping at their heels , too . a good design conundrum , flat trackers . Optimisation aint what it neccesarilly is elsewhere .



Appears to be some tarted up saurkraut job . Ineligable in US with that many cylinders . Restrictions like that mean most ' thewper bikes are U J M 4s . ( Barff Icon )
NOW a evenfire V 12 would have to be at least Interesting . Looks a bit odd , actually http://www.bikeexif.com/triumph-flat-tracker

Normally bits sticking out get knocked off , in the rough'n tumble . :?

o.k. Would a aluminum Custom Norton Commando Do It , Pwr / Wt . THEN ! ?

man i wish people would quit calling these things a Massey Ferguson. i have a MF255 and it is smoother, quieter and has more uses :lol:

Matt Spencer said:

Looks like old Massey furgeson's come up with something new , too . Looks a bit better than the street bike , at least .

Click to expand...

The Harley XGR was campaigned last year on a limited basis. This year, like Indian, they will field a 3-rider team. The Indian FTR was debuted at the last race of 2016 by 39-year-old former #1 plate holder Joe Kopp. He got a hole shot and led the first laps before being overtaken by younger, stronger riders. The BMW 800 flat tracker is a Ron Wood creation that has been raced with some success by #23 Jeffrey Carver.

As for the Japanese. the Kawasaki twin has dominated GNC Miles and had some success on Half-Miles for several years, winning the #1 plate in the capable hands of Scotty Parker's former protege Bryan Smith. Yamaha's FZ-07 is in the mix as well as entries from Euros Ducati, Triumph and KTM. There's even a couple of Honda RS 750s out there. One guy that races an RS told me there is no factory support or parts available and when they need something, they have it custom-made. For those who stay home thinking GNC flat track is a one-brand (H-D) show, it has not been that way for several years, although without H-ds participation and support, flat track would be dead and buried.

If you have never been to a Grand National Flat Track Race, especially a Mile, try to make one this year. You won't be disappointed. Access to the riders and machinery is unprecedented compared to any other form of motor racing.

Danno said:

If you have never been to a Grand National Flat Track Race, especially a Mile, try to make one this year. You won't be disappointed. Access to the riders and machinery is unprecedented compared to any other form of motor racing.

Click to expand...

Danno, have you ever been to any AHRMA races?

A GNC Mile is as good as it gets!

BSA Rocket III - This Trackmaster BSA was tuned by Tom Cates and ridden by National #24, Jim Rice. Rice won the
Sedalia 25 Mile National on this BSA and is also the same bike he rode in the film "On Any Sunday".

ETC



etc etc

https://www.youtube.com/watch?v=yGWfIE2M9Zg

[video]https://www.youtube.com/watch?v=yGWfIE2M9Zg[/video]

Or REAL Ones .

https://www.youtube.com/watch?v=aoyxQb2TL54[video]https://www.youtube.com/watch?v=aoyxQb2TL54[/video]

etc [video]https://www.youtube.com/watch?v=j9Vhb7N5lp8[/video]

And if you want to get really modern , On Board with the 1925 Excelsior Super X . with the Petrol Engine , so you dont even need a Horse .

[video]https://www.youtube.com/watch?v=O8FCLKAaT8E[/video]

These Veteran devices are pretty far out , actually .

Theyd be impractical on the road nowadays tho . you couldnt carry enough Bricks to throw at all the cars that pulled out in front of you .

In case you missed it Matt, that "jap" bike nipping at their heels is a Triumph !!
Not sure there is much japanese content there ?
Made in Thailand maybe though...

Matt Spencer said:

aparently the Japs are nipping at their heels , too . a good design conundrum , flat trackers . Optimisation aint what it neccesarilly is elsewhere .

Click to expand...

Interesting subject/rant...

grandpaul said:

Danno said:

If you have never been to a Grand National Flat Track Race, especially a Mile, try to make one this year. You won't be disappointed. Access to the riders and machinery is unprecedented compared to any other form of motor racing.

Click to expand...

Danno, have you ever been to any AHRMA races?

Click to expand...

Barber 2016. My buddy who races E-bikes was 2008 & 2010 Heavyweight Superbike Champ in AMHRA. I'd like to make Mid-Ohio 2017.

Matt Spencer said:

BSA Rocket III - This Trackmaster BSA was tuned by Tom Cates and ridden by National #24, Jim Rice. Rice won the
Sedalia 25 Mile National on this BSA and is also the same bike he rode in the film "On Any Sunday".

Click to expand...

And for those who have never been to Carl Donelson's Museum, there's also a Romero Triumph and an Aldana Norton among the relics and memorabilia.

Do you really need a lot of torque in a dirt bike ? My brother runs two Kawasaki triple two strokes in historic speedway, both on methanol. The tyres are critical - too much grip is a real problem. I would have thought a top end motor would be better than a very torquey one ? Is it permitted to use JAWA speedway bikes on the mile in America ?

Hasn't your slogan always been "torque wins races".
Are you renouncing that ?

Maybe we need a careful definition of torque here too.
As has oft been pointed out here, engines make torque ALL THROUGH THE REV RANGE.
Don't just concentrate on the max torque... ?

acotrel said:

Do you really need a lot of torque in a dirt bike ? My brother runs two Kawasaki triple two strokes in historic speedway, both on methanol. The tyres are critical - too much grip is a real problem. I would have thought a top end motor would be better than a very torquey one ? Is it permitted to use JAWA speedway bikes on the mile in America ?

Click to expand...

Jawa Speedway bikes run on alcohol for one thing, so, no. It would be fun to see how their lap times compared to a good single-cylinder flat tracker, but singles are now the support class. With no rear suspension and very little on the front, it's doubtful they could keep up.

Years ago it was discovered that increasing horsepower in a flat-track engine did not go hand in hand with a reduction of lap times. It was postulated that any more than around 100-105 bhp was useless because it could not be put down on the track and only brought on excess wheelspin. Then, someone out of the inner circle took a look at a dyno graph of an XR 750 and discovered something curious: We all know the hp and torque graphs intersect at 5250? rpm, but most graphs show hp continuing to rise while torque maxes out and starts falling off. The XR 750 chart showed the lines intersecting and crossing the opposite way; as the hp fell off, torque continued to rise. They really don't start to honk until the large valve overlap is overcome by rpm. This is why the air-cooled 750s could best larger-displacement, more modern machines and why people thought more power was useless. This kept the XR 750 competitive for many years beyond it's development cycle.

Of course, everyone knows this now and are using the XR tuning parameters (see the thread here on XR ports) to make the modern ohc liquid-cooled twins suitable for flat-track competition. And this is why H-D has been forced to develop their liquid-cooled, ohc Street 750 engine for track use,

Danno said:

Years ago it was discovered that increasing horsepower in a flat-track engine did not go hand in hand with a reduction of lap times. It was postulated that any more than around 100-105 bhp was useless because it could not be put down on the track and only brought on excess wheelspin.

Click to expand...

Wellllll, there is that famous story of Kenny Roberts on a TZ700 (TZ750 ?), where he cruised with the pack and really opened the throttle on the last lap, and BLITZED em !
And reportedly parked it and quipped "they don't pay me enough to ride that thing" and never rode it again.
And they (multicylinder roadracing strokers) were banned.

But it did show that all the perceived wisdom about hp and torque and traction was just talk.
A good rider can use as much hp as possible...

Danno said:

Then, someone out of the inner circle took a look at a dyno graph of an XR 750 and discovered something curious: We all know the hp and torque graphs intersect at 5250? rpm, but most graphs show hp continuing to rise while torque maxes out and starts falling off. The XR 750 chart showed the lines intersecting and crossing the opposite way; as the hp fell off, torque continued to rise.

Click to expand...

Technically, we'd need to see those graphs.

The torque curve is merely a reflection of how well the engine breathes.
It is not impossible for the most efficient/effective breathing to happen at higher rpms,
to or even beyond redline in some cases.

However, the hp curve is CALCULATED from the torque curve, so if torque keeps rising,
then the hp HAS to keep rising as the rpms increase - its a strict mathematical relationship.

You can't have torque with no power, or power with no torque - they are rather solidly bolted together...

5252 rpms is significant only because its part of the formula twixt torque and hp.
At those particular rpms, the torque in ft-lbs is numerically the same as the hp.
Thats why the graph lines cross (providing the ft-lbs and hp scales are drawn the same).

Regarding speedway bikes on AMA dirt tracks:
I was at the Daytona flat track in the early 70's and one of the top Euro speedway riders was there for a demonstration. Probably the most impressive display of riding I have ever seen. He sprayed dirt several rows up into the stands. I don't remember who it was.
Then for fun, after the races, they ran a match race of him against the AMA winner that night. I believe the speedway bike won, too long ago to remember.
It was impressive I know. Great night I will never forget.

Jaydee

jaydee75 said:

Regarding speedway bikes on AMA dirt tracks:
I was at the Daytona flat track in the early 70's and one of the top Euro speedway riders was there for a demonstration. Probably the most impressive display of riding I have ever seen. He sprayed dirt several rows up into the stands. I don't remember who it was.
Then for fun, after the races, they ran a match race of him against the AMA winner that night. I believe the speedway bike won, too long ago to remember.
It was impressive I know. Great night I will never forget.

Jaydee

Click to expand...

That could happen on a short track like the old one at Daytona, but a Mile is a lot different. Short track races are all but gone from AMA GNC Flat Track, with only one on the 2017 schedule. This years Daytona race will be a TT on a purpose-built track inside the Speedway. Twins are the top class with singles a support class. Even on a half-mile, a speedway engine would likely overheat and seize.

A buddy once tried to run an air-cooled 2-stroke motocross engine (no tuning changes) in his flat tracker and it repeatedly seized. The problem was that motocross bikes are designed to run at full power in short bursts. not a continual long stretch, Different porting and lower compression cured the seizing.

Rohan said:

Danno said:

Years ago it was discovered that increasing horsepower in a flat-track engine did not go hand in hand with a reduction of lap times. It was postulated that any more than around 100-105 bhp was useless because it could not be put down on the track and only brought on excess wheelspin.

Click to expand...

Wellllll, there is that famous story of Kenny Roberts on a TZ700 (TZ750 ?), where he cruised with the pack and really opened the throttle on the last lap, and BLITZED em !
And reportedly parked it and quipped "they don't pay me enough to ride that thing" and never rode it again.
And they (multicylinder roadracing strokers) were banned.

But it did show that all the perceived wisdom about hp and torque and traction was just talk.
A good rider can use as much hp as possible...

Danno said:

Then, someone out of the inner circle took a look at a dyno graph of an XR 750 and discovered something curious: We all know the hp and torque graphs intersect at 5250? rpm, but most graphs show hp continuing to rise while torque maxes out and starts falling off. The XR 750 chart showed the lines intersecting and crossing the opposite way; as the hp fell off, torque continued to rise.

Click to expand...

Technically, we'd need to see those graphs.

The torque curve is merely a reflection of how well the engine breathes.
It is not impossible for the most efficient/effective breathing to happen at higher rpms,
to or even beyond redline in some cases.

However, the hp curve is CALCULATED from the torque curve, so if torque keeps rising,
then the hp HAS to keep rising as the rpms increase - its a strict mathematical relationship.

You can't have torque with no power, or power with no torque - they are rather solidly bolted together...

5252 rpms is significant only because its part of the formula twixt torque and hp.
At those particular rpms, the torque in ft-lbs is numerically the same as the hp.
Thats why the graph lines cross (providing the ft-lbs and hp scales are drawn the same).

Click to expand...

Actually, Kenny DID ride that bike (or an exact replica) again at Indy several years ago. And his comments were to the effect if he had had today's tires back in the day, it would have been much easier to get the TZ tracker to hook up, which was it's biggest bugaboo, and highly evident in film of that particular race. The only way he was able to win was by the fact that the TZ had a full 40 horsepower on the Harleys. And it was still practically a photo finish.

The strict mathematical relationship between torque and horsepower is that they are both the same in ANY engine at 5252 rpm. How else would torque fall off while hp continued to rise? (see the vast majority of torque/horsepower graphs) According to your logic, torque would have to continue to rise as horsepower rises. it never does.

And since torque and horsepower are measured in different units, any graph is just an overlay of two different graphs with the intersection at 5252. Are you saying there's no way the graphs could intersect and then diverge one way but not the other? Please show YOUR graphs to illustrate torque and horsepower curves in parallel.

Danno said:

The strict mathematical relationship between torque and horsepower is that they are both the same in ANY engine at 5252 rpm. How else would torque fall off while hp continued to rise? (see the vast majority of torque/horsepower graphs) According to your logic, torque would have to continue to rise as horsepower rises. it never does.

Click to expand...

My "logic" doesn't come into it, its the mathematical formula that defines hp from torque that controls it !
It doesn't just apply at 5252 rpms, it applies right across the WHOLE rpm range.

And as long as torque falls at a lesser % than the % that rpms are rising, then hp will keep climbing.
If the torque falls at more % than the rpms are rising, then the hp curve starts falling...

Have you never graphed a hp curve from the torque curve. ?
I'd agree completely, the 2 graphs are quite separate, but often shown overlaid for convenience.
But that XR750 engine can't defy the laws of torque/hp curves....