Dick Mann Lean angle

I was at Daytona for the 200 in 1974 and saw Agostini win on the new TZ. Roberts' engine lost a cylinder due to the use of alloy head bolts like the blue ones in the photo.

The MV contingent, which had set up a display at the dealer show, loaded their bikes and stomped out, apparently having no notice that their star rider had suddenly defected.

Danno said:

According to Jay Springsteen, who rode an example years after the ban, the TZ tracker had about a 40 bhp advantage on the Harleys of the day. And according to all accounts, had absolutely zero flywheel, which is why the only way Roberts could have won the '75 Indy Mile in the fashion he did was to screw the throttle to the stop and hang on. Anything that could put fear in Roberts' heart would kill mere mortals from the fright.

In flat track, superior horses don't always translate into a faster machine if you can't use the power without wheelspin. The Indian FTR 750s have an exterior-mounted quick-change flywheel to tailor the power effects to the particular track.

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On a normal speedway circuit, a modern 4-valve Jawa would probably be better. The engine braking is used to get the bike sideways going into corners.

Danno said:

I was at Daytona for the 200 in 1974 and saw Agostini win on the new TZ. Roberts' engine lost a cylinder due to the use of alloy head bolts like the blue ones in the photo.

The MV contingent, which had set up a display at the dealer show, loaded their bikes and stomped out, apparently having no notice that their star rider had suddenly defected.

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I thought all TZs had aluminium head bolts. With a two-stroke motor, there is not so much stress on the head bolts and studs.

acotrel said:

I thought all TZs had aluminium head bolts. With a two-stroke motor, there is not so much stress on the head bolts and studs.

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Tell that to KR. Pretty sure they came from the factory with steel head bolts.

acotrel said:

On a normal speedway circuit, a modern 4-valve Jawa would probably be better. The engine braking is used to get the bike sideways going into corners.

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A high-comp Speedway single running alky would melt solid on a Mile. Nobody has seen fit to dump a Jawa motor in a flat track chassis as the tweaked 450's would run circles around it.

Danno said:

Tell that to KR. Pretty sure they came from the factory with steel head bolts.

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Or his engine builder swapped them. There has been a few interchangeable parts across the Yamaha range, for instance my LC 350 Yamaha has had lighter alloy head bolts swapped for the original steel head bolts.

Danno said:

A high-comp Speedway single running alky would melt solid on a Mile. Nobody has seen fit to dump a Jawa motor in a flat track chassis as the tweaked 450's would run circles around it.

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It would have to be a pretty flash 450 to beat a 500cc speedway Jawa on 16 to 1 comp. with methanol. Don't they have real speedway racing where you are ? When Jay Springsteen raced Harleys in Australia, he did always not have it all his own way.

Speedway is for tiny bowls. Flat Track is for actual racetracks.Speedway is virtually unknown in the USA except on the West Coast. Flat Track has been undergoing a resurgence in popularity the last few years. Is there such a thing as a 140-mph Speedway bike?

In Australia, we sometimes have long track meetings. A common bike is a speedway Jawa with a Norton gearbox. Motors which run on methanol don't get as hot as petrol motors. Power to weight ratio is important. I cannot remember if Jay Springsteen got beaten when he came here with his American race bikes. My friend went to NSW to see him race and I think he said the Jawas were quicker.
The thing that some people do not realise, is the adverse effect that excess weight causes. My brother uses a stroked Jawa motor in one of his speedway sidecars. He took it to Broadford and raced against four Vincents on quarter mile circuit and beat them all. It was the only time he had taken his wife and sone to a meeting for many years, and it was the one where he got the standing ovation. The Jawa is 600cc capacity, the Vincents are 1000cc - all methanol fuelled.
He won the Australian long track championship at Bendigo in 2001, with a methanol-fuelled H1 Kawasaki two stroke sidecar.

Speedway bikes are only 500cc with one gear,no brakes and a hard tail so are quite different to a flat track bike along with a shopping trolley castor steering head angle.
I saw 5 times world long track champion Simon Wigg (R.I.P) in action on one of the lay down engine bikes and he was not mucking about ........ a blur.

I think I saw Simon Wigg ride in the 1970s against Phil Crump - very spectacular. Very early-on, there used to be speedway bikes with gearboxes which were used at Mildura. Apparently they were extremely fast. Because a gearbox can be used for braking, might be the reason they don't usually do that. With no brakes, there are fewer crashes.

I think the Mile in America would be very spectacular, but it might not be as quick as it looks and sounds. You would be dragging a lot more weight around.