98.5 HP Commando motor after 97 races

Cheesy said:

It is very likely that flexifuel vehicles do have switchable intake runner lengths as well as well as some sort of VTEC system which could be used to alter the effective compression ratio between the two fuels, that and they are probably already running much higher compression ratios than the old Norton anyway.... maybe

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Yep, forgot variable valve timing (VTEC) and of course higher static compression which is likely higher than our old Nortons and especially WZ507's test ride.. The VTEC and higher compression may be a lot of it.

Dances with Shrapnel said:

WZ507 said:

The most telling anecdote of the endeavor to me was the sound of the pipe – you’ve never heard a sadder more pathetic sound in your life – just absolutely dead to the point that an old “hit- N-miss” engine would sound crisp in comparison.

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Too funny.

Yet Flexfuel vehicles seem to manage with the E85. I've never tried E85 in a Flexfuel vehicle but based on your description above I think it would fall flat on it's face in the market and I have not heard that. What are the things a Flexfuel vehicle can change:
Ignition timing - yes
Metering - yes
Compression ratio - not likely
Tuned lengths - not likely


Any chance there is something you missed on the E85 set up? Perhaps compression ratio (or lack of) is the issue.

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I don't think I missed anything in the set-up, but yes, for sure what is missing to run E-85 in my flathead engine is compression. The low static compression ratio of this flathead of about 7:1 (which is quite high for a flathead), in combination with a long duration cam knocks the dynamic compression ratio way back. As noted previously for Flex-Fuel vehicles, the relatively high static compression ratio (probably in the range of 10-11:1) in combination with the short duration cams fit to such passenger vehicles convey plenty of dynamic compression to burn E-85.

There are probably four main things to consider about alcohol fuels. - Latent heat of vaporisation. Antiknock properties. Flashpoint. and Calorific value. Only the calorific value can be estimated from the chemical composition. The rest are either test or suck it and see.

lcrken said:

acotrel said:

I once asked on this forum if anyone has ever hi-sided a commando - normally it doesn't seem to happen. So if you are tight in the corners, it is pretty safe to get hard on the gas really early.

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I don't recall if I answered that question in your earlier post, but for the sake of historical accuracy, the answer is yes, at the exit of turn one at Daytona somewhere around 1990. My friend Mark was riding his Commando and had a nasty high side crash that put him in the local hospital with injuries that included a broken pelvis. That was the end of his road racing activities. But I do agree with you that it isn't something that you normally have to worry about with a Commando. HIs bike is the silver and black one in this picture of our bikes at Daytona in 1990.

Ken

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I recognize that Alloy tank space frame Norton with the Yellow fairing. And is that Swartzfuger's racer on the near end?

The bike on the near end is Rob Tuluie's 750, not Swartzfigure's. The two yellow ones are my PR on the end, and, as you recognized, your old monoshock bike, both with 920 engines. Mark's bike was running a short stroke 750, and Rob a standard stroke 750. I was riding the PR and Rob the monoshock in the AMA Battle of the Twins race, Mark was riding in the AHRMA Formula 750 class, and Rob was riding his bike in the AHRMA Sportsman 750 class. Back in those days AMA and AHRMA ran their races just a few days apart, so we could compete in both with one cross-country trip. "Those were the days, my friend. We thought they'd never end."

Ken

We have never had BOTT or Formula 750 classes in Australia. It was always open slather. I think you guys were a lot smarter. We've had one single-make class for Harley 883 sportsters which died a natural death. My Seeley doesn't really fit any class where similar bikes compete, so it is a waste of space.
My feeling is that we could do worse than have four divisions in road racing and run them in capacity classes. - BOTT, supermono, Formula 4 for 4 cylinder four strokes, Formula 2 for two strokes.
I would dearly like to race my Seeley against two valve Ducatis - it is never going to happen. And now it is probably too late for me anyway.