Years ago when Mick Andrews was riding for Yamaha he developed a fuel injected bike. Can anyone remember whether he rode it in the Scottish?

Yes - Mick in fact won the Scottish on this bike in 1974 - the carb was developed using snowmobile technology. He told me it was really neat because it would still run even if it was upsidedown - not that Mick was ever in this position of course.

Thanks Dave.

Chainsaws also have carbs or injection systems enabling them to run normally in any position.

don't want to sound picky, but these are actually diaphragm carbs, not fuel injection. They still meter fuel into an airstream, then control the mixture with butterfly plate.

Most small 2 stroke handheld applications use these carbs. they are amazingly simple to work on, but tend to work at low idle and high speed only. the transitions are not too good, but maybe that is only because they don't have to be, son only have a few circuits inside. Older snowmobiles had these carbs and worked reasonably well through a wide range of speeds and loads.

they can work in any position, and don't have rich/lean issues with fuel sloshing around under impact ans shock.

I would bet some reader has already experiemented with them in the past.

k

Thanks for all the replies chaps. Now does anyone know if there's a site in cyberspace dedicated to prototypes that Magical Mick produced during his term with Yamaha? The man is a craftsman/engineer of note. It'll be lovely to drool over his creations.

I used to have a copy of "Motorcycle" with a pic of Micks (then) newly unveiled mono-shock Yammie. Nice big colour photo too. That's the sort of thing I was thinking of. Mind you I've a good colour pic of the 360 twinshock (laid down shocks, blue & white tank) in a copy of 'sport I could scan & post.

TFT

Seems to me that Big John is as big a fan as I am..'ere we go...

Seems them pics have gone awol. Will try again tomorrow.

TFT

Edited November 28, 200520 yr by TooFastTim

Try again.

Didn't come up too well in the preview but heck that's a great looking motorcycle (IMO).

Edited December 2, 200520 yr by TooFastTim

Big John, a friend of mine that was a key member of the Yamaha trials effort in the 70's was kind enough to share his experiences with this special carb. In his words:

" It is NOT a fuel injection, as fuel and air is mixed in a throttle body the same as is a conventional carburetor. There is no fuel pump and no electrics involved.

Here is a brief overview of the unit. This had a pulse line going to the crankcase and used crankcase pressure to regulate fuel volume. (larger throttle openings resulting in higher crankcase pressure and smaller openings less pressure) There was a slide and needle in the throttle body as in a conventional carb. it was not a pumper carb as used on chain saws etc., there was no diaphragm."

I always enjoy your posts John, I hope you enjoy this one.

Martin

Yes, John his name is Bill. Great guy.

I was a lad when I used to go get my spares from Derek when he was the parts manager at Montesa Motors in Los Angeles. Do you ever see him? If so please say hello for me.I have attached a photo of the American Montesa Tean 1973.

Cheers, Martin

That's the beast John.

Hey John - Another story on Mick's Mono - when he came to ride our World Round inear Calgary in 1975 - we had his bike delivered to the local dealer - Walt Healy MC ( quite a famous guy in Canada- sadly no longer with us) - Before the bike was put on the plane, Mick left the top of the crate just resting on the top - not nailed down at all so that customs could check it - he had his riding gear & everything in the crate alongside the Yam - and that is exactly how it arrived open for all to see - he got a big laugh out of that - he had a bad day at that event finishing 11th but when he started to moan about it Jill told him it was his own fault and that he had not been practicing enough - We later went for dinner at the top of the Calgary Tower ( Malcolm Rathmell joined us) & after a few drinks Mick was back to his old self cracking jokes.

I guess the funny thing about the open crate thing was that the Japanese were trying to keep everything so secret about this bike - not sure if Mick ever told then the story. It certainly wasn't "cheap" to build the one off bike. - Sorry to hear about Willie - my condolences to all the family.