Engine Adaptation to Road Frame

My search for the biggest single has come to an end...almost!

There is some disappointment insofar as the Big Berger has only a marginal crank. What I had hoped to do was adapt the engine to a Velocette 500 frame but, alas, without a flywheel comparable to its displacement it would likely prove a poor match. The Velocette 500 engines, as with the other large British singles, had massive flywheels which contributed in no small way to their handling and stability. I suppose the only alternative would be to add some depleted uranium to the Berg crank to give it the "***" it would need for a respectable road bike.

Suggestions and comments appreciated.

No to seem negative Thumpster, but would it not be better to repair your velocette engine than try to adapt a Berg power plant....
If you really have a Thruxton, as in the pic, it may be well worth keeping in classic trim.

Those Velocettes are awesome looking....I would just modernise it, with suspension, brakes , wheels, tires, and electrics -- and maybe a new exhaust. Lucky dog! One of my old rides...a 1964 Ducati 250, good for 110mph! I sold it back to the original owner for a $1...I was moving he was broke -- boy was he one happy dude...

somwhere in the states they make 750cc 2 stroke dirt bikes. Go one of them if ya mad enough.

ferret said:

somwhere in the states they make 750cc 2 stroke dirt bikes. Go one of them if ya mad enough.

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Are you talking about the Yamaha TZ750?

Hey, thats the one that scared the beans out of King Kenny! Parked it, if I remember right... That TZ would go real nice in my garage!

Crew-Chief said:

ferret said:

somwhere in the states they make 750cc 2 stroke dirt bikes. Go one of them if ya mad enough.

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Are you talking about the Yamaha TZ750? [/q


'' scare the beans '' highly appropriate in this case , WHAT AN ANIMAL .

personally i would turn up to race the above and notice the size and capabilty of the TZ motor

the next thing that would come to mind would be the knitting needle size front forks , the 2 pogo sticks that stop the mudguard touching the rear tyre .

massive concerns all round !!!

i think KR rode the 680 to victory , unsure about the 750

Not to mention the dry clutch...wonder how that works with dirt in it? That bike was certainly a creative effort by the Yamaha works guys...but light switch type power band doesn't work for flat track racing, this take the smooth stepless power of a four stroke. Could you image hitting the meat of the powerband while already in a full lock slide? I think this is what scared KR. 300 lbs and 150 HP are not a good combination on the flat track...it would be like a speedway bike, sliding in a wheelie, at a much higher speed...still would love to test ride it!

Thumpster,

If for some reason you are looking for a BIGGER single, sidecar manufacturer EML made an 1100cc single 2stroke, it is massive, with all milled solid engine cases, and a head that looks like 2 Maico 490's put together!!

A guy by the name of Walter Presig, multi World Motocross Sidecar pilot has one here in South Australia, I saw it in the flesh once, an its a beast!!

Azza.

1100cc single! Wow, I'll bet it was a joy to start....and when it did BOOM! Like shaking a bucket of water around -- probably needed the QEII for a counterbalance.....tires probably lasted two rotations: first ripped off all the knobs, second ripped off the rest tof the tire!

The very animal I speak of, published in Dirt Action No23, April 2001.

Azza.

Duh,

Pardon the anticlimax, its a twin (apparently), though when I saw it in the flesh, I am sure he was telling us that it was a single??!

120hp, who cares, thats enough nuts to catapault any rider and swinger from corner to corner with ease.

Azza :roll:

No mo gotty Thruxton. Head-on collision and consequential multiple somersault duet as my copilot and I made clean two point landings...cheeks of our arses...as I was attempting to frighten my passsenger with some daring and awe inspiring maneuvers only a steady steed Velo could perform! My success was apparent as he required a large hypodermic of Thorazine to bring him back around!

Still dream of the ultimate 4-stroke single roady. I remember hearing of a USAF mechanic who took the bottom end of a large British single and mated it to the piston and cylinder of a Pratt & Whitney radial aircraft engine...1000cc I believe. He said the thing hop scotched around spending as much time in the air as on the ground!! Precisely what one might expect from a half aircraft/half motorcycle conglomeration!

I also had a black Velocette 500 single MSS that my friends affectionately labeled "Blacktrash" (If it had been painted white they'd have called it 'Whitetrash').

They teased me so badly one day...cynically accusing it of being incapable of pulling a respectable wheelie...that in a rage I revved it up to valve float and dumped the clutch. Sonofabitch started bucking like a mechanical bull as the rear shocks alternately fully compressed and extended catapaulting the mass of raging machinery into the air and onto the front wheel in such a violent, uncontrollable cyclical fashion, that my life raced before my very eyes in anticipation of certain doom!

As you may have guessed, my friends literallly fell of their bikes laughing in complete derision at the entire spectacle. Oddly enough, they gained a new respect for my 'Trash', realizing as they did the enormity of power that had to be unleashed in order to produce such unbelievable gyrations and corresponding pavement pounding seismic events. There was also no small amount of marvel amongst my antagonists, insofar as I was able to survive what wound up being a gut wrenching episode for all of us.

sorry I think is just crazy, stay with that clasic bike, don´t do it¡¡¡¡¡