Super single road bike 700-900cc

[supersingle]

I'm in the process of looking at designing a large single cylinder road bike 700-900cc. Having difficultly obtaining a suitable motor gearbox, DR800 looked good but is scarce as. Today's effort 788 Honda quad engine but three speed gear box rules it out.

There's a guy in Canada, Goldhammer who designs/produces 900cc supercharged single(Half a HarleyD.) The guy's bloody brilliant. Have discussed it with old bike Australasia editor who is real keen but extremely busy. He suggested the concept of a large capacity single cylinder roadbike/racer i.e. A modern equivalent manxnorton with all the modern suspension,frame etc.

I'm looking for Input resuitable power trains.

Just general constructive comments needed.

[Conquiztador]

Golhammer has had his creations in the Custom Bike World Champs, and won. His engineering might be awsome, but his grashopper creations can be disputed. He has removed one of the the cylinders from a HD (or replica) motor and fitted a compressor in its place.

Why not consider a motor and separate gearbox? Solo speedway motors are 500cc singles. Some stroking and boring and you should be able to get the wanted cc's.

And what does the Rotax have on offer?

[hmmmnz]

a klr650 engine might be the way to go, 700cc kits are reasonably east to get hold of, and apart from the countershaft adjuster they are fairly bulletproof engines

or a yamaha raptor 700, you can also get 779 and 825 stroker kits for it... and you get a reverse gear as well
handy!!!

[pete376403]

Even with a 705 kit the KLR is still a tractor (just faster than a 650 tractor)
I have read that the head becomes the limiting factor; port design, valve sizes, etc., limit the potential.
A KTM 690 might be the go, or Husaberg, etc - more potential for go faster in those.
And the bit that fails in the KLR is the balancer shaft tensioner, aka the doohickey. Easily fixed though.

[Forest]

rSome dude was selling a Bimota Supermono Biposto 650cc single on trademe recently. I think it had a Rotax engine.

Asking price was $10k. Might be a good starting point for a custom sports bike.

[hmmmnz]

yeah the klr650 is a bit of a dog, i was kinda diapointed with mine, although the tengai tankrange was awesome, but the gearing is fuct, too high to be good off road and not high enough to be good on the road,
the pegasso runs a rotax engine and that wasn't half bad, a bit more ballsy than the klr,
the raptor quads are stupidly quick, well quick enough to give me the shits off road, i dont think i got out of 3rd gear, hard to say what it would be like in a proper frame with the correct amount of wheels

[koba]

There are alot of reasons bike manufactuers don't make singles over 650ish cc...

If you go for a non unit setup look here: http://www.ttindustries.com/
NZ made too.


Pretty much as pete says,
Wouldn't it be better to go for a smaller single?
I'm sure you would get more performance out of a 450-500 single and less problems holding the bike together.

KLR is a tractor partly due to MASSIVE rotating mass, as is desirable in that kind of bike. My 600 had 5kg taken out of the crank and balancer assembly.
It went like fuck.
It also vibrated pretty bad, this could be solved with alot of smart tinkering and all but it was looking like a hell of a lot of work to end up with a bike that is still not all that fast!
There are hurldes to overcome if using a dirt focussed motor in a road burner, gearing being one, the ratios are waaay wrong for good road speed.

[koba]

Another thought, If you want someone who know how to make a single VERY SUPER these are the people to talk to : http://www.srd.net.nz/

[popelli]

easy route would be to use 1/2 a harley motor and rebalance the crank accordingly

however for the same amount and effort and expense you could build a v twin bike with twice the power

[supersingle]

'Conquiztador', Point taken, I am aware of TT industries Nelson gearboxes, as for a suitable single engine???
Did read about Hele/Thomas Manx prototype 500cc but it's about 300cc short.
Sounds like Rotax might be worth investigating.

'hmmmnz' klr's 650-700cc! need to find out more about the kit. Yamaha Raptor quad never heard of it, to investigate.

'koba' ok large singles have inherant balance problems I get the impression dynamic balancing sorts it. But I aint no expert. Gearing! sure as hell wondered about that too.

'popelli' half a harley has been proved by Goldhammer, 125 brake horse power out of 900cc??? V twin??? not given up on the single just yet.

Even if I'm pushing it @#$% up hill. Can't beat the sound of a narley large single on full song.

Appreciate the ideas/help. Sorry but I don't have constant access to a computer. Will only check once a week.