and sohc since the gas tank would be removeable you would be able to access the valves that way the tank would be removeable like the s1 lightning buells and on the regular v-rods you dont even have to remove the motor to do a valve adjustment

JohninVT:

“If you added up all the component weights you’d be well over the 425lbs dry weight they list.”

and

“The Roehr has a super short swingarm to get a 56″ wheelbase.”

and

“It’s nice to dream but just because a V-Rod engine has more power than a typical HD doesn’t mean it’s any more appropriate to build a sportbike with”

There is little information to go on besides the Roehr website and the article below. The article states the dry weight = 432 lbs.

It looks like Walter pulled it off with the stellar materials and components. The supercharger is 6.4 lbs. Not bad. Remember John, he is building a streetbike, not only a racebike. The Aprilia website claims 416 lbs. for the RSV1000

“Anymore appropriate to build a sportbike” — ? This is what probably set off Bob, but I don’t want to speak for him.

“Appropriate” is highly subjective, especially when considering a streetbike. (and then add on top of that one that is niche-built).

I consider my V11 Sport Guzzi an appropriate sportbike. It weighs more than the VRoehr and has 2 valves per jug actuated by pushrods. The R6, R1, YZ750, Speed Triples, etc. that I have ridden through mountain roads together would agree…even factoring in the subjective skill level of their operators.

The Buell Firebolt is still one of my all time street sportbikes and it similar attributes on paper. Nonetheless, it makes an appropriate sportbike.
————————-

ROHORN:

“Your obsession over wheelbase and swingarm lengths tells me you read a lot of magazines – and have NO other experience with the subject”

“It’s cute when consumers claim they know somethign about the subject.”

While I agree with you on spec-sheet recitals and the hype of the supersport product marketing strategies, I think you jumped to conclusions about John. In addition, while not everyone has build experience, they maybe observant enough to know many manufacturers from all parts of the world pay smart and talented engineers a lot of money. Those engineers generally arrive at a comparable geometry of a sport motorcycle. This doesn’t mean we’ve reached thy holy grail, yet, either. But, with the technology and material science available, it is a safe bet.

Do you agree that there is a ballpark (infield) geometry to strive for when building a street, sportbike?….

not much more than 450 lbs wet
not much more than 57 inch wheelbase
not much more rake than 24.5 degrees
etc.

This is not to say bikes like the new XR1200 wouldn’t be sporty on public roads. It also doesn’t mean there aren’t other ways to re-think the general principles entirely.

Signed -
“Jim Lehrer”

http://www.motorcycle.com/manufacturer/roehr-motorcycles-1250sc-review-86824.html

p.s. the Vyrus (tesi-style front-end) nearly has its radiators underneath the engine.

Looking at the length of the muffler in the rendering above, I’d like to see a radiator fit underneath the engine with a small lip curved up on either side.

No one has put efforts into the radiator aside from curving it around the front wheel.

I would love to know where I can get someone to build a bulletproof 100hp CB350 engine. Oh yes – an old 4 speed Evo Sportster engine has the same tuning potential as a new one. The older ones weigh a bit less. But Mr.”You live in Fairytale land” or whatever his problem is/are wouldn’t know that.

Every year, Supersport new model intros show the same changes – one of which is x mm longer swingarm – whatever you see in GP, you’ll end up seeing in Supersport. Take the new firing order in the R1 (so it emulates a V4 or something like that), traction control, etc..

Back to swingarms – the length is nowhere near as important as the angle of attack (to borrow an aero term), its relative position to the output sprocket, and the spring rate. The only difference length makes is that it has a smaller angle change over any given length of travel than a shorter one. That allows a lower spring rate for better tracking over bumps with the power on, rather than relying strictly on spring rate to keep the swingarm angle from going out of its optimal range.

The above bike doesn’t have GP style output, so there’s no need for GP long swingarm. Yet he then claims that GP wheelbases are irrelevant or some such thing. Hey, is GP design important or not?

Like it says above, it is someone else’s design concept. Actually building something unfashionable and having someone walk up to you and claim that your bike won’t work, nevermind you just rode it there, this reminds me of that….

short swingarms can be problematic
long swingarms are used MotoGP due to insane hp. There’s also not a lot of hairpin, narrow turns on many of the tracks so a long wheelbase beyond 55-56 inches does not impact GP bikes as it would on WSB bikes that are sold to consumers.

we all agree the Revo motor is huge and heavy.
I think we all agree the concept above and the VRoehr is cool, for what they are, but disagree what we each would do given a clean sheet.