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[bigjohn]

Thanks for the lively thread guys I did not see a southward turn. Spirited discussions among passionate fellows that all love motorcycles.
Please remember that in the stream of knowledge there will always be guys behind and ahead of you. IMHO. My questions were answered very well and I appreciate you all. Next time I hear a big dyno bragger I can rest that there is more to a ride than it's numbers. I love my 120ft/lbs and glad that I don't have to live at 6K+.
Love live the beefy fat over weight HD.

Steve answered your question:
"Think about it just for a minute without looking at a dynosheet at all. Where do you run the engine when you ride? Then take the dynosheet and tape over all the areas that are outside that range."

Thats how you pick your cam, then its your choice, built for how you like to ride. 

[Half_Crazy]

Steve answered your question:
"Think about it just for a minute without looking at a dynosheet at all. Where do you run the engine when you ride? Then take the dynosheet and tape over all the areas that are outside that range."

I don't know about you, but there's nothing to tape off. I use the whole tach. There is no set RPM where I shift, no range of RPM I avoid, I ride at 2000 RPM and I wind it out to 6200 too.

I want the broadest spread of power I can get... The most average HP & Torque from 2000-6500 RPM. The best compromise of low end grunt and horsepower upstairs. If there has to be a choice made, choose displacement... less compromising that way.

[bigjohn]

I am thinking he is just going to be using it as a cruiser, probably two up...maybe hitting 4000 rpm on entering the highway. Which is good ... i should be more like that.
Whats your thougts on building a sportster? My son wants to race it, I have been researching different builds for it, just dont want to get carried a way on something that would hurt him.

[Half_Crazy]

Don't know jack about Sportys, but I know what you mean about him getting hurt. My stepson bought a CBR 929RR. Nobody needs a liter sportbike, much less a 22 year old with less than a year on bikes. He never had any interest in bikes or so much as rode a dirt bike even though his real dad has 5 Harleys. Now he has a bike that scares ME and I've been riding/racing for almost 40 years.

Building a bike with your son should be a great experience. I can't wait to see it.

[HILLSIDECYCLE.COM]

I am thinking he is just going to be using it as a cruiser, probably two up...maybe hitting 4000 rpm on entering the highway. Which is good ... i should be more like that.
Whats your thougts on building a sportster? My son wants to race it, I have been researching different builds for it, just dont want to get carried a way on something that would hurt him.

Some of the fastest H-D's have been XL's.
Friends of ours had a 107", that we loaned our cross-ram dual-carb set-up. That car-tire bike, ran 8.58/152 mph at Maple Grove, PA........................over 10 years ago.
Scott

[bigjohn]

I havent forgot yours Scott, Just doing some research. I was going to give you a call next month and see how busy you were.
John

[Spiderman]

Carl Morrow and his son of Carl's Speed Shop fame have set a bunch of records running Sportsters. Four cams and straight pushrods have a bit to do with it. Carl by the way while at one point holding a world record for hp on a dyno with an EVO motor he built (something beyond 200hp) thinks Dyno numbers are pure bastardized bullchit. But hey, it sells parts so sure he's gonna get in the game.

B B

[bigjohn]

could you imagine that, 200 + hp on a sportster. Man there would be a lot of praying (especially if you would see my son ride, he has no fear yet). Guess you wouldnt have time to worry....once you hit it you would be down the track.
That would definately be a non forgiving bike.

[HILLSIDECYCLE.COM]

That 107"er that I mentioned, set the AHDRA class record that day,(the record in now quicker) and I believe it is still the quickest/fastest pull a 107" gas XL has ever made.
That bike made over 181 hp here, on our dyno, during a closed-door tuning session with those guys.
Scott

[Half_Crazy]

That bike made over 181 hp here, on our dyno

I guess you don't subscibe to the philosophy that "Dyno numbers are pure bastardized bullchit"...

[timtoolman]

But how many times do you see the winner of the race doesnt have  fastest time  As Bobbie  Woods says"its not how fast you go its how quick you get there "  how many national titles/records  has he got with this theory?  read his web site,  and torq is the only key factor that gets that  done,  Ill take big torque figures anyday over hp with these bikes, and im always looking for more of it, if you get the hole shot from a dead start and that massive torque throws you out there so quick, combine that with gearing/pulley changes ,and all  engine mechanics'  (class cuin size) being equal or close   the other guy with less torque  just maybe playing catch up the rest of the race,  just look at the modern diesel trucks being built, high hp numbers but higher torque and they are quick and can smoke quite a few sports car on the track.  There is a old american Iron magazine issue (last year i think, I have it somewhere) that has a sporster that spanks hyabusas  regularly at the track,   sure isnt hp  that makes that happen,   my build has great numbers as indicated  by the dyno sheet  120 trq at 4500, as per Steve Coles theory  folding the sheet in half!!!  love that, !!!    but man that torq always has my attention torq is the main body of  cake  and hp is the  thin layer of frosting
my theory of dyno numbers  is  it tells you that the parts you bought and put together are working as advertised

torque,torque torque,torque torque,torque

[HILLSIDECYCLE.COM]

I guess you don't subscibe to the philosophy that "Dyno numbers are pure bastardized bullchit"...

No, as a matter of fact, I don't pay much attention to that guy.
Scott

[Half_Crazy]

If torque won drag races a CVO Dyna would spank a V-Rod, wouldn't it?

Don't get me wrong, nobody is a bigger torque junkie than I am. I build my motors for best average torque, but drag racing is a completely different ballgame than riding out on the street. Bikes I can crush in a 5th gear roll-on have spanked me badly thru the 1/4 mile.

Identical bikes: If the other guy makes more HP above 5000 RPM than I do... and he leaves at 4500 RPM and shifts at 6500... I don't have a prayer. He will never be at an RPM where I have any advantage. Nothin' but tail light for me.

However, mine is a much better street bike. Drivability, carrying a passenger, riding up a mountain, rolling into the throttle in high gear... he would have to downshift 2 gears to stay with me. That's where torque comes in handy.



 

[bigjohn]

identical bikes: If the other guy makes more HP above 5000 RPM than I do... and he leaves at 4500 RPM and shifts at 6500... I don't have a prayer. He will never be at an RPM where I have any advantage. Nothin' but tail light for me.

Thats the ticket. The best combo would be to find the best of both worlds.
Thats why I favor a torque curve that stays flat and brings the hp up to meet it (without losing much on the drop).
you want to see something interesting, look up dyno charts from hyabusa's and such. Thats amazing.

[Half_Crazy]

you want to see something interesting, look up dyno charts from hyabusa's and such. Thats amazing.

Those of us who love big ol' V-twins have to deal with the reality that our engines will never spin to 13,000 RPM, and even if they could they would run out of breath long before that. Those crotch rocket motors are big bore/shorter stroke w/lots of valve area and they spin to astronomical RPM. Maybe they only make 70 ft-lbs flat across the tach, but at 12,500 RPM that equates to 166 horsepower.

You could have that kind of HP and an equal amount of torque to go with it out of a V-Twin, but it would require HUGE displacement and would be seriously expensive. Those 155" R&R motors will take you beyond that, but it won't fit in your frame and you'd better have some deep pockets. One of those motors alone would set you back far more than the cost of a 'Busa. You'd have to want it pretty bad...