Still undecided (how to get 80hp at 6k)

[madnss]

Originally Posted by buckwild

after reading all the threads i could keep changing my mind on many things like carb, cams and heads lol
I know what i want to accomplish but not sure how to get there so I figured i would just ask.
I have seen many dynos runs where power is up to the 7000 rpm range, I dont want to run that high of an RPM. I would like to hit around 80 HP in the 6000 range but I want lots of lower end torque.
Im definately going with a 1250 kit. What else would i need to get to my goal?

Port your heads or newer 1200 heads if you want 80 hp at 6000 grand...your stock carb will be fine....any reasonable flowing air cleaner will do. Any 2 into 1 will basicly work for what you want.

You could always put stock thunderstorm heads on with 497's and have a great running powerful bike.

[madnss]

A stage 2 head with bigger valves and any of the screaming eagle cams are good choices. 497, 536, 575, all reliable and basicly bolt in cams...Put a mikuni on if you want but otherwise your stocker will work, put in an after market ignition and your good to go. even factory exhaust with a set of slip on mufflers are good for exhaust

[madnss]

First thing you could do is set yourself a budget...then look at what you might want to do...then see if that budget is going to work or you want to go bigger or smaller. I havent herd of anyone on here saying they have to much power.....lol......most guys fall short of there dyno god sheets....good luck.....you have zillions of options....budget.....1rst

[AustinXL]

Originally Posted by madnss

First thing you could do is set yourself a budget...then look at what you might want to do...then see if that budget is going to work or you want to go bigger or smaller. I havent herd of anyone on here saying they have to much power.....lol......most guys fall short of there dyno god sheets....good luck.....you have zillions of options....budget.....1rst

Probably the best advice anyone can give on an engine build of any sort - figure out what you are willing to spend....

[rocketmangb]

Buck
The exhaust system will be a big key to 80 80
You wont see 80 TQ at 6 K but you might see it at 5 K and more important you should see about 75 TQ at 3 K
FWIW
Here would be my build
Stock headers with the crossover and some Bassani slip ons
Dynatek ignition (only because i read that and I have a Rubbermount)
Good spark plugs (I like NGK) and wires (I like Sumax)
Billet air cleaner like a Hurricane or Air Hammer
1250 Kit with the reverse domes and compression of about 10:1 or whatever it comes out to
SE497 or the Andrews N4 cams
.040 Shorter pushrods (I guess you need them)
Competition valve job or if the budget allows the Stage I porting
Port the stock intake manifold
Mikuni HSR 42 carb jetted 165 main,27.5 pilot,97 needle to start with.

I would bet anybody here it will make 80 HP at 6k or less and 80 FT LBS at about 4.4 K

[aswracing]

Originally Posted by rocketmangb

Buck
The exhaust system will be a big key to 80 80

This is exactly right and I should have pointed it out.

As you put overlap into the cams, which all aftermarket cams do, the bike becomes really sensitive to the exhaust. That's because overlap connects the exhaust to the intake, and it does so at a very critical time, as the piston is passing through TDC about to start it's intake stroke.

If the exhaust pulls right then, it gets the intake charge moving before the piston even starts going down. This helps cylinder fill enormously.

Of course, if the exhaust pushes back right then, it really screws up the cylinder fill. You get a fog of fuel out the mouth of the carb and the bike goes rich because the intake charge passes through the carb 3 times (in, out, back in again) and the bike makes no power.

Exhaust systems work on pressure waves traveling up and down the pipe. These waves travel at the speed of sound, regardless of the rpm of the engine. So it becomes a timing game, getting a negative pressure wave to hit the chamber during that narrow window of time called overlap. As the rpm changes, the timing changes.

You can tell a lot about how the pipe is behaving by looking at the shape of the torque curve. What you see is that some pipes will hit it well at one rpm and completely miss it at another rpm. Some pull up high, some pull down low. Others will hit it over a wider rpm range.

Anyway, Rocketman's point is that the pipe is going to have huge control over the powerband, and has the potential to make or break your result.

My advice would be to look at as many dyno sheets as you can, paying particular attention to the shape of the torque curve, and select your pipe appropriately. All the other parts may be selected perfectly for your target application, but if your pipe is on a different page, you won't get the result you want.

[Folkie]

Right, having weeded out the off topic nonsense, I'm going to reopen the thread. If you would like to contribute constuctively, and on topic, please do so. If not, please go elsewhere.

[buckwild]

im lookin at keeping the CV carb. from my reading it should do fine, not quite as responsive as the mikuni but not as temperamental to altitude differences. still not sure what Im gonna do about the heads. I would like to go with 1200 heads but where can i find them used? The heads are my main hold up
Im gonna have to read up on the exhaust some.

[NRHS Sales]

used 2004-2006 1200 heads are getting quite expensive but sometimes you can still find a good deal on a set on e-bay.

[buckwild]

i hate ebay, doesnt anyone sell stuff like they used to or is it all ebay now.