Ok so i hit up a open house today with the bike and it only ran 90 hp... Was wondering what every one else is getting out of their F4? It does show 30200 on the clock but the sprockets have been changed a few times on it. Should i hang my head in shame at this number or for a 9 year old bike be happy?

 

Hp doesn't mean anything and in all reality 90 hp on a less than 300 lbs machine is great. In the works of carol shelby "horse power sells cars torque wins races"...

 

MmmmmK. Adam, do you drive your cbr with no gas tank, subframe and a huffy front wheel? Haha JK! 90 H.P. is about what you can expect. Mine is going on the dyno in June. I'll post results.

 

That would be great...

Mods currently on bike

* Jetted carbs
* K&N filter
* Shorty scorpion exhaust
* One tooth down on the front stock back and chain

 

Excuse me, after little research my f4 weighs 322lbs...
Kthanxbye

 

You should contact HRC then, they will be curious as to how you dropped 51lbs of the stock dry weight. Just don't tell them how you got it to run on dreams and cotton candy, that's special. Factory is 373lbs. Anyway, Yog you have a 520 chain? Gearing won't matter but anything lighter in weight in the drivetrain will help. Right now I have on my bike: Jets, AICV and reed valves removed, full M4 exhaust, 520 RK race chain w/ al. vortex rear sprocket.

 

Its not a 520 chain.. its just dropped one in the front. More for the wheelie factor =)

 

I was at the dyno with mine 2 years ago. One of the F4's with a hindle system made 105 rwhp, another fairly stock made 95... I was down from that at the time, but as it turns out cleaning the air filter really makes a difference (oops)

I'll try and get mine on the dyno again - after I finish the prep work (new spark plugs, carb sync, fuel mixture adjustment and a clean air filter - running a full M4 system currently) I had been running +1,-2 but I'm back to stock - it really hasn't made much difference, just changes where you get the power.

 

With just a slipon and stock filter mine pulled 96 rwhp at an open house. Dynos varry greatly though so a 5-10% range would be acceptable though I think.

 

I realize I'm a noob here, new to bikes but I think I understand horsepower.

If you're messing with your gear ratio then you absolutely will affect your dyno. I don't see how you couldn't.

Ironically the first reply guy who doesn't make much sense had a point. Your torque number shouldn't change but going down a tooth should change your horsepower.

Horsepower is nothing but a fancy way of multiplying torque and engine speed. You went down a gear, and essentially moved your torque curve to the left. That has to move your horsepower to the left as well which is going to have an adverse affect on your peak number in a high reving 4 cylinder.

Posting both dyno numbers or a graph would help.