I havent dynoed my 2003 XB9s but it has felt since I got it like it's not making as much power as it should be. It has 15k miles, not been wrecked, and has the race ecm and exhaust. Also I put a K&N filter and 07 xb12 upper airbox. The bike won't wheelie easily at all and I could never outrun my friends 67 rwhp Ninja 650. Apparently I should be making nearly 20hp more. What could it possibly be?
there was a article about even though the buell has more power and torque that its doesnt beat a engine with lesser numbers like CC's. hard fom me to explain, but it sounds like you bike is right where it should be.... its a numbers game of rev range and transmission effenciency and well the buell is just beat & slapped slow. the tranny is so un worthy, if it were a better one i bet a noob can pull 3rd gear wheelies like a pro and beat the 600's in a drag race.. flame on
I believe Charlie can wheelie anything, and make it look easy. 3.5 horse power, and 2 foot pounds of torque: 1:32 is him playing on a 50 wheelie like it's nothing.
check your plugs dude.. mine fouled @ 3000 miles.. changed em out and been fine since. and go beat the piss outta that thing, carbon bulidup will kill ya. i ride right with my buddies cbr600rr until like 135 then hes GONE!! something is def wrong... your clutch isn't slipping right? very easy to adjust if it is...
Guys, it's all numbers and physics and math and gear ratios. Understand them and you won't get frustrated. The top end of most Buells (except the 1125s) is about 135. Don't let the other guys get you there and you won't be disappointed.
Strategy, like the man said, it's all above the seat.
I had thought about carbon buildup. I have another set of new plugs so I may put them in for the hell of it. And no the clutch isnt slipping. Every once in a while it will slip out shifting into second but thats rare.
I have been on 2 wheels for 10 years and this is the highest hp bike Ive had. I have ridden my friends twin ninja 650r and it honestly feels faster most of the time I was riding it. Is there anything else besides carbon buildup? Maybe tranny fluid?
And Im not talking about how to do a wheelie. I can sit way back and stop-start in first or pop the clutch in second. I just figured it would power wheel by simply romping on the gas.
Here's why the 650 4 cylinder will typically beat a 900 cc twin in a rolling race.
650cc * 12,000 rpm / 4 = 1,950,000 cc / min
900cc * 7,000 rpm / 4 = 1,575,000 cc / min
I estimated engine speeds, but I think I'm in the ball park (if anything, I went conservative on the 650). Basically the 650 pumps more fuel / air than the 900 at peak horsepower and since it is water cooled it can run with high compression and hence greater efficiency.
Max safe rpm is limited by piston speed (okay, and engine longevity) which is determined by stroke length.
And now you see why Ducati adamantly fights for higher displacement for their twins in World Superbike and AMA.
Sloppy... Sense when is performance measured in cc/min?
I dont think that is accurate at all...
And maybe the 650 just feels faster because it rev's faster in relation to speed change?
I know my R6 felt faster because a 2000rpm change for the buell is more speed increase then the R6... When you look down on the buell (at first) your going a lot faster then it felt.
Also HP wise I would imagine rear wheel horse power to be pretty close for the 650 and the 900... Because the 650 is liquid cooled.
Dont know RWHP for the 650 but for the XB12 I have heard its around 100 AT THE CRANK and under 90 at the rear wheel.
So the XB9's rear wheel is probably close to that of the 650R's.
And Ducati adamantly fights for higher displacement in WSB and AMA because they are twins competing against I4's, and a twin makes less HP... The cc/min is not important...
And yes RPM is a factor, as higher RPM means more HP (HP is a product of RPM and torque), and thats one of the reasons I4's make more power... they can rev higher.
Think of it this way - your engine's displacement is how much volume of fuel and air it can burn. ALL OF YOUR POWER COMES FROM FUEL AND AIR. Hence, the more fuel and air you burn, the more power you can make.
The formula simply describes how much fuel and air can be pumped at peak horsepower. Since a 650, 4 cylinder can pump more fuel and air, it has the potential to make more power.
engine displacement * rpm / engine cycles.
Engine cycles is how frequently in a revolution your engine pulls in air. A 4 stroke takes 4 engine cycles before it brings in more air. A 2 stroke brings in air every 2 cycles.
Original formula is correct. Displacement has NOTHING to do with number of cylinders. The number of cylinders "dictates" what peak rpm will be.
You will need to cycle your engine 4 revolutions before your engine will displace 900cc. If you had a 2 stroke, it would only take 2 engine cycles to displace 900 cc. Which is why MotoGP had 500 cc two strokes competing against 1000 cc 4 strokes...
Think about this - 2 bikes of the EXACT same displacement; the one with more cylinders will always make more power. Why? Because it can spin at a faster rpm and hence pump more fuel and air; ergo, make more power.
FWIW - I believe Kaw had both a 4 cylinder 650 and a 2 cylinder. Which model of Kaw where you referring to - I can pull out actual peak RPM and see what the actual numbers are.
The 650 twin I was referring to is the one in the current ninja 650 and the ER-6 nakedbike.
Kawi also built an air-cooled twin back in the day.
They also had a series of air cooled 4 cylinder motors...originally as 650...and later overbored to 700 and 725cc...including an unbelievably potent turbocharged version...last used in the 750 Zephyr...they were outstanding motors...I raced a 650 in Prostar dragrace competition for several years..the motor was damn near bulletproof...
Sloppy,"You will need to cycle your engine 4 revolutions before your engine will displace 900cc."
4 cycles or strokes equals 2 revolutions as a stroke or cycle is the up or down movement of the piston. The piston goes up (1 stroke) and down (1 stroke) during 1 revolution. A 2 stroke engine (supposing perfect scavenging and accurate displacement rating) will displace it's entire rated displacement in one 360 degree revolution. Math is a strange art in that the smallest error in supposition can make a genius look stupid.
Thanks for the clarification Sloppy/Ochoa I suppose there is some truth to that but it just seems so much easier to just look at the HP figures and realize they are near identical for the two bikes .
My guess is that the 650 is both lighter, and geared lower.
If you want to know, just take your 9 to a dyno. For under $100 easy (probably a lot under), you can get a real plot and know for sure, if it means that much to you.
*sigh* Can't someone around here just be happy they HAVE a bike for once, instead of constantly worrying about why they can't outrun so-n'-so? There has to be a gazillion "My bike is slow" threads in the archive.
Oh, and for the record, I believe that ninja is a parallel twin rated for about 70 HP.
A great bike, particularly for the price, but nowhere near as good (suspension, handling, braking, or acceleration) as an XB9.
It is probably lighter and geared lower though... I suspect the difference you are seeing is gearing. It may outrun you at particular speeds, but both wound out on a salt flat and you would leave it behind.
Well I decided to go over the bike this evening to see if I could figure it out. First I took out the spark plugs and not only were they the originals, one had nearly no gap at all (less than .01 where it should be .035.) I gapped a new set and installed them and it was alot better. Then I checked the tranny fluid and it was ridiculously black so i emptied it and put in new synthetic. Its a whole new beast. The guy who had it apparently didnt maintain anything but the motor oil.