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Discussion Starter · #1 ·
I don't know if any of you have been following the saga , but I got my bike back a few days ago. [thumbsup] Obviously, an engine rebuild means a lot of new parts are on there. I've noticed quite a lot of new "oomph" that I didn't have before and am curious as to what it is: better compression? or more h.p.?

I'd been suffering a decent amount of compression loss prior to the rebuild, but I didn't think it was that significant. I can't imagine that the 944 would add that much horsepower to my ride, however. Last time I had my bike dyno'ed it put out 75 hp--that was when it was the 900. That seems about right given the age of my bike + the after market pipes.

So here's the question, what kind of power is your 944 putting out and with what modifications in addition to that, if any?
 

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You probably gettin 5-7 hp from your rebuilt motor w 944 kit. Hope they`ve tuned the carbs.
Could feel like more because of the freshly rebuilt motor. Bet it feels crisp & responsive.
Lotsa reply`s will follow... ;) Happy w it?
 

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Discussion Starter · #3 ·
5-7 sounds about right--I knew it would be something, but not a huge change. The difference I'm feeling is bigger than that however--I don't really have enough experience on bikes to gauge it accurately...It's not as powerful as my boyfriend's superhawk (that's a 998 I think) and it's 100 hp. However, this feels more like 10 hp stronger (if I had to venture a guess.) I haven't been able to really feel for the crispness yet--I'm supposed to be riding very smoothly right now in order to let everything break in properly. Haven't had a chance to just twist the throttle hard and quickly. I did notice pulling away from the shop that the front end got a little light. I've been riding my FZR400 around a little, so I'm thinking that my wrist is just used to that...

I didn't ask if the shop tuned the carbs and it wasn't on the labor list. I'll ask. Thanks for the tip. I'm also supposed to ask whether they rejetted.

So far, pretty happy with it. I'm just happy to have a bike back. I can't stop thinking about riding.... :)
 

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Mostrobelle said:
I've noticed quite a lot of new "oomph" that I didn't have before and am curious as to what it is: better compression? or more h.p.?
It's both, because they're intrinsically linked. The higher compression is (most of) whats giving you the extra horsepower - like you say, the extra 44cc is not even 5% more than what you had originally, which isn't enough to account for the extra performance you've got. The higher compression ratio means the motor is now producing more torque than it used to, and since power is torque times rpm, you've got more power from that as well, quite a lot more than the ~5% capacity increase might suggest. What you're feeling as "Ooomph" though is the extra torque...

Have a look at some of Brads dyno charts:

http://moto-one.com.au/performance/900ssiehicomppistons.html

and

http://moto-one.com.au/performance/900sscarb944.html

Look particularly at the torque curves (the second graph down on the first page, and the "flatter" set of lines on the first graph on the second page) - they show that you should expect at pretty much any speed to have around 20% more torque available - thats what you're feeling as "Ooomph", torque is a measure of how much force the motor is producing - ie, how hard its pushing you in the butt - and yeah you'll really be noticing 20% more of that!

Enjoy it!

big
 

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Discussion Starter · #5 ·
Wow! 20% more torque! Yeah, no wonder... [laugh]

well, I can't find my last dyno. I know it's around here somewhere... I seem to recall a number in the 30's for torque. The bf's superhawk is in the 50's I believe for torque.

So getting the 944 kit isn't what makes my bike feel like it's on steroids? It's mostly the fixing of the compression leak(s)? So my bike would have been feeling a lot peppier just fixing the leaks.
 

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Mostrobelle said:
Wow! 20% more torque! Yeah, no wonder... [laugh]

well, I can't find my last dyno. I know it's around here somewhere... I seem to recall a number in the 30's for torque. The bf's superhawk is in the 50's I believe for torque.

So getting the 944 kit isn't what makes my bike feel like it's on steroids? It's mostly the fixing of the compression leak(s)? So my bike would have been feeling a lot peppier just fixing the leaks.
I think your 900 was more like mid to upper 50s for torque. You had mentioned 75hp. That's right in line with what mine had and mine is like 58lbs/ft. I have a dyno chart somewhere too.
 

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Mostrobelle said:
Wow! 20% more torque! Yeah, no wonder... [laugh]

well, I can't find my last dyno. I know it's around here somewhere... I seem to recall a number in the 30's for torque. The bf's superhawk is in the 50's I believe for torque.

So getting the 944 kit isn't what makes my bike feel like it's on steroids? It's mostly the fixing of the compression leak(s)? So my bike would have been feeling a lot peppier just fixing the leaks.
Even the way your motor was when you dyno'd it should have been low/mid 50 for torque.

You're getting a little bit of everything contributing to the torque increase you feel:
Ring and valve seal are improved.
More compression.
More displacement.

Every little bit helps, but when you can take care of three things at once, it's pretty dramatic. :)
 

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Mostrobelle said:
So getting the 944 kit isn't what makes my bike feel like it's on steroids? It's mostly the fixing of the compression leak(s)? So my bike would have been feeling a lot peppier just fixing the leaks.
Where were you losing compression before? The 944 pistons are higher compression than the stock 900, so you're adding displacement as well as increasing compression over stock. Hi comp 900 pistons would have given you some of what you're feeling. Are you asking if just replacing rings and valves would have made a big improvement? Had you done a recent compression check before the work?

On a side note, do you have any idea the amount of envy and jealousy you've created by having the good fortune of having your motor **** itself, eliminating the need to somehow rationalize tearing a perfectly fine engine apart just to pack in some new (bigger) bits? [laugh]
 
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