My bike (900ss engine) dynoed at 67.2 RWHP...should I be asking WTF?

[Rudemouthsky]

   When I was first done with the mods I was stoked because I could do gas wheelies...then I started becoming very dissapointed in the power, espec freeway passing power. So I recently had it dynoed, thinking something may be up. Well the shop said the dyno found nothing wrong and the bike runs great, but that's my RWHP. I thought 900ss engines were supposed to be 80 fully stock, and I have a race exhaust, FCR's, and pods? is something wrong here? I'm pretty disappointed. Any thoughts on this? That's a lot of cash I put out to barely get more than my 750 was giving me...

[Dirty Duc]

http://bikeboy.org/900SSwithkeihinfcr39and41mmcarbs.html

Dynos can vary... but there you are.

[zooom]

just to clarify what you'de done because I am too lazy to go dig and look...you just bolted in a 900 motor with FCR41's on right? You didn't do any hot coils, not head work, and no kind of bore kit or anything right?

[Howie]

FCRs on their own don't usually add to dyno numbers, but the performance increase shows up on the butt dyno.  Some tuning and better coils, like Chris Kelley's Xact Fit coils might add to the numbers.

[Rudemouthsky]

I didn't do any engine work, no, aside from new rings. I bolted on the 900 motor and added FCR's. I do have CK's Dynacoils.

Thoughts?

[Rudemouthsky]

http://bikeboy.org/900SSwithkeihinfcr39and41mmcarbs.html

Dynos can vary... but there you are.

Ok then...I guess that's about right.  . I really can't complain too much I guess...The "streetability" of this bike is great, it's super fun...I had just hoped for more top end power for my highway riding. And TBH I already thought my 750 was a fantastic street bike. Oh well.

[ChrisK]

Have you thought of re-gearing? What are your sprockets at? If you're running like a 43T rear sprocket it might 'behoove' you to come down to a 40 or 41 to get a little bit more top end.

[Rudemouthsky]

Have you thought of re-gearing? What are your sprockets at? If you're running like a 43T rear sprocket it might 'behoove' you to come down to a 40 or 41 to get a little bit more top end.

I ended up going with 15/41.

[Dirty Duc]

Have you thought of re-gearing? What are your sprockets at? If you're running like a 43T rear sprocket it might 'behoove' you to come down to a 40 or 41 to get a little bit more top end.

I'll submit that with 67hp to the rear wheels, you'll benefit to going shorter on the gearing rather than taller as ChrisK suggests.  Top speed on a 2v Monster is usually drag-limited, you can pick up a few mph by gearing for acceleration.  It will rev higher at a given road speed, but it might make it feel a little more peppy.

I'm running 15/45 on the 800...

[ChrisK]

Yeah, well you can always come down to 39... or just buy the S4RS you're after  

Play around with gearingcommander.com if you're interested in that.

[ChrisK]

I'll submit that with 67hp to the rear wheels, you'll benefit to going shorter on the gearing rather than taller as ChrisK suggests.  Top speed on a 2v Monster is usually drag-limited, you can pick up a few mph by gearing for acceleration.  It will rev higher at a given road speed, but it might make it feel a little more peppy.

I'm running 15/45 on the 800...

I suggested to come down on teeth just because I thought he wanted more top end, maybe I misunderstood his desired results.

[Dirty Duc]

I suggested to come down on teeth just because I thought he wanted more top end, maybe I misunderstood his desired results.

I am interpreting Buck's concern as an acceleration problem - a smaller rear sprocket will make the bike accelerate slower and thus feel under-powered.  It will make the nominal (calculated) top speed higher, but neglects the (lack of) aerodynamics of a Monster.

Larger rear sprocket (or smaller front sprocket) has the opposite effect: accelerate more quickly, but with a lower theoretical maximum speed.  On a 2v Monster (relatively under-powered for a motorcycle) the key is to balance the limitations of aerodynamics with the limitations of the gearing (keeping in mind rider preferences and "normal" use for the particular bike).

[Rudemouthsky]

I get what both of you are saying.  But I believe my issue is just power...I love the way the bike pulls around town and in the twisties. I just wish I had more "oomph" when I'm accelerating from around 70-80 mph or so. I want to be able to blow by asshole cagers on the freeway a little easier.

[Steve.In.Atlanta]

I get what both of you are saying.  But I believe my issue is just power...I love the way the bike pulls around town and in the twisties. I just wish I had more "oomph" when I'm accelerating from around 70-80 mph or so. I want to be able to blow by asshole cagers on the freeway a little easier.

Drop 2 gears and give them bird as you go by. That'll make you look even faster!

[Dirty Duc]

I get what both of you are saying.  But I believe my issue is just power...I love the way the bike pulls around town and in the twisties. I just wish I had more "oomph" when I'm accelerating from around 70-80 mph or so. I want to be able to blow by asshole cagers on the freeway a little easier.

And that's why I run the gearing I do.