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Discussion Starter #1 (Edited)
Hi All,

Just purchased a second had 954, what a lovely machine , so smooth and controlled on the open road. ..but it seems to have a power spike at about 3000rpm...very noticeable whilst commuting thru town!

any one know if this is normal, or how to smooth it out?

The 954 currently has a Akra end can, other than that its standard. was considering putting the OE end can back on, do you think that will help? (or is this something the 'flapper' mod will sort?)

im going to do the -1 +1 sprocket mod but am little worried that the 3k surge in power and then the sprocket mod will leave me on my arse in the middle of the road or a roundabout...

thanks in advance for any help rendered.

kind regards

dan
 

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Sounds like the Flapper mod or just the HTEV cables need to be adjusted. The servo for the cables turns around or right at ( dont remember) 3k. So I would say it had some thing to do the the HTEV. With that said I heard they have a power boost. My 929rr did the same thing when it was working right.!
 

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Discussion Starter #3
hi esmarts,

cheers for the reply, i will have a look for the flapper and do the mod.

i was also considering perhaps its not a spike, perhaps its just the way the power comes in suddenly.

do you know, does a quality end can smooth out the power curve?
 

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I wish I could help you but I am not expert in this matter.. I am running a D&D slip-on. I would imagine that if you are running a more open can then it would eliminate a little of the power band via eliminating some back pressure that that power boost is feeding off of at low RPM. I don't know what you are experiencing but I would say it would be the power band like action that the HTEV is causing. Thats why they put it there to give alot of power in the low, mid and High rpm ranges...
 

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My bike is a 929 and it has a bit of a stuble/surge at around 3000. I've heard others talk about it like it's normal. When people buy power commanders, they often talk about it eliminating the 3000rpm surge. Maybe your pipe exagerates it or you are being super sensitive.
 

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basically, the way the 954's inline engine makes it's power is a little different from the VTR's V-twin. The V-Twin engine has long been known for it's linear torque curve throughout the power band. This due to the longer stroke of the V-twin engine. The longer stroke makes for more mechanical advantage, thus causing a higher torque value. This longer stroke is also the reason your VTR redlines a few thousand RPM sooner than the 954. The 954 has a very short stroke. Because of this shorter stroke, power is not readily available at very low RPM's. Cam lift, lift duration, and lobe separation play a huge roll in the inline engines power production. There has never been, and never will be, a cam that allows an engine to make power from idle all the way to 13k RPM. Because our bikes were designed as racers, the engines were designed to make more power in the mid to upper RPM range. This is because there is rarely a time on the track when a bike is at a low RPM. even through a low speed turn, the riders use a lower gear, which allows the engine to stay in it's "power band".
In other words, what you are feeling is very normal, and anyone who has ridden both types of bikes can probably back me up on this one. The sensation is only amplified by the fact that you are used to the linear torque curve of the VTR. It will just take some time to get used to the way this new bike "feels" under you.
 

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basically, the way the 954's inline engine makes it's power is a little different from the VTR's V-twin. The V-Twin engine has long been known for it's linear torque curve throughout the power band. This due to the longer stroke of the V-twin engine. The longer stroke makes for more mechanical advantage, thus causing a higher torque value. This longer stroke is also the reason your VTR redlines a few thousand RPM sooner than the 954. The 954 has a very short stroke. Because of this shorter stroke, power is not readily available at very low RPM's. Cam lift, lift duration, and lobe separation play a huge roll in the inline engines power production. There has never been, and never will be, a cam that allows an engine to make power from idle all the way to 13k RPM. Because our bikes were designed as racers, the engines were designed to make more power in the mid to upper RPM range. This is because there is rarely a time on the track when a bike is at a low RPM. even through a low speed turn, the riders use a lower gear, which allows the engine to stay in it's "power band".
In other words, what you are feeling is very normal, and anyone who has ridden both types of bikes can probably back me up on this one. The sensation is only amplified by the fact that you are used to the linear torque curve of the VTR. It will just take some time to get used to the way this new bike "feels" under you.
:

:plus1:

I have the same surge and i have a pcIII and a full yoshi exhaust on my 954. I agree because the 954 was made to be a race bike, so it's made to make more power in the midrange. The surge is normal and you'll learn to love it. Plus that's the surge that help me make a guy on a gixxer 1k rethink how great his bike was. Now he's trying to get me to sell him my 954.:smilebig: Gotta love Honda:leghump:
 

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I have a 954 and If you can get hold of any of the write ups on the bike you will see that there is a power spike or surge if you like at 3000rpm and at 7000rpm.This is perfectly normal and is the way the engine delivers its power
Cheers
Chukky
 

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iirc isn't where the exhaust valve comes into play at each of these rev 3000 and 7000?

You can smoothit out with a PCiii and a proper map to suit your set up. down loaded maps can be ook but nothing like a custom one will be for improved ridability imo. :)
 

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[ anyone who has ridden both types of bikes can probably back me up on this one. The sensation is only amplified by the fact that you are used to the linear torque curve of the VTR. It will just take some time to get used to the way this new bike "feels" under you.[/quote]





I have both and you are correct!
 

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Discussion Starter #14
wow! what lot of replies! thank you all my fellow bikers....

carolina_954,
i appreciate the time you took to explain in detail the differences in stroke and engine config. i knew that VTwins made more low end torque, but thought it was only due to the larger 500cc cylinder exploding. now i understand more. and kudos for noticing id come from a VTR too! thank you

To the rest of you guys,
i notice none of you recommended putting the OE end can back on!.. i bet youre a noisy bunch on the road!
thanks for all the suggestions and confirmations this is all normal. a PCIII + map will more than likely follow the sprockets in a month or so..#

great stuff, thanks again!! :thumb:



 

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even putting the stock can back on you will still find these steps in the power/torque at the rev you are describing so I would not go that route to get the bike to be as you would like it to be, which is why I would go for the mod of the PC to work with your can and set up.

always happy to share my thoughts :)
 

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wow! what lot of replies! thank you all my fellow bikers....

carolina_954,
i appreciate the time you took to explain in detail the differences in stroke and engine config. i knew that VTwins made more low end torque, but thought it was only due to the larger 500cc cylinder exploding. now i understand more. and kudos for noticing id come from a VTR too! thank you

To the rest of you guys,
i notice none of you recommended putting the OE end can back on!.. i bet youre a noisy bunch on the road!
thanks for all the suggestions and confirmations this is all normal. a PCIII + map will more than likely follow the sprockets in a month or so..#

great stuff, thanks again!! :thumb:
Not a problem man. I only brushed the surface of what is going on in the 2 engine configurations, but I don't like going into extra detail unless the situation calls for it. There are literally thousands of other points to consider when comparing engine types, and how they produce power. I'm sure there are a few other guys on the site who can give even more information on the subjects, and I don't want to upset them by not explaining that this is not the whole textbook on the internal combustion engine. (some guys take things entirely too personally:) ). Anyway, I hope you enjoy your new toy as much as I have mine, and hope to see you around the site in the future.
 
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