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Discussion Starter #1
So far i have converted to 520 lightweight chain and sprockets, one tooth down front. I did the flapper/servo/pair-mod, and now have two more things i´d like to do on my CBR929RR.

1. I will get my ordered Power Commander V any day now, so this will probably get me a smoother and perhaps more triggerhappy riding experience. For this "upgrade" i will probably find a map for my simple configuration wich is all stock but a Akrapovic can.

2. I would like to raise the compression a bit by changing to a thinner head gasket, so - is this a good and safe way of raising the compression/power a little bit? And is it possible to remove the head with the engine still in the frame?

3. Anyone know if there is a possibility to expect an existing PC-map that support higher compression?
 

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Finding a good ready to use MAP for your bolt on can and idea of a thinner head gasket will be difficult. Best to do a proper tune of your own MAP of your own setup.

My honest opinion, if this is a street bike, don't tear apart the head just to bump compression a little. If you are competitively racing and the rules allow for it, that's different.

The biggest gains you will get from bolt-ons will be from a full exhaust system. If you are craving more power, put the money towards that, and then the Power Commander. And then get the motor properly mapped with that setup. If you still want more, I would add cams and re-map.

In my opinion, ripping the motor apart just to bump compression with a head gasket change is not worth the gains, not to mention the possible complications and crap load of labour. I do no think you will be able to notice the power difference from a head gasket swap.
 

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^^^

Totally agree with all above.

We would be talking a very minor less than 1% raise in compression with negligible AND unnoticeable power gain - if any. Higher compression will not necessarily guarantee an increase in power without change to the valve timing and overlap. Get the exhaust system, Power Commander AND switch to 'premium' higher octane fuel.(y)
 

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Discussion Starter #4
Thank´s for your input : )

I was thinking of that compression raise because my ZX7 Ninjas loved high compression, and these bikes really gained from it.
Exhausts are so darn expensive, but i´ll have to think about that now that i have the PC and already run 98 octane here in Sweden.

108548
 

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A full exhaust will not only make more power, the bigger advantage is the feel of the engine. It will rev and flow much more freely.

Especially since I think the 929/954 have those electronic valves in the exhaust if I'm correct?
 

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A full exhaust will not only make more power, the bigger advantage is the feel of the engine. It will rev and flow much more freely.

Especially since I think the 929/954 have those electronic valves in the exhaust if I'm correct?
- Yes correct, but i have removed the complete servo system that controls both the flapper in the airbox and the exhaust valve that you mentioned.
 

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Totally agree with all above
A full exhaust will not only make more power, the bigger advantage is the feel of the engine. It will rev and flow much more freely.
 

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Totally agree with all above
A full exhaust will not only make more power, the bigger advantage is the feel of the engine. It will rev and flow much more freely.
even a good quality aftermarket full system and a remap will make a negligible difference in power. As you say it “feels” more powerful which is probably because it’s louder.

I’ve always been very dubious about the claims in added horsepower with a different exhaust, my experience has been that they never quite run as well as a stock system.
 

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Bang on, @Gunk. Figures sell products!!

But the boys will say: 'But the dyno proves it, I have more rear wheel horsepower.'

Maybe so, but I much prefer what my bikes do on the road rather than strapped up to a friggin' test bench. Granted, a dyno has its uses, but it seems to me that its more frequently used as a means of asserting 'bragging rights'.

(Think I'll get out of here before the hate mail arrives! :eek: (y))
 

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Most of the bikes I’ve ridden with “race systems” have had a rush of power at the top end but flat spots in the mid range and problems idling properly.
+1, I don't think it's worth to mess with the flapper & exhaust valve (unless it's broken and you want to get rid of it)

my stock 954 except bmc filter and bolt on exhaust made 139hp on the rear so...
 

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+1, I don't think it's worth to mess with the flapper & exhaust valve (unless it's broken and you want to get rid of it)
I'm of the same mind. Left all mine as they were intended. I sometimes wonder if it's just modding for the sake of modding, OR, is there a very REAL noticeable difference in power/performance?
 

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I heard (and saw the dyno graph) a picture of a 954 dynoed with 173 hp on the rear (190 crank), with just an akra full system, air filter, injection and ignition power commander

Do you guys it's possible or is he messing with me? If I'm not wrong, the 954's usually are around 135ish hp ...
 

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I'm of the same mind. Left all mine as they were intended. I sometimes wonder if it's just modding for the sake of modding, OR, is there a very REAL noticeable difference in power/performance?
You’ll be lucky to get another 10bhp just with induction exhaust and mapping mods. More than that requires proper surgery.
Prior to the 929 and 954 with their titanium headers, the big draw for an aftermarket system was weight savings. The giant old mild steel systems could add up to 20lbs, and with adding an aftermarket system, that's some serious weight loss (along with some added power). Also, I believe the design of the system can help with power increases. Going back to the "older days", a 4-2-1 might make less power than a 4-1, in addition to the tapered systems which were pretty cool. I think a lot of the modern stuff is so dialed in now with the sensors and exhaust can flaps etc. that the draw to get a full system is minute. I see a lot of modern bikes just replacing the end can if anything. I also think that modern exhaust systems have lost a bit of "flair" from the retro 90's systems............Like a nice Erion ;)
 

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Discussion Starter #16
On wednesday evening the truth will be revealed about the mods i´ve done so far : )
Bench and tuning with PC5 is ordered, and i´m curious about how much of an improvement the PC5 will do with the mapping of the bike.
The things done so far - sprocket one tooth down front, BMC filter, airbox flapper mod and end can.

What is your guesses about the rear wheel power with this mild setup?
 

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On wednesday evening the truth will be revealed about the mods i´ve done so far : )
Bench and tuning with PC5 is ordered, and i´m curious about how much of an improvement the PC5 will do with the mapping of the bike.
The things done so far - sprocket one tooth down front, BMC filter, airbox flapper mod and end can.

What is your guesses about the rear wheel power with this mild setup?
Mine is stock and did 138-139 except for BMC filter and slip on

My guess is 143 at most :p
 

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I'll be interested to learn if the PC5 has made a noticeable difference.

I won't get into the rear wheel horsepower question. In my mind, it's the same as asking a person who's completed an intensive 3-month gym campaign: 'What do you think I weigh now?' Point is that it means nothing to another person, so long as you are happy with the results.(y)
 

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Discussion Starter #19
I'll be interested to learn if the PC5 has made a noticeable difference.

I won't get into the rear wheel horsepower question. In my mind, it's the same as asking a person who's completed an intensive 3-month gym campaign: 'What do you think I weigh now?' Point is that it means nothing to another person, so long as you are happy with the results.(y)
- Maybe other 929 owners are interested in the actual power output of a mildly tuned 929RR...owners like myself : )
 

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Discussion Starter #20
An hour ago i dyno:ed and mapped my CBR929RR-01. Done is flapper mod, pair mod, lightweight chain and sprockets, and an aftermarket can.
Max RWHP: 140+ after 5 runs and tunes in the PC5.
From start it was 130 RWHP with a copied map, and the PC5 increased the power by 10+ hp at the wheel.
 
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