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- - More Power? K3. (http://forums.sv650.org/showthread.php?t=206632)

Hi Guys,

Can you please read the article in the following link and tell me if gaining more power is do-able this way, especially with the K3 cam swap?

http://www.johnnyrod.co.uk/sv650.html

Cheers,

Si

Sure is! Spears Racing also sells a thinner stainless head gasket for a little extra compression. You might even do a bit better if you add that too.
Add some 41mm flat slide carbs, and you can get 85rwhp.

Quote:

Originally Posted by wideguy (Post 2927713)

20%+ power increase at the rear wheel? That sounds a bold claim.

Quote:

just sit back and look at the fatness of the torque curve, and feel your ears bleed as you stand behind it on full chat coming out of bends while the GSXRs are dancing on the gear lever.

:-|

From what i understand though, its the crank thats known to be the weakest link on an sv engine as soon as you start tuning.

This is why iv always kept clear of tuning

Quote:

Originally Posted by Badeye (Post 2927697)

Can you please read the article in the following link and tell me if gaining more power is do-able this way, especially with the K3 cam swap?

Yes a cam swap will give you more power. Power that matches the Dyno readouts on the link I'm not convinced about. Traditionally its stated as a couple of BHP for a cam swap not what appears there. But then I'm no Dyno expert.

However my first question would be why are you looking at a K3 cam swap? It appears from your avatar you have a >K3 or pointy, not a curvy that the article is based on. However there is a similar cam swap that is available for the pointy that will still add a little power.

Quote:

Originally Posted by wideguy (Post 2927713)

Sure is! Spears Racing also sells a thinner stainless head gasket for a little extra compression. You might even do a bit better if you add that too.

My understanding is you can achieve the same result by taking the middle copper layer out of the standard gasket. I've not done this myself yet, but intend to do it on the next SV engine I build.

Quote:

Originally Posted by wideguy (Post 2927713)

Add some 41mm flat slide carbs, and you can get 85rwhp.

Out of interest, why the 41mm carbs and not the 39mm that are also available for the SV?

Quote:

Originally Posted by otaylor38 (Post 2927757)

From what i understand though, its the crank thats known to be the weakest link on an sv engine as soon as you start tuning.

This is why iv always kept clear of tuning

It depends on what part of tuning you want to do. A lot of people have done the cam swap trouble free. Some have even done the Hayabusa Piston tune without problems.

A SV tuner told me that you can take a SV engine to 700cc on the standard crank and rods, though I've not done this myself. Any more than that and you will need to replace the rods and crank.

My crank failed on the busa build as I think the regrind weakened it. Crank failures normally occur due to lack of oil. Also I think the first pointy cranks K3/ K4 have had failures reported at the alternator, some not all, in standard trim.

I wonder if my friend http://forums.sv650.org/member.php?u=98 wrote the article in the link? Ask him!

Anyway..... More power - buy a bigger bike ;)

Quote:

Originally Posted by dizzyblonde (Post 2927779)

.. More power - buy a bigger bike ;)

/\ /\
This. Unless your in a race class that prohibits it

http://spearsenterprises.com/
These folks have been building and racing SV650's since the beginning.
They have dyno charts for the various parts they sell and race.
Remembering back to 2000-2001, racers who were building SV's above 85 rwhp were breaking rods.
I just recently talked with Gregg Spears about strategies for more power for my '00 650, (just to make it more fun on track days). He recommended I not use the standard bore high compression piston, since most of my riding isn't track riding, but just add their cams (and the springs they need), a lightened alternator rotor and the thinner head gasket. They haven't dyno tested this combo with stock carbs, but I'll guess around 80 rwhp.
And sure, splitting a stock head gasket would have the same effect, more or less. And yes, 39mm flat slides would be an improvement on stock, and probably better than 41's unless you were boring oversize.

Re: More Power? K3.

Hello! Remember my bike is a '99 so wil have less power to start with than any of the later ones. Also the "stock" figures look a bit low, possibly due to the knackered chain on it, but as anyone who knows Dynojet dynos will tell you, you can make them read a whole range of numbers. Like the "after" ones, which also look a bit high. The weak bit of the crank is mainly the part extending to the alternator rotor if you are into crunchy downshifts, so if you must then think about a slipper clutch. Re. 700cc kit, the crank is up to some tuning but the stock rods are a bit questionable and the cylinder head studs want replacing. For >80bhp I would think you need head work, the stock engine is finding its limits there.

A friend of mine has a 700 with the cam swap (2000 model). The top end power is about 1bhp above mine (excluding fiddle factors) but the midrange is immense, and it feels very fast just from this. Now that I have more track time under my belt than when I wrote about my bike, I'm not sure how much difference this would make as I find myself mainly in the top third of the rev range anyway. The GSXRs are harder to fend off these days than they used to be... Still makes your ears bleed though.

Do a search on here for "pointy cam swap", there'll be loads more info for your bike.