Max BHP from an SV650?

[KayDee]

With some tuning etc... what is the most you are likely to gain from an SV650 bhp wise? What would need to be done to get this? Thanks

[sprocket]

Depends what you wanna do to it tbh check out http://www.jhsracing.co.uk They have a few dynocharts from different modifications

[suzsv650]

JHS wins all on SVs.. and i live round the corner from em :twisted:

[sprocket]

I live down the road but not been there yet .. gonna be ordering the ignition advance key off them soon :D

[northwind]

The rule of thumb for SVs is, more or less, 85bhp at the rear wheel before you end up significantly increasing the risk of a bottom end failure in the short term. Pretty much any power boost you do will reduce the lifespan of the engine in some way, but it's at that point the crank and rods are said to be no longer able to deal with it in the short-medium term and failure is considered to become when, not if. So the question is, what are you going to do with it? And what cost in reliability and price are you willing to pay?

IMO with this drawback in mind, serious extra power is just not reasonably achievable without spending a ridiculous sum of money. But you can still do a lot… Cams, breathing, maybe a little headwork can get you within spitting distance of that 85bhp. Mine I think will be bubbling just under the 80 mark with around £500 spent on power mods, with nothing too clever going on.

IMO, going further into the engine for a street SV isn’t too clever. I think I’m going to fit hayabusa pistons (lighter, not much more power) and deck the heads for higher compression but that’s taking it beyond the point where it really makes much sense. I just like mucking about with bikes.

An SV can be taken so much further than anything JHS have on their website, by the way... Some of the US bikes are kicking out ridiculous power figures. But that's a total engine rebuild, new crank and rods, bigbore, cams, FCR carbs... Total loss charging too generally, and race fuel. Combined with serious weight reduction, and you have a ridiculous machine…

JHS have a lot of good options, but IMO most of the more dramatic gains are pretty impractical. Big bore or the high comp pistons have a lot of potential for problems in "later life"- they're both much heavier pistons in the first place and so stress the rods and crank beyond that which you’d expect from the power gain. Likewise, flatside carbs and pod filters would give you a big boost in response and power- but they're pretty much impractical for a daily runner- no choke!

There's a bit of disagreement on how great these risks are- James Holland claimed to me that there were absolutely no servicing or lifespan (or even warranty!) issues with the 700cc pistons, which was the point at which I simply stopped trusting his advice. (I still have this email if anyone doubts me.) On the other hand, some people maintain it's sudden death for the engine, which likewise is unreasonable. The trust lies somewhere between I think.

Likewise the Stage 2 cams- they're very effective, but you're paying a heck of a lot for it. You can get probably 9/10 of the benefit with the K3 intake cam/carbed intake/exhaust cam swap for £130, since a home tuner's not likely to be able to make effective use of the adjustable cam sprockets. I

[trick]

i read on the net somewhere that with stupid things like nitrous and turbos on the same bike you can make upwards of like 200bhp but then it blows up and is completely destroyed. you can get it above 100 easy enough if you got a bit of cash to throw at it

TRICK

[northwind]

Yup, but you're talking into thousands for that... Not so much for the parts that make the power, but for the parts that support them. Billet crank and rods cost... Falicon's cranks, for example, are $2300 plus $230 per rod- plus crankcase machining I think, so add on a good few hundred's worth of labour too.

I think Ducowner off of SV Rider runs an 115bhp NA motor, if I recall right, but for that you're talking absolutely ludicrous money...

[suzsv650]

I live down the road but not been there yet ..


i live 2 miles away :lol: :lol: WINNER!

[trick]

there are other options to the falicon stuff and the falican crank set includes the rods anyway so you wouldnt need them at extra cost. it would cost a lot but for about 1500 you can get up to about 90 brake easy enough

[northwind]

Nah, the kits are more, nearly $3000. I'm guessing you must get something else in the kits, since they cost more than the sum of the parts listed there... There are cheaper equivalents of course, but none are actually cheap

Sorry mate, but I really doubt you're going to get 90bhp for £1500 without cutting serious corners on it...

[PeterM]

The stock SV crank is engineered to 90hp. As Northwind said, going above that require some serious cash to be thrown at it.

I've done the simple mods of, slip-on pipe, stage 2 jet kit & filter and the '03 inlet cam swap.

My bike has been dynoed with 76hp at the rear, an increase of 25% from where I started. All this was on the same dyno too.

Cost is fairly negligible compared to what some have done and rideability has been maintained.

http://i23.photobucket.com/albums/b381/k2svpete/PeterMDynoSheet.jpg

Specs for the fuelling with the cams are: BMC 205/10R filter, mains 160fr &157.5rr (Mikuni), Needles shimmed on bottom clip (Mikuni).[/img]

[TSM]

Is much work needed to put K3 cams into a K2??? Is it just a swap over or does anything else need to be changed?

Is is just K3 cams or also K4 & K5 ones?

[northwind]

It's pretty straightforward... It's been covered before, but basically you need a pair of K3 intake cams (I'm sure K4 and K5 is the same) and a pair of cam chain tensioner gaskets. Some would replace the cam followers (is that the right word? The thing that the cam actuates against to move hte valve) but I didn't. (the reasoning for this is that like chain and sprockets, you get matched wear on the cam and the, er, things. But it would add a lot to the cost to do this, and tbh I don't consider accelerated wear on the cam to be a concern in an SV engine, since they're good for 100K+ miles no problem.

There's a lot of good writeups out there, and on SV Rider- probably best to go straight to the source rather than get my 3rd-hand chinese whispers version. But £130, one evening in the garage, doesn't get better than that as far as power mods on an SV.