Tuning up sv650?
 

I have done a search but there is not much on anything im looking for.
This is for an 2000 carbed sv race bike.
i have an akrapovik system, dyno jet kit, bmc air filter and i need more speed.
she handles fine.

First Flatside/ flatslide carbs(whichever one it is) are they worth the money?
Any info appreciated or experience?

high lift cams? where can you get these? what money? i can fit them myself.

High compresion pistons, what gains can one expect? i can get these for 450euro but is it true the jepordise the reliability of the engine?

Ram air makes no difference as i researched this. but is there anything else i can do to get more bhp?

im 10 stone, but the bike could lose weight what weight saving options are there?

Thanks for the advice!(in advance):)

Re: Tuning up sv650?
 

I go with Flatslide. But that might be wrong :)

Now, a disclaimer here... They make no sense at all for my purposes so I don't know a great deal about them, never bothered to learn. Also, I doubt you'll find a huge amount of knowledge on this forum as they're banned from our main SV racing class and the thunderbikes guys are mainly running FI. But, what I do know is that the US tuners, who have a lot more choice in their spec, absolutely love the flatslides, without qualification or limits :) Basically, they say if you can afford 'em, get 'em. It's pretty much universal even amongst the rivals, and that's unusual. But I reckon you'll get a load more useful advice on SV Rider.

Pistons... Are you allowed to overbore, or just to work in the standard bores? Any sort of change here does increase the risk of an engine failure, especially on a standard bottom end, but that doesn't make it a grenade- the SV motor's decently strong so an increase in stress doesn't have to be a problem, especially not in the short term. I wouldn't do it on mine, but that's just a case of different roles as much as anything else. And obviously there's different degrees here.

Hayabusa pistons and decked heads are a popular option... Needs a hone so I think it can be cagey for some race classes but you get the benefit of higher compression and also lighter weight pistons. Bizarrely, there's no aftermarket piston out there that's as light as standard. I'll probably be doing this myself, with a mild compression boost- the lighter pistons help to offset the extra bottom end stress, since all the other options mean adding weight as well as bang. Cheap too, if you can do your own build- the hone really needs pro help of course. But less actual power than you get with an overbore or a really high comp setup (you can machine the pistons for clearance but that's getting a bit out of hand). Again, the UK race guys tend to either leave it standard or go big, you'll find a bit more variation on SV Rider I think.

Or, you've got the Wiseco 13 and 13.5-1 pistons. Relatively easy to do, but they weigh a ton. They seemed a great option to me till I found out they're heavier even than the 700cc pistons, which is frankly rubbish.

I'm not the person to talk about bigbores really, but SV650Racer and Robw could write you a book I reckon, or James Holland if he looks in here. 've looked into it, decided against it, but then I expect this engine to last forever :) For a racer 700cc seems a good option, but I wouldn't do it for a road bike, different stresses.

Cams, there's all sorts of options, the most poular is to fit an intake cam from an injected SV, and replace the exhaust cam with the old carbed model intake cam. This works a charm with standard compression but it's a bit less good with high comp, the benefits are less. This isn't the best option out there, but it's incredibly popular as, well, it costs £130 :) You can get custom ground cams, and adjustable cam sprockets, etc etc, but that adds hugely to the price for not much more benefit (though all bets are off with a high comp motor) and, to get the best out of degreeing cams, a load more work- probably pro work. You're well into diminishing returns, you can spend 4 times as much easily for an improvement of just a few percent. IMO something to do only when you've done the other big-gain stuff. It's a superb mod for the price. I run this setup myself, it's dead easy to fit and has only the smallest possible impact on the low end. You get a nice power kick, but more importantly a good curve- mine just barely tails off before the redline, instead of falling like a stone.

Another mod is to chuck in an SV400 CDI- raises the rev limit by 1000rpm or therabouts. This one's for the brave :) On a stock motor it's pointless, the engine's wheezing by the standard limit, and on a tuned motor it's a lot more stress at some points. Very rare to see this done, or other CDI tricks used, the SV's not well inclined to limit boosts really.