Working on the SV

Found an engine and am waiting for it to get here. Thinking about building my other engine and pumping a little more juice out of it. I do not want to get to carried away ,would like to keep it where it very streetable. Any ideals on pistons and cams?

northhwind is your man on this ,,

who might this be ?

a certain mythical figure on this site sometimes ,some say he has special powers when it comes to motorbikes ,well he fixed mine thats good enough for me .guy from edinburgh ,top man ,he;ll wax lyrical on engine internals and if its do'able on an sv he'll have done it ,or at least know about it ,..he knows everything

Second that!

Originally Posted by jim@55

a certain mythical figure on this site sometimes ,some say he has special powers when it comes to motorbikes ,well he fixed mine thats good enough for me .guy from edinburgh ,top man ,he;ll wax lyrical on engine internals and if its do'able on an sv he'll have done it ,or at least know about it ,..he knows everything

I heard he was born in a mental institute and sleeps only one hour a night.

I think he lives in a garage, in Scotland, sleeping on his SV surrounded by carcasses of engines and frames that hes devoured all the good bits from, absorbing all knowledge of SV and other bike engineering he can use to his goal of absolute SV power with out loosing reliability of coarse, with a small Cult of followers worshiping his every modification

ALL HAIL NORTHWIND, THE ALL KNOWING ONE

Originally Posted by andyaikido

I heard he was born in a mental institute and sleeps only one hour a night.

Is this an episode of Top Gear I've accidently joined? "Some say the outline of his left nipple is exactly the same shape as the Nürburgring...." Maybe Knockhill for Northy.

Originally Posted by Law

Is this an episode of Top Gear I've accidently joined? "Some say the outline of his left nipple is exactly the same shape as the Nürburgring...." Maybe Knockhill for Northy.

Actually pinched it from Fight Club but I see where your coming from.

[northwind]

All I did was steal everyone else's ideas And I was just conceived in the mental institution. My nipples are nobody's business but mine, frankly, and I'd thank you not to talk about it.

Usual disclaimer applies- building an SV engine for power costs more than selling your SV and buying an old GSXR But, most of the realistic tuning options for the SV don't impact usability at all, which is nice.

I'm very happy with mine, it's about 11 dynojet hp up on its standard figure (the numbers are meaningless but they're useful for comparison, works out at about 12%) but the difference to the curve is far more important, the flat peak and earlier power is just lovely on a road bike. I take it for granted now, of course, but riding a stock SV reminds me (every time I stall it at traffic lights or rev it out when I'm not expecting to) For reference, that's cams, ignition advance, some gearbox work, lots of breathing work. No one bit makes a huge difference but it all works well together. My bores are standard for now. It's all in pretty mild tune, which is what I think is really called for on a street bike, you can get miles more out of an SV but it's hard work and starts to seriously impact servicing and lifespan.

Lots you can do that's fairly easy. The K3 cams are hotter and still perfectly streetable, probably the best power mod for a standard bore SV that there is on balance. Basically, you put a K3 intake cam on the intake side, and move your old intake cams to the exhaust side. Costs around £120, pretty easy, and makes (depending on who you believe) between about 3 and 7bhp. More importantly though, it doesn't significantly hurt midrange, and it massively lengthens the peak- great for drivability. Instead of dropping like a stone after the peak, it carries on to redline on mine. You could get JHS Racing or Megacycle racing cams, but the increased benefits don't measure up to the increased costs, IMO. You also don't need stiffer valve springs with the swap, so no extra valve train losses.

The ignition advancer's good- speak to JHS Racing about this, they've got the bits. It just brings the power down the revs, which is a nice boost for a street bike. Some claim extra peak power, but I wouldn't expect it. It can cost peak power in a tuned bike, it may be costing me just a touch now, but I'd sooner have the midrange.

I like Factory Pro's gear shift star and detent arm- very expensive if you pay full ticket, but it works well. Much more positive shifting... I think K5 and K6 engines come with a knock-off of the shift star as standard, might be cheaper? (I got my detent arm for a tenner off Ebay, and the shift star for free )

SV650Racer among others can advise you better on the 700cc boreout, personally I've decided against it since I need my bike to be rock-solid reliable, and there's a possible risk of terminal failure But if it's a spare engine then the (low) increased risk of a failure's probably not such a concern?

If I ever rebuild my collection of broken engines (I didn't break 'em!) then I'll likely put the Wiseco 700cc kit in it, and give it a moderate compression boost at the same time, but even a small risk of failure's too much for me- can't afford to have the bike off the road for a week while I source a new engine. The numbers are impressive though, torque curve like the himalayas Would be very nice indeed for a street bike.

Sarah's also looking into a better cam setup for 700cc bikes as well, I think- she mentioned that her Thunderbike's spare engine makes less power on the cam swap than on standard (K3) cams, which is odd, not something I've ever seen mentioned elsewhere... (high comp engines should be less sensitive to overlap, and the SV's exhaust cams are just plain restrictive) but stranger things have happened.

Another alternative is hayabusa pistons, which are lighter... Just needs a very slight hone, it's in the thousandths. Then, deck the heads till it just about rattles Good for as much of a peak power boost as the 700cc kits, but with less stress, though you don't get the midrange. Only concern is that Hayabusa pistons are designed for coated bores, but it's tried and tested without reported issues. I reckon I'll be doing it to my main engine over the winter, just for a laugh. High comp calls for premium fuel, though.

The Wiseco high compression kit is just rubbish, by the way. Heavier than the big bore! So worse in every way bar heat absorption/dissipation.

SV heads are pretty good as standard, the exhaust valves are shrouded but there's not a lot you can do about that without serious work, and the coating on the valves is thin son lapping them for better seals is tricky. Wee bit of rudimentary head work (roughing up the intakes, removing seams) could pay off but it's not worth getting too into it, I reckon, not unless you're chasing every last bhp. Cylinderheadshop tell me they'll not do head work on an SV other than decking the heads, they don't think it's worth it and aren't happy charging their cost for the small gains...

One last thing... Money on the SV is better spent on handling than power. If you've got a standard or near-standard suspension setup, I'd fix that first. I bet you a whole english pound that the suspension work I've done is worth more time off a lap (or a commute!) than the power work, and it cost roughly the same.

Tons of good stuff on here in the search, including a good dust-up on the 700cc kit a few weeks back