Carb Upgrade

[northwind]

I'm fitting tracks to mine next There's always something to do...

[yorkie_chris]

Originally Posted by northwind

but you can't chase the throttle, they just sandbag.

What you mean by chasing the throttle?

[northwind]

Crack it open and wait for the revs to catch up- do that with flatslides and the engine bogs down, you need to match hand to revs much more closely. When you do, it's great, when you screw up it's rotten.

[yorkie_chris]

Like a butterfly carb with no accelerator pump then.

Are the flatsides a pure slide carb or is there no assistance for them at all?

[northwind]

No idea tbh I just know that next time I have to start the bike when it's covered in snow I'll be glad I don't have them...

Just wondered how much a difference injected kams, dyno jetting a good quality race filter and full race system make, on the carbed bike when its all done properly, oh yes does it cost alot?

If your really bored you could try fitting a FI system, but as I understand it the Suzuki FI is a bit cheap and a decent setup carbs work better then the FI. Though watch me be corrected shortly.

[yorkie_chris]

Not a lot, maybe ?40 for injection cams at a guess?

Degut the stock filter, very free flowing ?20, rejet it and a bit of dyno time not sure.

My micron system, albeit the worst of the race systems was ?50 delivered.

Though it should give a bit more power, or at least accerlation, umm just thinking thats all, don't worry I'm not going to anything!

[northwind]

Mine has cost me just over ?500, plus a load of my own time. When I last put it on a dyno it made 79bhp at the rear wheel, but was lean up top, so I reckon it should be near 80 with the current jets. That's compared to 68 with just an end can on the same machine.

That's BMC Race RS and bits of a DJ Stage 1&3 kit plus bigger jets (?80 or so, mostly bought used), a cheap WRP full system (I have two, the one I use cost ?250, the spare was ?80! But the spare is all stainless and a bit heavy), a pair of K3 cams bought new for ?125 including a pair of cam chain tensioner gaskets, and also an ignition advancer (?50 inc the tool and gasket I think) which probably adds nothing to the peak power now. I'll be removing it once I get the genny cover gasket.

I'll be chucking in Busa pistons along with a compression hike and a little head work, but that's all just for giggles, I just like doing this stuff.

Now... If that was set up by pros. Well, it'd be hard to find a pro willing to work with such a grab bag of parts for one, but if you do, there's hundreds of pounds worth of labour to be added. I did it all myself- and it's not hard, I'd never seen a cam til I did the swap- and jetted by feel, which IS hard but you soon pick it up, I'm now pretty good at it but then I should be, I've changed jets alone at least a dozen times... Again, because I like doing this stuff. It would have been more economic to work some overtime and pay a pro to do it...

What i like isn't the peak power... That's more or less irrelevant to me in fact. But along with it comes lots of benefits. It'll pull from 2500rpm (I can pull away at idle with careful clutching) and doesn't lose power past the peak like a stock SV does, and it's up above the standard SV peak power for something like 4000rpm... It's within 5 horse of the peak for a long way too, something like 3 times as long as with a standard engine. In other words, tractability and usability. The peak power is nice to have but it's not that real world useful, you just adapt to it, and it's still 30 horse less than a GSXR600. And if I was racing another SV, well, it comes down to rider so I'd still lose.

Disclaimer- none of this stuff really makes a night and day difference to the bike in the way suspension does. You just get used to it, the only time mine feels strong is with a direct comparison. I find it really hard to ride a standard SV now, they don't turn fast enough and I stall them all the time