Engine Tuning

Originally Posted by northwind

Aye, but then the old intake cams go on the exhaust side, with a bit of loving attention since all the timing marks are wrong. I just marked the lobes on the sprocket and counted teeth, but if I ever have anyone else work on the bike I'd better warn them

Mmm, they will certainly work but not quite as well as the K3 ones from what I've heard.

Apparently (though I don't know this to be true) it gives the exact same specs as the stage 2 cams, and the old double intake swap from before the K3 came along was the same as the stage 1. Just obviously without proper adjustment, which of course matters not to me since I'd only **** it up if I had it

The only people who I've heard put that forward have been those unwilling to spend the money or heed the advice from those that have compared them a bit closer.

Could be wrong or course and, like everything, it comes down to performance vs. cost.

Any idea how the stock ones in your Raptor compared? Actually, I've been kind of curious what inspired the use of a Raptor in the first place, but never asked...

Raptor ones are stock 2000 model cams.

The choice of the Raptor was purely political, well, and the intimidation factor of USD forks and nice four pot Brembo callipers

[northwind]

Originally Posted by Mike1234

Mmm, they will certainly work but not quite as well as the K3 ones from what I've heard.

The only people who I've heard put that forward have been those unwilling to spend the money or heed the advice from those that have compared them a bit closer.

Hmm... Well, they certainly run the exact same max lift figures, or so it seems... Don't have any figures for duration though but Zoran and Clayton on SV Rider have both said they're the same... Although again, obviously without practical adjustability, and quite possibly with a lower build quality, and the recommended timings are possibly not as good.

99-02...........In = 8.1 ...............Ex = 6.1
2003............In = 8.7 ...............Ex = 7.3
Yosh............In = 8.8................Ex = 7.2
JHS..............In = 8.1...............Ex = 8.1
Stage II.......In = 8.7 ..............Ex = 8.1
Stage III......In = 9.4...............Ex = 8.7

I'm perfectly willing to be convinced otherwise, of course, but the people saying it know their bikes better than most, and don't have any reason to give false information. OTOH, I've never heard anyone actually provide info to the contrary (including you or James Holland, BTW, though if you want to tell me I'm wrong I'll listen of course. Same goes for you Mr Holland, if you're reading.)

I see the website states "These are not K3 cams" which is certainly true- I'd think it'd be in his interest to put paid to any wrong info on the figures as well.

But anyway, drifting slightly off the point- if they're not exactly the same, it's certainly likely they give most of the performance boost... Is it worth it to pay nearly 3 times as much for the cams without adjustability (I'm assuming the stock sprockets come in the £350 price) or nearly 5 times as much for the adjustable sprockets? For most people, definately not. For someone trying to get every last bit of power out of the engine, with a bigger investment in the bike, it's a different story of course.

[Sid Squid]

The lift may be the same, or at least similar, but I'd guess that the duration and profile would be different and that the timing would be altered to suit the differing cam, so the outcome would likely not be the same. As you're no doubt aware cam timing is not adjustable with standard sprockets, making it difficult to get the best from the cams, you'd need alternative sprockets as the standards are near impossible to slot, they're so bloody hard.

[northwind]

Like I say, i don't have any way of verifying the duration figures myself- way out of my league- but those are guys who know SVs inside out and have worked with the parts...

I think if I'd heard conclusively that the figures are different from the source, I'd put what they're saying down to an error, but when it's the only absolutely solid opinion I've heard stated I go with it, if you know what I mean?

But I do know, if I was James Holland I would put on the website "These cams run a longer duration to the K3 cam swap", since it's widely held that they're identical and it's got to undercut him...

To be honest I have never seen the spec. of the JHS cams and have heard only anecdotal evidence from a very few people who have actually seen them.

There are lots of people who claim to have compared the JHS ones, the stock ones, the K2 inlet cams, the K3 exhaust cams, etc.

I haven't and seriously doubt that more than two or three people that any of us come across actually have. More importantly which JHS cams are being discussed, I really doubt that James hasn't refined his set up over the years.

I'm not suggesting anyone is right or wrong merely pointing out that some of the more detailed discussions I've had with some of these people suggest that the K2 inlet cams can be modified to make quite useful K3 exhaust cams but aren't exactly the same and more power can be had from the genuine K3 exhaust cams.

Perhaps not much but for some people it is enough to justify spending the money and for other, well, perhaps not.

[northwind]

Originally Posted by Mike1234

More importantly which JHS cams are being discussed, I really doubt that James hasn't refined his set up over the years.

Ah ha, not considered at all.- even if the figures were identical when someone first did the K3 swap, who says they are now. Good point.

I'd definately agree that most of the people saying it are just repeating what they've been told- I try to make that clear when I do that, but a lot of people don't, and I only repeat things which I'm confident about, but a hell of a lot of people will gladly tell you something their friend heard a colleague once read on the internet as gospel