[Guest]

I've been looking into getting some new cams for my S4 preferably SPS. While asking around, I was told that the heads off a 916 were different.

"They have a drooped port to allow for tire clearance. The belts are in a different position too. Just be sure to degree the cams. With a 916 head, the front tire would hit it."

I wasn't aware of this. Does anyone have any experience with different heads on there S4? Also anybody have access to some SPS cams?

 

[DucSea]

this is correct information. Ducati used the ST4 chassis and motor on the S4. The 01 996 and 748 used the dropped heads as well...

 

[Speeddog]

More specifically, the exhaust cam is lower (closer to the deck) than the intake, by about 1/2". Allows the motor to be that much closer to the front tire, getting more weight on the front tire for improved stability/handling.

With the cam lower, the pulley is lower, so the belts are different.

IIRC, at least one of the listers here, infoage1/Tom, has put SPS cams in his Foggy. I_think_he got the whole "Kit Corse", which is the cams, 'spaghetti' exhaust, new ECU, and air filter with hacked lid. I_think_he put the cams and ECU on his Foggy, and sold the exhaust and his old ECU to Scott S. who has a regular S4.

I know Scott S. got his cams degreed, said they were way off from the factory.

 

[infoage1]

Actually, my deal with Scott was more a joint purchase; At the time, Scott was going to buy Termi slip-ons, and I wanted SPS cams. So, it worked out very well for both of us.

As far as the heads (and I could certainly be wrong on this), I thought only the S4 and the ST4s had the different heads with the lowered exhaust cam towers and not the ST4 (I know that wouldn't make sense). What I do know is that the S4 and the ST4s share the shorter duration intake cam profile and the ST4 does not, so maybe I'm just projecting that thought onto the ST4 heads.

http://www.moto-one.com.au/performance/monsters4diff.html

As to the value of SPS cams, after you factor in the cost of adjustable pulleys and a proper installation, it is pretty hard to justify.

But, if you were to buy them right, and would enjoy installing the cams yourself (like I did), then it is worthwhile, let's say 5 HP. My interest in them was more anticipation of possible future engine mods, knowing my intention to keep my bike. Also, as PowerCommader and FIM had yet to come out with a 5.9 solution, this was the only way I could get the matched ECU (map). As important, I thought it would be a fun project.

In a recent sixth gear roll-on against Scott, he pulled me until about 6000 rpm...after 6000 I would pull him, but it really wasn't dramatic either way.

(Although a day later, after disassembling my fuel tank for painting, I found my fuel filter was at least 80% plugged, so...we will see