Since the bike will be torn down, engine swap?

[fouramdesigns]

What motors will bolt right in? What all will I need to complete the swap?
And what is my motor worth with the DP ECU? 22K, just serviced, has Rizoma belt covers. Just kicking the idea around at this point since I will have it completely a part, replacing the exhaust etc.

[Speeddog]

AFAIK:

ST4 - basically the same as what you've got, except with the wide-ratio transmission.
Coolant hoses are a bit different, not sure about the fittings, and oil supply to the heads is different because they have oil coolers.

ST4s, S4R - 996cc instead of your 916cc, also with the wide-ratio transmission.
Pretty sure St4s has different coolant and oil lines as well.
S4R has different oil lines as well.

I *think* the ST4 and ST4s heads have the threaded bosses, which are part of the battery box mount on an S4.

ST are set up with the fuel pressure regulator in the tank, not on the throttle body assembly.
ST have plastic belt covers.

Probably a few other things different, but I think I got all the big ones.

[gage]

General Question:

Is the drop cast cylinder head there for a reason on the S4's or were they just left over. Also, do the motors referenced above also have the drop cast head?

[ducpainter]

My understanding from the vet is that the drop cast head was intended for the SBK, but wasn't used too often in that application.

Most of those ended up on ST and Monster models.

Left over...or a change in thought? ? ?

[Duck-Stew]

Info I heard on the dropped exhaust cam head for the desmoquattro was that it was used for add'l tire clearance on the ST and M frames.  SBK frames didn't need it...

But I could be mis-led and have no way of checking that at this time...

+1 to Speeddog's comments.

[Speeddog]

S4, ST4, S4R and ST4s all have the drop-cam heads.

Exhaust cams are 10mm lower.

This corresponds to the engine position relative to the front wheel.
My S4 has the engine approximately that much closer to the front wheel vs. a 916 here in the shop.

[fouramdesigns]

I'm going to finish this, ride the crap out of it. Buying an 848 to go balls to the wall with. Unless a great motor deal falls in my lap, and soon before I buy exhaust.

[gage]

I'm going to finish this, ride the crap out of it. Buying an 848 to go balls to the wall with. Unless a great motor deal falls in my lap, and soon before I buy exhaust.

Judging by the cornacopia of posts you have scattered throughout this forum and others looking for more performance I would suggest you forgo the 848 and get an 1198 or a hayabusa.

[gage]

Good info on the drop cast heads - hard to believe that there is that much deflection in the front fork under hard braking.

[TAftonomos]

 just measured my st4s motor clearance  from mounting point to head.  The 2005 testa motor I have sitting next to it has the same measurment.  That means you should buy the testa motor to swap in your s4r before I swap it into my st4s!!!

[Speeddog]

Good info on the drop cast heads - hard to believe that there is that much deflection in the front fork under hard braking.

One of the SoCal guys put SBK heads on his S4 Foggy.

A *severe* bump put rubber on the cylinder head.

[fouramdesigns]

Judging by the cornacopia of posts you have scattered throughout this forum and others looking for more performance I would suggest you forgo the 848 and get an 1198 or a hayabusa.

I would never buy a Yapper. If I ever left Duc's, it would be the KTM Super Duke R. If I made the kinda of money I use to, this bike would have been done, and the Duke next to it. Cornucopia....snicker 

[fouramdesigns]

LT recommended a 996 like you guys, mated to a 749 high ratio clutch. I'm going to finish the suspension/frame. Will locate a 996 maybe in the future. I decided to lighten as much as I can, Quat D ExBox, Fuel Cel tank, Nemesis ECU, CM rotors, 4 pad calipers, Marchesini 5 spoke mags and some tuning.