[99cobradrvr]

I lost a main crank bearing in my high mileage 2000 ST4 with the 916cc motor. I have metal shavings throughout the entire motor now. I found a guy near me selling a 1998 916cc motor. Anyone know if it would be a direct swap?

 

[dnldfte]

I have seen an ST4 with superbike heads on the internet somewhere. The owner claimed to have had no clearance issues with the front wheel. Worst case scenario would be reuseing your ST heads. I say go for it.

 

[99cobradrvr]

I have seen an ST4 with superbike heads on the internet somewhere. The owner claimed to have had no clearance issues with the front wheel. Worst case scenario would be reuseing your ST heads. I say go for it.

What about the electrical & exhaust? Would my ST4 916 stuff work with the superbike motor?

 

[dnldfte]

your bike is 3 phase and the 916 is not. You would also have to modify your exhaust. The flange would have to be raised to connect to the superbike heads. The electrical could be an easy fix by changing you regulator/rectifier to the single phase version.

 

[Desmo_Demon]

Other than the head/exhaust and charging system issues, you will probably also run into a potential issue with the swingarm bosses on the engine cases are considerably shorter than those on the ST4. You may be able to get away with simply making some large spacers, but I am not exactly sure....

If you are concerned with the different heads and having to modify the exhaust, I believe you should be able to take the heads off of your stock engine and install them on the '98 engine. If you do this, you will not have to worry about modifying the exhaust, will not have any potential issues with front wheel/horizontal head clearance, and it will give you a reason to inspect the heads, do a valve adjustment, and give you an excuse to change the belts.

IIRC, the engine mounting bolts are 10mm on both the '98 and '00, so you should be fine there.