Motor decision for SBK

[accludetuner]

Just looking for feedback. I have an 01 748 with a perfectly good motor in great condition. I also have a 99 748SPS motor sitting around that I've tossed around the idea of installing it.

I'm keeping the SPS motor around incase anything happens to the stock motor, but I don't know if I want to get into another project in the near future with an Fox 890 conversion kit and full blueprinting rebuild of the SPS and swapping it in. It's relatively cheap, huge gains for the $, and it's still streetable. I'm tired of having to max the throttle trying to keep up with the larger bikes. I'd really like to do the conversion but all said and done will end up costing $3k+ on the low side. I will have access to a shop that I can perform all of the work at in the near future. It would be a gradual, long term rebuild lasting probably a year to complete. Again, my motor is fine now but stuff happens. Keep the SPS as a backup ready to go or project 890 route?

If you had a good daily rider duc and the spare SPS motor, what would you do and why?

[Pedro-bot]

That doesn't sound like too bad of a problem to have.
a. A great riding moto.
b. A spare SPS motor.


I think you've already decided that this motor will go into this bike. Either as a planned project or as an absolute necessity following a mechanical breakdown. I think to answer your question you have to take both scenarios into consideration. Would you rather have a planned project or one that catches you by surprise?

[Raux]

would the stock motor ecu be a direct swap? wouldn't there be a lot of changes to get the full effect of the new motor? Does the SPS use the same diameter exhaust?

IMO go all out on the SPS motor w/ecu/exhaust/R-intakes,Injectors&airbox then do the swap.

[zooom]

IMO go all out on the SPS motor w/ecu/exhaust/R-intakes,Injectors&airbox then do the swap.

+1...don't half ass it...do it all or not at all...

.... I'm tired of having to max the throttle trying to keep up with the larger bikes.

FWIW...sounds like you are using the wrong tool for the job...the 748 isn't meant to be a flat out bike...it is a weapon in the corners...to put it in terms that you might better put it in perspective for you...it is like taking an 1/8th mile turbo Civic and putting it against a Pro Stock big block 1/4 mile car

[Speeddog]

1) Sell 748SPS motor

2) Buy 996 motor

3) Replace stock 748 motor with 996

4) Sell stock 748 motor

5) Tune ECU to suit

[brad black]

what he said.

i was going to write a whole bit, but that's better advice.  748sps is a top end power motor, a report about one and comp to a base 748 - http://www.bikeboy.org/748SPchangedcamtiming.html

i was surprised how well the sps did in the midrange, they feel quite flat on the road.

[accludetuner]

Raux - the SPS has 45mm from the motor with 50mm half system stock.

I will be comparing the ECUs and note any differences. I'll be comparing EPROM dumps from both.


Thanks for the input so far!