Replacing an engine-a k8 in a k4 chassis

Hi
My minitwin went pop a couple of weeks ago (snapped crank) and ive been offered a good k8 motor. My bike is based on a K4 chassis and wiring loom. I was wondering, what is the easiest way to get this running in my bike? Obviously I'll need the extra coils, what about the ecu etc? Finally, because time is running out before the next meeting, could I just blank off a plug and bung it in and have a bike that would run well enough to race? That last one's more in hope than expectation

[andrewsmith]

in theroy yes.

Check with Spannerman or Yorkie_Chris

[yorkie_chris]

I hear the twin plug heads are no good for power.

I would put your K4 heads on K8 bottom if they are OK.

Thanks for the response. I hear what you're saying about the heads but certainly for minitwins, I've know people on k8's and 9's who've got them on the power limit with a can and a trip to a good dyno. Maybe it's when you tune them up they become restrictive? Sadly, my front head is lunched so really I'm looking to get this motor in complete as it is. I'm just wondering if I could get away with just changing the coil pack andmaybe the ecu? I'm new to sv's so don't have much experience of what can be done. Do the twin plugs spark at different times? Could I just blank off a plug? I'm going to try these things over the coming week but the next meeting is 15th may so things are getting tight. Any help much appreciated

Originally Posted by yorkie_chris

I hear the twin plug heads are no good for power.

Where did you hear that?

[yorkie_chris]

A well known builder of SV engines tried doing same mods to a twin plug one and got less power than a comparable original design head.

Originally Posted by crisis95

Could I just blank off a plug?

That would be easiest way.

That's what I thought of doing but figured that there would be more engineering going on than just another plug added and that it wouldn't run as well, bearing in mind that I need to race it and not just pop to the shops. I'm going to try it over the weekend and see. I was hoping somebody might have done it and could save me some heartache.

Originally Posted by crisis95

there would be more engineering going on

Yea, they did some engineering to screw up perfect head

Originally Posted by yorkie_chris

A well known builder of SV engines tried doing same mods to a twin plug one and got less power than a comparable original design head.

We have mapped two K8/K9 minitwin spec bikes and they both made circa 71-72bhp on our dyno. The RSV replica special we have just done was built from a 2009 bike and makes 89bhp on our dyno with tuning work. No problems found here.