Anyone know if an 88 or similar year 600f motor will fit into an 88 NC23? I got a stuffed 400 engine, big end gone and need to replace apparently.....heard a rumour a 600 might fit!
Cheers !

DOn't think it is a plug and play, but it can be done as a few on here have done it.....

It's far from a straight swap, you will need to cut and weld the frame, you will also need the 600 loom.

It's been talked about a fair bit on here and a quick search will give good results.

I do wonder if this is a mod worth doing. What is the difference in weight? How much extra power are you likely to get? Is the handling going to be affected?

I was going to swap the motors with my 1990 CBR600F - 85bhp but stonks of torque low down, not quite the same screaming top end or redline as the 400 but still not shabby! Would have made a good bike methinks...

Only potential hassles would have been the airbox/s.

Wozza wrote:I do wonder if this is a mod worth doing. What is the difference in weight? How much extra power are you likely to get? Is the handling going to be affected?

Weight difference negligible I should think. Extra power from 60 to 85bhp. More torques.
Ballache welding the frame and fitting an airbox.
Lose gear driven cams.

Honestly I think a bike that has this conversion loses the spirit of what makes nc's great. I wouldn't do it.

That said, it takes all sorts.

amorti wrote:

Wozza wrote:I do wonder if this is a mod worth doing. What is the difference in weight? How much extra power are you likely to get? Is the handling going to be affected?

Weight difference negligible I should think. Extra power from 60 to 85bhp. More torques.
Ballache welding the frame and fitting an airbox.
Lose gear driven cams.

Honestly I think a bike that has this conversion loses the spirit of what makes nc's great. I wouldn't do it.

That said, it takes all sorts.

I would get hold of a crashed/cheap CBR6 and swap everything over, then eBay what CBR6 parts you have left...

Easy swap as you are guaranteed to have all the parts (bar an airbox to fit the CBR4 tank & CBR6 carbs - but the motors are extremly similar, it can be that hard!)

No prob with the gear-driven cams, the 6 has a lovely induction whistle, is arguably bombproof & has a well-buff-and-sturdy hyvo camchain anyways...

I think I understand now - you are upgrading a CBR600, rather than upgrading a CBR400

Wozza wrote:I think I understand now - you are upgrading a CBR600, rather than upgrading a CBR400

Is it a CBR4 with a CBR6 engine or:

A CBR6 with CBR4 frame, forks & wheels?