any difference between Jap Spec & uk spec engines

[rigsby]

Hi,

I have the option of buying a spare engine for my nc30 race bike, the guy who owns the engine removed it from a uk spec nc 30 because the chain derailed and holed the crankcases by the final drive sprocket. He replaced it with a jap spec engine . He is convinced that the uk spec engine is slightly different than the jap one and that the uk engine is more powerful in stock trim than tha jap one. I know that the carbs were different on uk/ jap import bikes but i would have thought the engines would be the same, he said he weighed the flywheels (for some reason) and the uk one was lighter, this wont matter to me as i run total loss with no fly wheel though, but if anyone knows of any differences between the two that would be greatly appreciated.

Thanks

[richyrd5]

UK motor had different jetting and twin oil pumps for the cooling circuit... Apart from that they're the same..never heard of flywheels being lighter on UK model

[pauliealdridge69]

The rvf flywheel is lighter.
Quite possible someone had changed it over through the years when a genny packed up.
When I did the gsxr genny conversion I weighed mine for comparison. The rvf side walls were thinner.
Both motors are the same other than the oil pump.
Just picked up said bike I think lol
Only reason I want the uk lump is to repair and reunite it with the correct frame :)

[rigsby]

Thanks for the info that has put my mind at rest. Can anybody explain the reason for the change in oil pump for the uk spec engine, which engine had the superior oil pump? and is it of any benefit over the jap version.

Thanks again

[jim157]

The UK bike has an oil cooler, the Japanese market bike doesn't.

[Neosophist]

The UK bike has an oil cooler, the Japanese market bike doesn't.

Yep... Castings are already in the block.. fit an NC24 oilpump and you can retro-fit.

I heard a long time ago it was done as a marketing ploy to compete with the ZXR400 but if there is any truth to that i don't know.. the NC24 had oil cooler as stock... Temperatures in Japan are a lot hotter than the UK but they deemed the oil cooler unnecessary so no idea why it was added to UK model?

Stock exhaust is different too, maybe camshafts also, id have to check the microfiches..

I think the UK nc30 was specced at 65hp and the jdm 60?