could anyone tell me what the threads are on the NC 21 engine mounts, I have tried a metric bolt but it doesn't seem to match, I don't want to force it for obvious reasons. I have bought a second engine and would like to mount it to a stand to work on it without having to first take my current engine out of the bike to utilise the bolts if possible.

i would say they are metric fine m10 by 1.25 as a guess

http://www.cmsnl.com/honda-vfr400rh-ii- ... ml#results

you can look at the microfiche here..

i assume bolts 25/27

there an 8 x 28 and a 10 x 60

not sure if they are standard or fine pitch but id have thought standard. definatly metric bolts unless you have stripped out engine.

why not take just one of the bolts out the original engine and try it in the new one just to make sure there not knckered, you can also take the bolt to a bolt shop or use a pitch gague if you have one to get the specs.