Hi guys,

Does anyone know of a "Haynes-esque" manual that would give me info on tuning a v4 engine.
I know there's web pages but I'm old school and like to sit and read a proper manual lol!
Any help would be greatly appreciated
Thanks, Greg.

Which engine?

What state of tune do you wish to achieve?

The NC13 engine (VFR400 series) was designed to produce 60hp. Apart from exhaust and carb jetting (which is detailed in cammos guide)

Anymore power from these engines isn't cheap or easy... HRC parts will take it upto the 70's but there obsolete, rare and hard to get hold of.

You could look into the inlet / exhaust ports too but without spending lots on a professional job you won't get a lot of benefit from DIY work.

If you have lots of money you can do things such as an oversized piston set, HRC carbsetup and pistons / rods et al.

Quietning gears is something that can be done cheap but will make the bike sound rough at idle and doesn't release much power.

In terms of conventional tinkering though there isn't a great deal you can do that will give you much more extra power.