what mod is there to move the cam timing gears (centre cam train) so you can maximise the amount you can take of the head

Do you mean removing the backlash gears?

You shim the idler gear carrier and cam carriers up to compensate for skimming the head.
If you remove the backlash gears it will be pretty noisy, you can reduce the number of shims to reduce the backlash/noise.

regards
jon

i've removed the quietening geard and skimmed the heads on my RVF, you have to shim the cam carriers when you put it all back together, the quietening gears will give you a few hp extra if you take them out.

im sure i've got some pics of when it was done....

Nice.

Its something id potentially look at doing. I dont really care for the noise.

I'd do it just for the noise! Sounds like it just wants to be let loose.

If it's done properly you won't get any extra noise, not sure of the details (cue nc/rc experts here...).

you do get extra noise, all the quietening gears have been removed on mine, it does rattle but i think it sounds really well....

http://uk.youtube.com/watch?v=jUbbEk9AGHg" onclick="window.open(this.href);return false;

this is mine you can hear the rattling in there somewhere

without getting really technical and measuring chamber volumes to work out exact cr what is the guide amount to remove from the haeds without causing problems, assuming all standard at present

As stated, if its done right there will be minimal extra noise.

Each cam gear needs to be shimmed individually to get it right.

If you, for example take off 0.1mm off the head face and remove the backlash gears you do not simply add 0.1mm of shim under the cam carrier.

You need to set up a dial gauge and turn the motor over and measure the backlash clearance ever 90 deg of the cam wheel on each cam shaft.

Average this figure out and then work out the size of shim (or the amount you need to remove from the cam carrier... it has been known!)

Of course you have to know what sort of clearance you need to run in the backlash gears but that comes with experience.

Engines that rattle because the backlash gears have been removed just proves who ever did it was lazy or didn't know how to set up gear driven engine.

i had a total of 12 thou taken off block and heads, could take a bit more off though to up the compression a bit but we left it safe and its never let me doen yet and pulls well enough with my fat arse on