Inlet & Exhaust Valve dimensions ?

Hi All,

Does anyone know the VFR800Fi Valves dimensions ? Don't seem to come up readily.

I assume they are the same as the RC45, but again I can't seem to find that info !

What I'm after is,

Inlet & Exhaust
head diameter =
stem diameter =
overall length =


Cheers

Mohawk.

 

Not sure. But I think its in the manual. Here is a link to the service manual I can't open it on my phone right now to check it. Honda VFR 800 98-01 Shop Guide - Go Fast Video

 

The manual only lists the stem O.D, intake @ 4.475-4.490 and exhaust @ 4.465-4.480. I cross referenced the valves from the gen 5 and gen 6 in an effort to see if Kibble White offered info from another application and they are unique to the two bikes. Sorry.

 

Thanks Toe Cutter, that was pretty much where I ended up ! I'm fairly sure they are the same size as the RC45, as the heads are stright swaps, but I can't even find the RC45 info !

I've just picked up a cheap crashed bike engine, that broke a couple of the engine mounts (why its cheap), so will strip the heads off & see if I can do a bit of tuning work. I reckon that with some reworked cams & a bit of gas flowing & matching I can squeeze another 10-20HP out of this baby. The standard UK spec RC45 with a slightly smaller engine (749cc) was good for 118-120RWHP & I've got 102RWHP at the mo. The basic differences I can find are cam duration & lift.

So if I can afford it in the spring, I'll get the spare cams reground to RC45 spec & see what happens :wink:
Might even entertain upgrading the throttle bodies to a larger size, but that's a whole other project, maybe one for next winter !

 

Found the info for RC45, as follows;-

Inlet & Exhaust
head diameter = in 29 - ex 24.5 (Looks like the head won't take anything bigger !)
stem diameter = 4.5mm (guide id, in VFR manual)
overall length = TBC

No exotic replacements avilable, so STD it must be.