Has anyone measured a stock camshaft or read it's specs anywhere? In the quiet moments when it's pouring with rain outside I've been trying to build a VFR 750 engine model in my Desktop Dyno software but haven't got a clue where to start with the cams.
Any idea about duration, lift, lobe centres etc would be gratefully received.
[image: View Post]93 VFR750 RC36, on 05 October 2010 - 02:42 PM, said:
Has anyone measured a stock camshaft or read it's specs anywhere? In the quiet moments when it's pouring with rain outside I've been trying to build a VFR 750 engine model in my Desktop Dyno software but haven't got a clue where to start with the cams.
Any idea about duration, lift, lobe centres etc would be gratefully received.
Stew
I'm sure this has been beaten to death somewhere before... closest would be looking at an RC45, but it's nothing like the 5th gens.. different firing order, and different valve angles..
discussion
just go torocharger... best bag for the buck.. LOL
Anyway, I still can't find lift figures. I have overall lobe height, but not base circle height so can't calculate lift. If anyone knows the base circle of a stock cam, I'd be happy to receive.
[image: View Post]ss_burns, on 05 October 2010 - 03:52 PM, said:
[image: View Post]93 VFR750 RC36, on 05 October 2010 - 02:42 PM, said:
Has anyone measured a stock camshaft or read it's specs anywhere? In the quiet moments when it's pouring with rain outside I've been trying to build a VFR 750 engine model in my Desktop Dyno software but haven't got a clue where to start with the cams.
Any idea about duration, lift, lobe centres etc would be gratefully received.
Stew
I'm sure this has been beaten to death somewhere before... closest would be looking at an RC45, but it's nothing like the 5th gens.. different firing order, and different valve angles..
discussion
just go torocharger... best bag for the buck.. LOL
I'm absolutely sure it has been beaten to death somewhere else. However, I cannot for the life of me, find it anywhere.
I'm not really interested in a torocharger type setup. I'm all for simpler, not more complicated and shaving pounds off is more important than adding hp.
I'm just toying with the idea of head/valve work and figured that if I could get some stock mechanical specs, I could reverse engineer the head flow with my desktop dyno. It's all just button pressing and computer simulation at the moment.
An Australian engineer named Ivan Tighe did a lot of work with the earlier VF-series motors. You can find some specs at this page which may be of some assistance.
The RC45 had 8mm lift on intake and exhaust but I can't find the RC36 or 36a figures. I also can't find details on valve sizes for either the 750 or 800 V4.
More importantly I can't find is a decent set of stock cylinder head flow figures. I'm sure all this has been done before by someone but unlike the car community, there is little available online on bike head flow. I could fudge a set of generic flow figures but it'd all be a bit of a guessing game and of little value when testing the results of an overbore etc.
Considering the power increase quoted for a 4mm overbore with very little other changes, it would seem to me that the stock head porting is almost too large for the 750 and almost right for an 850 (with the stock cam and rpm range). A 20% jump in power from an 12% increase in capacity can't all be explained by a small rise in compression ratio.
For those who are interested, I'm using Desktop Dyno's SportsCompact simulation.
Stew
End of thread · 6 posts recoveredWayback Machine snapshot 17 Jun 2011