Swapsies

[BiKenG 119]

Just toying with ideas and wondered if anyone can help with answers to the following:-

Are the intake port locations/dimensions on the 750 the same as the 800s? IOW, could the FI throttle bodies be fitted onto. 3rd and/or 4th Gen?

Similarly, are the frame and engine mount positions the same? Can engines and frames be swapped around?

Can anyone save me the time of searching for this info, what are the crank angles used from Gen1 to 8? I could make an educated guess, but does anyone have the definitive answer?

Thanks.

[JZH 661]

Sorry, dunno. But I have a 3rd gen frame, engine and carbs in the shed, if you want to measure them... Now that I think about it, I should also have a set of Fi throttle bodies (minus injectors). By crank angles, do you mean 180-degree/360-degree? I believe all VFRs were 180-degree, except NC30 and RC30. NC24 was 180-degrees. Not sure about RC45.

Ciao,

[BiKenG 119]

Actually measuring frame engine mounts points could be tricky to do well. I thought someone was bound to have tried such a swap and could comment from experience.

If you have both Gen3 carbs and injection throttle bodies, it would be good to have a comparison. Either they are the same, or they're not, that's all we need to know. How different they are would not be so important. But again, surely someone must have already tried to push a set of 800 throttle bodies on a 750?

I've been able to establish the crank angles of each model now and you're basically correct. The RC45 is 360° same as RC30 and also the earlier VF750 models. I always thought they had swapped between 180 and 360 along the way for the VFRs as the Gen3 feels so different to the Gen2. But the Gen4 seemed so like the Gen2 in engine feel and the Gen5 seems to me to be more like the Gen3. I had thought this was due to crank angle changes, but apparently not. Mind you, they could have changed the firing order. I'll check that now too.

[JZH 661]

If I get a chance, I will, but things that require digging can take some time...

Ciao,

[Veefer800Canuck 822]

3rd and 4th gen engines may interchange within their frames, the 800 gear drive engines and VTEC engines can certainly be interchanged, with work, but I would not expect the 750 and 800 engines to swap over given the 800's "tuned flex" chassis and lower cushion arrangement for the suspension, and the swingarm pivot in the rear of the engine cases.

[BiKenG 119]

3rd and 4th gen engines may interchange within their frames, the 800 gear drive engines and VTEC engines can certainly be interchanged, with work, but I would not expect the 750 and 800 engines to swap over given the 800's "tuned flex" chassis and lower cushion arrangement for the suspension, and the swingarm pivot in the rear of the engine cases.

Yes you're probably right. I bet someone somewhere has tried it though.