2nd gen engine in a 1st gen frame?

Ok, have kind of a wacky question. I have the option of getting a 1983 VF750 rolling chassis for 100 bucks. heres the link if youd like to look at it Honda interceptor

I have also found a replacement engine but its out of a 1990 model. I am not that familiar with the 750's but would love to build one if its possible with this engine/frame combo. Anyone know if its doable? And by doable I mean will it bolt up and not require any quirky fabbing/machining/welding etc.

 

Not to be a jerk.......but not a stone cold chance in hell.........a lot like bolting a small block chevy in a Ruckus..........you can do it but I estimate the time in beer trucks not beer cans.

 

Haha, no offense taken. It was just an idea I put together but I'm glad to hear something cant or shouldnt be done BEFORE I commit time and resources to it. Thanks for the warning.

 

Engine mounts are surprisingly similar. Definitely do-able. If I was given both items I would do it just for fun. If it was free or very cheap why not. That steel perimeter frame can handle the extra ponies in anything but the toughest of track conditions. The HRC race bikes of '83-85 made as much if not more HP than a stock VFR and they ran basically a stock frame. You'd have to use the VFR's ignition box and maybe a few other items as well.

Food for thought in case anyone wanted to try it.
Joeps bike...
VF750F frame:


And an VFR750F RC24 Engine:


The left front engine tab has to be shaved off a bit to make it inside the frame. Allso the ring welded on the frametab has to come of making it look like this:


On the right front, the original bushing from the VF750F engine has to be used, except shave the collar of, making it look like this:


Also, the frame insert has to be altered a bit... The frame tab on the inside of the engine has to go.. Except only the bolthole. Strength between the frame is regained by using a piece of roundbar through the engine mounting points and frame, making it look like this:


The bottom left engine mount stays the same... The original bushing has to be shortened from 65mm to 50mm Making it look like this:


The bottom right engine mount also stays the same, except a 25mm bushing is needed and can be used from the original top engine bolt, except the hole has to drilled from 8mm to 10mm. Making it look like this:


The rear valve cover fits between the frame if you shave of both sides.. There is some curving made on the outside, but if you flatten in out it should fit with about 2mm on each side to spare:



The front bank stays the same:


Just a peek on the left side of the engine:


And an overview so far on the bike in total:


You'd have to make a custom top engine mount cause the VFR mounting hole is lower than the VF's.

Exhaust install, needs the vfr headers because the ports are more on an angle compared to the VF750F..

 

wow. Thats alot of fab. I mean I prob could handle it, but it would take me so long to get it all done I might just quit on it. I already had a 2 year project getting my cafe bike going, dont think I could go through that again.

 

I was surprised at how little fab work was involved but it would take time to get everything jiving together. Keep searching...you'll find a cool project that will tickle your fancy.

 

Yes, the engines are very similar. As shown above it is almost a drop-in. The fabrication needed is pretty minimal, IMHO.

 

Yeah, it seems to me like I could get it done eventually in my one car garage with no metal working tools (yet). You never know. But thanks to your write up and all your pics....been thinking about it. Thanks for all that info by the way. Good to know that someone has accomplished something similar to what I'm contemplating doing and has actual documentation of it. If I can get the engine for substantially cheaper, I might just give it a shot. I'll update this thread again if I go ahead with it. Thanks again to everyone who offered their help and opinions.

 

Hi,

Amazing job, was wondering about that for a long time, will it fit or not!
Got more photos of the project somewhere?

Br.,
Quaca