motor swap 91 CB 750

It might be easier if you take the cam cover off- but be careful not to
smash up the cams/sprockets/etc. However, that said, if it came out of
the frame without taking off the cam cover, it will go back in the same
way. If you are creative about coming up with some sort of harness to
hang the engine from without touching the frame, an engine hoist *might*
help. Personally I would get a couple more brawny friends to help.

Have you considered the suggestion that you were given about laying the
bike on its side?

 

I took off all those plates, but the frame juts out where #10 attaches
and the motor hangs up there...also down at the front bottom corner,
where the right front engine mounting plate was attached...its tough
to get the oil drain bolt over the bottom of the frame here, because
this part of the engine sits a couple inches lower than the frame when
the motor is installed. Plus the rib on the top of the camshaft cover
catches on the bike's spine. When I try to just slide it in, it always
gets hung up on at least 2 of these points. It seems we need to wiggle
it around to get around them and just aren't strong enough to do it.

 

Another protuberance is the oil filter and cover. I only took one of
these engines out, didn't put it back in, but removing those after
draining the oil seemed to give more room. A little jack with a piece
of plywood on it also seemed to help to keep the mount holes aligned.
just my two cents.

 

More good suggestions, but to the OP-- make DAMNED sure if you elect
to remove this stuff to get the engine through the frame, you don't
scratch up the surface of the head where the cam cover goes, or the
sump where the oil filter cover mates up. Those surfaces are sealed
with an O-ring style gasket and an O-ring and can't tolerate much if
any damage without leaking.

The trick is to pre-plan all the moves the engine is going to make
and do it with finesse rather than main force.

 

Mark Olson wrote:
....

My pet theory, which is probably half-baked but still seems to help me
when I'm in a bind, is that the more I apply my pathetic muscles, the
more they reduce the oxygen going to my brain. Sometimes it takes me a
while to figure out the best angle to lift from, where to position my
feet and so forth. Sometimes I find it easier to manoeuvre if I raise
the bike about twelve inches off the floor, my cheap way of doing that
is with some 2x10's lying on patio stones. Usually gives me a better
view and lets me get better advantage from the stronger leg muscles.

Also, if this bike has spark coils mounted above the engine, removing
them might not help clearance but would at least make it easier to see
how things are lining up. I'm pretty sure one person could put this
engine in if they use tie-downs and a jack or two-by-fours, maybe even
the end of a wide flat pry-bar for leverage, with a towel or rag to
prevent scrapes, even though two people might make things a little more
comfortable. If I were doing it by myself I might even consider using
straps on the frame to help raise and level the engine, as long as I had
the frame strapped to the floor or a heavy plate to keep it stable.

Just rambling on, I know, but I like these kinds of topics, when you
finally succeed the first time, it's a great feeling of confidence to
prepare you for the next problem.

 

I know I suggested this a while back - if not to this geezer, then to
another.

 

Not sure where anyone got the idea I was a "geezer," I may be a bit
eccentric but I am only 26


I have rigged up a hoist using some rope and a 1-ton come-along. If
that fails, I will consider laying the frame over onto the engine...
but I'm not sure how that's going to help, since a direct slide-in
approach doesn't seem to work. We have already ruined the paint job on
the frame so I won't risk taking any parts off that cover delicate
parts...of course the oil filter and ignition coils and all that stuff
is already off.

Thanks for the suggestions, I was hoping someone who actually had
experience with this particular bike would chime in.

Andy

 

Because manhandling a frame that weighs a couple of dozen pounds i
rather easier than manhandling an engine that weighs five times as
much.....

 

Finally got it in with the help of the hoist...the trick was to go
sideways, bottom (heavy) end first, supported by the hoist, then tip
it back over and wriggle the top through. Snapped off a piece of the
drive sprocket housing in the process though. Good thing I have a
"parts engine."

Now the challenge will be to put Humpty Dumpty back together
again...