motor swap 91 CB 750

paul c <toledobythesea DeleteThis @oohay.ac> wrote:

> The Older Gentleman wrote:
> > paul c <toledobythesea DeleteThis @oohay.ac> wrote:
> ...
> >
> > Oh for Christ's sake, the Nighthawk doesn't have this feature.
> >
> > <snip>
> >
> >> I wonder how long it would take a pro' mechanic to replace the starter
> >> clutch?
> >
> > We did this before, some time ago, and the OP says he's been quoted 1500
> > bucks.
> >
> > Wake up.
> >
>
> so just how many hours was that?

Refer to previous posts on the subject.

But count on a dozen at least, unless you've done so many of them that
you can now perform the task in your sleep.

Remove engine - which means, obviously removing exhaust, bodywork, all
umbilicals, carbs, footpegs, gear lever, brake pedal, etc etc.

Strip engine down to crankshaft.

Replace chain.

Rebuild engine from crankshaft upwards.

Replace engine.

Don't forget to add cost of complete gasket and oil seal set as well as
cost of knackered chain.

These engines are notorious for this problem, which first surfaced in
the Honda CBX750 (the Nighthawk uses the same engine).



--
BMW K1100LT 750SS CB400F CD250 CB125 SL125
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
 >> Stay informed about: motor swap 91 CB 750 

Ok, so I have got the original motor out and have another one ready to
install! I only stripped allen two bolts in process so I am pretty
satisfied with how that went. I have everything in boxes and baggies
labeled and ready to put back on.

Last night three of us spent over an hour trying to maneuver the new
engine into place in the frame and could not get it in. It always
seems to get hung up somewhere, and it's too heavy to pull any
complicated maneuvers to get around the hangups Is there some trick I
am unaware of that would help? It's like trying to put in a 200 pound
puzzle piece. I'm considering an engine hoist, but they seem to be
more designed for dropping an automotive engine into an engine bay/
hood, so I'm not sure if that would help or get in the way.

I know the motor is identical except for the age and milage, just to
get that out of the way.

thanks
Andy
 >> Stay informed about: motor swap 91 CB 750 

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.




On Oct 1, 10:38 am, "Albrecht via MotorcycleKB.com" <u33665@uwe>
wrote:
> Andy wrote:
> >Last night three of us spent over an hour trying to maneuver the new
> >engine into place in the frame and could not get it in. It always
> >seems to get hung up somewhere, and it's too heavy to pull any
> >complicated maneuvers to get around the hangups Is there some trick I
> >am unaware of that would help?
>
> http://houseofmotorcycles.bikebandit.com/partsbandit/ShowSchematic.as...
>
> What the heck could it be hanging up on?
>
> Did you remove the two #27 front engine mount plates plate and the #10 rear
> engine mount? It looks to me like installing the new engine would be a piece
> of cake, with engine mount plates that unbolt and no frame rails above the
> cam cover.
>
> I would just slide the engine in from the right hand side, line it up with
> the fixed engine mount plate on the upper left rear and slide the long bolt
> through the crankcase and then slide the right rear engine mount into place
> and bolt it up.
>
> Then I would raise up the front of the engine and install the front engine
> mount plates.
>
> Two people should easily be able to handle the 180 pound motor. I would do it
> by myself, maybe with the help of some 2 X 4's for levers.
>
> You might rent a coffin hoist (aka "come along") and hang it from the rafters
> of your garage. Then wrap a nylon webbing sling around the engine to pick it
> up.
>
> One old guy told me that he used to avoid wrestling with a heavy motor by
> setting it on end and tilting the motorcycle chassis horizontal and lowering
> it over the motor.
>
> Once the motor was bolted into the frame, he could lever up the chassis by
> turning the handlebars to force the tire against the floor.
>
> --
> Message posted viahttp://www.motorcyclekb.com
 >> Stay informed about: motor swap 91 CB 750 

Andy wrote:
> Ok, so I have got the original motor out and have another one ready to
> install! I only stripped allen two bolts in process so I am pretty
> satisfied with how that went. I have everything in boxes and baggies
> labeled and ready to put back on.
>
> Last night three of us spent over an hour trying to maneuver the new
> engine into place in the frame and could not get it in. It always
> seems to get hung up somewhere, and it's too heavy to pull any
> complicated maneuvers to get around the hangups Is there some trick I
> am unaware of that would help? It's like trying to put in a 200 pound
> puzzle piece. I'm considering an engine hoist, but they seem to be
> more designed for dropping an automotive engine into an engine bay/
> hood, so I'm not sure if that would help or get in the way.

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?

--
'01 SV650SK1 '99 EX250-F13 '98 ZG1000-A13
OMF #7
 >> Stay informed about: motor swap 91 CB 750 

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
 >> Stay informed about: motor swap 91 CB 750 

This message is not archived
 >> Stay informed about: motor swap 91 CB 750 

paul c wrote:

> > 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.

--
'01 SV650SK1 '99 EX250-F13 '98 ZG1000-A13
OMF #7
 >> Stay informed about: motor swap 91 CB 750 

This message is not archived
 >> Stay informed about: motor swap 91 CB 750 

Andy wrote:

>Last night three of us spent over an hour trying to maneuver the new
>engine into place in the frame and could not get it in. It always
>seems to get hung up somewhere, and it's too heavy to pull any
>complicated maneuvers to get around the hangups Is there some trick I
>am unaware of that would help?

http://houseofmotorcycles.bikebandit.com/partsbandit/ShowSchematic.asp...eptId=1


What the heck could it be hanging up on?

Did you remove the two #27 front engine mount plates plate and the #10 rear
engine mount? It looks to me like installing the new engine would be a piece
of cake, with engine mount plates that unbolt and no frame rails above the
cam cover.

I would just slide the engine in from the right hand side, line it up with
the fixed engine mount plate on the upper left rear and slide the long bolt
through the crankcase and then slide the right rear engine mount into place
and bolt it up.

Then I would raise up the front of the engine and install the front engine
mount plates.

Two people should easily be able to handle the 180 pound motor. I would do it
by myself, maybe with the help of some 2 X 4's for levers.

You might rent a coffin hoist (aka "come along") and hang it from the rafters
of your garage. Then wrap a nylon webbing sling around the engine to pick it
up.

One old guy told me that he used to avoid wrestling with a heavy motor by
setting it on end and tilting the motorcycle chassis horizontal and lowering
it over the motor.

Once the motor was bolted into the frame, he could lever up the chassis by
turning the handlebars to force the tire against the floor.

--
Message posted via http://www.motorcyclekb.com
 >> Stay informed about: motor swap 91 CB 750 

Mark Olson <olsonm.DeleteThis@tiny.invalid> wrote:

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

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


--
BMW K1100LT 750SS CB400F CD250 CB125 SL125
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
 >> Stay informed about: motor swap 91 CB 750 

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...
 >> Stay informed about: motor swap 91 CB 750 

Andy <andrewcjoiner RemoveThis @yahoo.com> wrote:

> 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.

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


--
BMW K1100LT 750SS CB400F CD250 CB125 SL125
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
 >> Stay informed about: motor swap 91 CB 750