CB750 Engine Removal Tips

Quote from: jdigga on June 08, 2007, 11:19:07 PM

So the weeping from my fins is at the point where stuffing half a Shop Towel in between isn’t enough to stem the spray.  I’m a bit tired of having to wear a specific pair of oil-stained riding jeans, so it’s time to make the necessary repairs.

I started the tear-down around 5:00pm.  Most everything came off without any problems.  I did have to use an impact driver on the front sprocket cover and found to my dismay that the sprocket bolt was loose!  Luckily it appears that the cover has a little shaft on the inside to keep the bolt in check.  I also discovered that the rear brake splined shaft is slightly bent, but it functions just fine.

I knew the actual removal of the engine would be challenging, but I had no idea what I was in for.  I tried putting the bike on its ride side but I could get the right angle to pull the frame off.  The engine was getting hung up everywhere, and as soon as I’d release one spot, it would hang up somewhere else.  I must have put the bike upright and back down again half a dozen times.

By now it’s around 8:30.  Took a breather for dinner and browsing this forum for some tips.

Went back out for one last attempt before calling it a night.  The bike was on its side and while staring at it I realized the engine wasn’t going to come out that way.

I put it back upright on the centerstand and broke out my set of lady fingers.  Shoved one in the lower right rear mount hole, one underneath the rear of the engine, and one in the upper right rear mount hole to act as a handle.  Pried the rear up to clear the lower mount.  Pulled up the front of the engine to move it towards the right a bit.  Basically I walked it out of the side, front-back-front-back.

Turned off the garage lights and closed the door at 10:30pm.

In the process of putting the bike down so many times, my points cover took a beating (even though I put it down on those rubber puzzle mats).  The right bar on my clubmans is pointing slightly more downward than the left.  I forgot that I left my key in the seat lock and it broke off–I was able to retrieve the bit inside the lock, but I only have one key.

Honda made a huge access improvement in 1979 with the DOHC bikes.  The lower right frame rail is detachable and the engine pretty much falls right out.  I pulled my other engine the other week, and other than it being a heavy SOB it was hardly a challenge.

And to think I’m only 1/4 of the way there.  I still have to take the engine apart–I have no doubt I’ll run into problems there.  Plus all the cleanup of old sludge buildup and repair the busted up bits.  Then put it all back together again.  Don’t get me wrong–I love tinkering with my bikes and learning about them.  But sometime it’s just frustrating as hell.  I’ll feel better when I’m back on the road again.

Just had to get that off my chest…

Before you put it back in….there is a flange on the motor mount on the lower right side. Grind or file the top of the flange off to the height of the rest of the mount, then shoot a bit of paint on it. This makes the whole assemble-disassemble job MUCH easier. This little flange has probably left several notches in the rib on the bottom of the engine where the bolt goes thru, which can actually jam the engine so badly on the way out as to require a frame cutout to unjam the whole thing (don’t ask me how I know that….). But, removing this tiny little flange top will prevent all of this…