Topic: Removing and Installing a CB750 Engine

[BenelliSEI]

In a few months (hopefully) I’ll be ready to install the Sandcast engine, back in the totally restored motorcycle. The frame is primed and coated in black lacquer. I’ll cover it all with old hand grips, bubble wrap and pipe insulation, but the job is always a struggle. My buddy Gary (spends one day a week in my shop, so I save the heavy lifting for then) and I are not getting any younger.

The Rickman CR needs the engine out/in at least one more time and there’s a K6 at the back of my shop waiting for it’s fresh motor..... I know the smart guys just lay the frame over the engine, as step one. I’m not that clever, and always seem to have to do it at the end, and often more than once. I’ve restored +10 cb750’s, so I plan to smarten up.

Today I started building a “two man engine cradle” that I’ve been thinking about for years. It’s more of a stretcher than a cradle. The plan is to fully support the engine with long handles out both sides. In theory, two people, using four evenly spaced handles, will be able to lift and move the engine into place. It’s going to be all welded steel construction and be able to hang flat in a corner, when not in use. I’m going to make dimensioned drawings and take photos of the build, should anyone want to replicate. I am going to solve this annoying problem, for good.

If you’ve already built some brilliant contraption, I’d love to o see it. More to come.

[RAFster122s]

Seen a wooden one built that the head is strapped to after carbs come off of course. Someone posted photo of it attached in last 2-3 weeks…

[madmtnmotors]

Like this?

http://forums.sohc4.net/index.php/topic,58210.msg1684742.html#msg1684742

http://forums.sohc4.net/index.php/topic,100352.msg1675840.html#msg1675840 (scroll down a little)

By myself I can have the engine out of a fully assembled bike in about an hour and a half. Getting the engine back in the frame takes about ten minutes and then the other hour and twenty minutes hooking everything back up. Hardest part is setting up the hoist, which ain't that hard, insert legs and tighten the bolts...

With a helper you may be able to avoid engine to frame contact completely. 

The C-hook method could also be used with a chain fall and overhead trolley. I've thought about an overhead trolley in the race trailer but if I need to swap engines at the track I figure my efforts at that particular event are likely done at that point! 

EZPZ

[Ujeni]

I do exactly what Honda did in 1969:

[Ujeni]

You can make it easier by not installing the oil pump and oil pan until the motor is in the frame.

I know lots of people that bring the motor into the frame instead of the frame onto the motor. I prefer the latter as the frame is lighter and easier to handle than the motor!

[BenelliSEI]

The hoist and “C” lifter is neat, and I did use my engine crane once. Just too big and the legs are tough to get under the bike, or lift table.....

The “frame drop” is brilliantly simple, but not useful when pulling the engine from a complete bike.

[BenelliSEI]

Here’s what I’m starting with. Used light alloy plate, this is the template. The next one will be 3/16” or 1/4” steel plate (whatever I find in my scrap). It is held in place by the two cover screws and the two bolts that hold down the starter motor. There are two 17mm long dowels under the plate, between it and the starter. When all four bolts tighten down, the plate is firmly attached to the starter AND the top half of the case.

[BenelliSEI]

Here’s how it fits in the case. I will likely weld some lengths of square stock, ground to fit snugly, under the plate, under the long sides. This will prevent the plate from “rocking”.

[BenelliSEI]

I have a few lengths of left over 1” square tubing, from mounting the fuel cell in the Lexus. Going to use a long length as the “cross bar”. It will be welded across the steel plate, centred on the cover screws. Drilled right through, with two longer screws, the correct length. Here it’s just sitting on centre.

On the LHS I plan to weld on a 12” piece of tubing as a “T” handle. On the LHS the centre beam will be left long enough that the “T” will be through the bike when the engine is sitting alongside.

[BenelliSEI]

On the RHS the pipe will be left straight, sticking out about 8”. Plan to fabricate a second handle, about 8” long, that bolts to the RF engine mount. That area is clear on the frame, before installing the triangle plate. The main centre pipe will be cut to length, sticking out the same distance. The “lifter” on this side will be easily able to control the angle the engine goes in at. Here’s the mock up.

[BenelliSEI]

In theory, both guys can lift together and easily control the angle of entry. No need to grab the engine and nothing marring the fresh paint........ We’ll see!

[Ujeni]

So are you hanging the engine on the two starter bolts via a plate? That would make me a bit nervous. Perhaps I am misunderstanding your plan.

[Stev-o]

I've done it both ways:

1. Lay the frame over the motor, simple one man job [with a bare frame]
2. Using a helper, it only takes about ten minutes to carefully remove or replace the motor in the frame.

I dont really see the need for a lift or contraption although I do have a "cherry picker" [that we used on a Camaro]

[beemerbum]

I have  a  neighbor who has two sons, both of whom play varsity football (defense). Engine in and/or out and I enjoy a beer meantime.

[BenelliSEI]

So are you hanging the engine on the two starter bolts via a plate? That would make me a bit nervous. Perhaps I am misunderstanding your plan.

It’s four, but the main load is carried by the starter case lugs. The starter is held on by the two. They thread in a long way and by adding the spacers between the plate and the starter (see second photo), they are tightened right down and the nose is tight in the boss at the other end. These tie the bar directly to the case. They carry the majority of the load. The two that usually just hold down the chrome plate go in quite deep too. Four bolts should easily carry the total load.

[Ujeni]

You are probably right. With my luck, it would snap off somehow. The engine, without oil, should weigh around 185 lbs. Looking forward to pics of your setup!

[BenelliSEI]

You are probably right. With my luck, it would snap off somehow. The engine, without oil, should weigh around 185 lbs. Looking forward to pics of your setup!

We’re off to Australia and N.Z. for six weeks, so it might be a while before this gets finished, but I’m not installing (or removing) another one without building this first.

[70CB750]

Very neat idea.  Following. 

[HondaMan]

Watching!
I have a wooden 'rotisserie hook' that I'm going to try, which someone here (the member's name escapes me at the moment, sorry!) made for me some years ago. Interestingly enough, this year is the first one since I got the "hook" when I have to pull an engine: they are usually just bare engines that show up here, in boxes and on pallets. The idea of it is to use my chain hoist for the hook, and nylon ty-straps around the engine to lift it the 1.75" it needs to come out (when the oil pump is out and the gasket surface protected with a 1/4" thick plate I made for replacing the pan).

First, though...I have to finish the 450 and 750K2 and sandcast engines occupying that spot...

[BenelliSEI]

Very neat idea.  Following.

Thanks! I want to build something safe, solid, easily installed and removed. Will report on progress.

[Don R]

 I just use a nylon strap under the motor between the clutch and points cover, under the motor then back up in front of the dyno cover and loops through itself near the cam chain tensioner. It balances good enough so I can put it in by myself. I looked for the pic, didn't find it.

[Gamma]

Following with interest

[ekpent]

You are probably right. With my luck, it would snap off somehow. The engine, without oil, should weigh around 185 lbs. Looking forward to pics of your setup!

We’re off to Australia and N.Z. for six weeks, so it might be a while before this gets finished, but I’m not installing (or removing) another one without building this first.

Are we going to see any pics of you hanging out with Terry or other members of the Aussie contingent ?

[BenelliSEI]

You are probably right. With my luck, it would snap off somehow. The engine, without oil, should weigh around 185 lbs. Looking forward to pics of your setup!

We’re off to Australia and N.Z. for six weeks, so it might be a while before this gets finished, but I’m not installing (or removing) another one without building this first.

Are we going to see any pics of you hanging out with Terry or other members of the Aussie contingent ?

Not sure if that will happen. Packed schedule.

[MauiK3]

Have a safe and fun trip.
I'm with Ujeni, I put the frame over the engine, I've even done it with forks on (no tire).