Engine reinstall

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Mark_smugglers

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Feb 20, 2014
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Hi

I’m in the middle of taking my 1972 750 combat engine apart. All of it is a new experience so bear with me! I took the head off, then the barrel and then lifted the crankcases and bottom end out.
Thinking ahead, when I come to put it back in frame, will I have to reverse this order or can I build it all on the bench and put the whole lump in as one unit?

I ask because I can see that lining the pushrods up when putting the head on is going to be much easier on the bench than in the frame.
 
Mark_smugglers said:
Hi

I’m in the middle of taking my 1972 750 combat engine apart. All of it is a new experience so bear with me! I took the head off, then the barrel and then lifted the crankcases and bottom end out.
Thinking ahead, when I come to put it back in frame, will I have to reverse this order or can I build it all on the bench and put the whole lump in as one unit?

I ask because I can see that lining the pushrods up when putting the head on is going to be much easier on the bench than in the frame.
Click to expand...
It's horses for courses
Personally I prefer to put the head on whilst the bottom end is in the frame
I twist a rubber band to hold the pushrods up into the head
Then when it's almost down I cut the rubber band and pull it out
It's a fiddly job but not difficult
If you haven't worked on one of these motors before I think it may be better to assemble the whole engine on the bench
Cheers
 
As Baz says, its certainly doable to reverse your strip down procedure and assemble the top end in the frame. The key advantage to this method is that you don’t have to manhandle the whole engine unit.

Personally, I prefer to assemble the engine on the bench. The advantage to this method is its easier to take extra care with engine assembly. The disadvantage is the potential hernia and chipped frame paint !
 
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Personally I went with putting the head on with the engine in the frame.
I can still do "fiddly" but I'm definitely less able to do "strong" these days.
I once put a T160 engine in, including starter, on my own. That said I was only 23. And today I'm the oldest I've ever been.
 
I am still with the build on the bench, lay the bike on its side (minus tank of course) on a pile of blankies or foam,
protect the frame with tape-thin ally sheet-tape, ease in the great lump and secure .
Always worried that Ill score the pushrods putting the head on whilst cases are in frame.
 
I also prefer to assemble my engines on the bench.
My daughter helps to put the first engine bolt in while the g/box and engine plates are held in place by a floor jack.
Mind you it may get to the stage whether she will not help any more or I cant lift the total weight, or both!
Regards Mike
 
+1 on building the entire engine on the bench then manhandling the engine into the plates and frame with a helper. I usually end up assembling and disassembling the top end several times until I am sure it is right and I want to do this on a clean bench under the lights.
 
When the occasion/opportunity arises, I build the whole engine on the bench (engine stand).
Then assuming is a series 2 frame, I put a piece of 2x4 on the front cross bar.
The engine only being about 80 lbs, I lift and swing it down on top of the 2x4, or get a kid to do the actual engine lump drop.
A few tapered pinch bars or long round punches gets the 3 engine /tranny cradle bolts installed in short .order.
Repeat for the front 2 engine iso mount bolts.
Raise the engine off the 2x4 and slip the long 1/2" bolt through the front iso/frame.
Last time I did it for my combat and it certain took well under 15 minutes probably under 10.
The final dressing is what took the huge bulk of time.
I'm not overly big @ 160 lbs but I seem to manage OK
 
I'm also one for building the engine on the bench, plenty of light & 360 degree access. lay the engine over on the timing side cover and lower the frame over it.
 
olympus said:
I'm also one for building the engine on the bench, plenty of light & 360 degree access. lay the engine over on the timing side cover and lower the frame over it.
Click to expand...

I would have infinitely more trouble putting a fully assembled rolling chassis and lowering it down onto an engine.
 
Thanks all.
so to be clear: if I build it all on the bench, there’s enough clearance in frame to get it all in- with the front mounts off? I’m presuming I will need to tilt it forwards initially whilst i insert the rear into the engine plates.
anyway, it’s a way off yet. I still need to get the crank pinion off and split the cases...
Thanks for all the input.
 
dynodave said:
I would have infinitely more trouble putting a fully assembled rolling chassis and lowering it down onto an engine.
Click to expand...

If someone was that genius to try and do that, all they have to do is sling the bike horizontal off the rafters or maybe a tree outside.
Where there is a will, there is a way.

If only it was the days of phones with camera's.
Welding portal frames on site but no way to turn them over (no crane until installation) that was until I attached a chain, a vertical timber leaning toward the portal and a rope from the chain to the 'Reverends Datsun station wagon towbar.
Up and over they went as he drove off.

Aucklanders might know the spot, the big church beside the motorway in Greenlane.
#
I am going to try and fit the biggest lump as possible into the Norton frame, maybe with the carburetors if it will fit.
 
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i put mine in fully assembled had a pal and the handle of a kiser blade as a pry bar ...give me a lever and i can move the world (or a norton engine) sez archimedes
 
If putting a engine into an assembled bike was done by me that often, I'd make a triangle shaped 5/16-3/8 steel plate-pad that bolts into the 3 head holes on top. A 1x1 thick wall box tubing a few feet long (can easily hold a hanging 80lb engine) and use an engine hoist with caster wheels to roll it into position and very gently set it in position.
 
I’m so glad I removed and replaced my Commando motor BEFORE doing it on a Tonti Guzzi. Otherwise I would really hate the Isolastic setup. The Guzzis are a dream. But then again clutch work requires major frame removal... sorry to hijack the thread.
 
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