Pulling the Case Apart for the 1st time: What all should I be checking?

[Niels B]

ahha- yeah I totally just assumed that was the top of the engine off when I was looking at those videos.

For the jack- I could make this work with wooden blocks? Or no?

Also, how heavy is that transmission- Something I can lift out of the frame myself once the top part of the engine is off of it? I imagine it couldn't be more than 75-80 lbs.

I’m not even aware that you can take the top off without removing the engine from the frame .
I have done full resto, which always cause a total strip down. Then I lay the frame and engine on th side and lift the frame off the engine - can be done by one person, except when assembling I like an extra hand to avoid scratching the newly painted frame, otherwise in my case it’s a two man job to lift the engine out of the frame ( I’m not that strong )

 

[meteorgnome]

I should be more precise with my language here- apologies- I meant the head and cylinders

please excuse my ignorance!

 

[Niels B]

It’s all good but have below in mind when you do this

Disassembly: You'll need to remove the fuel tank, airbox, and other components that might be in the way.
Remove Components: Disconnect the wiring, fuel lines, and other connections to the engine.
Remove Cylinders and Heads: Loosen and remove the bolts that secure the cylinders and heads to the engine block.

Challenges:
Space: Working in the frame can be tight, so you may need to be resourceful with your tools and techniques.

Access: Some bolts might be difficult to reach, requiring extensions or specialized tools.

 

[Jim]

I’m not even aware that you can take the top off without removing the engine from the frame .

There's a mod you can do from the Yamaha racing manual of that era. Otherwise no, you can't remove the rocker box, head and cylinder with the engine in situ.

And to do the mod, the engine needs to be disassembled. So it still needs removal from the frame.

 

[Raymond]

The Big Lift is taking out the engine and gearbox, which is removed as one big heavy lump. Yes, as Jim mentioned it is possible to modify the engine so the head can be taken off without removing the engine but that is outside the experience of most here.

I invested in a block & chain to lift the engine out but otherwise your options are lift it out yourself - be warned, it's heavy. Or borrow a strong friend or friends to help you lift. Or lay the bike on its side, loosen the mountings, and lift the frame away from the engine. This can be a good route if the whole bike is being dismantled anyway, otherwise probably not.

That's the big step. Once the engine & gearbox is out, it will sit on the floor or on a workbench. A few short bits of timber will wedge it from falling over. You could roll it forward to sit on the cylinder head, again prop/wedge it, then the lower crankcase half can be taken off to give access to both gear shafts. But TBH, since the big step is removing the engine, once it's out, might as well strip it top down which gives the opportunity to check throughout.

Just my 2c.

 

[Bob Wegman]

If you don't want to break the cam chain apart, you can still disassemble the top end. Remove the cam covers and slide off the bearings from the camshaft and you can then have enough slack in the cam chain to remove the cam from the head.

 

[meteorgnome]

My clymer manual says specifically that "The cylinder head can be removed with the engine in the frame"

I'm working on a 1979 xs 750 - which I guess I haven't mentioned until now in this thread.

 

[Niels B]

There's a mod you can do from the Yamaha racing manual of that era. Otherwise no, you can't remove the rocker box, head and cylinder with the engine in situ.

And to do the mod, the engine needs to be disassembled. So it still needs removal from the frame.

View attachment 346196

My clymer manual says specifically that "The cylinder head can be removed with the engine in the frame"

I'm working on a 1979 xs 750 - which I guess I haven't mentioned until now in this thread.

Well I think all the replies you’ve gotten here relate to the xs650 - at least as far as my replies go - have never worked a xs750 - total different animal as far as I know your model is a 3 cyl with dual cams.
Good luck - I’m sure other here have knowledge of this model !

 

[Raymond]

My clymer manual says specifically that "The cylinder head can be removed with the engine in the frame"

I'm working on a 1979 xs 750 - which I guess I haven't mentioned until now in this thread.

Uh-oh, different kettle of fish . . .

 

[Jim]

I'm working on a 1979 xs 750 - which I guess I haven't mentioned until now in this thread.

Wait, what?!?

 

[jetmechmarty]

I'm working on a 1979 xs 750 - which I guess I haven't mentioned until now in this thread.

Yes, you can dismantle the top end in the frame. At least, the XS1100 comes apart in the frame. It’s my assumption that the XS750 is the same.

Keep in mind the XS750 has very little in common with the XS650. Specify up front. Those who can help, will.

 

[meteorgnome]

My fault- I'd intended this thread to be more of a general "What should I check" as the title said and had planned on making a more specific project thread once a few new tools arrive.

Got into the weeds pretty quickly here.

The transmission is basically the same design between the bikes though, am I wrong in this? Unfortunately there's much less info out there RE the 750 than the 650s.

 

[Jan_P]

Not sure if mentioned But second gear and all shiftforks inspection ---Can be an issue on other bikes
Depending on Mileage I am quick to replace springs and bearings .
I feel the cost is mostly not so high doing it and I sleep better.
A few bucks in relation to the work do it later.
With a new set of gaskets and cam chain link
I am a slow mechanic and dont have a good shop
So If I need to do something I do more and putting the next time longer into the future

The replacing of Springs I believe comes from, Other machinery Industrial sewing machines And to some extent Excavators I have worked on
Fishing reels
Many times the cleaning and perhaps a new spring Or shorting one , makes the difference + Adjustment
Rarely much more is needed On the German Pfaff Sewing Machines I have worked on

So generally speaking I replace almost every spring I can se .Unless expensive a few times one can Measure and inspect,
But again say a Unknown mileage on the machine Once in there I pay the extra money putting in new parts if not expensive
I am Economical and try to use parts well past " Best Before " but not in this.
Clutch springs -- Valve Springs - Shifting mechanism and so on
maybe overkill but it works for me


But maybe it depends I dont sell motorcycles I keep them and rides
And as mentioned .Cam chain parts .Just renew I do believe it is common practice for all vehicles these days