Water in Engine

i wonder why you couldn't swap just cylinder liners like they do on those small bores

 

That depends on the state, and when the bike was first registered. One of the guys in town that I ride with occasionally has a titled '78 sporty engine, but it's not in a titled frame. That's a comment meant to disagree, but to inform those who are just getting started with old bikes.

 

maybe it's a '79
http://www.harley-performance.com/harley-vin.html

 

Oh yeah, my first bike was a 79 XLH, they are notorious bastards with unique frames, rear brake cylinder, all kinds of stuff. The infamous "Fits All Models Except 79".

 

You might want to think about it now, before you spend a bunch of money and effort on the top end of the motor.

Swapping cranks could get interesting real fast, because of the bearing-shell tolerances that Polock alluded to.

The transmission itself, if horribly rusted internally, won't last long once you put it back in service. If the bearing surfaces and load-bearing surfaces of the gear teeth have been compromised by rust, they will quickly erode or fail outright under load.

I'd drop the sump and pop the LH (shifter) cover off and have a look before going too much further up top.

 

I pulled the shifter cover last night, everything was coated in milky oil but once I cleaned it out the internals were spotless. Once I get the engine out of the chassis I will drop the sump. Looking down the bores into the crankcase, everything looks nice and clean, and spins freely. I am rather encouraged. I am still going to pull it apart and clean everything, but I am hopeful that replacement parts would be minimal, at least on the bottom end.

 

You might have gotten lucky, and the exposure to water wasn't long-term enough to do any serious damage. Sounds promising.

 

Shank,

Happy times. This is interesting. I was hoping you would go this far before you scrapped the mill but didn't want to sound "crazy" for suggesting such a thing. XJ's have very durable engines yet there are those things with any engine, like water damage, that doesn't make it cost effective to try to save. I know water damage to the lower end would have ruined it. Have you pulled the clutch cover yet? I know you have the sandblasting cabin but have you tried Evaporust? It's good stuff.
Roc

 

Well the way i look at it, I am into this engine for nothing more than time and a ton of shop towels. Oh, and a gallons of new oil which I already drained back out of the case. Nasty stuff, but it ran pretty clean by the time it was almost out. There were a few globs of uck which are probably sitting just in low spots on the bottom of the case near the rim of the drain plug.

 

Quick answer No, they are not the same piston:
1985 XJ700 Piston (Std bore) part #1FG-11631-00-00
1983 XJ750 piston (Std bore) part #5G2-11631-00-00

Now, the first three symbols indicate the model, so in fact there remains the possibility that, after further research they actually are the same, but so far my research has not come up with a solid answer. Even though they are the same bore, the skirts, valve cut outs, crowns, ring lands, any number of things could be different. I do know that the 700 had a slightly higher compression ratio than the 750 to make up for the loss of displacement.

For fun, I went ahead and collected the part numbers for the 650/700/750 conrods and cranks for comparison:
XJ650 Connecting Rod part #4H7-11650-00-00
XJ700 Connecting Rod part #1FG-Y1165-00-00
XJ750 Connecting Rod part #5G2-11650-00-00

XJ650 Crankshaft part #4H7-11411-10-00
XJ700 Crankshaft part #16G-11411-00-00
XJ750 Crankshaft part #5G2-11411-00-00

Now, this may indicate that the connecting rod is the only difference between the three bikes, other than of course the smaller pistons in the 650. Oh yes, and the 700 cylinder block is shorter due to the shorter stroke.

XJ700 Cylinder part #1FG-11310-00-00
XJ750 Cylinder part #5G2-11310-10-00

At this point, without putting parts from all three side by side and taking some measurements, we may never know. I am now really tempted to buy a junkyard 750 engine in order to do just that.

 

In most cases, the model prefix DOES make a lot of difference.

There are a lot of parts with similar numbers (mufflers, exhaust pipes, tank badges, fenders, etc., etc.,) where the parts are completely different and the only difference in the part numbers are the model codes.

 

I get that, I am not hanging my hopes on them being the same, just pointing out the research I have done. In all honesty I realize it would be easier (assuming my bottom end is solid) to just swap on a replacement top end from another 700 and be done with it. A 750 engine swap is still on the table, but I'd really like to reuse as much of the original engine as possible, and based on my research on cranks and the color coded bearings and shims, swapping the crank doesn't sound like a way to build a reliable engine.

 

I have been on vacation for the past week, and prior to that was yet another cold snap, rendering the garage too cold to work in.
However I am home now and back at it. I went ahead and finished removal of the starter and rotor/stator. I pulled the rotor with the old M16-1.5 bolt, popped right off. Then I spun the bike around to give myself better access to the right side, and pulled the clutch and right crank end cover. One legacy of the PO, he had both crank end covers chromed, and now both are bubbling/flaking. Who plates aluminum? Stupid people, thats who. I then pulled the clutch springs, plates and inner clutch basket. I am at the point where all I have left is to go ahead and pull the engine out and up to the workbench. This weekend, big time.
Not much in the way of pictures, sorry.

 

Nice pic of a clutch with oil/water syrup dripping out of the housing. I always thought oil and water wouldn't mix until my Dad blew a head gasket in his Ferrari. Then I found out that it IS possible.

Just pitch the friction plates and replace them with "aftermarket" plates; and clean up the originals with Scotchbrite.

Pop that brake pedal off so it's not in your way.

 

Isn't that what we call an emulsion? Like vinaigrette or mayonnaise?

 

Motor oil mixes with water - because there's an additive that MAKES them mix, to save an engine with a blown head gasket from destroying the crank. Straight water in crank or rod bearings turns right to steam !

 

My fingers are crossed for a triumph of hope over expectation..

Good luck !

JS

 

Engine out biotches!


I then proceeded to pull the middle gear assembly, oil sensor, ignition pickup, and am ready to pull the oil pan. Guess I should have done the oil pan before pulling the cases, but que sera.

 

put the nuts back on the cylinder studs, don't bugger up the threads.
do those have the hidden bolt under the oil filter?

 

One of the cylinder studs is snapped, and four others have rust so I'll probably pull them out, but thanks.
And yes, there is a bolt inside the filter housing. I assume that that is what you referring to.