Water in Engine

So, I bought a once well-loved XJ700 from a neighbor for $70, with a title. The problem is, this neighbor had left the bike sitting outdoors, uncovered, with the valve cover, exhaust and spark plugs all removed. So yeah, rolling the bike into the garage caused watery oil to bubble out of the gear case breather. I can imagine there is more.
The head looks like this;

If, and this is a huge IF, this engine can be salvaged, what would be your first step?

To me, I would drain the oil/water concoction and replace with clean oil, understanding that that will not fully cleanse the bottom end but at least it will reduce the contaminants inside. Then, (the engine is seized) add an acetone/ATF mix into the cylinders to free the pistons and maybe expose the master link in the cam chain to enable easier head removal. I can imagine that the head is scrap, but replacement heads from parts bikes can be had for $75, so no problem there. At least with this plan one would not circulate the contaminated oil around the bottom end bearings. Then, remove the cylinder bank, mic and hone the cylinders and pistons, replace the rings (assuming everything is within spec), clean the carbs, check out the iggy, put it all back together, change the oil again, give the engine a few test start ups, flush the engine with new oil and maybe some MMO, then start into work on the ancillary systems like the shaft drive, brakes and suspension. Worst case, a replacement engine can be sourced for these for a few hundred, or even a later (non-tariff restricted) 750cc engine.

 

If the crank and transmission guts are rusty it ain't worth it.

 

After draining it I'd pull the clutch cover and have a look. It'll give you some idea how much corrosion was going on in the bottom end.

If it collected much water the clutch will be shot anyhow.

 

I drained the oil, lots of water. Just under 8 quarts of "fluid" came out of the engine through the crankcase drain plug and filter housing. I went ahead and poured in 5 quarts of 5W-20 just in the hope that it will squeeze into the bottom end and displace any remaining water. Can't hurt.
Tomorrow night I will take a stab at draining the gear oil out of the tranny.

 

Gear oil should only be in the rear end. The tranny has the same oil as the crank, although there is another drain plug, it's likely contaminated with the same stuff...

 

I would start looking for an engine. Go ahead and hold on to that one. Eventually it will be economical to rebuild (30 to 40 more years on).

 

Well I mixed up some acetone and ATF and poured a few ounces in each cylinder. I'll check back in the morning to see if it soaked past the rings.

 

I don't like the idea of acetone in a motor. Acetone will eat seals.

http://www.advrider.com/forums//showthread.php?t=391529

 

Once freed up, his engine will need to be torn down, and have all the seals replaced as part of a rebuild anyway.

 

This.
I have heard nothing but amazing stories about how acetone and ATF make for a fantastic penetrating fluid. Never tried it, so I figured I would give it a chance here.

 

dude, what you have there is a boat anchor

 

Most likely, yes. But I am a tinkerer, so I will at least pull off and clean up what parts I can for resale, and if I can get it running one day (either with this engine or a swap) so much the better.

 

hank, if nothing else, save the cases and build your new engine from them---that way you'll have matching numbers.............assuming the engine is still the original one to the frame.....

dave F

 

Oh, I'm not that married to the idea of originality. Fact is, it would probably be easier to find a 750 to swap in rather than another 700 if and when it becomes obvious that this engine cannot be saved.

 

Then empty the cases and someone might be interested in the parts.........

 

Patience, let me get there on my own.

 

Anyway, the penetrating fluid drained out of three of the four cylinders, so I took a crescent wrench to the left end of the crankshaft and sure enough it moved about 1/8". Baby steps.

I also went ahead and removed the carbs and cams to help with the engine rotation. The carb boots are in pretty good shape, and the cam journals looked good for the most part, but I haven't really cleaned them up yet.

 

If any of the cam "toes" are as rough as the "heel" in the upper left - get different cams.

 

Hey, look at the fun you are having! It is keeping you out of other trouble. Now if this was a Vincent or a Gold Star everybody would be advising you to save every little original part. If this goes back together-cool! If not, you at least had a lot of fun for little money. Good Luck, this is going to be fun to watch.

 

Replacement cams are cheap, but I'll still take a little 00000 wool to these and see if they shine up.

Somebody gets it.

 

Hmmm, well the head came off with relative ease. One stud was rotted and came off with the nut, and sadly the right cylinder was full of rust. Even the combustion chamber and both valves were rusted up.

 

#4 cylinder is definitely not happy times. I think you will find that the effects of water are widespread. like polock said earlier, "what you have there is a boat anchor".

CN

 

Well, once you realize you need to replace that motor let me know. I have an '85 engine with right around 35k on it. Has a very slight tick on one valve I think it's on the number one cylinder. Shim it and go.

Also, if I'm not mistaken the 700 frame won't hold a 750 the mounts are to different.

 

Oh I'm there, between here and a couple other forums it seems I have reached the limit of this engine. I am going to call some local breakers and see what they have; one not too far from where I work had a good condition 750 a couple months back. No idea what he wants for it, but there are several on eBay in both 700 and 750cc variants that would be between $4-600 shipped.

This from the Information Overload Hour

Not sure why it would point out that one would need to use the 700 frame engine mounts considering that I would be swapping into a 700 frame, unless someone got excited and started cutting them out thinking they wouldn't work.

 

I believe you're getting some years mixed up with the engines.

IF I remember correctly, the 85-86 700 and the 85-86 750(Canadian......was not available in the USA) airheads are the same bike, just diifferent displacements. The 85-86 750 airhead should drop right into the 85-86 700 airhead frame. You may need to swap the TCI.....................

Your swap has nothing to do with the 650, unless you're looking at a 81-83 XJ750 engine. In that case, yeah, you'd run into the 650/750 swap stuff, but again, that would be for the 81-83 years. It seems like I'm reading that you're getting the earlier 750 engine mixed up into the later frame.........

carry on--

dave f
Dave Fox

 

Just going by what was posted, I have no idea.

 

Couple local salvage yards have XJ's in various flavors, I am going to swing by and see if I can get an eye on one this afternoon. If possible, I'd like to get a complete parts bike

 

Last year, my old lady wrecked her '85 700. Amazingly enough I found another one, same color, same year and within 75 miles of the same mileage.
The replacement bike had some carb issues. I swapped the carbs off the wreck onto it and down the road we went.

The wreck destroyed the front whee,l the forks, the handle bars, the tank and the frame. Front brake lever was also broken off. I kept the rest of of the bike. Cut the frame up for scrap.

Shipping the motor from Wisconsin to Texas may be cost prohibitive, but if you need anything else, I sell parts pretty cheap.

 

Shit, as soon as I was ready to toss this engine in the bin, the damn thing made me happy again. Figured I would try and pull the cylinder block, and damn if it didn't pop off with just a few whacks with a wood block. Sure, the pistons and cylinder walls have some rust on them, but I'm seriously encouraged. Had it been a major chore to pull, I'd be more convinced that it was f***ed, but nope.

 

Jeez, you got to believe!

 

I am nothing if not determined.
I did run by a salvage yard that said they had several XJ's in decent shape. They did certainly have several, three 750's, a 650 and a 550 Seca that I really liked. Sadly, "decent shape" is a very subjective term. The 550 was the most complete missing just some body parts, all the others were all missing their starters, only one had carbs, one was completely open much like the engine I already have, none of them looked worth the $200 he was asking for a mill.

 

Hey, maybe you can get the EvapoRust folks to sponsor your rebuild to prove how good their stuff is. At least get them to give you a sample. You can show them this thread and to "before" pics. Still having fun?

 

I wish, at any rate I will photograph the hell out of everything for a reasonable Before:After slideshow.
I would be having fun if I haven't had to work till past 8 the past few nights and still had some time to wrench when I get home. But I am clear this weekend so I am looking forward to removing the pistons, rings, dunk them all in the sonic bath and maybe even get a hone and try to clean up the bores.

 

These are the worst of the pistons

 

Going to back to my local salvage yard engines from earlier; most of the engines he had didn't appear much better than what I've got already, except for the fact that they are 750's. I have searched through a couple dozen different terms trying to find this answer, so I apologize if it has been answered, but the 700 and 750 share the same bore, with the 750 having a longer stroke, thus a different crank, correct? I understand, though, that the cylinder height and pistons are different, as well as compression ratio. So simple crank swap isn't a real consideration.
Thus theoretically, if one had two questionable engines, a 750 and 700, both of which would need work to make them functional, one could take the internals from the 750 and move them to the 700 cases (to keep the VIN matching the frame). This would require the use of the 750 cylinders and pistons and likely the head. Basically the only thing left from the 700 would be the cases themselves. The advantage is a greater parts availability for 750 stuff. Big bore kits and the like.
I am not considering the tranny at this time, although input on that would be helpful for the future.

 

don't worry about VIN #'s the only one that counts is on the frame

 

I know, the title is tied to the frame, I've been around vintage bikes for a while. But if I would have to rebuild a junkyard engine, I may as well keep the VINs together. Meaningless except to me I guess.

 

Pistons turned out well. I'll probably still soda blast them to get the ring lands cleaned out.

 

the thing with swapping cranks is the bearing colors, green, pink, poka-dot who knows, the cams should be kept with the head too

 

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.