Complete XJ650 Rebuild

Just, uh, put a block of wood or something on top of the piston. Those become freakin' missiles.

 

Not with a grease gun it doesn't. It becomes a missile with an air gun. Grease doesn't compress and force out via uncontrollable expansion. It forces out by hydraulic pressure, and loses its pressure instantly every time the piston move the tiniest bit. It will slowly force the piston out. The extra thing you need to do is clean up the grease.

 

Was putting my cases together today and a lot of the bolts I had from the cases don't seem to match up with the numbers from this thread
http://xjbikes.com/forums/threads/xj750-engine-removal-and-split-pictures.38545/

Is there any other link of what bolts that go to which hole. The manual doesn't list them, just the Thread Size, not the length?

 

Also 11-17 is listed as 8mm but I think they are 6mm?

 

I'm afraid that you'll have to do some measuring to figure that out. TO the best of my knowledge all of us on here make a cardboard template to put the bolts into as we tear the engine down.
Here's how I tackle the process of finding out the depth of a blind hole. Take a length of stainless wire, or of a wire coat hanger. Put it down the hole and mark it wih a sharpie, then remove and match the marked length to the closest lenght of bolt that size. The sharpie can be wiped off with brake cleaner when you move to a different depth of hole.

 

The Yamaha crankcase fastener system is a "can-o-worms" because there are two different numbering "systems" for the various fasteners:

- in the service manual, which has the fasteners numbered IN ORDER OF LOOSENING (AND THEN DURING ASSEMBLY, THE ORDER OF TIGHTENING). Thus each and every fastener position has a unique ID number.

- in the parts diagrams, the bolt fastener positions are given ID numbers based on their SIZE, thus multiple bolt hole positions can (and do) use the same size fastener, and thus carry the same " ID number".

The numbers that are cast into the engine cases (in some positions) are the unique position numbers and correspond to the numbers in the service manuals (i.e. the order of loosening or tightening). These numbers, ALTHOUGH SOME OF THEM "OVERLAP" WITH THE POSITION NUMBERS IN THE PARTS MANUALS, have nothing to do with each other and should never be confused!

The "use at" numbers listed below are the PARTS MANUAL POSITION NUMBERS, and thus are not what is cast into the crankcase, nor what are listed in the service manual diagrams.

And finally, the position ID numbers in the PARTS MANUALS differ between various engines; what is listed below is correct for Devin's 1982-83 XJ650 MAXIM model, but may (or may not) be the same for other XJ650 models, years, or for any other engine size, even though there will, in fact, many of the same size fasteners used on other engines.



*HCP15951
OEM crankcase upper-to-lower retaining BOLT
use at: position 25 (2 per engine)
size: m6 x 55mm


*HCP15952
OEM crankcase upper-to-lower retaining BOLT
use at: position 27 (3 per engine)
size: m6 x 35mm


HCP15945
OEM crankcase upper-to-lower retaining BOLT
use at: position 17 (use 10 per engine)
size: m8 x 105mm


*HCP15946
OEM crankcase upper-to-lower retaining BOLT
use at: position 19 (use 2 per engine)
size: m8 x 65mm


HCP15947
OEM crankcase upper-to-lower retaining BOLT
use at: position 20 (use 2 per engine)
size: m6 x 120mm


HCP15948
OEM crankcase upper-to-lower retaining BOLT
use at: position 22 (use 3 per engine)
size: m6 x 80mm


HCP15949
OEM crankcase upper-to-lower retaining BOLT
use at: position 23 (use 3 per engine)
size: m6 x 70mm


*HCP15951
OEM crankcase upper-to-lower retaining BOLT
use at: position 25 (use 2 per engine)
size: m6 x 55mm


*HCP12786
OEM crankcase mounting BOLT
use at: position 26 (use 7 per engine)
size: m8 x 45mm


*HCP15952
OEM crankcase upper-to-lower retaining BOLT
use at: position 27 (use 3 per engine)
size: m6 x 35mm


Although all of the above is screwy (but, at least it's semi-logical "different diagrams for different purposes" point of view), there's just no getting around the other more interesting aspect of rebuilding these engines: bearing sizes: compare scrawled on engine case vs. cast on crankshaft numbers, subtract A from B, the sum is the bearing "color" code, which is a surrogate for the bearing thickness. Now, measure your bearing clearances with plastigauge. If the cleanance is out of spec (let's say, too big of a clearance, or "loose") then what replacement "color" (size) bearing should you use?

Good luck on answering that question!

 

Hey guys, back for an update. Got the Flu and was down and out for a bit.

I ended up doing what K-Moe suggested and just measuring each hole and have some different numbers than what Chacal has listed above. Having trouble finding bolts at local hardware stores for really anything over 55mm, especially the longer ones.

But outside of that I got the Crankcase together. Not sure if I mentioned but I remeasured all bearing journals with Plastigauge again and had much better results.
I used Loctite 518.
After a weeks or so the "Squeeze Out" is still wet, is that normal??

Everything feels like it is moving smoothly, the shifter forks move freely and all the gears spin fine! So I think I am good there.
One I get the hardware complete for the crankcase, on to the rest of the assembly.

In the meantime, got some fresh tires and started putting it back together to start figuring out Lights, Fenders, Etc.

Here is what she looks like

 

Loctite 518 cures anaerobically. The squezeout will never cure (which is the whole point; no risk of goobers coming loose inside the crankcase and blocking an oil passage. The excess just mixes with the oil). Clean it up with a rag and some carb cleaner or mineral spirits.

 

I'm liking the looks of your progress, very nice neat work.

 

Hey Chacal.
I see position 25 and 27 are repeated. But according to my parts diagram I need bolts for position 24 and 21?

Am I missing something?

 

Cases are together and moving on to assembling the rest of the engine.

Got another question for you all and a little update on progress.

Update.
I was putting together the Oil Pump / Filter and the gear that turns the chain was not turning smoothly. So I disassembled it and found out between the screen and the cap of the filter was completely packed with debris and metal shards (from the old engine). Unfortunately I did not get a picture of it but I highlighted the area that was packed with crap. Got that cleaned out and all put back together, everything turning smoothly.


Question.
I was now onto putting the clutch housing into the case and everything goes in very smoothly but this jumped out at me.
The teeth on the housing rub up against case but since it sits around the transmission shaft, I have no room to move it or anything.


Now I looked at the old case where this hosing came from and it looks like it rubbed up against it too.


So I am just curious is that how it is supposed to be or is that something that can be "shaved" down?
Because when I do spin the housing with my hand, it does catch that lip every now and then.

 

It's a tight fit but the basket shouldn't rub the case at all.

Gary H.

 

Been working on a lot of things lately but good news, the engine is complete and everything worked out when checking the timing!

I will update with pictures but I am moving onto electrical and this could be a head ache:/

First thing that jumps at me is the diagram shows a ground wire coming from the Starter Motor.

But I don't see how that is possible. The only Stud coming from the Starter Motor is for the wire coming from the Stater Switch, so where would the ground attach? I do have a large gauge wire that is bolted to the middle-back side of the engine that I have not found where to attach that to yet either.

Outside of that, just mounting and placing all my new things like Turn Signals, Tail Lights, Gauges.

 

There is no ground wire for the starter, it's grounded by bolting to the engine. The electrical schematic just shows that it is grounded.

There are two wires bolted to the back of that motor. One goes to the battery negative terminal and the other goes to the frame.

 

Thanks, That is what I was thinking was going on, but I wanted to make sure incase I was understanding it wrong.

 

I am looking at replacing my Rectifier. Are all of them universal or am I crazy. I have been search a bunch of different sites and when I enter my make and model of bike, nothing comes up but a lot of them list other types of bikes. So I was curious if there are specific ones for different types of bikes or uses?

 

Start a conversation with Chacal. He has the correct regulator in stock. They are not a universal part, even though they all do the same job.

 

Electrical update. I don't have the link but I got a diagram from these forms of "Simple Wiring for Xjs" and I have that complete.
I have my tail light turn on and when I flip the switch to run and click the start button, my starter circuit cut off relay clicks but that is it.

I was expecting to hear something from the stater motor.
Should I here something and if so any idea what is wrong?
I am still in assembly so I don't have any fluids, gas, or carbs on yet:/
I know that sounds stupid but I was thinking I am just trying to get the starter motor to make sound

 

Jump the two post on the solenoid. The starter should spin.

Gary H.

 

I am not an electian but what do you mean jump?:/
I think I know but want to make sure and if so what does that mean for my solenoid?