Engine Swap - XJ to F

[bikerphil]

both the main clutch nut and the countershaft bolt will rotate the gear assembly, should I get them loose prior to disconnecting the output shaft? What about reassembly - tighten the countershaft bolt as much as I can on the bench but wait until it's in the bike to tighten and install the clutch basket?

You can do as you mentioned, that will work fine. If you have an impact gun, that should work with the engine on the bench in most cases.

[DGXSER]

+1 the torque is for resisting engine operation forces. Long as you remember to torque them before you put the pans on and run the engine all will be just fine.

[trbig]

I think he's talking about torqueing the counter shaft, and clutch drum nuts Tod. ( Well, technically the countershaft has bolt)

It may be against Hoyle but I just stuck a screwdriver in the teeth of the gears to keep them from turning.

Ahhh.. OK.

On the clutch side, above the clutch basket, there's a gear with a slot in the case next to it that I have always presumed was to be used for what you speak of. I stick a screwdriver in there that fits well and have always torqued those nuts this way...

[XS11UFO]

Update

Hay guys! Thanks for the help so far – update first then questions.

The engine arrived…



… from the wear on the shift peg rubber as well as how clean it is inside the valvecover it really
looks like an engine with only 10k....


... Check out those cam lobes!

Thanks to the help I got here, I got the engine out..



…I cheated – see the engine hoist in the background?



..I only had to move the engine about 6 inches to the right with the floor jack before I could use the hoist.

Now the questions :
1. The red sensor on top of the ’79,



I am going to move it to the ’82 – correct? What is it?



2. The alternator, all the plugs are interchangeable but the 4 pin connector on the ’79 has all 4 wired...



...on the ’82 only 3 are wired...



Crazy steve said – “The alternator is a easier swap; you can leave the XJ unit in place as all the
harness wiring is the same, but you do need the matching XJ regulator”. The colors on all the wires
are the same in both 4 pin connectors, white? The colors of the wires in both of the smaller plugs
are the same on both engines (green/black)...



... Do I use the ’82 or the ’79? If I put the ’79 charging system on the ’82 engine, do I have to switch
everything: stator and rotor? (I like the alternator cover from the ’79 – the ’82 has a little road rash.)
The rotors / covers are totally different -
’79...




’82 ...




– do I need a puller to get the rotors off?
3. DGXSER mentioned the XJ has an oil level light instead of an oil pressure switch. IT also has the
clutch and side stand safety switches. Do I have to do anything with them?
4. Exhaust studs – The ’82 studs...



...are a lot shorter than the ’79 ...



(headers must be different), replacing all the studs sounds like a total PIA. Is there a bennifit to
running the ’79 cams / ignition with the ’82 top end? I know I will lose compression doing it that
way and I will have the YICS to deal with. Trbig – said “I used the early cams on my XJ and it
absolutely killed low end torque.”. Was that with the older ignition profile? Maybe that might help?
I was thinking with the larger valves but the aggressive cam / ignition the performance might be a
wash but be comfortable on regular gas?

Tomorrow I’ll pull the ’79 pan and try the 1st & 2nd gear mod / washer fix. I am uncertain enough
so that I am glad to have the seized engine to practice on. I am looking forward to seeing the 2nd
gear on the old engine as it was getting pretty bad prior to dying. Then I will tackle the new engines
trans. I have seen others here (besides me) looking for video of the procedure, I may get ambitious
and video my screw-up’s for posterity.
When I’m done with the old engines trans I will start disassembly / autopsy (I’d like to know why it died).

Thanks again for all the help.

[IanDMacDonald]

I fell asleep reading this post, lol. the red sensor is your oil pressure sensor for the oil light.

[XS11UFO]

Sorry it was so long.

[DGXSER]

First off, never mind Ian, he apparently needs more naps in his day. Your post is fine, good pics of your questions.

Congrats on getting the new engine and the old one out, remember, if your not cheating, your not trying hard enough.

I'll do my best to answer what I can of your questions.

Now the questions :
1. The red sensor on top of the ’79,



I am going to move it to the ’82 – correct? What is it?

That is the oil pressure switch, you will want to move that over to the 82 engine. Your harness is wired to use that switch and not the oil level switch in the XJ. I would assume (Never owned or seen in person an XJ motor) there is a switch in the oil pan for the oil level in the XJ engine. I would plug it, or just leave the switch. Your harness will not have a wire to hook to it.

2. The alternator, all the plugs are interchangeable but the 4 pin connector on the ’79 has all 4 wired...



...on the ’82 only 3 are wired...



Crazy steve said – “The alternator is a easier swap; you can leave the XJ unit in place as all the
harness wiring is the same, but you do need the matching XJ regulator”. The colors on all the wires
are the same in both 4 pin connectors, white? The colors of the wires in both of the smaller plugs
are the same on both engines (green/black)...



... Do I use the ’82 or the ’79? If I put the ’79 charging system on the ’82 engine, do I have to switch
everything: stator and rotor? (I like the alternator cover from the ’79 – the ’82 has a little road rash.)
The rotors / covers are totally different -
’79...




’82 ...




– do I need a puller to get the rotors off?

Now, this is where my lack of XJ knowledge limits the answers I can give you. I tried to pull up the XJ manual but I think the link in Marshall's site is not fully functioning.

If it were me, given the differences in wiring harness, unless your enough of an eletrickery guru to figure it out, I'd swap the alternators to keep the same components and wiring. Keep in mind the XJ alternator has better output than the XS though. And yes you will want to swap the rotor out as well, there is a special bolt that most folks use to pull it.

HERE is a thread with good info and alternate approaches.

3. DGXSER mentioned the XJ has an oil level light instead of an oil pressure switch. IT also has the
clutch and side stand safety switches. Do I have to do anything with them?

The clutch switch and the side stand switch are separate form the engine, I probably misled you a little there, sorry about that. Nothing important to do with those for this swap.

4. Exhaust studs – The ’82 studs...



...are a lot shorter than the ’79 ...



(headers must be different), replacing all the studs sounds like a total PIA.

You can test fit your headers to the engine and see if the studs reach through enough to get a nut on them appropriately. Otherwise, you will need to swap either the heads, or the studs. The studs are not horribly tough to get out. With the aluminum they seem to come out MUCH easier than in an old cast iron block.

Is there a bennifit to
running the ’79 cams / ignition with the ’82 top end? I know I will lose compression doing it that
way and I will have the YICS to deal with. Trbig – said “I used the early cams on my XJ and it
absolutely killed low end torque.”. Was that with the older ignition profile? Maybe that might help?
I was thinking with the larger valves but the aggressive cam / ignition the performance might be a
wash but be comfortable on regular gas?

I have nothing for you on the performance aspect. I have often stated that the level of performance increase from such mods is only going to be noticeable if you really use and test the torque and power these bikes have. Most of us never do. I have never put anything over 87 Octane in my XS11s. They run great on it and get good millage.

Tomorrow I’ll pull the ’79 pan and try the 1st & 2nd gear mod / washer fix. I am uncertain enough
so that I am glad to have the seized engine to practice on. I am looking forward to seeing the 2nd
gear on the old engine as it was getting pretty bad prior to dying. Then I will tackle the new engines
trans. I have seen others here (besides me) looking for video of the procedure, I may get ambitious
and video my screw-up’s for posterity.
When I’m done with the old engines trans I will start disassembly / autopsy (I’d like to know why it died).

Thanks again for all the help.

You can have lots of fun playing with getting the gears in and out with the method in the tech tip, or make your life simple since you have the engines out, and just split the cases.

[BA80]

Looks like everything has pretty much been answered.

On the alternator, That yellow wire is the trigger for the headlight relay I believe. It would be much less complicated just to use the 79 alternator. The XJ alternator is more powerful but will probably require some wiring issues to need modifying.

On the exhaust studs, the 79 ignition will need to be used so the 79 cams will also need to be used since the ignition timing curve is tuned to THOSE cams. This is why I suggested before that you just swap the entire head.

That would not only render the exhaust stud issue moot but would also eliminate the YICS ports that would otherwise need to be plugged. The only possible issue would be valve to piston clearance (due to a higher crown on the later piston) which should be checked since no one seems to have tried this before. It would be a fairly simple check and I don't think the clearance will be an issue because of the slightly smaller intake valve.

Swapping heads may even prove to be beneficial to power.

[XS11UFO]

2nd Gear Fix Question

I am having a difficult time getting the gear set out. I think the problem is the kick starter gears, the one on my ’79 trans binds the middle drive gear and won’t allow the gear set to shift far enough to the right (5th gear side) to allow me to lift it out. The kick starter gear that I’m talking about seems too tall to allow the 1st gear to get by vertically. This is the blown engine so I’m doing this one for practice before I dig into the new engine, the XJ engine shouldn’t have these gears. I toyed with the idea of putting the kick starter gears into the new engine but I can’t even get the gears out.

I know I’m missing something stupid, I appreciate the extra eyes seeing what I’m missing....

[bikerphil]

The transmission should be in 4th gear to allow the countershaft to be removed, is it?

[DGXSER]

The middle driven gear and first gear can slide on the shaft, the first two gears on the end by the kickstart gear. So the shaft can slide without those two gears moving.

Also, make sure the shift forks are all three clear of the gears.

[XS11UFO]

It's in 4th. I was able to slide the shaft to the right while the middle and 1st gear slid left on the shaft, was able to get the shaft bearly clear of the case on the left but was unable it get the shaft with the 1st gear on it vertically past the kick starter gear.

Anybody done this with all the kick start gears in there?

[BA80]

I am having a difficult time getting the gear set out. I think the problem is the kick starter gears, the one on my ’79 trans binds the middle drive gear and won’t allow the gear set to shift far enough to the right (5th gear side) to allow me to lift it out. The kick starter gear that I’m talking about seems too tall to allow the 1st gear to get by vertically. This is the blown engine so I’m doing this one for practice before I dig into the new engine, the XJ engine shouldn’t have these gears. I toyed with the idea of putting the kick starter gears into the new engine but I can’t even get the gears out.

I know I’m missing something stupid, I appreciate the extra eyes seeing what I’m missing....

It's in 4th. I was able to slide the shaft to the right while the middle and 1st gear slid left on the shaft, was able to get the shaft bearly clear of the case on the left but was unable it get the shaft with the 1st gear on it vertically past the kick starter gear.

Anybody done this with all the kick start gears in there?

I have done it several times. It will come out but requires some finesse. I have found it's easier if I remove the shift drum. The detent for the drum is a REAL PITA to put back in from this side but I've done it a few times. That largest gear, not sure what it is right now, has to slide off the shaft before everything will come out.

[DGXSER]

Once the shaft clears the case you will need to wiggle and slide things back toward the shift drum. Or, you can split the cases and make it real simple. Main reason most folks don't split the cases is it requires removing the engine. Yours are already out.

[XS11UFO]

Wow, no worries for me this one was just practice but I didn't see any mention of differences in the tech tips. Maybe in the addendum, would only have to be a note of warning? Good idea? Bab?