80 SG engine compatibility

[thebottle]

What other year/model engines fit into a 80SG? I am looking to swap engines because this one died on me and I am not going to spend the money to rebuild it when I can find engines and titleless bikes with less than 10k miles for under $400.

[cywelchjr]

If you don't want to have to move the ignition stuff under the left side cover on the engine, then anything 80 or older will swap in. If your willing to swap in your ignition components, then anything up to an XJ1100 engine will swap in, you just have to put the SG's ignition timing and pickup components and covers on (for the XJ the cover as well, for an 81 engine just the components). I've got an 81 engine in my 80G with my original timing and pickup components and it works just like original.

[skids]

What other year/model engines fit into a 80SG? I am looking to swap engines because this one died on me and I am not going to spend the money to rebuild it when I can find engines and titleless bikes with less than 10k miles for under $400.

If you swap the heads with the engines from a 78, 79, or 80, it will be plug and play. 81's have different black boxes and pick-up coil systems and no ballast resistors.

[tcoop]

IIRC all the xs11 engines will swap into. (with some ignition mod on the newer ones) Once I get some extra money I to will be getting a new to me engine for my 78. I have to replace the valves on my 80 (Now that I have a title I will be rebuilding it from ground up).

[cywelchjr]

If you swap the heads with the engines from a 78, 79, or 80, it will be plug and play. 81's have different black boxes and pick-up coil systems and no ballast resistors.

No head swap needed as the heads have nothing to do with it, it's the ignition components under the left cover on the engine. The 80 and 81 have the same heads, just different timing systems and different ignition boxes. Oh, and you can plug 81 coils into an 80 or earlier bike, just bypass the ballast resistor and your good, just like doing an aftermarket there, except you still don't have replaceable wires or higher spark voltage.

[crazy steve]

..If your willing to swap in your ignition components, then anything up to an XJ1100 engine will swap in, you just have to put the SG's ignition timing and pickup components and covers on (for the XJ the cover as well, for an 81 engine just the components).

Cy is correct, except on the XJ motors there are a few additional differences that need to be addressed. The big one is the YICS system the XJ used, which complicates carb syncs. Next, the XJ has a different alternator (a bit more output, but harder to find parts for) that uses a different regulator. Last, the XJ uses a low oil sensor, not pressure. You can swap the earlier parts for all of this except the YICS; well, you can swap for this too, but you need to change the barrels/head, so it's easier to just block it off. A member here sells the fix for this...

[tom clisham]

engine

Hey Bottle:
Where are you in the badger?

I've got a great running 79 sf engine 70,000 mi, plus a low (16000) mi 80g
engine that doesn't run. you can have them both for $100.00

I'm at the border just South of Broadhead Wi

PM if interested

[skids]

No head swap needed as the heads have nothing to do with it.

Yeah I was meaning to indicate "complete engine swap" for those years is plug and play and I was thinking about differences in the heads. Sorry about that.

[cywelchjr]

Steve has a good point. Any of the XS motors will swap with nothing more than making sure you keep the same ignition timing gear that your engine had, the XJ engine can also be swapped in, but there are additional issues. My understanding though is taht while the charging system is different, the reg/rect is the same, but the connectors are different, so it's just changing of connectors to make it work.

[crazy steve]

..My understanding though is that while the charging system is different, the reg/rect is the same, but the connectors are different, so it's just changing of connectors to make it work.

That's what I thought too, but the parts fiche shows a different part number; seems odd that they'd change the connectors only...

[cywelchjr]

That's what I thought too, but the parts fiche shows a different part number; seems odd that they'd change the connectors only...

Think about it, since it comes with the connectors on it, it would be a different part number. If it was different, they wouldn't be able to use a geezer regulator by just changing the connectors on it. Any time a part/assy includes the connectors as part of it, that would change the part number.