ignition pick ups

[erldrums]

hello there! first time on this marvelous site.... first question,.. i've got a 1980 xs 11 special with vacuum advance, motor in the bike is very nearly dead ,bought a spare from bone yard serial no 11G 000374,...yics motor,is it a later xs or an fj?[told it was an 82 xs] can i fit my vacuum ignition onto this motor?,..it has the pickups on it, but i'm presuming the advance is built into the cdi..?.don't want to fork out on a new black box if i can use the one on the bike.secondly there is a wire coming from the bottom of the sump casing [white lead ]..what is that ? i've got to switch my old alternator over as well. take it that should be no probs?
thanks for any help, been using your info since i got the bike, finally got round to signing up!
Thanks , Erl

[TopCatGr58]

Hey there Erl,

Hope you kept your receipt so you can take it back!!! What you got was the motor from an '82 XJ 1100. It has a totally different CDI box vs. the 80-81 models, it's advance unit is a little black box that a vacuum hose and electrical wires plug into under the tank. It also uses a totally different charging system than the XS. That little wire on the bottom is the oil level sensor, but that's the least of your worries. Without many of the other aforementioned parts, it won't transplant into your frame and function!? Some other GURU's(present company excluded!) may chime in with more info?

T.C.

[erldrums]

oh dear!!...the xs went south tonight! think the cam chain slipped and things got bent...it was making a lot of noise..just trying to get to the end of the summer!.will pull it apart tomorrow and have a look
back to the other motor..the 82 xj..the mounting for the ignition pickups looks the same, i havn't pulled the pickups off yet so i don't know if it has a slot for locating the mechanical advance from my 1980 special,
this is what i was wondering, [ unless there is some other problem i'm missing!!],same on the other side of the crank, has the xj got a different way of mounting the alternator?looks like the same kind of tapered fit as the xs ...could be wrong though!
things going from bad to worse if i can't use the 82 motor,as i took it on a bargin price.. no return basis!!!!
any ideas lads???!!

[sixtysix]

I think you can use the XJ motor if you go back and get the ignition box, coils and wiring harness for it. The ignition box for the later model had a built in advance curve, and the coils were a different Ohm value and did away with the ballast resistor. Never did it though, just the things I think you will need to do.

[Ken Talbot]

SWMBO's 'H has an XJ motor in it (s/n 11G 010453) 'as we speak'. The valve cover and the YICS passage are a dead give-away. However, when it was installed, they used the pick coils and vacuum advance, the CDI box, and the alternator and alternator cover from the original motor. This gets you away from the hassle of swapping in a lot of XJ parts that you probably don't have and having to muck around with a new wiring harness. Except for the few electrical bits, it is the same motor. The only unresolved issue is the wire hanging from the extra oil sender at the bottom of the crankcase, and it does not bother me one bit that is is not connected to anything.

[erldrums]

Hi !
well tonight i think i found the problem with the 80 motor..cam chain slipped a couple of teeth after i took of the ajuster to 'check ' it... it was seized half way out...but as i read elsewhere in the forum [after the big bang!]...this is a dodgy thing to do, unless you know for sure your chain isn;t so stretched it will hang below the the crank sproket and posibly jump a few teeth.
The good news is ...looking at the two motors 82 xj 80 xs..it looks like the alternator will swop straight over,.. same goes for the mechanical advance/vacuum ignition,..the peg is there on the crank, so looks fairly straight forward.
The oil level sender is not a prob...so next step is two bribe a couple of mates into elping me lift the bloody thing into the frame!!!
Thanks for the help...and thanks to Andreas for the really quick offer of a spare motor!...might just take you up on it bud....still don't know for sure how good the xj is!!!!........

[Geezer]

Before I wrote off the engine swap, I would check the differences. Since you’re stuck with the new engine, remove the ignition and see if the older XS11 parts will fit. You have nothing to loose if you try. Also it’s possible that if it doesn’t fit, it will only take little machine work to make it fit.

If the later model alternator does have a different taper on the shaft, that’s not a big deal either. Both of them will have 3 AC leads out of the stator and 2 leads to the field coil and it’s no big deal to wire it up.

The big difference really isn’t a big problem. The cylinder head has a long port that goes under the intakes and you need to use a block off tool when you sync the carbs.

The engine bolts right in, why not go for it.

Geezer