Ignition Plate/Timing Help

[SethL1987]

Hi Everyone,
I'm a newbie who just accquired a 1979 XS1100 from a friend of mine. The bike hasn't been started in maybe 10 years. I have done the whole restoration bit (cleaned carbs, worked on wiring problems). Just wanting to get it started first before I work on anything else. I finally got it running a few nights ago but only for about 2 mins. Every thing sounded alright then it just died. Tryed to restart but just got back fire from the airbox and small flames coming from the vaccum lines. Check cam timing, that was good. But I noticed that the timing plate is no-where near the (T) or even (F) marks. It's like its about 90 degrees from the pointer. The No. 1 piston is on TDCC but it just seems like the timing plate is out of spec possibly along with the ignition timing. I just can't see how this could be that out of whack. Has any body else dealt with this?

[TopCatGr58]

Hey Seth,

Just want to make sure you are viewing TRUE TDC, by removing the valve cover and observing the cam lobes and valves to be sure they are CLOSED, otherwise it could be Exhaust cycle?? ALSO, #1 cylinder is farthest left as you are sitting on bike. No aspersions on your knowledge, skills, we just can't always tell what experience folks have with bikes, engines, etc.! DO you have a service/repair manual?

Next, the PO could have removed the timing plate, but there's a notch/key that provides orientation only 1 way IIRC!

Folks have been known to oops the REPAIR and installation of the PU coils and wires, and gotten them 180 degrees out that way!
T.C.

[randy]

How are you checking the firing timing? With a timing light? It can be checked while cranking. 90 degrees is a long way off, longer than possible with the adjustments available on the timing plate. Actually 90 degrees at the plate would equal 45 degrees of timing. Is everything at the timing plate tight, no loose bolts?

It's a stretch, but it's possible that your advance mechanism just blew up. or got stuck from sitting all those years. Take a look and let us know.

[red bandit]

Yeh...What they said. You can remove the #1 spark plug and with a light visually see that the #1 piston is at TDC and then check timing plate.

[trbig]

Mine did this last year. There's a pin in the crank that orientates the timing plate on the crank as TC stated. That pin came out and the timing plate twisted. Take the timing plate off with an allen wrench and check that.

I used some Tri bond (Yamabond) and put the pin back in the crank... no problems since. At least I think there's no problems... lol. Not exactly sure which motor that was, but it did fix it at the time.


Tod

[SethL1987]

Hey Guys,
Thanks for the input. Looking at the orientation of the cams, and cyl. no. 1 it appears to be on TDC. Looking at the timing plate, the (C) mark is just about 180 degrees from the pointer. If I try to move the plate 180 the other way, it doesn't fit flush but the (C) mark lines up with the pointer. This way just doesn't seem right. I don't have a service manual which sucks. Hey TC by the way, you mentioned about the PU coil installation, My friend said he did replace the coils but never got back to working on it. Could they be installed wrong? Been working on bikes for a couple of years but this has got me stumped!

[trbig]

Did you check the pin in the crank? It's a quick thing to look at. If it ran and at first and then quit, it sounds like the plate just slipped and isn't sparking at the right time. If it's backfiring and popping, it's getting spark... just not when it needs it.


Tod

[SethL1987]

Hey Tod,
What pin am I supposed to be at? And how do I adjust it?

[79XS11F]

Originally posted by SethL1987
Hey Guys,
Thanks for the input. Looking at the orientation of the cams, and cyl. no. 1 it appears to be on TDC. Looking at the timing plate, the (C) mark is just about 180 degrees from the pointer. If I try to move the plate 180 the other way, it doesn't fit flush but the (C) mark lines up with the pointer. This way just doesn't seem right. I don't have a service manual which sucks. Hey TC by the way, you mentioned about the PU coil installation, My friend said he did replace the coils but never got back to working on it. Could they be installed wrong? Been working on bikes for a couple of years but this has got me stumped!

The "C" mark is the cam chin adjustment location mark. You need the "T" mark at the pointer with the #1 Piston at TDC in the firing stroke.
Rob

[SethL1987]

Hey Rob,
Thanks for the reply. I know the piston has to be the (T) mark but when it is, the piston is on the down stroke about half way down the cylinder. But it is supposed to be right at TDC. It seems like the timing plate is off and I don't know how to re-adjust it.

[79XS11F]

OK make sure the timing plate in on the shaft properly. It is set up to go on only one way when installed properly. Loosen off the Allen bolt and remove the timing plate. Check out the back side where it meets the shaft. The tabs on the back fit into the slots at the end of the shaft. Those tabs are of different sizes so the plate can only go on one way if it is seated fully onto the end of the shaft. If that set up is already correct then your going to have to pull the timing shaft and confirm proper placement onto end of the crank. However it should only go on one way there as well unless that locating pin is missing as was already pointed out as a potential issue. When all is in proper alignment the reluctor fin should be directly above the slot in the timing shaft base.
Rob

[SethL1987]

Rob,
Thanks for the info! The plate is on correctly. To do what your saying, do I have to remove the whole advance assy? I don't have a service manual yet-but I've ordered one.
Thanks, Seth

[trbig]

In the center of your timing plate, there's an allen screw/bolt. 6mm I believe. take that bolt out. It screws directly into the end of the crank shaft. That timing plate will come off, and underneath you SHOULD see something like this pin there.



If it's not installed still into the crank, dab some glue on the end of the pin and stick it back in. Install your timing plate the only way it can... with the cut-out over the pin... and you'll be good to go if that's what the problem was. That pin should still be in there if it fell out of the hole.

Tod

[SethL1987]

Hey Tod,
Thanks alot for the pic. Would the advance assy need to come off to get a better look to get to the pin? Thanks again for the help!
Seth

[trbig]

I can't answer that one since the XJ (My bike) doesn't have an advance unit like the XS. Maybe someone else will chime in on that one. Sorry.


Tod