Ignition TCI question

bpeckm

XS650 Enthusiast
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Hey all... my son and I bought an '82 Special almost a year ago, it had'nt run in forever, a pretty-close-to-basket case. Took it all down to the frame, had to split the case and found a coupla bad gears, got it all back together, and FINALLY got it started last week...

Sorted out the carbs pilot jets/mixture etc and had a real run-around with the ignition, swapping plugs, coil leads back and forth, 'cuz it would run well on one cylinder but not the other. Finally got it going well enough to ride up and down the street (funnel and fuel line only, no tank yet!).

BUT, I think I still have an ignition "on one side only" problem.... does the ignition have a 'wasted spark' firing sequence?....i.e. firing at every revolution but only one side is in the compression/spark sequence?

When I first start the bike, one side runs well immediately, but the other side doesn't (it fires intermittently and pops/backfires)... any thoughts??

:banghead: fwustwating!
 
Here's a pic for those who need pics ....

IMG_2569-M.jpg
 
I think it's the carbs rather than the TCI, although it could be a bad coil. After a little running the plugs will tell you what's up. If they both want to foul quickly it could be the coil.
 
From what I have read
swapping plug wires with a TCI ignition wont do anything
I have yet to read a post about the TCI causeing one cylindr not to fire
 
A bad plug wire would switch the problem to the other side if you just swap over left for right.
Might just need to clean the little holes in the carb bowl choke circuit......something I need to do later today. Left cylinder isn't firing on startup but fires when I add a bit of throttle.
 
Thanks for replies, guys... I figured it was a wasted spark system (I also have an old BMW airhead, same system), but I am getting a lot of misfiring on just one side. I have a plug-tester on order, but it probably is something in the carb circuit....

I have only run it for about fifteen minutes all together, still trying to sort things out, but am also hearing one louder tappet, so I will be checking valve clearances again.....

:wink2:
 
Just wanted to say that I cleaned out that choke circuit in the carb bowl, used a fine wire from a torch tip cleaning kit and some spray carb cleaner with the straw attachment. Worked it untill the carb cleaning spray showed the passage was clear. Put the bowl back on....I'll note here that I've replaced the phillip head screws with allen heads so's to make removal of the bowl in situ possible.
Turned the petcock on, choke on, prime kicked a couple of passes, key on, kicked and she fired right up, left header warming immediately. Runs like a charging bear.
 
Got more into it today, and isolated out the problem: carb, plus a bad plug. Switching leads from side to side didn't switch the non-firing, so I put in another plug, nfg as well, and then finally a good plug!! yahoo!!!

I got my left cylinder firing and idling nicely, but the mixture screw on the right carb has had the slot fubar'd so I have only minimal chance of adjusting it. Working some carb cleaner and air blasts through the port on the rim of the carb, and it's "getting better".... so there is hope!

Also got my headlight wiring straightened out so that the headlight works (I have had to put in a non-XS turn signal switch and dimmer) after removing all the crap circuits for the headlight safety, the turn signal cancelling etc. I had to put in new brushes in the alternator, and it is working and charging (will wonders never cease....!!)

Rode the bike up and down the street and am pleased with clutch, power, performance.

...Now, if I could just get my front brake working.... two separate m/c's and both are nfg. ..but that's another problem for another day! Cannot get the m/c to take fluid pressured in from below, nor will they pump out so that I could bleed in the old-school way.... :eek:

:thumbsup:
 
On your M/C with the line unhooked put a finger tip over the bolt hole. Now slowly pull and release the lever. As you pull the lever air gets pushed out past your finger tip. This will bleed your M/C. Now quickly reinstall the line. Move down the line to the next joint. Remove the line, as before use your finger tips to seal the end of the line. bleed at this point. Reinstall the line, work your way down to the caliper. Once you get fluid all the way to the caliper then it should bleed as normal.
If you can't get them to bleed check the holes between the reservoir to the piston. If either is plugged no fluid will flow. Even if it will bleed and pump fluid it still may not pump fluid well. I might suggest tearing it apart, cleaning up the piston and seals. Reassemble and try again.
Rebuild kits are available and work wonders.
Leo
 
Thanks for the brake bleed advice!

I learned my bleeding the old-school way, from the top, but I cannot get this one to push fluid out.... so I bought a "syringe" to push fluid up from the bottom, and no joy there either.... I think that my pressure-release orifice in the m/c is plugged, the one that allows the fluid to come back when the brake is released.... so a tear-down is definitely in order. ugh.

:)
 
You might not need a complete tear down. Remove the reservoir, this lets you see the holes better. Now carefully probe the holes. I like to use the wire tie from a loaf of bread with about 1/2 inch of the cover pealed off. This wire is small and very soft. Gently probe the holes and spray brake cleaner through them.
I can't guarantee it will work, but it helped on one of mine.
Leo
 
Good advice! I didn't realize that the reservoir could be moved or removed, and the problem was in the front hole, the one that is normally under a little lip.... I rotated the reservoir, and worked the plunger with some brake cleaner, brake fluid, my vacuum syringe, and it was unreal how crappola came out... pretty sure it's gonna work now, just have to find the time to reinstall, bleed, etc.

Thank you!
 
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