Looks like my carbs have to come off again.

[DGXSER]

Factory compression is 142 +/- 10%. Generally speaking if they are relatively even across the board it will run. I have one that measured from 80-120 IIRC, when I put the carbs on it ran pretty nicely.

[dbeardslee]

I test with the plugs out too, wot, bike on the center stand, and crank until the needle stops rising. Spec is around 150 psi IIRC, with a maximum variance between cylinders of 10 or 15% (can't remember which).

Dang Don, you're quick on the keyboard tonight .

[XS1100 Newbie]

I did not pull my carbs last night. I am going to take a short ride today, and pull a proper compression check. I figure if my compression is low, i'll ride it the way it is for now, and pull the head this winter if i can afford it. With only 16500 miles on it, it is hard to believe that the compression can be down that much.

[dbeardslee]

When you run the compression check, if the numbers still look low, try putting a small amount of oil in each cylinder just prior to testing. That will insure that the rings are sealing as well as they're going to, and should provide the most accurate readings.

I've got a couple more ideas too. When you had your carbs apart, did you disassemble the slides? Don (DGXSER) had a problem with his that he traced to a washer the was in the wrong position on one slide needle that really made his run like crap. You wouldn't think one washer would make that much difference, but it did.

I'm assuming you're still running the stock coils with the original high tension wires? If you are, chances are excellent that the high tension wires are shot. You can test them with a digital multimeter for primary and secondary resistances. You check the primary resistances at the four prong connector at the tci. Pull the connector and hold it so the slots are horizontal. Put a probe in each of the top connectors, and check the resistance with your dmm set to the 200 ohm range. Readings should be around 3.3 ohms. Repeat on the lower slots. To check the secondary resistance pull both high tension wires for a coil, remove the plug caps and put a probe in the end of each high tension wire. Readings should be 10-12k ohms (meter set to 20k ohm range). Check the caps separately - should be 5k ohms each.

I had a problem last year with a defective set of coils, and the problems it exhibited looked for the world like a carb problem - poor low rpm performance that improved as the rpms rose above 2.5k, vacuum doing all kinds of crazy stuff, and backfiring through the carbs. After 15 trips into the carbs (no exaggeration) I made myself look elsewhere. The coils were black mikes, and they only had 7k miles on them, but they were about all that was left to change out so I did. I was amazed to find that they were the problem all along.

If you check the readings on your coils and the secondaries are out of whack, you might want to consider grafting new high tension wires into them. There are also some voltage tests that you can run at the TCI. This will give you an indication of the condition of your electrical connectors which can rob voltage and cause your ignition to misfire. Probably the single biggest offender in the wiring is the red/wht wire that runs from the TCI to the handlebar kill switch, and then feeds the coils. Between cleaning the connectors on that wire, and your ground straps, you can solve a lot of problems.

The starting point is to run the tests - compression and the dmm tests. As you run the tests, hopefully a pattern will begin to emerge that will point us in the right direction. The more information the better. Diagnosing this stuff is as much a process of finding out what isn't wrong as it is finding out what is.

[XS1100 Newbie]

Ok, the first part of the chacks is done. The compression is 130 LBS on all four. I didn't worry about putting oil in, as 130 is good enough for now. The coils: I checked the primar resistance at the 4 prong TCI connector as suggested. My first reading was .7 ohms. I went WTF, and double checked my setting on the 200k scale. I checked again, .7 ohms. I replaced the battery in the meter, .7 ohms. ****! I took the caps of the plugs, and check the secondary, 14.5 +or_ .3 ohms on all 4. ****! Checked the caps, and pretty much all 4 were a about 7 ohms. It sounds to me like i got some very bad coils, wires, boots. I don't believe my meter is off, but it may be. It doesn't make sense that it runs this good with the coils that bad.

[dbeardslee]

Assuming you meant 14.5k ohms on the secondary, that actually doesn't sound that bad. Caps sound like they could use replaced, and probably about 1/4" of wire trimmed off the end with new ones. .7 ohms sounds real screwy on the primary. Is your ballast resistor in place? I don't think it would matter, but the ignition was off during the test, right? You could check the primary at the coil by putting a probe on each coil lead. IIRC resistance should read about 1.5 ohms there. That low reading at the TCI is a cause for concern - .7 ohms (assuming the meter was reading correctly) might be low enough to damage the TCI if you ran it like that long enough. Probably a good idea to run Randy Rago's TCI quick test, but you'll need an analog multimeter for that one. That will tell you if your TCI is functioning properly. Also be a good idea to check the voltages at your TCI. In a nutshell, you leave the connectors in, turn the ignition on but not running, meter set to dc volts, and insert a probe in the back of connector to the gray, white/red, orange and red/white, and touch the other probe to a good ground - one at a time. Readings should be 12v on all four. Do the same thing with the black wire and you should get a reading of 6v. Among other things that test will give you an indication of the condition of your wiring and connectors. Definitely need to trace those wires down that lead to the coils from the TCI, and clean all the connections along the way - might get lucky on the resistance. I sort of doubt it though, as resistance usually increases with bad connections. It might be a good idea to check the continuity on those wires as well - connector to connector so your testing the them too.

[XS1100 Newbie]

Ya, it sounds like i have a bit of checking to do. I'll borrow an analog meter, and check that TCI. Time to go through all the connections on the bike i think.

[dbeardslee]

You didn't say, so I'll ask again - is your ballast resistor in place? It bumps the resistance from 1.5 ohms to 3.3, and if it's missing (bypassed) that might explain the low reading at the TCI connector.

Something you might consider when doing your connectors. Disassembling the connectors and cleaning them is a good idea - with one caveat. You can clean the connectors, but that last 1/4" of a wire can be corroded inside the sheath. If you want a really first class job, check with Geezer for a good double crimping tool (he sells a real nice one for $24 that will do a factory double crimp), get yourself a bunch of new connectors (Geezer probably has them too), and don't just clean them - replace them with new. I went through every connector on Ole' Betsy when I first got her. After the cleaning I had about 11 volts at the TCI. Last summer I went through every connector on the bike and replaced the crimp-on connectors, and in some cases replace the plastic housings too (you guessed it - Geezer ). After each connector was complete I checked voltages again. With each connector I'd recover 1 or 2 tenths of a volt. By the time I was done I had recovered a full volt at the TCI, and I was back to 12v on all my '12v' wires, and 6v on the black one.

A good crimping tool is very important if you want your connections to last. The double crimp not only crimps the core to the connector, it crimps the casing too. Not only does this help to protect the core when tugging on wires (stronger connection), but it also helps to keep the air out of the end of the wire so it won't corrode as quickly. The factory crimps that are on it have lasted 30 years - why mess with success?

Here's the good news. With the readings you're seeing on your coils chances are very good that you located your problem. Might not be the only one, though (I'm an eternal optimist - can you tell? ). Be systematic about it when you go through your wires, and don't forget the connectors behind the fuse block mounting plate, the ones inside the headlight bucket, and the handlebar kill switch (be careful with that on disassembly - there's a small spring and ball bearing inside that can do a disappearing act if you're not.) While your cleaning/changing connectors, check the overall condition of the wires for breaks in the casings and shorts. If you see any connectors that have obviously experienced heat definitely replace the wire ends, and if you come across cracked or broken plastic housings replace them too. And lastly , if you've still got the glass fuse block get rid of it. TC sells a nice replacement for about $10.

[XS1100 Newbie]

Dang, that means i have to go pull my tank again. I have thought about doing the fuse box, but mine looks so good, i hate to screw with it. This bike was allways stored inside, so was never exposed to inclimate weather for long. I do understand what you are saying about the connectors, and the plu gires have been snipped off a while back. Can't go any more on them.

[tinman905]

Did you hold the throttle open when doing you comp test ,sorry I didn't read that anywhere. even if you are low as long as you are consistent straight across. 150's psi is give or take 10% is what you would hope for.

[XS1100 Newbie]

Tinnman: yes on the second test i did.
I checked the coils at the coil themselves, and they read 2.4 ohs. rechecked at the TCI, and had the same .7. Guess this would indicate a bad connection somewhere. Time to print the wiring diagram.

[dbeardslee]

Don't forget to check/clean the connections for the ballast resistor. Sounds like your coils might be good candidates for new high tension wires. Should pretty much restore them to factory specs.

[XS1100 Newbie]

I don't know if i like the mod for putting new wires on. I think new coils with wires may be the way i go.

[WMarshy]

I don't know if i like the mod for putting new wires on. I think new coils with wires may be the way i go.

New coils are not cheap, I suspect that why someone originally decided to replace the wires. if you do get new one I would get the Green ones from MikesXS.com...

[XS1100 Newbie]

Before i do anything rash, i am getting a new multimeter, and checking again. Still going through the connections. What's the best recomendation for cleaning the connections? Just lectra-clean or is there a small brush kinda thing that fits in the connectors?