Still have problems after carb removal/rebuild

[ejoy1220]

The 3ohm coils are fitted, which means that with the bypass resistor not bypassed, it's not getting the full 12v??

[ejoy1220]

OK just got back. I never touched the ballast resistor the whole time I've had the bike, and when I went to bypass it today...it was already bypassed. That means, the ballast resistor was bypassed and the bike was running the stock coils. Wtf? Seems like a previous owner was mucking around with things.

[ejoy1220]

Also, cylinder #3 was very cold again, so we decided to do a compression test on all 4 cylinders, maybe we were losing compression with a bad valve. Pulled the plugs, hooked up the gauge, disconnected the Neg coil leads, and let it crank.

Cylinder 1: 180 psi (!)
Cylinder 2: 180 psi (!)
Cylinder 3:190 psi (!)
Cylinder 4: 180 psi

Tested it twice, same results. With the throttle WOT on a warm motor. Aren't there supposed to me around ~142 psi in each cylinder?! How is it possible it's reading that high?? We thought the gauge was bad, but we recently did a compression test on our other XS1100 with 140 psi across all four cylinders.

[boyat68]

ejoy1220:

Maybe the PO did a piston modification to raise the compression??? You may want to test the Top Dead Center to plug hole on that bike and compare it to the one you tested at 140PSI. Also could of shaved the heads.

[ejoy1220]

Originally posted by boyat68
ejoy1220:

Maybe the PO did a piston modification to raise the compression??? You may want to test the Top Dead Center to plug hole on that bike and compare it to the one you tested at 140PSI. Also could of shaved the heads.

I have no way of contacting the PO anymore as he moved, but he never mentioned anything about any motor work. Not to say there wasn't any, who knows at this point

Anyway to find out if it has a big bore kit, giving higher compression?? Could it be carbon deposit buildup in the combustion chamber? I've seen it pretty bad in cars, but never enough to increase cylinder pressures ~+40psi in all cylinders.

I'm beginning to regret buying this bike, this $600 deal is turning out to be a little maddening

I also think I'm going to try and find a good TCI unit to swap mine with.

[LegendJet]

I watched the video on youtube of the supposed rev limiter. I have a '78e and mine does the same thing. I have been working on it for about 2 months now. tracking down the probs. The charging system on mine is not working and I have gone through one reg/rect on ebay which was not good. I bought one from Geezer, it should be here some time next week. I have heard from a friends with a xs triple that if it isnt charging then they wont run very well. I also found about a half a gallon of water in the bottom of the tank...fixing that this weekend hopefully...I was wondering if you ever got the problem solved?

[tarzan]

You are right about not charging and not running well are possibly related.With the electronics on these we neeed at least 10.4 volts ,IIRC.
Also if you put a reg/rec on it and it didnt work,did you install it and it worked then it quit working?The reason I ask is that if you have a short somewhere it could do that. Then again ,maybe it is dumb luck and you did get a bad unit.

[LegendJet]

I think that the goofball that sold it too me had no idea what he was talking about....when i put it on i saw the voltage jump to 13 when i reved it up and i was like yyeahhhh its workin and i didnt give it a second though. soooo i knew that it should be higher thinking about a car charging at around 14 volts, but i figured its a bike it might charge with less voltage...i guess im wrong. And i have a red/white wire coming off of the tci that isnt connected, but i have one that is. well i bypassed the resistor becasue i have accel 3 ohm coils, and i re drew the wiring schematic for just the red/white wire, and it seems like both of them should have the same voltage going through it at the same time. so they should be connected, but i am kinda scared of doin that...

but i have gone through the wiring for the reg/rect and all that looks right, no shorts or deads or anything...

[TopCatGr58]

Hey Legend,

Did you test that red/white wire for voltage levels while it was running? The TCI sends out 12 volts directly to the coils, bypassing the ballast resistor during startup, but once running, it directs the power THRU the ballast resistor to prevent frying OEM coils. SO...since your BR is bypassed, and the bike runs, then the other unconnected red/white wire is probably the starting circuit, and would NOT be energized after started anyways, so you probably can just tape it off and not worry about it!
T.C.

[LegendJet]

well....I have really done it this time. the red/white wire is really the red/yellow wire...i figured maybe the white had faded to yellow, well the wire i dont know where it goes (red/yellow) comes off of the larger plug on the tci. According the the wiring schematic that wire goes straight to the starter...nothing in between the tci and the starter motor. I took the starter cover off and there is no wire coming off of it....so i have no idea. the bike will start....anymore ideas?

[egsols]

I believe there is also a red/yellow going from the TCI to the pick up coils.

Is the wire part of plug with more wires or is it just by itself?

[ejoy1220]

Well it's been over 8 months, and having been frustrated with not being able to get the bike running, and with the craziness of getting married and having a baby, I've neglected the bike and let it sit in storage

I'm getting the itch to work on it again, and I'm going to dive into the bike again in the next few weeks, for now I'm going to try and research what else could possible be wrong too. I have an extra set of carbs available that I'm going to swap out and see how the bike run, and then I'm going to test the TCI unit.