not over 2000 rpm

[rfaass@yahoo]

The xj1100j 82 tci box repaired, new transistors. Starts and runs on 4 again. But does not get above 2000 rpm, looks like the ignition switches off. Is there a protection somewhere? I also looked at the vacuum booster, is there a way to test it? I applied vacuum, but the contacts stay the same, open. Any help appreciated...

[TopCatGr58]

Hey there rfaass,

There isn't a rev limiter on the XJ's TCI that I know of! The Vacuum sender unit has 3 wires, the R/W power into it, and then 2 other lines out of it. It's probably some form of potentiometer providing variable signals depending on amount of vacuum, and these signals are then processed by the TCI to adjust the advance/retard curve depending on engine throttle/vacuum demand.

Randy is our resident Electrical GURU, but the XJ has a few Eproms and such that make it to where he can't replace or repair them. You said you had some transistors replaced! By Whom, and WHY? Were they burned up in the TCI?

Sounds like you may need to first find some one in your area with a spare XJ TCI that you could borrow to verify that the bike will run properly otherwise? But, "WE" don't know where you are, hint, hint, edit your profile or signature to include your general location....city/state. You'd be surprised how many of us are around!

Regrettably the XJ was only made for 1 year in the USA, a couple more for Canada and possibly EURO, etc., so finding extra TCI's are pretty hard to come by, and also $$. Another alternative is to convert your machine to the mechanics of an earlier XS, the combined centrifugal and vacuum advance mechanisms that you could put on, and use an older TCI from the 78-80 series XS, much more plentiful and cheaper, as well as you can even make your own out of auto parts...see tech tips!
T.C.

[rfaass@yahoo]

Thanks for the answer. Yes, another XJ close by would be the idea. I tested the vacuum booster with vacuum but did not move a bit... I did replace the transistors myself, as the tci had no output while having input from 12 v and the pulses coming in on cyl 1 and 4. After the mod the bike fired up on all four and reved up as it should. Soldered the headlight fuse in, as the panel was broken and I got display again. After that the bike did not rev higher thanb 2000 rpm... and the ignition fails at that rpm it looks like. I checked the fall over switch, that works as it should and was wondering what it would be. The transistors used were darlingtons as indicated by another site where yam tci where repaierd (not my version though) and looke dat the specs and they look excellent for the job. The bike fires up and runs as it should until 2000 rpm... it would be nice if somebody could disconnect the vacuum booster and see what difference that makes, I have no way to see if it could be that thing... I did use a timing light and the ignition advances up to 2000 rpm but than the light starts to work intermittent, so i think the tci plays up for a reson I cannot figure out as of yet... Thanks for reading my post. Robert in Port Townsend, WA.

[TopCatGr58]

Hey Rob,

The plot thickens. The more info you provide, the better we can GUESS what to check next!

Have you checked your alternator and power across the battery with the engine running? Are you charging properly? The TCI is sensitive to low voltage, and will crap out when it gets near 10 volts. After soldering the headlight fuse, you were then drawing more power to the headlight and the control/info dash panel. The XJ uses brush type alt, they can get worn. ALso the reg/rect can go bad. IF you're not getting ~14.5 at around 2krpm, then, you'll need to research that before worrying about the TCI, and fixing that MIGHT fix the TCI problem?
T.C.
PS, there are many folks, including a GURU DELUXE named Prometheus at least in your state, don't know how close, haven't looked at a map, and folks know my geography skills are lacking!

[John]

The vacuum booster will not move anything. All it does is sense the vacuum, and sends a signal to the TCI to adjust the spark. There are no moving parts inside the timing cover other than the reluctor (rotor). Maximan or Jerry may be able to help you out with this problem, as they are the XJ gurus.

[rfaass@yahoo]

The voltage of the TCI is the first thing I check as it goes over the contact switch and the stop switch, if I remember correctly, the voltage was over 14 volts...
By the way, I saw on ebay ignitors for $170, aftermarket, hyperpack, out of New Zealand, anybody experience with these? I slowly come to the conclusion, that if there is no other rev limiter function anywhere, i should try another tci or try the aftermarket one... O yeah... the bike had been sitting for 2 years... but the idle jets are not plugged up and it did rev up at first... and starts at first touch of the starter....could it still be the carbs??? ;-)

[John]

Check to see if the diaphrams/slide needle are lifting as you open the throttle. What type of air filtration do you have? OEM or individual pod style filters? Some pod filters have a lip around the ID that can block off the air entering the diaphram chamber, and the slide needles will not raise. The port for the diaphram chamber is the cresent shaped port on the top of the air inlet bell.

[rfaass@yahoo]

The air intake is stock and during storage there was a sock in the air inlet, to prevent a rodent, or at least slow it down. The sock was removed OK... the baffeling part to me is that it first reved as should and a couple of hours later (after doing soem more elctric work, as the panels, headlight etc did not work, it stopped what it did first OK... I am a bit resistant pulling the carbs as that is a lot of work with possible the problem still persisting... beeen there done that, ha!

[John]

Have you checked the diaphrams for holes or tears? That will affect high speed acceleration.

[rfaass@yahoo]

Did not check that yet, can that be done without pulling the carbs?

[TopCatGr58]

Robert,

When did you check those voltages...before you fixed the headlight and dash system? If it worked before you did those electrical repairs, sounds like something is amiss there.

But we don't know what ALL you have done to your machine?

SO...it's hard for us to say whether it's carbs, electrical, etc.?

If you do a search for Hyperpak you should find a thread about it. A member got it and tried it. They had the plugs wired wrong. Also, IIRC, it doesn't use the vacuum sensor, it just has a centrifugal timing curve programmed into it. It'll work, but won't work as well under low throttle cruising.

A more thorough description of what you've done, how you got or how long you've had the bike, etc. will help us steer you in possibly more fruitful diagnostics and repairs.
T.C.

[rfaass@yahoo]

Actually, this bike was left two years ago at the local Honda dealer by a guy from the east coast and the dealer asked me to take a look at it. The long journey from Alaska was interrupted by the fact that the bike started to run on two cylinders. I put in new spark plugs, measured the coils, replaced three of the four spark plug connectors with NGK ones as the resistor seemed to have failed. Started it up and it run on 2 cylinders. Measured the output of the pulse coils and adjusted the airgap of the one with the lower output. They are now equal but did not solve the problem. Looked from the tci connector into the coils, and they measured the same resistance, so there was little else that can fail. Took the tci apart and measured each component (except for the few unmarked ic's) and replaced the output transistors. Started it up and run on 4 and reved up as you would expect, after some smoke from the ones that did not run for a while. Saw that the dash was out, the headlights were not working and the horn did not sound. Inspected the fuse box, cleaned it up and soldered the headlight fuse in, as i did not have a better solution for fixing the broken connector. After that started the bike and it runs fien, except that the rpm's do not go above the 2000 and the machine starts to bang. The timing light is used to check advance but at 2000 the light flashes irregular, so the ignition is failing... probably still asnag in the tci... anybody close to Port Townsend/seatte with a tci i could try?
Thanks for reading the thread.

[skids]

Never rule out the battery causing those problems without doing a load test.

[planedick]

Transistors...

Some switching transistors won't turn on and off fast enough for ignition purposes. Are you sure the type you put in there are the right ones?

[rfaass@yahoo]

That is a good thought but I used the same transistors as in here:
http://www.jetav8r.com/Vision/TCIReb...I_Rebuild.html
the nte2317, which are specifically for ignition systems... I think perhaps something else broke inside... the originals were the same as in the visions repairs...
I am still mystified why this happens. The tci needs to have a circuit in it which depends on the rpm, in order to get the correct advance, that seems to be broken. The logic is in a number of ic's, so it is difficult to debug. I did check all the resistors, diode's zeners and transistors, they seem to be Ok. Also the solderings are solid. I am thinking of building my own, as that should not be too complicated. The pic processors are very fast and cheap. I already have the transistors, ha! I still hope to find a tci to try out if that indeed is the problem.