Yamaha XV500 TCI problems

[Glyn]

As an ex owner of a Vision (and past multiple postings), I hope it is OK to ask members advice about a Vision sister ship (XV500) TCI. My problem is the rear cylinder on the bike runs very sporadically (mostly not at all). I've changed all the obvious things and even changed all the valve stem seals in case weeping oil was fouling the plug. All the ignition coils and pickups check out OK for resistance readings, wires, caps plugs all new. I have a single carb on the bike so fuel not the problem. Front cylinder runs great! Reading the Yamaha diagnostic chart seems the TCI could be at fault. I,ve tested the resistance on the male 4 pin socket where the female pickups plug joins. I'm not sure it the pins should have resistance or not? What I found (with the TCI off the bike) is that the pair of front pickup pins on the TCI had a completely open circuit (ie the good running cylinder), the rear (bad) cylinder pick-up pins has a really high resistance of 11,000 ohms. Looking at the TCI circuit board I cannot see any immediate dry joints or burning etc. My questions are does anyone know (from XZ experience) if these male pickup pins should show an open circuit or a resistance? Surely they should be the same (ie both open or both with resistance)? If the pins with the resistance are the problem is there a way to fault find this on the board or is it just better to buy a new set up from the company IGNITECH. I've heard good reports about there TCI's. Anyone used them? Still miss that XZ, and if I can advise anyone, anyhow, on the changes I made to mine please feel free to contact me. Cheers Glyn.

[The Prophet of Doom]

Hi Glyn, nice to see you again.  You are most welcome here


Wiring on the XZ is


Unused            |  |  Common Ground (Black)


Rear (White)    |  |  Front (Red)


I get Black-White 4.58MOhm  Back-Red 4.53MOhm on a known good TCI

[Glyn]

Thanks for that info. I suppose the readings from an XZ TCI will differ from an XV TCI but as I suspected the readings between the front and rear pickup pins on the TCI should be the same (or very close). As in Phrophet's TCI. Mine looks suspect then, having a high resistance on one pair and an open circuit on the other. Has maybe anyone installed an Ignitech unit on their bikes and has it turned out well? I'm thinking that may be the best option. Cheers  Glyn.

[The Prophet of Doom]

I can't say first hand as mine (Ignitech TCIP4) is still in the box.  I couldn't find a single bad thing said about them though.


I got the programmable one, which has 3D map support.  Very easy to program but you need a Windows PC with a serial port (or a serial/USB adapter)

[Glyn]

Sounds goods. I'm keen to get try their unit but would still like to now for certain if my TCI is faulty. I'm thinking that it is however.

[The Prophet of Doom]

Swap your TCI inputs and outputs from front to rear and vice versa.  Now your rear should run, and the front hardly at all.  If it stays where it is, then you have some other sort of issue.

[devotee]

ProfitOfDoom said: "Swap your TCI inputs and outputs from front to rear and vice versa.  Now your rear should run, and the front hardly at all.  If it stays where it is, then you have some other sort of issue."

Nice. A solid bit of diagnostic insight. 

I don't even have this issue but I will file this tidbit away.

[cvincer]

Don't know if it will help your set-up, but the diagram attached is how I test the sensors & TCI on an XZ.

[The Prophet of Doom]

Please correct me if I'm wrong but I think this would work only to show there is a spark visually.  The sensors and cylinders are 70 Degrees apart - unless you also change both the TCI inputs and outputs over, then the engine will not run in the configuration you have drawn (albeit on one cylinder only in this case).

[devotee]

Yes, that's what i pickup (intended).

[cvincer]

The engine won't run;  I believe wiring up as per the diagram enables you to decide if you have a dead sensor (& which one)

or a problem TCI (& what part).   If all check out good, then the problem is elsewhere in the ignition circuit.

[admin]

Thanks for that info. I suppose the readings from an XZ TCI will differ from an XV TCI but as I suspected the readings between the front and rear pickup pins on the TCI should be the same (or very close). As in Phrophet's TCI. Mine looks suspect then, having a high resistance on one pair and an open circuit on the other. Has maybe anyone installed an Ignitech unit on their bikes and has it turned out well? I'm thinking that may be the best option. Cheers  Glyn.

2 months and a couple thousand miles on the ignitech, so far so good.
plugged right in, started right up, runs excellent.
highly recommended, and worth the peace of mind ( assuming of course it doesn't leave me stranded somewhere...)

-R