FJowners.com

Hi,
I bought a 1TX a few years ago that has a been giving me a hard time!
That's why she's been in the back of the shed for a long while, I'm starting to get the issues sorted.
Low miles but has been dropped both sides, hole welded in the clutch cover and the ignition cover too,
Nice 4 into one uni filters and a Barnett clutch!
Bits of ally in the sump, stretched starter chain and timing chain!
Cdi units? What's the difference in them?
Mine has a vacuum pipe coming from the opposite end to the connections, another 1tx that I have broken for spares has an ignition unit without, what's going on here then?
The one without the vacuum take off won't work on my 1tx, anyone able to clarify?

Be sure you are looking at ignition boxes from the same generation (84-87 vs 88-95) because there are 2 flavors of oem FJ ignition boxes
1) TCI (transistor controlled ignition) uses a dual pick up coils which were installed on the USA 84-87 FJ's
    The TCI boxes have a built in vacuum advance module. See exception below.***
2) DCI (digital controlled ignition) uses a single pick up coil which were installed on the USA '88 to 95 FJ's
    The DCI boxes used a remote vacuum advance module (better design, easily replaceable) therefore, there is no vacuum port on the DCI box.
You can not mix these 2 different systems together. You can not use the DCI box (no built in vacuum advance) on a early FJ and a TCI box on latter FJ's.

Quote from: Pheasantplucker on July 25, 2021, 04:16:12 AM
Mine has a vacuum pipe coming from the opposite end to the connections, another 1tx that I have broken for spares has an ignition unit without, what's going on here then?

Again, be sure you are not comparing a DCI (no port) to a TCI box (with port).
Apples and oranges systems.

***Here's an exception: Not all FJ's with TCI came with vacuum advance. It's been reported by our FJ brothers in Australia that their FJ's do not have this vacuum advance feature. Early TCI boxes in Aussie land do not have a vacuum port on the TCI box. All USA bikes do have the vacuum advance.
If you *are sure* you have Ignition boxes from the same 1TX model, perhaps you have a USA box with a vacuum port and your other box is an Australian box without a vacuum port?


What does the vacuum advance do?
*The vacuum advance has nothing to do with performance*
It is a emissions control feature. It advances the timing when you close the throttle to burn off unburned hydrocarbons. Your FJ will run just fine without this vacuum advance as I can attest along with our mates from the land down under.
If you want to bypass the vacuum advance, no worries, just be sure you cap off the vacuum port on the intake manifold. Use the heavy oem Yamaha vacuum caps down there, it gets plenty hot on the engine side of the heat shield. Thin wall vacuum caps are not appropriate.

Aftermarket Ignitions (Dyna, etc.) do not have any vacuum advance features.

Here you can read more about the vacuum advance: http://www.fjowners.com/index.php?topic=11690.0 (http://www.fjowners.com/index.php?topic=11690.0)

Cheers.  Pat

Hi Pat,
Thanks for the reply, my manual has no mention of the vacuum advance, looking at the bike there is data showing it to be a Canadian model!
How it ended up in the UK registered new?

I believe the Canadian FJ's had vacuum advance....and according to the UK folks, those UK FJ's along with the EU FJ's also had the vacuum advance...

It's only the Australian FJ's (that I know of) that was reported not to have the vacuum advance.

Folks, feel free to chime in and update me....