update and questions

Hi all
I have finally got the carbs and loom done and everything works (lights, horn, starter, fuel guage.) My problem is there is no sparks at No 2 and 3 cylinder. Am i right in thinking that he left hand coil does 1 and 4 and the right does 2 and 3 which would indicate that the right hand coil is knackered. The biggest problem i have is that the frame indicates that it is a XJ900 but the engine is a 750cc. The engine turns over and i get good compression approx 120 PSI I don't know what the spec is for a 750cc engine. Also i can feel the suction at the carbs and there is exhuast pressure but it just wont fire and run. sorry for the long winded message but if anyone can help with any answers it will be greatly appreciated.

 

Yes, but no.

Yes, the left-hand coil fires 1 & 4, but that doesn't neccessarily mean the other coil is bad.

In fact, since it sounds like you just redid your wiring harness, I'd say it's much more likely (no offense) that you have a problem in the harness.

The two ignition circuits (1/4 and 2/3) are almost entirely separate. They have separate pickups under the timing cover, seperate circuits in the TCI, and separate HT coils. You need to check thoughout the two circuits to see where the problem is. You can also swap between the two sides to isolate which parts are working and which parts are not.

First thing I'd check is whether, with ingnition on, but not cranking or running, you have 12V on both the Orange and Grey wires at the four-pin connector of the TCI. If you don't on both, then the problem is probably that you're not getting power to the 2/3 coil.

If you are getting 12V on both, then you could try swapping Orange and Grey... at the TCI. If swapping on the 4-pin switches spark to 2/3 then the TCI is bad. If that doesn't change anything, but swapping on the 6-pin changes spark to 2/3, then the 2/3 pickup, or its wiring, is bad.

Paul

 

Wolfie.......well, first of all, there are no 1983 XJ900F models.......the F models didn't come until later years.

1983 XJ900 models are either rk or RL models.

750 engines in an XJ900 frame are XJ750RL or XJ750E-II models.....both very rare.


You might want to read thru this:

http://www.xjbikes.com/Forums/viewtopic/t=14577.html

to get a clearer picture of what your bike really is. It may be an XJ900 model that someone has swapped an XJ750 engine into, or it may be one of the above models that came from the factory with an 750 engine (in which case the frame and engine case "serial numbers" will match).



Now Paul.......a question arises. Suppose the battery is fully charged (13V +) and you turn the key on and measure the voltage on the orange and gray wires at the coil connector terminals, and you have LESS than 12V there (like, say, 11.5V). Where (and in what order) would you start checking to determine why there is less than 12V at that connector.......or, is it not typical to have 12V that far upstream (at the coil primary input)?

 

I don't think 12V or 11.5V is the issue; I think it's more a case of voltage (something close to 12) or not. I'd worry about 3V or 4V, 11.5 is probably doable.

Define typical.

And the answer to the 11.5V is most likely grubby connections.

 

To clarify my comments, by 12V, I mean supply voltage, that likely will be 12V +/- 1V. As Fitz pointed out, we're looking for supply voltage as opposed to nothing, rather than 12V versus 11V.

During cranking I'd expect the 12V to drop down to 10V or so.

Also, since, in this case, one side has spark, I'd not expect to see some low, but non-zero voltage on the other side; the supply to the two coils is in parallel. If I did see that, I'd expect a bad connection at the coil, or maybe an open connection at the coil and some voltage leaking back through the TCI. I'd probably remove the TCI 4-pin plug to verify the voltage at the connector without the TCI involved.

In general, on these bikes, if I were dealing with a voltage more than 1/2V or so below battery voltage, I'd check the fuse box, fuses, and ignition switch.

Cheers,
Paul

 

need an 81/4 in head light bulb for a 82xj650rj anyone? please guide me somwere

 

chacal here is your friend for that.
PM him or create a post in Buy/Sell

 

The Seca 650's stock headlight bulb is a "modular" halogen unit; unless the glass is broken you only need a new bulb. It's not a sealed beam; the 8" light is quite rare.

Please start a new thread if you need any more help rather than hijack this one.