XJ700 no spark-Backfire

:cry: Hello can anyone help me, I bought this bike last year, didn't run, had to clean carbs, not taken care of, but I started the bike 2 or 3 times over the winter OK, this spring I put some stabilizer in the tank wite some new gas, started 1 or 2 times then couldn't get it to start, took the carbs off and cleaned them, oh buy the way it will not start but big backfires, checked spark with a tester, sparks once then nothing, tried different plug same thing, bothe sides, don't have the money to start replacing parts till it runs, can anybody help me Thank You
Garry
It's a 1985 xj700 maxim x

 

Update your profile with the year and model of the bike so we can all help you. There are several possibilities to produce this symptom. The pickup coils might be at fault.

Does the ignition spark when the key is turned on and again when it is turned off?

 

It's a Yamaha 1985 xj700 maxim x

 

Being really fuel-starved can lead to backfiring. That's easy to test: spray some starter fluid in the air box and see if it will run for a couple of seconds.

If so, you've got a fuel problem. If not: http://www.xjbikes.com/Forums/viewtopic ... t=tci.html

 

It seem with the spark tester that when I hit the kill switch on and off there is a little spark from the tester

 

I tried the starter fluid no change
Garry

 

SQLGuy
This link on spark seems like a lot of help, i printed it out and I am going to try, problem is I am not that well versed on a meter, I have one from Harbor Freight but am not sure what to put the probes on, sorry
Garry

 

Check the battery. If you don't have a good strong battery the starter will starve the current needed to create the spark. You may notice that the motor only tries to crank or in this case backfire when you let off of the starter button.

 

My battery is good plus I have a charger that suplements the juice when low
Thank You
Garry

 

Ok SQLGuy
I tried some of the list
#1-I tried for spark, one spark on each then none, it also seams that there was a little spark when I hit the kill switch to off
#1c-NA
#2-OK for volts
#2a-NA
#2b-NA
#3-I disconnected the B/W wire at the TCI no difference
#3a-NA
#4-???
#5-???
#5a-I switched the O&G wires on the TCI, I had spark on 1 & 4
But still not on 2 & 3???
#6- Low volts but the battery was running down, 8.9v - 9.6v
what is this about a bad pickup
can you tell from this what is wrong, is it a bad TCI
Help
Thank You
Garry

 

Pickups are in the left side cover of the engine

I would be looking at a bad igniter by sounds of it, or a leak in the loom seeing as you have a variable current, it should attempt to fire with the black White wire out
Try a second TCI if you can get one before you go shredding the loom
What do your plugs look like when you pull em?

 

With a weak spark when the system is shut off leads to either the igniter or pick up coils. The igniter would be the first suspect.

 

5a. Switch the Orange and Grey wires from the pickups (6-position TCI plug) at the TCI. If the sparking and non-sparking pairs of plugs swap (i.e. if you had spark on 1/4 and not on 2/3 prior to swapping Orange/Grey and now have spark on 2/3 and not on 1/4) then you've got a bad pickup. If this didn't make a difference, swap the wires back and go to 5b.

5b. Switch the Orange and Grey wires from the coils (4-position TCI plug) at the TCI. If the sparking and non-sparking pairs of plugs swap, then you've got a bad channel in your TCI. You'll need to replace the TCI or get it repaired.

5c. You've most likely got a bad coil or bad wiring to a coil. Swap the Orange and Grey wires back to their original positions and go to step 6 for more detail on testing the coil.


Keep in mind that there are two sets of Orange and Grey wires at the TCI. One set comes from the pickups, the other set goes to the coils. Step 5a calls for switching the pair from the pickups. If you switched these and then still only had spark on the same pair of plugs as before (1/4?), then the pickups are good, but the TCI could be bad or the coils or their wiring could be bad. 5b and 5c's checks are to isolate which of these is the case. What did you find from 5b and 5c?

 

I guess I need to clarify that I get one spark from each plug when I turn it over, when I switched the O/G wires from the 6 wire plug not the 4 at the TCI the 1/4 got continual spark, still nothing from 2/3, I will check 5b & 5c, just wanted to make sure I was explaining it right
Thank You All
Garry
No riding Yet!!!!!!!!!!!!!

 

Main Switch??
Can you have a main switch that you key on and the engine turns over but will it affects the spark??????
Just asking, my switch is loose, dose not lock and last year a couple of time I had to turn it off and on for it to work???
Thank You
Garry

 

Well, yes, and no. Yes, a bad ignition switch can cause loss of spark, but no, it won't cause loss of spark to only two cylinders.

 

SQLGuy
I have no Idea whats going on, the only thing I can think of is moistur and water, My garage burnt down 3 years ago and I am just trying to rebuild it, I don't have the roof on so it leaks and is damp through the winter, I tried to keep it dry but but but, it's like my 8n, when it gets wet with moisture it won't start, I went out to check the TCI and all 4 sparked and now it's running, Hurrey - but what do I do now to stop it from happening again, I had 2 days of dry weather plus my air compressor drying it off, what next
Thank You
Garry

 

Usually it's the coils themselves that are don't like moisture. If you're running original coils, a new pair of Dynas would probably be a good idea.

If you wanted to try to salvage them, you could try drying them out really well (inside for a few days, maybe use a hair dryer on them for a while), then paint them with something like this: http://www.amazon.com/GC-Electronics-10 ... B000B62YO8. Not really sure it would be worth the trouble, though. I think the peace of mind of new if you're out riding on a damp day would be worth the cost of the new coils.