With the spark plugs out engine will not suck any gas/air in through the carbs.
Does the backfire happen while you are cranking it or after you stop?
Does the backfire happen while you are cranking it or after you stop?
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No gas going to spark plugs?
- Thread starter leodr
- Start date
So just like this. Bare copper from any old piece of house wire you got laying around, thin soft steel wire (like picture hanging or repair wire) would work just fine also.
The bare copper needs to be touching an engine part or the frame NOT just the carbs.
Now you can crank the motor over and watch the plugs for sparks, nice bright blue sparks across the electrodes is what you want to see.
The bare copper needs to be touching an engine part or the frame NOT just the carbs.
Now you can crank the motor over and watch the plugs for sparks, nice bright blue sparks across the electrodes is what you want to see.
Like this.
Doesn't hurt to clean, dry the plugs with a propane torch. Clamp them in a vice, get em good and hot.
Had many an engine start, once the plugs were dried.
Had many an engine start, once the plugs were dried.
Try squirting a little bit of fuel in each spark plug hole, put plugs in, caps on, and try to fire. If the bike fires up for a couple seconds or so, it's probably a fuel delivery issue. That picture shows that you have strong spark. If the bike still doesn't start, it may be a timing issue, but let's not get ahead of ourselves. Just remember, air, fuel, spark. This is what you need. Try to isolate what isn't working.
leodr
XS650 Enthusiast
Back fires after stopping.
Thanks for spark plug testing pictures and clarification. That helps alot.
I will test mine to see if they are ok., then I will try a little fuel in spark plug hole to see what happens. I have left bike at cottage and will not be back until next week and I will get back to advise outcome. I still think it is a fuel problem, but I will get to the problem one way or another.
Thanks to you people
Leo
Thanks for spark plug testing pictures and clarification. That helps alot.
I will test mine to see if they are ok., then I will try a little fuel in spark plug hole to see what happens. I have left bike at cottage and will not be back until next week and I will get back to advise outcome. I still think it is a fuel problem, but I will get to the problem one way or another.
Thanks to you people
Leo
leodr
XS650 Enthusiast
Ok. I am back with my bike. I will continue by testing spark as per wiring described and see what happens. And if spark good then try a little bit of fuel in cylinder with plugs in and see if it fires up for a bit. If it does then I am sure my problem is carbs. Let you know later on.
Thanks
Leo
Thanks
Leo
I'm expecting you now have an issue with the TCI unit.
leodr
XS650 Enthusiast
Ok. Tried spark test. One very low slightly sparking on cracking other nothing? Changed them over and got nothing on both sides? I can try new plugs but that may not be the problem? Could be battery not giving enough amperage, volts look good.
This looks like a compounding problem. Should I try new plugs?
This looks like a compounding problem. Should I try new plugs?
leodr
XS650 Enthusiast
Ok put new plugs and no sparking? What is my next step? Anyone?
Check and service ground connections on ignition parts
Check power supply in to coil and ignition parts
I dont exactly know these but there are service and fault finding manuals
Bit busy now
https://thexscafedotcom.wordpress.com/2011/01/10/xs650-manuals/
leodr
XS650 Enthusiast
I will thru that site and see what it may say to do. Get back to me later, thanks.
I have trickle charger on with battery charger to battery terminals and I have voltage meter on and it shows 14, so itbi k it is not a battery issue?
I have trickle charger on with battery charger to battery terminals and I have voltage meter on and it shows 14, so itbi k it is not a battery issue?
leodr
XS650 Enthusiast
I think I may have to give up and put this bike to sleep for another time.
I will drain everything, gas from tank and carbs and oil, remove plugs and put a little oil in there until I get back into it. I probably have to check the electricals first. I will store battery as well.
Before I do put it away, maybe there are few other things I can check as it still together. How to check ignition or other electrical systems. Maybe starter although it is cracking?
I will drain everything, gas from tank and carbs and oil, remove plugs and put a little oil in there until I get back into it. I probably have to check the electricals first. I will store battery as well.
Before I do put it away, maybe there are few other things I can check as it still together. How to check ignition or other electrical systems. Maybe starter although it is cracking?
Do you have hard black plastic plug boots? Or soft rubber? If you have black plastic you need to remove the nipple on plugs when you install them or they will not seat fully in the boot.
Sparking only when you turn the ignition off points to maybe the ignition pick ups which can be tested with a VOM but more likely TCI ignition module problem, that is a rather complicated and or expensive fix.
I'm giving long distance advise which is not so simple but what I said above is pretty likely at this point. IF battery, wires and FUSEBOX are all in good shape. Rotted fuse holders that LOOK "just fine" is very common on the specials.
Last edited:
leodr
XS650 Enthusiast
How to test ignition pick ups with vom? How to test or check TCI ignition system. Any easy way.
I have already replaced fusebox when I got it. That should not be the problem. I also removed resistor caps on new plugs. I tightened grounds to motor and tighten around plugs as per pictures above. I will look at books I have about TCI and maybe I can figure this out simply??
I have already replaced fusebox when I got it. That should not be the problem. I also removed resistor caps on new plugs. I tightened grounds to motor and tighten around plugs as per pictures above. I will look at books I have about TCI and maybe I can figure this out simply??
leodr
XS650 Enthusiast
Bike is 82 heritage special. Stator was replaced a while back. I rebuilt carbs last year and had it running but then got a scr 950 scramber and use this one. I also have a 83 virago 750 which was running last year also but now it is not changing gears and making grinding sounds when starting. I have replaced starter already once an it may. Be the same problem again or it could be clutch.. Which has never been done. I may start on this one and come back to XS later??
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