I'm new here to the forum. I just got a "75" XS650 to do a cafe build. Starting to go through it and I don't have a consistent spark at the plugs. I've seen it spark just a couple times while turning it over. Any thoughts?
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No spark at the plugs
- Thread starter Joel1022
- Start date
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- Tags
- electrical
Do you have a repair manual? If so follow the steps for a tune up.
A tune up consist of several things. They should be done in this order.
#1 adjust cam chain tension
#2 adjust valves
#3 set points, gap and timing
#4 carbs
At this point you can skip down to points. If they are dirty or burnt they won't get the plugs to fire well. they make small files just for cleaning points. A bit of sandpaper folded in half will work. Once you get looking good you will have to adjust the gap. Often feeler gauges have a coat of oil as a rust preventive. This oil can get on the points. Once you set the gap use a strip of clean white paper, business cards work well. Dampen with electrical contact cleaner. Open the points, slip in the paper, let points close, pull out paper, repeat as need to remove any oil.
This should improve the spark.
Once you get good spark you need to insure it happens at the right time. For this you time the points. Your repair manual explains how.
If cleaning and gapping the points doesn't help you might have dirty connections somewhere between the battery and points. This often happens at the key switch and engine stop switch. If careful you can take the switch apart to clean the contacts. Cleaning any wiring connections along the way will help.
You might want to start at one end of the bike and work your way to the other cleaning and tightening every connection in the wiring. A bit of dielectric grease will help keep them clean.
Leo
A tune up consist of several things. They should be done in this order.
#1 adjust cam chain tension
#2 adjust valves
#3 set points, gap and timing
#4 carbs
At this point you can skip down to points. If they are dirty or burnt they won't get the plugs to fire well. they make small files just for cleaning points. A bit of sandpaper folded in half will work. Once you get looking good you will have to adjust the gap. Often feeler gauges have a coat of oil as a rust preventive. This oil can get on the points. Once you set the gap use a strip of clean white paper, business cards work well. Dampen with electrical contact cleaner. Open the points, slip in the paper, let points close, pull out paper, repeat as need to remove any oil.
This should improve the spark.
Once you get good spark you need to insure it happens at the right time. For this you time the points. Your repair manual explains how.
If cleaning and gapping the points doesn't help you might have dirty connections somewhere between the battery and points. This often happens at the key switch and engine stop switch. If careful you can take the switch apart to clean the contacts. Cleaning any wiring connections along the way will help.
You might want to start at one end of the bike and work your way to the other cleaning and tightening every connection in the wiring. A bit of dielectric grease will help keep them clean.
Leo
Thanks for the reply. I have a manual. Went through steps. Points are clean. I checked the coils with a test light on both terminals while turning the motor over. There's a point on each coil if I bump the motor over the light goes out and comes right back on. Kinda new to this. Is that normal.?
That's normal...
A basic summary is that you get a spark every time the points contact (on alternating plugs)...left/right/left/right...the timing of each "spark" is based on the points setting to the cam shaft rotation (where the pistons are relative to intake/exhaust stroke, etc)... If you had an earlier model with an electronic ignition, the spark would be at both plugs (I believe) and at the same time...but it would still come on/off/on/off... as you don't want to have a spark plug constantly firing...hope that makes sense.
Maybe it would be better to describe what issue's your having?
A basic summary is that you get a spark every time the points contact (on alternating plugs)...left/right/left/right...the timing of each "spark" is based on the points setting to the cam shaft rotation (where the pistons are relative to intake/exhaust stroke, etc)... If you had an earlier model with an electronic ignition, the spark would be at both plugs (I believe) and at the same time...but it would still come on/off/on/off... as you don't want to have a spark plug constantly firing...hope that makes sense.
Maybe it would be better to describe what issue's your having?
Thanks. It does make sense. The issue is that the the electric system seems to check out. Just can't get the plugs to fire. Checked and cleaned connections. I think I'm just missing something.
Without knowing more, it's going to be hard to help...Does the bike run at all?
"Electrical system seems to check out" -- Meaning everything turns off? Nothing comes on? the electric start works/doesn't? More specific?
Earlier you stated that you'd get spark every few times when you "bump" the motor over (do you mean using the kick-start?)... If you get spark...then you have spark...so it could be a timing issue, meaning it isn't sparking at the correct time?
Sorry, I'm not sure I follow...
"Electrical system seems to check out" -- Meaning everything turns off? Nothing comes on? the electric start works/doesn't? More specific?
Earlier you stated that you'd get spark every few times when you "bump" the motor over (do you mean using the kick-start?)... If you get spark...then you have spark...so it could be a timing issue, meaning it isn't sparking at the correct time?
Sorry, I'm not sure I follow...
Sorry, Your right. When I turn the key on everything comes on. I have power to the coils. ( checked it with a test light, both terminals ). The starter is working good. While cranking it over (with the starter )I saw just a couple very faint sparks then nothing. It may be the coils. I'll do some research to learn how to check correctly. Thanks for input.
