I'd say it's very comparable. It's a very bright spark on both sides. I could try swapping the plugs to see if that changes anything.How does the strength of the spark compare to the side that runs?
Weak sparks can disappear under compression while being wet by fuel. A drop of fuel condensed on the tip will short the plug meaning no spark.
Okay thank you! I'll give that a shot this afternoon.Try that. Then try swapping the plug caps. They unscrew from the leads.
Thank you for this, I'll have to check it all!As a sanity check run this test if you have a DMM. Also, you can remove the screw in the intake runner and give a small shot of starting fluid to see if it fires to rule out/in a carb issue
View attachment 212585
Thanks Bob, I just added all that, my apologies it took so long!It is often said that it should run if you have fuel, spark and compression but in reality they all have to happen in the right amount at the right time do do any useful amount of work.
Since the plug on the side that isn't running is wet I'd start with checking the ignition system but I'd also check for flooding, possibly caused by the float bowl overfilling and the overflow not allowing the excess to drain (a couple of things I saw on the forum today made me think of that).
It might not hurt to check the valve clearances either to make sure they were set with the engine at the correct points.
BTW: Don't forget to add your bike's model and year and your location to your profile (see Forum Settings link in my signature) like I asked you to last month.
One of the plug caps is suspect. Measure the resistance of the plug caps.Update for everyone:
Swapped spark plug caps: Neither cylinder would run. It also sounded like the battery was struggling to turn over when I flipped them. I'm not a huge electronics guy so I wasn't sure what that was about.
Replace the float bowl drain tube with clear hose and run the hoseup beside the carb. Open the bowl drain screw and observe the height of fuel inn the clear tube. It should be a couple of millimeters below the joint between the carb body and the float bowl.I'll make sure to look into the float bowl flooding as well. Is there a straight forward way of checking this?
Yes that's a good idea!When having difficulty that requires a lot of cranking with the starter it's good to keep a low amperage charger on the battery between tests and check voltage after charging, it should be around 12.8v fully charged.
Should I measure the resistance of the plug caps from each other or just a ground?One of the plug caps is suspect. Measure the resistance of the plug caps.
Replace the float bowl drain tube with clear hose and run the hoseup beside the carb. Open the bowl drain screw and observe the height of fuel inn the clear tube. It should be a couple of millimeters below the joint between the carb body and the float bowl.
I see. I'm pretty sure I made a mistake, I didn't realize they could unscrew. I took the ignition modules off (under the gas tank) and switched each side. Let me try again!Unscrew the cap from the wire and measure it end to end. They both should read 5000 ohms if they are in original condition with their resistors intact or zero ohms (the same as when you touch the test leads together) if the resistors have been removed.
Just a thought: When you switched the caps from side to side you did unscrew each of them from the wire it was on and screw it into the other wire didn't you? If you just moved the caps from side to side attached to their original wires (& coils) the left side would have spark when the right should and vise versa, which could explain why it struggled and didn't start.
Hi Bob. The left cylinder cap was reading in the 5000 ohm area while the right side was all over the place, pretty sure it was in the mohm range.Unscrew the cap from the wire and measure it end to end. They both should read 5000 ohms if they are in original condition with their resistors intact or zero ohms (the same as when you touch the test leads together) if the resistors have been removed.
Just a thought: When you switched the caps from side to side you did unscrew each of them from the wire it was on and screw it into the other wire didn't you? If you just moved the caps from side to side attached to their original wires (& coils) the left side would have spark when the right should and vise versa, which could explain why it struggled and didn't start.
