Ignition problems

[Team Junk]

Check your carb boots for cracks or leakage.

 

[Team Junk]

I'll use carb cleaner though the straw with the engine idling to pinpoint air leaks. Hylomar blue is my goto for "gotta seal" joints. Check the throttle shafts also. A carb overhaul isn't complete without new throttle shaft seals.

Words of wisdom.

 

[Markxs650]

Hey guys so these plugs are new and just been replaced I got a picture of them below. The top one is the left and the bottom is the right. They are looking better tho then the other ones then again I have run them that long probably around 3 hours.

 

[Markxs650]

There is no oil on either so i guess that’s good but they’re not super pretty. Also I do plan on checking the carbs again myself this time to see if there is something wrong.
PS- also sorry about that I was confused too when my account changed I was thinking it was a glitch but it’s actually my old account that wasn’t working at first but now it’s made me switch over for some reason

 

[gggGary]

Hey no problem mike! and welcome back. What plug # you using ? Looks like you have BPR7ES. Have you ohmed out the plug caps? With those plugs your caps should not have any resistance. If you are using stock BP7ES then you should be seeing about 5K ohms in the caps. Unscrew caps, check that the wire end is clean and making good connection inside the cap. One issue may be using resister plugs AND resister plug caps together that can make resistance high enough to cause misfires..

 

[5twins]

Yes, you only want one instance of resistance in your spark plug line. That can be either the plug cap or the plug, but not both.

 

[Marksxs650]

I haven’t thought about the caps and idk I think they might stock plug caps but I’ll check into that. Also I did do they test for the coils where we switch the plug wires of the spark plugs and nothing changed. There was still only backfire out of the left exhaust, so the carbs are looking more and more like the problem.
Also sorry about the late message I’m still figuring out this site and signing in I’ve made about 3 other accounts cause I forgot how to log in or retrieve them!

 

[5twins]

If you still do have the original spark plug caps then their resistance is probably even higher than 5K. Yamaha used some oddball value like 8 or 9K ohms. Do swap them out for some NGK caps if they are the originals. It'll be like the best $5 you spend on the bike. If you're going to continue to use the resistor plugs (they are easier to get) then get non-resistor caps. NGK makes a very nice one, the LZFH .....

If you're going to switch back to non-resistor plugs, you can run 5K ohm caps .....

I prefer the LB05F that fits on the terminal stud, I think they grip better.

 

[650Skull]

Also I did do they test for the coils where we switch the plug wires of the spark plugs and nothing changed. There was still only backfire out of the left exhaust, so the carbs are looking more and more like the problem.

Swapping the coil leads from one side to the other won't do anything. With a Pamco you have a single coil with 2 leads that uses a wasted spark system. This fires on both leads at the same time but only one cylinder is on the combustion stroke.

If a spark plug was suspected to be faulty..........Swap the leads and spark plug, If the problem followed and went to the other cylinder, then that would prove the spark plug was faulty