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Discussion Starter #1
First, I have a 1970 SL350 with 722A carbs

I've had issues with my right cylinder firing intermittently, and judging by the spark plug, is running very rich.

So today I pulled my 722A carb apart and cleaned out every hole. The carb was rebuilt before the bike was running at all: Diaphragm is like new, float is set to 26mm, new springs, jets and o-rings, slider moves freely.

After cleaning it out, it was reinstalled and left the pod air filter off. It started on the left cylinder alone, and the vibration was flicking gas out of the intake of the right carb. No matter how much I adjust the Carb Gas Screw or throttle position, all parts of the intake feel very wet, whereas the left carb intake feels relatively dry.


SO, does anyone know where exactly I should check to figure this out?



If you need to know, all electricals are new (plugs, wires, points, condenser, coils, battery, etc.) and compression is around 130 psi cold on both cylinders. Timing is spot on. Fuel tank is recoated, fuel lines are new. Seat cover is new, the works.

thanks in advance
 

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You can try changing the float valves. Sometime if they are low quality they might not seal correctly and keep allowing fuel to flow into carbs.

Does float have holes? Check them.

Just my 2 cent.

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Discussion Starter #3
You can try changing the float valves. Sometime if they are low quality they might not seal correctly and keep allowing fuel to flow into carbs.

Does float have holes? Check them.

Just my 2 cent.

Sent from my SM-G930T using Tapatalk
I will check the float valve in the morning, that definitely could be the issue.
I did check the float earlier- shaking the floats soon after draining the carb, there was no liquid inside.

Is the slide needle adjustable on these carbs? I just thought that may be at fault as well
 

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I will check the float valve in the morning, that definitely could be the issue.
I did check the float earlier- shaking the floats soon after draining the carb, there was no liquid inside.

Is the slide needle adjustable on these carbs? I just thought that may be at fault as well
I don't know if they are adjustable, but the needle can be changed.

Turn off fuel, take the bowl off, turn on fuel, amd push up on the floats. Fuel flow should stop.

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Discussion Starter #5
Update:

I adjusted the float, and replaced the needle. Seems to be doing better! It's not running as rich but now, thanks for the input. Now I just need to figure out the intermittent ignition/non-firing of one cylinder.

Thanks
 

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Update:

I adjusted the float, and replaced the needle. Seems to be doing better! It's not running as rich but now, thanks for the input. Now I just need to figure out the intermittent ignition/non-firing of one cylinder.

Thanks
Take off the points cover and check ignition. If both fire it mean the wire for the intermittent cylinder was grounded against the cover.

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Discussion Starter #7
I didn't run it with the points cover off, I'll have to try that. I did notice that the points for the right cylinder look way cleaner/newer compared to the points for the left cylinder, even though they're both new (left one has slight discoloration from actually firing). Is it common for the points to ground out on the cover?

I'll test it later today, thanks
 

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Discussion Starter #8
Update:

I tried starting the bike with the Points cover off and it was running about the same. I decided to try swapping things on either side of the bike to see if it would make a difference. So I plugged the left wire into the right spark plug and vice versa, then switched the leads going to the points. When I kicked it over, the right cylinder was running good and the left was not so great! So either the ignition coil, wire, or cap is bad!

Huge relief, as I was starting to consider having to redo the valves again or something.

i just noticed what looks like a pinch in the bad ignition wire just outside the ignition coil. Maybe I'll just cut that part shorter.

Thanks for pointing me in the right direction.
 
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