wet #3 plug

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wet #3 plug

02 Jan 2019 20:46 - 03 Jan 2019 07:48
#796094
i have a 82' 750 E with CV34 carbs and i was doing some winter maintenance tonight when i noticed the my #3 spark plug was soaked with fuel.. again, and the piston was a little washed. This happen last year on the same cylinder. At that time i thought it was because i was running a vacuum line to #3 carb from the petcock. i think i was planning on rebuilding the petcock but just ended up removing the diaphragm,capped the vacuum ports and just let the fuel gravity feed ever since , the bike ran great all summer up until the last few rides when #3 started to miss.

last time i did the " clear tube test" to verify my float wasn't stuck. ... if this passes again. . does anyone have any suggesting on what to check next?

do you think this could happen if the carbs weren't vacuums synced correctly?

any and all suggestions are appreciated!

-Eric
1981 KZ750e
Last edit: 03 Jan 2019 07:48 by gixxerkidd03.

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Re: wet #3 plug

06 Jan 2019 15:09
#796287
so a little up date... i did the clear tube test and all carbs passed .. even the problem child #3. i pulled the carbs off to take a look at three and found a few little holes in the vacuum diaphragm.

would this cause excessive fuel to load up in a cylinder?

i dumped my oil and change my pan gasket so i had to removed my headers, the #3 exhaust port and exhaust runner was also very wet . so fuel is making it into the exhaust manifold too..

anyone have any suggestions for me ?
1981 KZ750e

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Re: fouled spark plug

09 Jan 2019 20:56
#796465
my number three cylinder is being over loaded with fuel, soaking the plug and into my exhaust system, clear tube test seem fine. i did find a fuel small holes in my vacuum diaphragm of the carb slide , would this cause?
1981 KZ750e

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Re: wet #3 plug

10 Jan 2019 22:31
#796510
No one has any input on why this may be happening?
1981 KZ750e

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  • Scirocco
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Re: wet #3 plug

11 Jan 2019 01:54 - 11 Jan 2019 01:58
#796512
Do a compression test with carbs in full throttle position. Remove all spark plugs for a better cranking.
Post the readings. A very low compression (no firing = un-burnt fuel) on #3 looks like a burnt valve or zero valve clearance.
Last edit: 11 Jan 2019 01:58 by Scirocco.
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