Motorcycle Questions? Ask a Mechanic.
Hi and welcome to JustAnswer,Thank you for the question and your patience. Should you still need assistance for information purposes only...Initially, proposed preliminary tries (if have not been done):
Additionally, proposed repeat checks (if have not been done) on the possibility of over/under-voltage, regulator/rectifier and/or stator issue. With a volt/multi-meter, determine again the battery voltage when:
Please post back results / observations of the above once tried.
Appreciate the post back.
And for some reason, the "... the plug is sooty (as stated in the first part)..." appears to be missing in the initial post.
Still, consider with a fully charge battery to try the quad with the voltage regulator temporarily disconnected.
Would appreciate an update when the carb + spring has been addressed.
The regulator would look something like the part HERE and can be disconnected through its connector. With a fully charged battery the Suzuki should be able to start run and rev.
If problem persist, then an over-voltage condition would be the least likely cause.
A lean condition can either be carb or air cleaner issue. Is the air cleaner / box correctly fitted? ...as air entry should only be through the designated air cover opening.
And yes please, a video when able.
And the voltage appears to check good/acceptable.
Have you checked the air box / cleaner (filter-element) ? ...correctly mounted, sealed and air entry only through the designated opening?
For the moment, let's say that mix is lean, there is a hesitation/flatspot when attempting to rev but there is no air leak; are you able to try raising the needle?
Depending on the carb (model) by lowering the clip or adding small washer/spacer(s).
...and with the air box / filter on please.
Almost always, the needle would be tapering thus the fuel allowed is not equal at any given height. At 1 point, the fuel may still be not enough and the air is as required thus the lean but not constant and likely 1 of the reason the slight hesitation to rev and then the 'backfire' or delayed fuel in rush.
Yes please; an update when able.
Thanks and very significant results:
And have you tried further restricting air entry; i.e. replacing with a more denser filter element or over laying with add-on/universal air filter?
And yes please on the video though there may be a bit of a delay on my next post.
Appreciate the post back and would look forward to an update when able.