I just recently finished a moderate restorative project on my 1992 ZX1100C-3 Ninja. The work included all the usual things one would concern one's self with if the bike had been sitting for about 5 years un-operated. Replaced were fuel filter, air filter, oil filter, fresh oil & coolant, brake fluid (F&R) and so forth. I had noticed that the air filter had been left unchanged in the bike (which now has 56K miles on it) and part of the black foam side facing the carb venturies had dissolved and was entrained into the (driver's left) #1 carb, jamming up the vertical throttle slide in that carb. Fortunately I was able to remove the black guckie foam debris with some solvent and restored the carb's slide to operating condition and thought "Fine, resolved that!", giving it no further thought until today...when I started up the engine for the first time in 5-6 years. Fresh fuel and some RED LINE fuel cleaner enabled me to start the machine, although as one can imagine, it was a bit reluctant at first to fully wake up from its long slumber.

At any rate, with the engine now idling, I let the bike continue to run for about 10 minutes but began noticing a progressively stronger fuel smell. That proved to be caused by a small pool of fuel puddling under the engine, just below where the fuel filter/pump and carbs are located. Not a huge or steady flow but a small, consistent dripping and definitely somewhat alarming. Oh-oh! Fuel leaks make me a bit anxious, so I shut the bike down and further contemplated the discovery. A local Kawa shop I occasionally use was fully booked for about 3 months (a common result of the pandemic, from what I have heard), but they were VERY helpful in suggesting a few 'likely' causes. #1 suspect was the foam debris that had been sucked into the #1 carb, in their opinion. #2 was the possibility that the fuel pump (which I had NOT replaced) was not working properly. Either one of those could indeed cause such a slow leak (due to blockages).

It remains now to go through the whole nasty business of removing the fuel tank, unfastening the air filter box (pain in the ***) and checking those two possibilities out, but I wanted to air this situation on the forum in case anyone has had a similar fuel leak situation after painstakingly 'restoring' critical component parts and finding a similar potentially hazardous fuel situation. ARRRRGH! The ultimate fall-back is, of course, to take the carbs to a good carb service facility and have them thoroughly cleaned and 'restored', but I am hoping that that costly work won't be necessary!

 

OK, here's an update: Let the bike sit overnight after its first start-up in 5 years of sitting (unused in a covered garage). The first start-up resulted in the previously mentioned (and very worrisome, to me at least) small puddle of fuel directly under the carbs/fuel-filter/pump. Today, after the battery was fully charged, I decided to restart it to see if it still leaked fuel, fully expecting a further puddling issue. Amazingly...and you could knock me over with a feather, so amazed I am!...there was NO leak today. Not even a single drop! Warmed the bike up to operating temp and let it idle for about 20 minutes. Not a single further drop of fuel! Further, the idling was smoother and overall better than the first day (after the major 5-year hiatus). And I hadn't done a thing to the bike since yesterday (except run about 20 minutes of fresh fuel mixed with a proportionate amount of RED LINE fuel cleaner through the fuel system).

HOLY-MOLY! I am a total loss to explain what caused this transformation from a fuel leaking bike to one that is perfectly 'non-leaky' today! Is RED LINE really that good at improving long-sitting bikes' running or is this in fact a great miracle of faith (saintly intercession by Saint Gertrude of the Perpetually Worn O-ring). It's enough to make me go seek indulgence from Father O'Hallihan!