Sportbike Racing Forum banner

Best Fuel/Carb Gum Cleaner

24K views 5 replies 3 participants last post by  theoldF2guy  
#1 ·
Hey Guys,

Can anyone recommend THE BEST product for cleaning gum out of carbs?

I won't bore you with an in-depth explanation as to "why" I'm asking other than to say: several years ago before I became my own mechanic - or is that my own best enemy? :crazy - I had issues with my carbs. After being "referred" to a local Honda dealer (who supposedly had the best carb guy working for them in the local area) I was told that the #1 and #3 carb were almost completely clogged. In any case, I've recently realized that the guy put the float bowls back on each carb in such a way that you can't get to the carb drain screws. At least not in the normal way! :banghead If I'm right, two carbs each are supposed to have the drain screws facing the "outside" of the bike (away from center). Well... mine don't. Two on either side are facing "inward" toward the others meaning that I have to go from the "opposite" side of the bike to turn the freaking drain screws! If I'm right on my assumption here, that means this butthole mechanic deliberately placed the carbs in this manner in the hope I would (again) have to return for more carb work in the future! :soapbox

So to solve my problem I bought a 3/16" screw driver with a 10" shank. Although I still have to go from the opposite side of the bike to get to the drain screws, I "can" (with some effort and removal of the right side lower fairing and both under-seat rear fairings) drain the carbs.

In any case I started it up for the first time today and it ran a bit rough. Not "bad" but enough to make me question if there might be some more gum build-up in the carbs. Hence the reason for my question.

I have used (and still do use) Lucas Upper Cylinder Lubricant with Injector Cleaners and Fuel Conditioners. However - this is a "lubricant" and thus it does feel slick like an oil. I'm wondering if I need to use strictly a "fuel cleaner" that contains acetone?

Any advice would be greatly appreciated... :waytogo
 
#2 ·
I'd say it's far more likely that the mechanic was careless rather than malicious in re-installing the float bowls--recently, I unintentionally/carelessly did the very same thing myself when rebuilding my ZX1000R carbs. Any one of the bowls will fit on any one of the carbs, and if you're just not paying attention, you've got a 50-50 chance of getting it wrong. FWIW, it's easy enough to swap the float bowls over onto their proper carbs.

As far as the present function of the carbs, you can certainly try fuel system cleaning additives--might work--but the best/most thorough solution is to pull the carbs apart and soak them in parts cleaner, especially if the problem occurs at, or just off, idle. The idle circuit fuel passages are really small, and the fuel--and any cleaning additive it may contain--is not pulled through them with any real vigor, so if they're clogged, they don't self-unclog very well/easily.
 
#4 ·
Hey South,

Have a question for you...

I've checked into this SeaFoam stuff that LynnM has recommended and I've been told (by more than one person) that this stuff will probably clean the idle circuit fuel passages as well. I've been told to add a little more than what's recommended to insure that this stuff will help clean the idle circuit fuel passages.

That said, and since you seem to be one of the forum "Gurus" here on almost anything technical, I wanted to get your opinion on this SeaFoam.

Be honest please, as you've not steered me wrong yet! :wtg

Thanks,
 
#5 ·
By any chance, were these "more than one person" the same guys who were offering it for sale? :smirk

Seriously though, as I said, the stuff *may* work/help--I've used SeaFoam and similar products previously--and, at worst, you're out the $7-$8 you paid for it.

If the analogy helps: fuel additive cleaners are like "Liquid Plumber" and the like. Sometimes they'll unclog a drain, and sometimes they won't and you have to use a snake which is basically guaranteed to do the job. Pulling the carbs apart and soaking them in a good parts cleaner (like the 1 gallon kits of "Gunk" brand parts cleaner available at many auto stores) is the equivalent of snaking a clogged drain.

So, it's just a question of whether you want to first try the Liquid Plumber and see if it works--and there's nothing wrong with that, just a little time and money--or go right for the (sure thing) plumbing snake.

With any luck, the SeaFoam or similar will work. Just bear in mind that you may have to resort to plan "B", that's all. :waytogo