View Full Version : How long until my carbs gum up?


headshrink
February 4th, 2014, 10:18 PM
I've been riding daily since 2008, so I've never had to worry about cleaning my carbs. Since my bike has been in pieces for over two weeks, and with the weather thinking about getting cold here in the west (lowering my motivation to get it fixed fast), I'm wondering if I need to worry about my carb gumming. After how long a break does this become something to worry about?

cuong-nutz
February 4th, 2014, 11:48 PM
I would guess a month.

Just disconnect the fuel hose and run the bike until it dies. Open the float bowl drain screw to drain any residual fuel.

KawiKid860
February 5th, 2014, 12:29 AM
A month seems way too fast, you'll be fine at 3-4 months especially if you can run some seafoam through them and then drain em out. My 500 has been sitting since August and I rode it in November and it was fine, not sure about now but it should still be okay.

Klondike1020
February 5th, 2014, 12:42 AM
Treat your fuel with marine grade stabil. I let a bike sit over a full year
Drained the tank , put fresh fuel in it and worked awesome!

Use te old fuel in my truck lol

Yarhj
February 5th, 2014, 05:51 AM
It really depends on the gas quality. I've had it happen to me in as little as two weeks, but your mileage may vary (We only have access to the E10 stuff down here, so ethanol free gas might last longer).

The simplest way to avoid it is to just go out there and drain the float bowls (http://faq.ninja250.org/wiki/How_to_drain_the_float_bowls), which will take you maybe 5 minutes.

You shouldn't need to run the bike until it dies -- both methods accomplish the same goal of getting all the gas out of the carburetors. When you need to start it up again it will take a bit of cranking to fill up the carburetor bowls (it will seem like it's not going to start for a while), but as soon as that's done it should fire up with no problem.

If you're worried about draining your battery too much with all that cranking, you can get a simple hand/pump vacuum at your local hardware store and use it to apply vacuum to the vacuum line on your petcock for about 2 seconds to get some gas into the bowls. Don't keep it on there too long, as you could end up with gas leaking past the float bowl seals if they've been sitting for too long (they dry up and shrink a bit if the carbs are empty, so the first time you fill them up they may leak a little).

DaBlue1
February 5th, 2014, 06:43 AM
Gas can start to be come weak in about 3 months in ideal conditions. Use of a fuel treatment that does not contain alcohol may work better in prevent gumming and gas contamination.

See Fuel Testers. http://www.fuel-testers.com/expiration_of_ethanol_gas.html

jkv45
February 5th, 2014, 07:29 AM
Add the correct amount of Stabil or Seafoam and fill the tank to the top. Ethanol-free gas will last longer, but gas with ethanol can go bad quickly (90 days from when it was added to the gas), so it's best to treat it sooner rather than later. No need to dump it when you are ready to ride if it was fresh at the time you added stabilizer. I've run stabilized gas that was over a year old without a problem. After running the stabilized gas through I will usually run some fuel system cleaner in the next tank (once a year). Techron Concentrate at 1 oz per gal with ethanol-free 87 is my favorite.

The key is draining the floatbowls. That's where the gas will breakdown and varnish the fastest - and give you the most problems when you try to get it going again after sitting.

As noted - make sure you have a fully charged battery (12.6V) when you go to start it after draining the carbs because it will take some cranking to build enough vacuum to start the fuel flowing from the vacuum-petcock.

g21-30
February 10th, 2014, 09:32 AM
Treat your fuel with marine grade stabil. I let a bike sit over a full year
Drained the tank , put fresh fuel in it and worked awesome!

Use te old fuel in my truck lol

Stabil Marine is the ONLY way to go! 1 oz per every 5 gallons of gas. Been using it for years, now! Bike starts everytime, no matter how long it has been sitting. Still on the original battery, also, thanks to a "battery tender"!

Klondike1020
February 10th, 2014, 10:00 AM
Stabil Marine is the ONLY way to go! 1 oz per every 5 gallons of gas. Been using it for years, now! Bike starts everytime, no matter how long it has been sitting. Still on the original battery, also, thanks to a "battery tender"!

+1000

I used to use plain stabil but the marine grade is better, it has ethanol neutralizer also!

protects soft parts! no corrosion or varnish residue !

I fog oil my cylinders when I let an engine sit longer than a couple months.

kirk595x
February 10th, 2014, 10:56 AM
Gumming can occur in as little as two weeks. Seafoam and Startron are proven products.

g21-30
February 11th, 2014, 05:38 AM
+1000

I used to use plain stabil but the marine grade is better, it has ethanol neutralizer also!

protects soft parts! no corrosion or varnish residue !

I fog oil my cylinders when I let an engine sit longer than a couple months.

I used plain stabil the first year and then I found out about Marine. I use it in everything: lawn mower, riding mower, weed whacker, and chain saw. The chain saw is a 2 cycle engine, so I pour the treated gas into another container with the premeasured 2 cycle oil. Works great!

headshrink
February 11th, 2014, 11:37 AM
Does it seem to run better with Seam foam in it, or is that my imagination?

Klondike1020
February 11th, 2014, 06:13 PM
Does it seem to run better with Seam foam in it, or is that my imagination?

I use sea foam to treat my high mileage cars.

but not religiously.

maybe you and I have the same imagination because I swear my cars run better after a healthy dose of that business.

headshrink
February 11th, 2014, 09:15 PM
I use sea foam to treat my high mileage cars.

but not religiously.

maybe you and I have the same imagination because I swear my cars run better after a healthy dose of that business.

Maybe we're not crazy then.
To be clear, I am talking about while it is mixed in the gasoline that is burning, and not a post-treatment fill-up. I added SF to my tank and let it run for a bit while I was buttoning up my bike, and once it warmed up it sounded smooth and strong. This was all on the paddock stands, but she rev'd like crazy. However, I've noticed she occasionally has exceptional days, depending on weather.

headshrink
February 25th, 2014, 05:59 PM
Since I've been back on the road, after about 2 weeks break, I'm now having an intermittent issue. My first assumption is that my jets may have started to clog, since I haven't done recent engine work, but I want to see what you all think. For the most part everything seems normal, but sometimes when I roll on the throttle aggressively (1/2 to 3/4 throttle) before the RPM gets close too the rev limiter (guessing @ 8-10 RPM maybe) it feels like it cuts out. It doesn't feel like a lean surge, and I don't THINK it feels like a rich bogging... it's difficult to describe. Almost like it sputters and looses all power, but only a second.

What does this sound like?

jkv45
February 25th, 2014, 06:04 PM
Did the tank sit with a low level of fuel for the last couple of weeks? If so there could be a significant amount of condensation that formed.

Drain the floatbowls and look closely at what comes out. If it's not good, drain the entire tank by removing and dumping it - that's the only way to get the water out.

Always use ethanol-free gas if you can.

Motofool
February 25th, 2014, 06:39 PM
......

What does this sound like?

Yes, as Jay has explained, the alcohol in your fuel has been absorbing air humidity and condensation may have accumulated at the bottom of your tank and then some may have flown down into the bowls.

Draining the bowls is a simple and effective work in that case.

Keep rolling that bike and the fuel + Seafoam will hopefully dissolve any built up deposits in 200 miles or so.
They have done it for my bike more than once. :)

misfitsailor
February 25th, 2014, 07:53 PM
One of my carb jets became blocked after a rest of only 3 weeks last year. (California gas sucks) Other times I have gone months between rides without issue. Seems to be more of a problem on small carbs, their jets have such tiny holes! Any kind of stabilizer should help. You will not enjoy removing the carbs just to unclog them!

headshrink
February 25th, 2014, 09:42 PM
Yes, it was relatively empty when it sat. Since I had only planned to have it out of commission for one weekend, I didn't treat the fuel, but did add Seafoam when I put it back together. I've re-filled the tank since then. I'll let the fuel level get a little lower then dump as suggested. Thanks!

jkv45
February 26th, 2014, 08:34 AM
One of my carb jets became blocked after a rest of only 3 weeks last year. (California gas sucks) Other times I have gone months between rides without issue. Seems to be more of a problem on small carbs, their jets have such tiny holes! Any kind of stabilizer should help. You will not enjoy removing the carbs just to unclog them!
Right. Gas with ethanol will go bad faster and gather more moisture along the way. Warm temps help the fuel evaporate quicker in the floatbowls as well, decreasing the time it takes to varnish. Keeping the tank as full as possible will help reduce any condensation problems.

It may be worth it to add a small amount of stabilizer to every tank. I wouldn't go the full recommendation, just 1/2 or so. Might be a good idea if you are having consistent fuel-related problems and especially if you aren't planning to ride regularly.

I keep 5 gal of ethanol-free 87 at home for my small engines and to top off the cycle tanks if needed. Every time I fill the can I add stabilizer. I never have any fuel related issue - even after the fuel has sat for more than a couple months.