Vacuum issues? I hope so.

[Guest]

Hey all! Long time no post :P Guess things happen when you start working 7 days a week again, and get a CBR project bike to boot


The other week when I got the tank on my 650, I tried cranking her to see if she would start... Nothing. Broke out the starter fluid, and up she fired (but not for long). I tried on prime, reserve, and on. I was tired, and went home thats how she sits at the shop now.

Here are my thoughts...
-obviously not getting fuel, has spark and air runs on starter fluid
-Simply not enough gas in the tank? (put in maybe a gallon or 2 for starters)
-vacuum isn't doing the job (Brand new, OEM petcock and tried on PRI/RES)
-Spark isn't strong enough to ignite fuel? (don't know why that would change when it worked perfectly fine when it was on the AUX tank)

You have any insight feel free!
Thanks in advance

[tkent02]

How long has it sat since it last ran well? Did you drain the carbs when you last put it away or just shut it off and walk away??


Just a guess, the carbs are plugged up from sitting too long.

[Bonehead]

How long has it sat since it last ran well? Did you drain the carbs when you last put it away or just shut it off and walk away??


Just a guess, the carbs are plugged up from sitting too long.

Been about a month since I put some gas through it. I might have just walked away from it... The things I do to myself!

How long does it usually take for the gas to muck it all up? Since, you know, I'd prefer for this not to happen again

[tkent02]

Hard to say, in a dry cool climate it can last for months. Hot and humid, maybe a few weeks. It depends a lot on the composition of the fuel, how airtight your fuel system is. FI bikes start right up after a long tme sitting, carbureted bikes not so much. I know California's fuel is different than everyone else's but don't know how long it lasts. i think it's got a real high alcohol content?

A month since you put gas in it or a month since a good long hard ride where everything got hot and all of the carb circuits were cleared out? Could that month maybe have been three?

[Bonehead]

Hard to say, in a dry cool climate it can last for months. Hot and humid, maybe a few weeks. It depends a lot on the composition of the fuel, how airtight your fuel system is. FI bikes start right up after a long tme sitting, carbureted bikes not so much. I know California's fuel is different than everyone else's but don't know how long it lasts. i think it's got a real high alcohol content?

A month since you put gas in it or a month since a good long hard ride where everything got hot and all of the carb circuits were cleared out? Could that month maybe have been three?

by good hard ride you mean running for about 5 minutes and making sure she still runs, and there's no weird noises... Right?
Well, at least it isn't too hard to take the carbs off! I can also possibly dip/powdercoat the carburetors... Hmmmm decisions decisions.

[tom203]

Make sure gas is getting to carbs- pull fuel line, put petcock on "PR", gas should spill. Make sure you got "choke" system attached correctly and it operates at carbs.This bike likes full "choke" at wake up. How old was that gas you put in 1 month ago??

[Badooka]

I can start flaking gunk off the bowls after 2 weeks without Seafoam.
Fuel today is garbage, I'd pull the carbs and give them a good going through. You can try a Seafoam treatment- you might get lucky.
If your in the right area and can find gas with no ethanol- use it.

[Triam]

+1 on the seafoam.

Not to hijack the thread, but is the ethanol what makes the carbs get dirty?

[tkent02]

+1 on the seafoam.

Not to hijack the thread, but is the ethanol what makes the carbs get dirty?

Hmmm, not a fuel expert here, but I've read a bit about it. The ethanol itself lasts a long time. It absorbes water so it helps the water stay dissolved in the system rather than settling out in liquid drops at the bottom of the fuel. That's a good thing. In short term use that's fine, it helps to dizzolve and burn whatever water gets in your system. In storage, not so good, the water, just like water in a brake system is still there rusting and corroding things. Other things are changing in the fuel, chemical changes I don't understand, but in some sealed fuel injection systems, it can last quite a while. My Jeep just sat three months on a half tank of old gas, no problems at all. In an unsealed motorcycle system, with vents for air to go in and out of, the gas goes bad faster, I don't know why. I wouldn't dream of letting a non FI bike sit three months with unstabilised fuel in it, with the FI bikes, no worries.

[Badooka]

STP has come out with their version of Seafoam- I read up on and it it supposed to be better- I have a can but have not used it- gonna take a road trip soon and will update on it. I think it comes in a buck cheaper. You'll know you've found it since it's the same type of bottle as Seafoam. Wal mart has it.