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Thread: 2009 SC 250 Evap System

  1. #1
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    Question 2009 SC 250 Evap System

    My SC stalled on me 5 times in the last month - one time as I was pulling into an intersection...very scary as I almost got taken out by a car. The other times it was around town - didn't matter if the engine was hot or cold, it did it in both scenarios.

    I did some research and found others who have had the same issue. Some were pointing to the fuel pump stating that the old design had a flaw which caused random stalling. I removed my fuel pump and found that I already have the latest pump. Other's pointed to the evap system. They say that over filling the tank or a bad canister has caused the issue. I didn't overfill the tank - in fact I only had a half tank.

    I would like to completely remove this system to eliminate any possibility. Does anyone have instructions or a diagram showing how to eliminate the evap system? I found this picture from the parts list and I'm not sure which hoses would get eliminated or rerouted.

    - Replaced gas
    - Removed injector and had it professionally cleaned
    - Changed spark plug & air filter
    - Verified I have the latest fuel pump

    2009 SC 250 with approx. 5,500 miles

    Any help would be greatly appreciated.

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  2. #2
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    replace the vacuum valve (cheap thing and often a unreliable peace) and the fuel filter of the fuel pump
    drive it somewhere safe and when it dies open the fuel tank and listen if you hear a hiss if yes the decompression system is clogged and you need to clean it (it will build a underpressure in the tank that is so powerfull that the pump wont be able to pump fuel out of it and the engine will die)

  3. #3
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    Overfilling will make it stall shortly after you try to leave the fuel station. Overfill it enough times and you will have clogged the fuel tank vent and need to do as Jog described. In the fuel tank fill neck there are two ports with the higher of the two being an over flow tube that will pour/dribble gas out on your feet if your standing on the left side of the bike with the lower going to the evap and vent. The way its designed clean filtered air and any condensated fuel left in the evap gets drawn into the tank to replace volume of space left when fuel is consumed by the pump. Mine has been trouble free for 30,000 miles.

    Be sure that hose number 22 is connected to the vacuum valve number 7 so that it opens when the engine is running and that check valve number 17 and the vacuum valve are not clogged.

    Its actually a pretty good system and helps keep gas fumes in your garage and shed down to a minimum.

  4. #4
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    Quote Originally Posted by jog View Post
    replace the vacuum valve (cheap thing and often a unreliable peace) and the fuel filter of the fuel pump
    drive it somewhere safe and when it dies open the fuel tank and listen if you hear a hiss if yes the decompression system is clogged and you need to clean it (it will build a underpressure in the tank that is so powerfull that the pump wont be able to pump fuel out of it and the engine will die)
    Thanks, Jog - are you referring to part #7?

  5. #5
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    Quote Originally Posted by Rockynv View Post
    Overfilling will make it stall shortly after you try to leave the fuel station. Overfill it enough times and you will have clogged the fuel tank vent and need to do as Jog described. In the fuel tank fill neck there are two ports with the higher of the two being an over flow tube that will pour/dribble gas out on your feet if your standing on the left side of the bike with the lower going to the evap and vent. The way its designed clean filtered air and any condensated fuel left in the evap gets drawn into the tank to replace volume of space left when fuel is consumed by the pump. Mine has been trouble free for 30,000 miles.

    Be sure that hose number 22 is connected to the vacuum valve number 7 so that it opens when the engine is running and that check valve number 17 and the vacuum valve are not clogged.

    Its actually a pretty good system and helps keep gas fumes in your garage and shed down to a minimum.
    Thanks, Rocky - I will check those in the morning. If everything looks ok then I still want to proceed with the removal. It looks like I would just run a longer fuel line (part 15) directly to the fuel rail, am I correct?

  6. #6
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    Quote Originally Posted by DjSaneR View Post
    Thanks, Rocky - I will check those in the morning. If everything looks ok then I still want to proceed with the removal. It looks like I would just run a longer fuel line (part 15) directly to the fuel rail, am I correct?
    No the vent does not go to the fuel rail that is what the fuel pump is connected to. The vent releases excess fuel tank pressure build up into an air inlet to the throttle body via a port in the plastic behind the air filter housing or draws it back in again so there won't be a vacuum in the fuel tank as the fuel level drops with the carbon canister being an additional safety reservoir in the line between them. So you won't be potentially sucking dirt into the fuel tank and messing up an expensive high pressure fuel injection pump which is sitting inside the fuel tank, when there is vacuum in the fuel tank that hose gets clean air that has passed through the air filter.

    Myself I prefer a garage that is not full of gas fumes especially living in Florida where most homes have the laundry with a clothes washer and dryer in the garage along with the water heater and HVAC Air Handler so I would leave the system intact and working properly otherwise its ban the bike from the garage.

    I don't understand why so many people get a tick in their head against the EVAP system as rarely have I had one actually be at the root cause of any problem with a car or bike in the past 50 years of wrenching. Yes I have heard a lot of unfounded blame placed on its existence but only on occasion have found the issue to actually be the EVAP systems design or it having a failed component. More often its user error over filling the fuel tank or pulling the check valve and putting it back backwards. Folks upgrading the vacuum tubing and putting the check valve back in backwards is actually one of the more common issues I have found.

  7. #7
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    Sorry, I didn't look carefully and I assumed that #15 was the main fuel line.

    I don't want the smell of fuel in my garage either, however, after almost getting plowed by a car because my bike died in the middle of an intersection, I'll deal with the smell. This is trial and error - if the issue happens after the removal of the evac system, I'll put it back, investigate, and move on to the next suspect.

  8. #8
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    Just be careful on how you do it or you can end up venting gasoline over the top of the engine or have fuel dripping out on hot engine parts if you dump the bike. Look at how and where the overflow vent is routed and try to mirror that if you remove the entire evap system.

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    Will do, thanks for the tips. I will post my findings

  10. #10
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    yet another thread Rockynv contributes his 30,000 mile benchmark again.

    I fill my tank all the way to the neck and never have any issues. Also thats ALOT of parts/work for an issue like stalling...lol

  11. #11
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    I removed my evap system without any issues, just make sure you block the right lines and leave breathing room for the others. It's not hard to figure out. Good luck...!


    '09 SC 250
    V4 Malossi Head & Cylinder (ported & polished ; j )
    203cc Injector (Scarabeo 500)
    Akrapovic slip-on
    12g sliders w/ stiff clutch & contrast springs
    Michelin Power Pure

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