Motorcycle is a 1981 Suzuki GS450. Ever since changing the air filters the bike chugs to speed up. Only tops out at around 55MPH now. There was a rubber tube going from the motor to the air filter that has nothing to go to now. Im suspecting this is the problem. But now that the bike is bobbed I cannot put the old filter back on. What could the problem be?
Anonymous
Favorite Answer
I've gone through this before.
Your motorcycle is no longer running because you have an incorrect fuel/air mixture being pumped into your engine.
Solution: Carburetor jetting
In a nutshell it goes like this:
Upgrade your main jet, if it feels like your bike lacks power, upgrade to the next size, if it feels like it accelerates smoothly with the right amount of power but jerks at all (don't mistake with ignition cutting) then you must downgrade to a smaller jet.
Next, You can shim the needle, this will only effect performance from about 1/4 throttle to 3/4 throttle. You can easily find a tutorial or detailed instructions on google.
Lastly, you want to adjust the pilot jet to get the smoothest idle, turning it left richens the mixture while right will lean it out. Adjust it to where it sounds the best, when it sounds good rev the engine, if it returns back to idle immediately after revving, you have a good mixture.
That rubber tube you speak of? I've been riding suzuki's all my life and there's only two tubes that I can think of. One of them is approximately 3/8" wide and is just for drainage, the other is approximately 2 1/2" wide (varies by the engine size) and feeds the air directly into the carburetor where the fuel is injected as a mist and pumped into the engine. I assume you're talking about the drainage line though, that does not connect to anything, it's just ran down to let whatever backs up into the airbox drain out the bottom of the vehicle. So that's supposed to be disconnected on the opposite side.
?
Aftermarket Motorcycle Air Filters
vulcvoy
Air fuel mixture is now wrong. Need to either fix air box and put correct filter on, or adjust fuel side of mixture to get ratio back. Take it to a mechanic.
Good luck and ride safe,
Mike
Candid Chris
Your spark plugs are the best place to check, sounds like it's running rich.
Did you plug-up that vacuum tube, if so unplug it and either find a small filter to fit the end or a way to attach it to the air-boot.
Anonymous
Aside from needing to re-jet for the new air cleaner , it sounds as if you've created a vacuum problem by not reconnecting that line.