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does my stock 2008 400s have....

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an accelerator pump inside the carb? Reason i ask is i was fiddling with a friends yzf 250 cracking the throttle while the bike was sitting in the shed (not running) and he was like whooah, don't do that as you will flood the bike and make it hard to start. Then i watch this video about some guy doing it and causing crank failure as he diluted his oil sufficiently to cause the oil to thin:

http://www.youtube.com/watch?v=jqhGssr9AJo&NR=1

As i keep my 400s indoors i'm forever hopping on it and clutching it and perhaps cracking the throttle (cant wait for the weather to warm up so i can ride), am i in trouble??? Should i change the oil before i go for the first ride of the season? Does it have an accelerator pump (remember its a stock 400s)?

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does not have one. crack away.

can you still dillude the oil from cracking away? or does the float stop the gas?

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on the stock carb there isnt a ac pump so you cant squirt gas into the intake and flood the motor or dilute the gas but if your vac operated petcock malfunctions and lets fuel in to the intake then you can dilute the fuel.this can also happen when the float valve gets stuck open and the petcock malfunction or you have a manual petcock which you left on and it lets fuel into the intake and then into the motor.usually when the second senario happens you'll have fuel coming out of the overflow and onto the ground.best thing to do is check your oil after you warm up the bike and smell it for fuel

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on the stock carb there isnt a ac pump so you cant squirt gas into the intake and flood the motor or dilute the gas but if your vac operated petcock malfunctions and lets fuel in to the intake then you can dilute the fuel.this can also happen when the float valve gets stuck open and the petcock malfunction or you have a manual petcock which you left on and it lets fuel into the intake and then into the motor.usually when the second senario happens you'll have fuel coming out of the overflow and onto the ground.best thing to do is check your oil after you warm up the bike and smell it for fuel

The mikuni carb on the s,sm (and now some E's?) does not have an overflow. I found out the hard way, my bike was hydro locked.

jbw

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on the stock carb there isnt a ac pump so you cant squirt gas into the intake and flood the motor or dilute the gas but if your vac operated petcock malfunctions and lets fuel in to the intake then you can dilute the fuel.this can also happen when the float valve gets stuck open and the petcock malfunction or you have a manual petcock which you left on and it lets fuel into the intake and then into the motor.usually when the second senario happens you'll have fuel coming out of the overflow and onto the ground.best thing to do is check your oil after you warm up the bike and smell it for fuel

what if you crack it with the manual petcock off?

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^ There is no way for the stock Mikuni to put gas into the engine by twisting the throttle without the engine running.

When you twist the throttle with the Mikuni when the engine is not running, you're just turning a round plate positioned in the air stream.

That's it.

This is one of the main reasons why they get replaced with a Keihin FCR39 (which does have the ability to squirt gas by twisting the throttle) and sold for peanuts on EBay and message boards.

In order for the Mikuni to let gas into the engine while the engine is not running, something has to malfunction, like a float valve not shutting off the fuel flow if the valve is dirty or the bike being on it's side for a while.

Under those situations, it doesn't get squirted in in a controlled manner by a pump operating off the throttle grip - it just pours in with an uncontrolled manner.

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