Nope....it pulls fuel up from the float bowl.  I believe it uses the Enrichement Circuit to obtain fuel.

The TEV has nothing to do with the shut down POW.  When you turn off the ignition, the engine is still turning and it pulls fuel and air though the engine....and pumps it out the exhaust since the spark plug is inactive.  When the fuel/air mixture in the hot exhaust is heated up to the flash point - it ignites.  I lean mixture burns faster than a rich one....so if the bike is lean at idle the mixture is more explosive and makes a louder bang.  Lawn mowers used to do this....and most modern mowers have a fuel shut off that closes when you turn the key off, and it prevents the bang caused by the hot muffler filling with fuel.

You cam limit the pops and bangs while riding, by holding the throttle open about 1/16 turn when you shift and decelerate.  It makes very little difference in the amount of braking you have to do as it is not enough throttle to make any power....just enough to allow fuel to flow into the engine while you are braking or shifting.  The pops and bangs when you shift or decelerate are caused by the engine going lean when you have shut the throttle and closed off most of the fuel flow...only the idle circuit is providing fuel.  The TEV (Throttle Enrichement Valve) is supposed to add fuel when you have the throttle closed and the engine has gone lean....but it does not add much and doesn't seem to eliminate the problem.  Richening up the pilot jet can reduce the popping and banging - but the problem is that when you make the pilot jet bigger to reduce pops and bangs - you may be running too rich and get crappy fuel mileage.

Dave

shorty wrote on 06/10/14 at 15:47:27:


Maybe inside the engine....but not in the muffler.  The folks on this site who have had "gun shot" explosions on shutdown....then replaced the pilot jet with a larger one....or turned the mixture screw richer....report the explosion is reduced to a "poof".

Tocsik wrote on 06/10/14 at 12:58:39:

I got ride of the downshift and decel pops on my bike by cutting one-half of a turn off of the TEV spring, after turning out the mixture screw didn't solve the problem. Keeps the TEV open slightly longer. YMMV.

verslagen1 wrote on 06/11/14 at 07:20:33:

That's just what I did. I cleaned the TEV and carb, adjusted the mix screw, tried a larger pilot jet (got rid of the backfire but wouldn't idle when cold), tried a washer, and tried a softer spring. The softer spring got rid of the backfire but caused an irregular idle. I also read through the threads on the spring mod for the TEV and saw that most people were removing a substantial piece of the spring. I started with a half-round, and that tiny adjustment was enough to get rid of the backfiring. Of course, as I said, YMMV.