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Silverado
06-25-2010, 01:39 PM
I recently rebuilt a 250sx with one of the members on here and i would like to hear from the rest of you in case you know what this is.


On the left side of the machine there is a single loud knock when you turn off the machine, it happens 90% of the time, but occasionally it shuts down without the sound.

The knock comes from the side where the starter motor is (shifter side). I noticed this problem before the rebuild. I have since replaced the starter motor with a new one as well as the bearings on that side. I tried a new set of starter gears in there and still got the sound. The only time I could make the sound go away fully and completely is to take the gears out so they don't touch the starter motor. Although this works it takes away my ability to use electric start.

It is just one loud knock from that side when you turn the bike off.

Anyone have any ideas ?
Dirtcrasher
06-25-2010, 05:07 PM
It's gotta be the one-way bearing on that side. They have one on each side but usually it's the centrifugal clutch center one-way brng that dies........
tapper190
06-28-2010, 07:13 AM
It's gotta be the one-way bearing on that side. They have one on each side but usually it's the centrifugal clutch center one-way brng that dies........

I changed that bearing as well (both sides), It has me stumped....
Tapper
atc350xer
06-28-2010, 09:38 AM
Does the kick start work? My one way bearing is shot, I can only start it with the electric starter, and it knocks then spins down at shutdown.
tapper190
06-28-2010, 03:17 PM
yes the kicker works great.
Tapper
Xhumeka
06-29-2010, 08:09 AM
Did it make this sound last time we gathered at the Ganny? I don't remember there being any issues with your trike (other than your stripped shift pedal).
Silverado
06-29-2010, 08:21 AM
Yep it still made the sound when we were at the Ganny. Due to the pedal shift getting stripped you never got to hear the bike shut off at close range.
I just got back from New York, I was riding down there and the sound still happens most times at turn off.

I did get the machine a little wet when I was cleaning her in the shallow end of the lake ,so I was trying to start her wet and she would still make the knocking sound with a failed ignition. I just let her dry off and she stared fine, but the clunk is still there. As Tapped said the kick start works beautifully and the one way bearing was replaced.