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View Full Version : Topend HELP!!!


balls2da-wall
09-01-2005, 06:41 PM
Alright my friends 440ex needed oversized studs installed...so i put them in and when it was all back together it wont stay running when idling and it acts like its running lean by being sluggish on the bottom end but pulling good up top...so i though maybe i timed it wrong so i went back and checked and its spot on...ive done this head stud conversion on mine and everything worked fine but his seems like it running lean but doesnt backfire...and it ran fine before we tore it apart....what could be wrong?


I though maybe something got in the carb or a fouled plug maybe...not sure though.
jhoppa
09-01-2005, 06:50 PM
Sounds fun....

1) Get a timing light and confirm that the timing is correct. Take off the inspection plug on the crank and shine this light in there. Should see the timing mark on the crank, while engine is running.

2) Remove the rag that you left in the intake

Thats all I have, good luck.
cals400ex
09-02-2005, 06:50 PM
is the idle adjustment high enough?
balls2da-wall
09-02-2005, 08:16 PM
would that make it sluggish on the bottom end? And how would it be changed from when it was running fine to being too low?
RiderTRX400ex
09-02-2005, 09:05 PM
bump the pilot up from stock 38 to a 42 and try the mixture screw 2.5 turns out from seated... lihtly seated
balls2da-wall
09-02-2005, 10:10 PM
maybe i need to clearify....This was a 440ex jetted and everything...it was running fine until one of the head studs pulled out so we swapped them out with the heavy duty ones...when we put it back together it began to act up.
prepracing
09-05-2005, 03:48 AM
I would check the timing and the valve clearances again, if all u done was put in new studs that would be the only thing that u would have put back differently, unless its something simple like the idle adjustment screw got bumped :confused:
Xowner
09-05-2005, 09:57 AM
when one of the studs pulled out did it warp something and now maybe your not getting a good seal?
balls2da-wall
09-05-2005, 11:12 AM
Im convienced it something simple...nothing is warped i checked around the gasket after i ran it to check for leaks...timing is spot on...and its not backfireing at all like it would if it was running lean. I will try a few things and get back to you