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Sanchez
Posted on Wednesday, December 13, 2006 - 10:59 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Every once in a while when I blip the throttle for a down shift, my M2 cuts out on me for a second. There seems to be no rhyme or reason for when it happens, and my recent rejetting hasn't helped (or hindered). Is there a known solution for this?
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Cyclonecharlie
Posted on Thursday, December 14, 2006 - 07:42 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Sanchez,
What have you changed in regards to the carb. other than the main jet? Did you drill the slide, cut the spring, change the slide or change setting on "off idle" screw? If you can't find the cause there's always the "dyno"............Charlie
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Djkaplan
Posted on Thursday, December 14, 2006 - 08:09 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

My Cyclone does that too. I heard someone refer to it as a 'stack fire' - the bike is backfiring through the carb, causing the engine to stumble. I haven't been able to jet this problem away and it seems to get worse in the winter... this kind of leads me to believe it could be a lean condition. It could be not enough accelerator pump volume or leaness when the carb transitions from the idle circuit to the pilot jet.

Heck if I know, but I'm going in the carb again to see it I can get rid of the 'stack fire'. I'm wondering if the single fire ignition could be exacerbating this problem?
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Cyclonecharlie
Posted on Thursday, December 14, 2006 - 10:35 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

DJ,
Make sure your idle is not too low. It can effect the transition even when down shifting.......Charlie
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Daves
Posted on Thursday, December 14, 2006 - 06:23 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

check your intake seals
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Sanchez
Posted on Thursday, December 14, 2006 - 09:36 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

> What have you changed in regards to the carb

The previous owner put in a 45 slow jet and drilled the plug off the idle mixture screw. The screw was turned way out, so I reseated it and then backed if off 2 1/2 turns.

I don't know if this helps narrow it down, but the motor doesn't cut out under load. It's only when I blip the throttle with the clutch lever pulled in.
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Bad_karma
Posted on Friday, December 15, 2006 - 01:38 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Sanchez
I'm with Daves on this one. Let us know what you find.
Joe
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Sanchez
Posted on Friday, December 15, 2006 - 07:41 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Is there a quick way to check the seals without removing the manifold? Maybe spray some carb cleaner around them and see if the revs jump?
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Daves
Posted on Friday, December 15, 2006 - 09:50 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

That will work
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Bomber
Posted on Friday, December 15, 2006 - 01:14 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

if your seals are OK, adjust the screw for the highest idle while the bike is fully warmed up (if you figure out how to do this without burning yourself, please let me know)

you can really cut down on the coughing, but some scoots cannot have it dialed completely away -- mine still does it from time to time -- but much less that before I fiddled with the screw
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Cyclonecharlie
Posted on Friday, December 15, 2006 - 01:36 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Like Bomber said, raise your idle to about 11 to 12 hundred and see what happens. Your slide is coming up too fast and there is not enough flow across your needle jet.Also try slowing your hand speed down when you "blip" the throttle.........Charlie
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Nevrenuf
Posted on Saturday, December 16, 2006 - 06:37 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

after i had a yost power tube put in the other m2, never noticed any coughing out of it. just might have been a coincidence. definitely better throttle response if nothing else.
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M1a65
Posted on Thursday, December 28, 2006 - 11:54 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Matt, +1 on the Yost power tube. Better fuel atomization (so sez the add)...
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Djkaplan
Posted on Thursday, December 28, 2006 - 12:16 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I must have one now.
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Cyclonecharlie
Posted on Thursday, December 28, 2006 - 12:16 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

The Yost power tube was a plus(had one when I was useing the stock carb) and might help with the cough too..........Charlie
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