SuzukiSavage.com - Rich and dies on hard accel/deccel

dasch

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Rich and dies on hard accel/deccel
05/19/09 at 08:09:39

50 idle, 150 main, needle one slot up (yes, I have the one with recesses), K&N cone, open HD exhaust. Idle mix perfect, 2.5 turns out, acceleration great and smooth through entire range. The problem is that after a hard (1/2-WOT) acceleration it will not ide right for 2 seconds. Eventually dies sometimes. Really makes me nervous on stop lights.
I tested today while standing still; if I blip the throttle hard, and then quickly release it - it will rev up, than down and give out a puff of black smoke when it reaches idle speed! idle will drop to 2 beats/second, and then recover. If I hold it on WOT a bit longer - it will die when reaches idle. For some reason it gets RICH after WOT. Why? How do I fix it?

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Serowbot YaBB Moderator ModSquad Offline OK.... so what's the speed of dark? Posts: 28649 Tucson Az Gender:	Re: Rich and dies on hard accel/deccel Reply #1 - 05/19/09 at 08:18:23 possibly a sticky needle jet slide?... or,... is your idle speed set too low?...
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dasch Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 1137	Re: Rich and dies on hard accel/deccel Reply #2 - 05/19/09 at 09:57:05 Idle around 1300. It acts as though you poured a small shot of gas in the carb while idling. Y'know, it goes thump thump thump thump.....thump...........thummmmp............thump....thump, thump, thump. This is as technical I can get with explaining it
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Sandy Koocanusa

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Re: Rich and dies on hard accel/deccel
Reply #3 - 05/19/09 at 18:34:03

Are you sure that middle one is a thump, and not a thud? A thud indicates a faulty ribbensnort modulator.

2 1/2 turns on the 50 idle would have gas running out of my muffler. I'm at 3000 feet, and as it is getting warmer, I'm down to about 1 1/16 turns and tightening up every day.

I have a devil of a time with that idle jet. 47.5 is too small. 50 is too big. I need a 48.375, I think.

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Savage: (adj)1. Wild 2. Uncivilized : Primitive 3. Ferocious 4. Cruel or merciless : Brutal --- Webster's. (n.) 1. A motorcycle named for its seat.--- Sandy's unabridged

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LANCER

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Re: Rich and dies on hard accel/deccel
Reply #4 - 05/19/09 at 20:18:06

Play with your pilot adjusting screw, take it back down to 1.5 turns out. Basically, go down as low as you can before the backfiring starts up in earnest. Reports back with what it does.
Was it working properly for you before ? Has it started messing up just lately ? Other changes to the engine/carb or outside stimulas affecting it some way ?

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Reelthing Serious Thumper Alliance Member Offline Fish or ride that is the question Posts: 5397 Houston,Tx Gender:	Re: Rich and dies on hard accel/deccel Reply #5 - 05/20/09 at 06:53:16 Serowbot wrote on 05/19/09 at 08:18:23: possibly a sticky needle jet slide?... or,... is your idle speed set too low?... I'll sure second this check - if the slide is dirty or sticky in anyway it will hang going back down and cause a very rich situation when you let off the throttle
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dasch

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Re: Rich and dies on hard accel/deccel
Reply #6 - 05/20/09 at 07:28:49

Sandy: Ribennsnort modulator is clean. Replaced last year

LAncer: Tried pilot screw. Has no effect to the problem. It does effect the idle/backfiring, but the problem is still there. It started a little after I raised the needle one notch. But I had to raise to eliminate slight surging in midrange.

Reel/Lancer. I will check on sticky slide today. It makes sense to me.

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Reelthing Serious Thumper Alliance Member Offline Fish or ride that is the question Posts: 5397 Houston,Tx Gender:	Re: Rich and dies on hard accel/deccel Reply #7 - 05/20/09 at 07:35:16 No oil on the slide - nothing - just clean and the slide bore
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dasch Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 1137	Re: Rich and dies on hard accel/deccel Reply #8 - 05/20/09 at 09:12:25 Understood. I just prepared this ABRO silicone spray, but I will try without.
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dasch Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 1137	Re: Rich and dies on hard accel/deccel Reply #9 - 05/20/09 at 09:14:08 ribbensnort modulator... that's a good one. Glad I replaced it.
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Reelthing Serious Thumper Alliance Member Offline Fish or ride that is the question Posts: 5397 Houston,Tx Gender:	Re: Rich and dies on hard accel/deccel Reply #10 - 05/20/09 at 09:34:22 Was having a bad time with the '95 - cleaned the slide with contact spray - might need a new slide spring
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dasch

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Re: Rich and dies on hard accel/deccel
Reply #11 - 05/20/09 at 10:03:06

I haven't done anything yet, but I remember the slide has a worn area, as though it scrapes that part regularly during movement.

How 'bout I just stick a 32/32 dual Weber carb on the darn thing and go from there??

I have one, came off of a 750cc Fiat. 32 horses stock, 40 and some with the carb. What do you all think?

Regression: I will clean the slide and post more. Thanks all for help.

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marshall13

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Re: Rich and dies on hard accel/deccel
Reply #12 - 05/20/09 at 10:10:49

dasch wrote on 05/20/09 at 10:03:06:

I haven't done anything yet, but I remember the slide has a worn area, as though it scrapes that part regularly during movement.

How 'bout I just stick a 32/32 dual Weber carb on the darn thing and go from there??

I have one, came off of a 750cc Fiat. 32 horses stock, 40 and some with the carb. What do you all think?

Regression: I will clean the slide and post more. Thanks all for help.

if there's a scuff on the slide, that's probably your culprit... check the bore it rides in... casting flash? scratch? build up of funk? if the defect is above the surface(flash, funk, etc) you can carefully remove it(funk, seafoam and lint free rag... flash, very fine sandpaper(1200 grit or so)... if its a gouge or scratch that is below the bore surface, time for a new carb body.... is the tab on the top of the slide aligned correctly?

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BurnPgh

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Re: Rich and dies on hard accel/deccel
Reply #13 - 05/20/09 at 14:58:19

Mine SORT of does the same thing. With no spacer and a quick decel it would stall out especially when cold. After I added a washer it got better. Still does it on occasion but i lost my jet set from lancer and every #4 washer ive found has too large an OD so until i get a new one..... If you've moved the needle up you've leaned the midrange while the rest of your set up is richer than stock. Try lowering the needle back or changing to a 47.5 pliot.

PS - clenaing the slide is a good idea but I wouldnt worry too awful much about the worn area. Mine's a '95 and has the same thing. Works flawlessly.

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Reelthing Serious Thumper Alliance Member Offline Fish or ride that is the question Posts: 5397 Houston,Tx Gender:	Re: Rich and dies on hard accel/deccel Reply #14 - 05/20/09 at 15:59:23 The black coating is sacrificial - it’s the grime that forms causes some issue – in it’s worse case a little black ring will form in the bore at the bottom of the slide travel – if you have more than 1 slot in the needle – what year is the carb?
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