SuzukiSavage.com - Carb tuning - questions and unfamiliar terms

Rivenin

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Carb tuning - questions and unfamiliar terms
12/06/21 at 15:56:27

I've read this thread a number of times.
I have a Jardine exhaust on currently and bought a jetset as well as a uni filter from Lancer that should be here later this week.. so as i'm getting familiar with carb tuning i've been reading and doing some research.

From what it sounds like below it's pretty simple and straight forward, i just want to confirm some questions.

1 - idle speed
"if you can get the smoothest/highest idle speed by setting the idle mix screw between 1 and 3 turns out from closed"

question 1 - idle mix screw - is he speaking of the idle screw? or the fuel/air mix screw?
question 2 - do i just need a decent high idle that's steady and not surging?
question 3 - i do this after the bike has warmed, correct?

i'm also guessing i can reference this thread
- http://suzukisavage.com/cgi-bin/YaBB.pl?board=tech;action=display;num=1157720585

2 - Main Jet

question - he is referring to going up one size as in the next step up (145 > 147.5) correct?

3 - needle tuning

" if you get some acceleration, set your needle up a notch, or reduce the spacer..."

question - do these needles have a few notches in them to place a washer? i was thinking these carbs ONLY had the white spacer?

Are there some other good threads that i might be missing? i just do'nt want to go lean and blow up my engine.

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1309246277
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General, seat of pants tuning...

Idle speed...
Set your idle speed with knurled screw on the left side, near the enrichment knob... Set it to be smooth and steady,... not loping or stumbling, (this ain't a Harley, don't try to make it sound like one).. (a slow loping idle is very bad for your engine)...
Idle mix... and pilot jet...
If you can get the smoothest/ highest idle speed, by setting the idle mix screw between 1 and 3 turns out from closed,... you have set your idle mix, and your pilot jet is the right size... (if you have to go more than 3 turns out,.. go up one step on pilot jet)..(if it seems to make very little difference turning the screw, you are probably rich on the pilot, and can go down a step)...

Main jet...
To test the main, accelerate from 30 or 40 mph, in 4th or 5th gear at full throttle for several seconds, then reduce throttle by about 1/8,...if power increases for a second, you are lean on the main jet. Go up one jet size and test again.

Needle jet...
If your main is good, and your pilot is good,... but you have surging at steady low speed... try pulling out the enrichment knob, one notch (do this with a fully warmed up engine)... if you get some acceleration, set your needle up a notch, or reduce the spacer...
... if it bogs instead of accelerating,.. you are either rich, or good... increase the spacer, or set the needle down a notch, until surging goes away, but you still get some bogging with the enrichment valve pulled out a notch...

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verslagen1

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Re: Carb tuning - questions and unfamiliar terms
Reply #1 - 12/06/21 at 18:31:50

Rivenin wrote on 12/06/21 at 15:56:27:

1 - idle speed
"if you can get the smoothest/highest idle speed by setting the idle mix screw between 1 and 3 turns out from closed"

question 1 - idle mix screw - is he speaking of the idle screw? or the fuel/air mix screw?
question 2 - do i just need a decent high idle that's steady and not surging?
question 3 - i do this after the bike has warmed, correct?

1 idle mix screw is air/fuel mixture at idle
2 easier to hear the difference in rpm at a lower rpm. if it's surging, you got different problems.
3 yes
Quote:

2 - Main Jet

question - he is referring to going up one size as in the next step up (145 > 147.5) correct?

yes
Quote:

3 - needle tuning

" if you get some acceleration, set your needle up a notch, or reduce the spacer..."

question - do these needles have a few notches in them to place a washer? i was thinking these carbs ONLY had the white spacer?

these are old style needles or from an after market kit

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Ruttly Serious Thumper Offline Thumpers Rule Posts: 5113 Manteca , CA Gender:	Re: Carb tuning - questions and unfamiliar terms Reply #2 - 12/07/21 at 17:33:10 Get a Sudco manual
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Rivenin

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Re: Carb tuning - questions and unfamiliar terms
Reply #3 - 12/08/21 at 06:59:51

verslagen1 wrote on 12/06/21 at 18:31:50:

Rivenin wrote on 12/06/21 at 15:56:27:

1 - idle speed
"if you can get the smoothest/highest idle speed by setting the idle mix screw between 1 and 3 turns out from closed"

question 1 - idle mix screw - is he speaking of the idle screw? or the fuel/air mix screw?
question 2 - do i just need a decent high idle that's steady and not surging?
question 3 - i do this after the bike has warmed, correct?

1 idle mix screw is air/fuel mixture at idle
2 easier to hear the difference in rpm at a lower rpm. if it's surging, you got different problems.
3 yes
Quote:

2 - Main Jet

question - he is referring to going up one size as in the next step up (145 > 147.5) correct?

yes
Quote:

3 - needle tuning

" if you get some acceleration, set your needle up a notch, or reduce the spacer..."

question - do these needles have a few notches in them to place a washer? i was thinking these carbs ONLY had the white spacer?

these are old style needles or from an after market kit

Thank you! one last question i thought of that i think can clear all the confusion...
Do you tune from the idle on up?
Ie, get the idle right, then pilot jet if needed, then the main jet?

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Rivenin YaBB Newbies Offline SuzukiSavage.com Rocks! Posts: 19	Re: Carb tuning - questions and unfamiliar terms Reply #4 - 12/08/21 at 07:00:23 Ruttly wrote on 12/07/21 at 17:33:10: Get a Sudco manual Thanks! i just searched and think i'll grab one of these dudes
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verslagen1

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Re: Carb tuning - questions and unfamiliar terms
Reply #5 - 12/08/21 at 07:57:59

Rivenin wrote on 12/08/21 at 06:59:51:

Thank you! one last question i thought of that i think can clear all the confusion...
Do you tune from the idle on up?
Ie, get the idle right, then pilot jet if needed, then the main jet?

The main feeds the needle jet and the pilot feeds the idle mixture.
If you can't affect the idle speed with the idle mixture then your pilot is too big.
If it's more than 3 turns out then your pilot is too small.

Then on to the speed test to get the main.

Then do the cruise test for the needle.

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Dave

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Re: Carb tuning - questions and unfamiliar terms
Reply #6 - 12/09/21 at 03:00:55

When I jet a carb.....I do the Pilot Jet and Idle fuel mixture setting first (after fulling warming up the engine), then the main, and they the height of the needle.

It is rare that you will need to make changes to the needle that will affect the main jet size.....and the Pilot Jet doesn't care what the Man circuit is doing.

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