never thought changing jets help that much
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Cruiser
Joined: Nov 2010
Posts: 100
Likes: 0
From: Greenville,NC.
never thought changing jets help that much
i got a 84 evo, did the top end cause it started piston slap, i put some cash in it going with S&S heads, 10.5 pistons,EV27 cam, SE slip ons, S&S E carb, and a few more things along the way. It ran a whole lot better but when the weather warms up, say like 80 or better, it started spitting and sputtered,the carb had a 029.5 int. jet and a 72 main, i changed it to a 032 int. and a 78 main and now that thing runs like someone put a fire under it and no jerking at low RPM now, wow, what a change!
Club Member
Joined: Mar 2009
Posts: 66,114
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From: Niles Canyon Ca.
Your main is way too fat , a 74 should be more than enough for that motor configuration . S&S E are real touchy with the intermediate jetting you might want to try a .031 instead of .032 and 72 or 74 main .
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Joined: May 2011
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From: holland
another?
Makes no sense to me.
If it runs good it is good..period.
Road Captain
Joined: Mar 2008
Posts: 601
Likes: 6
From: Aruba
You know your main jet is hardly ever used. Just at 3/4 to full throttle. The rest of the time you're running off your slot jet or your idle mixture or both.
The easiest way to get close on your main jet is to get out in some open space with a warmed up bike. Get into 3rd or 4th or 5th and get running at full throttle. Back the throttle off quickly to 3/4 and see what the bike does. If it actually picks up some speed, your main is too big. If it stumbles, it's too small. If it keeps running good but just slows down a bit, then you're within a number or two of the correct jet.
But you can't really do anything until you get your idle mixture perfect and get really close on the pilot jet.
The easiest way to get close on your main jet is to get out in some open space with a warmed up bike. Get into 3rd or 4th or 5th and get running at full throttle. Back the throttle off quickly to 3/4 and see what the bike does. If it actually picks up some speed, your main is too big. If it stumbles, it's too small. If it keeps running good but just slows down a bit, then you're within a number or two of the correct jet.
But you can't really do anything until you get your idle mixture perfect and get really close on the pilot jet.
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Cruiser
Joined: Nov 2010
Posts: 100
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From: Greenville,NC.
thanks for the advice, but it seems to be just fine, before the adjustment screw was out over 3 turns, now i got 1 3/4, as for wide open, took it out on the by-pass at 110 and still pulling hard before i let off, thats plenty for me, before it had a small serge around 2800rpm, now the acelaration is smooth as glass all the way up to 6000rpm and drops as soon as i let off, no popping or anything
Last edited by bubba4u; Jun 12, 2011 at 10:53 AM. Reason: add more
Club Member
Joined: Mar 2009
Posts: 66,114
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From: Niles Canyon Ca.
To the OP good luck man .
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Stellar HDF Member
Joined: Apr 2007
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I would agree - that jetting sounds WAY big for that setup, but if he's happy let it be.
and to repeat his original point - jetting changes can make a world of difference.
EV27 cam isn't designed for a compression ratio that high either, but if he's happy its all good.
and to repeat his original point - jetting changes can make a world of difference.
EV27 cam isn't designed for a compression ratio that high either, but if he's happy its all good.
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Joined: May 2011
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From: holland
I've dealt with more shovels in every possible configuration with S&S carbs than you have even seen . I'm running a 93" hipo motor with an " E " and my jets are only .031 & 72 main so his are a bit on the big side for a stocker . The man has a stock 80" with a bit of compression , no headwork or huge cam . The jets I suggested are the normal range for that motor .
To the OP good luck man .
To the OP good luck man .
I had that line for ages coming from audio devices.
If it sound good it is good.
In sports..never change a winning team.
And the O.P..is happy about it..right?
I wish him well..and you too.
Cruiser
Joined: Dec 2010
Posts: 110
Likes: 1
From: central NC
I have similiar mods with a Woods W6 cam and I run a 28 and 70. Mine runs the best with a 68 but it shows slightly lean on a hard top end run so I went with a 70 to be safe. All bikes are different and if the plugs look OK I say go with it. What kind of gas mileage are you seeing? If it was very rich you would see a decline in gas mileage. I believe S&S says to shoot for 45 MPG or so.