Jet Size Question
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Intermediate
Joined: Nov 2011
Posts: 30
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From: Alberta, Canada
Jet Size Question
I picked up a '93 FLHS this past summer. Picked up a K&N air filter and a Samson true dual exhaust set up just recently and figured a re jet was in order.
Pulled apart the carb and its got a 160 main and a 42 slow jet.
The manual says the California models ran 160 main and 40 slow
Other 49 states ran a 175 main and 40 slow
I've read on here to up the jets one size, but since i am only running a 160 should i bump up to 180?
Pulled apart the carb and its got a 160 main and a 42 slow jet.
The manual says the California models ran 160 main and 40 slow
Other 49 states ran a 175 main and 40 slow
I've read on here to up the jets one size, but since i am only running a 160 should i bump up to 180?
Stellar HDF Member
Joined: Feb 2009
Posts: 2,936
Likes: 20
From: Driftless Area
Never done much with the jets, see how it runs. years ago running higher elevations in Wyoming never had any problems, others may differ. don't really know what the elevation is where you are. May not even come into play??!!?
Former Sponsor
Joined: May 2010
Posts: 555
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A 180 jet would be a good start. There is also more adjustment to the carb that can be done for fine tuning. I used to run a 190 main with the "C" clip in the center position and the bike ran great. Many people will run a 185. Different factors come into play when playing with the carb. A jet kit would be a good purchase so you can tune to the bikes best performance settings.
Thank you,
JR
Thank you,
JR
Road Master
Joined: Apr 2009
Posts: 1,123
Likes: 43
From: NJ
42/160 is a very common stock set up. You should see how the bike runs after you add the stage one items and jet from there.
From what I've experienced going to a 45 slow would be OK but I feel a 180+ main would be a waste. The main only comes into play at the very upper end of the throttle band, a 170 would be plenty for what you are doing and maybe a washer under the needle to help midrange.
Look around this site..lots of goog info..
http://www.nightrider.com/bt30/carbadjust.htm
D
From what I've experienced going to a 45 slow would be OK but I feel a 180+ main would be a waste. The main only comes into play at the very upper end of the throttle band, a 170 would be plenty for what you are doing and maybe a washer under the needle to help midrange.
Look around this site..lots of goog info..
http://www.nightrider.com/bt30/carbadjust.htm
D
Extreme HDF Member
Joined: Sep 2010
Posts: 14,744
Likes: 402
From: Phoenix '53, '88, '09 Big Twins
Yup, look over the nightrider site.
when I'm going to tune I replace the 4 phillips head screws for the float bowl with allens ( 4mm) so I can get the bowl off quick and easy- use a mirror to see up into the carb body.
I always mod my slide, drilling the air bleed hole to .125", and usually end up with a 42 or 45 and 165, 170 or 175 main, with the sportster needle.
great carbs, easy to tune, great results no matter the altitude ( which would be a concern to you if you heading West)
I would guess that with the true duals, you will be using less fuel at low to mid rpms, ( no scavenging) so the 40 might be right for that bike.
If the idle mixture screw plug is still in place, you can be pretty sure that nobody ever monkeyed with the carb- if it is gone, proceed with caution, check the slide.
mike
when I'm going to tune I replace the 4 phillips head screws for the float bowl with allens ( 4mm) so I can get the bowl off quick and easy- use a mirror to see up into the carb body.
I always mod my slide, drilling the air bleed hole to .125", and usually end up with a 42 or 45 and 165, 170 or 175 main, with the sportster needle.
great carbs, easy to tune, great results no matter the altitude ( which would be a concern to you if you heading West)
I would guess that with the true duals, you will be using less fuel at low to mid rpms, ( no scavenging) so the 40 might be right for that bike.
If the idle mixture screw plug is still in place, you can be pretty sure that nobody ever monkeyed with the carb- if it is gone, proceed with caution, check the slide.
mike
Last edited by mkguitar; Jan 25, 2012 at 01:13 AM.
Tourer
Joined: Aug 2009
Posts: 359
Likes: 2
From: central Mississippi
I've got the K and N filter, duals, SE-4 cam. After experimenting with different jets, I finally settled on 190/45. Throttle response seemed best with these. Every bike is a little different though. I would definetly go up from the 160 though. At least 180. Jets are cheap. Buy several sizes and try them.
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Ultimate HDF Member
Joined: Jun 2007
Posts: 9,193
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From: Richmond, VA
I went threw the jetting wars not long ago on my bike. These guys here helped me a lot. Since your new setup is a basic stage one, I would install at least a 45 and probably a 46 slow jet and a 180 or 185 main. The reason I would is because of where you live. If you lived in a nice warn climate, you could run smaller jets, but in the frozen north, you gonna want more fuel to reduce the carb farts. Your adjuster screw is gonna be the final adjustment. Probably gonna want it right between 2 1/2 and 3 turns out.
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Thread Starter
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Intermediate
Joined: Nov 2011
Posts: 30
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From: Alberta, Canada
Thanks for all the replies!
I already had the carb off and pulled the bottom out to see what size jets were in there before I posted. The mixture screw cover was already punched so Its been messed with before. I'll post again when I see what seems to be working.
It could be a while till I can test out the main jet though, roads are snow covered here.
I already had the carb off and pulled the bottom out to see what size jets were in there before I posted. The mixture screw cover was already punched so Its been messed with before. I'll post again when I see what seems to be working.
It could be a while till I can test out the main jet though, roads are snow covered here.