choosing jet size?
Club Member
Joined: Feb 2007
Posts: 16,320
Likes: 306
From: Boynton Beach, FloriDuh
RE: choosing jet size?
ORIGINAL: kawsakimx6
so i should go 42/180?
ORIGINAL: x2lee
Im saying to stick the 180 size jet in there with your setup.
Im saying to stick the 180 size jet in there with your setup.
Thread Starter
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Road Warrior
Joined: Jun 2007
Posts: 1,338
Likes: 0
From: NC....Charlotte
RE: choosing jet size?
ORIGINAL: cHarley
IMO, I would start with a 45/180. That seems to be the magic combination for most late model 1200 bikes at low altitudes.
ORIGINAL: kawsakimx6
so i should go 42/180?
ORIGINAL: x2lee
Im saying to stick the 180 size jet in there with your setup.
Im saying to stick the 180 size jet in there with your setup.
Cruiser
Joined: Jan 2008
Posts: 213
Likes: 1
From: The Suncoast (FLA)
RE: choosing jet size?
I could be FOS, but isn't the drill bit that comes with the Dynojet kit for drilling out the EPA plug? Read the instructions. A Stage I set-up probably doesn’t want a bigger low-speed jet.
From my experience, don't go overboard. Stay to the lean side initially and open the mixture screw a half a turn or so. That will help with the cold stumble. You may just want to raise the needle a bit by putting a couple of shim washers under where it sits in the diaphragm. Thats what they do with the Riceburners.
Good time to put one of those nice shinny carb tops on it too. And get rid of those cross-recessed screws while you're at it and put some socket head cap screws in there.Top and bottom. Get stainless-steel ones and they won't galvanize in and it will go easier the next time you go in. If you want, you can polish them on a grinder with a rouge wheel and the look better than chrome.
At least you only have one to dowith a Sporty. My other bike has four carbs and then you have to synchronize them.
Get a manual if you don't already have one and enjoy yourself. The"professional" at the shop probably isn't as bright as you are, and doesn't give a sh*t either.
From my experience, don't go overboard. Stay to the lean side initially and open the mixture screw a half a turn or so. That will help with the cold stumble. You may just want to raise the needle a bit by putting a couple of shim washers under where it sits in the diaphragm. Thats what they do with the Riceburners.
Good time to put one of those nice shinny carb tops on it too. And get rid of those cross-recessed screws while you're at it and put some socket head cap screws in there.Top and bottom. Get stainless-steel ones and they won't galvanize in and it will go easier the next time you go in. If you want, you can polish them on a grinder with a rouge wheel and the look better than chrome.
At least you only have one to dowith a Sporty. My other bike has four carbs and then you have to synchronize them.
Get a manual if you don't already have one and enjoy yourself. The"professional" at the shop probably isn't as bright as you are, and doesn't give a sh*t either.
Outstanding HDF Member
Joined: Jul 2007
Posts: 2,192
Likes: 2
From: Metro Milwaukee, WI
RE: choosing jet size?
ORIGINAL: kawsakimx6
ok so looking at the Dynojet site, the kit only comes with a man jet (many sizes) but no other jets (the 45 part of 45/180) any suggestions?
ok so looking at the Dynojet site, the kit only comes with a man jet (many sizes) but no other jets (the 45 part of 45/180) any suggestions?
Free customer tech support comes with it. From what I have read they can guide ya go get really close by knowing your set up and elevation above sea level keeping dyno time to a minimum.
They sell em on ebay for about $10 less.
Road Master
Joined: Aug 2007
Posts: 1,183
Likes: 1
From: Graham, NC
RE: choosing jet size?
42 slow (pilot) and 175 main are the stock sizes on late model 1200's.
Depending on your set-up, you should either go 42/180 or 45/180 and drill out the idel mix screw plug. Some (like I) have also drilled out the small vacuum hole in the slide to change it's opening rate. (Instructions here: http://www.nightrider.com/biketech/hd_cv_mods.htm )
With a modified stock air box and SE II's my best performance was at 42/180.
After adding the ARBS, I changed the 42 to the 45 for best performance.
The swap is easy and takes 10 minutes to do, so start with whatever you want, run it down the road, and if you have to change something it should be quick and easy.
The only real way to know what your A/F ratio is is to run it on a dyno with an A/F meter. That being said, you should be able to tell by the power and sound as to how close you are and what needs to be changed.
Basically there are three tuning points:
Idle-low RPMs - Adjust idle mix screw
mid RPMs - change slow jet
Upper RPMs - change main jet
It's really just trial and error seat-o-the-pants tuning.
Depending on your set-up, you should either go 42/180 or 45/180 and drill out the idel mix screw plug. Some (like I) have also drilled out the small vacuum hole in the slide to change it's opening rate. (Instructions here: http://www.nightrider.com/biketech/hd_cv_mods.htm )
With a modified stock air box and SE II's my best performance was at 42/180.
After adding the ARBS, I changed the 42 to the 45 for best performance.
The swap is easy and takes 10 minutes to do, so start with whatever you want, run it down the road, and if you have to change something it should be quick and easy.
The only real way to know what your A/F ratio is is to run it on a dyno with an A/F meter. That being said, you should be able to tell by the power and sound as to how close you are and what needs to be changed.
Basically there are three tuning points:
Idle-low RPMs - Adjust idle mix screw
mid RPMs - change slow jet
Upper RPMs - change main jet
It's really just trial and error seat-o-the-pants tuning.
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Club Member
Joined: Feb 2007
Posts: 16,320
Likes: 306
From: Boynton Beach, FloriDuh
RE: choosing jet size?
I suggest you go here http://*******.com/37f6jp
Specify in your order that you want#45 & #180 jets. The kit comes with the jets and new SS hex head screws for the float bowl.
Specify in your order that you want#45 & #180 jets. The kit comes with the jets and new SS hex head screws for the float bowl.
Thread Starter
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Road Warrior
Joined: Jun 2007
Posts: 1,338
Likes: 0
From: NC....Charlotte
RE: choosing jet size?
ORIGINAL: Sundog
I could be FOS, but isn't the drill bit that comes with the Dynojet kit for drilling out the EPA plug? Read the instructions. A Stage I set-up probably doesn’t want a bigger low-speed jet.
From my experience, don't go overboard. Stay to the lean side initially and open the mixture screw a half a turn or so. That will help with the cold stumble. You may just want to raise the needle a bit by putting a couple of shim washers under where it sits in the diaphragm. Thats what they do with the Riceburners.
Good time to put one of those nice shinny carb tops on it too. And get rid of those cross-recessed screws while you're at it and put some socket head cap screws in there. Top and bottom. Get stainless-steel ones and they won't galvanize in and it will go easier the next time you go in. If you want, you can polish them on a grinder with a rouge wheel and the look better than chrome.
At least you only have one to do with a Sporty. My other bike has four carbs and then you have to synchronize them.
Get a manual if you don't already have one and enjoy yourself. The "professional" at the shop probably isn't as bright as you are, and doesn't give a sh*t either.
I could be FOS, but isn't the drill bit that comes with the Dynojet kit for drilling out the EPA plug? Read the instructions. A Stage I set-up probably doesn’t want a bigger low-speed jet.
From my experience, don't go overboard. Stay to the lean side initially and open the mixture screw a half a turn or so. That will help with the cold stumble. You may just want to raise the needle a bit by putting a couple of shim washers under where it sits in the diaphragm. Thats what they do with the Riceburners.
Good time to put one of those nice shinny carb tops on it too. And get rid of those cross-recessed screws while you're at it and put some socket head cap screws in there. Top and bottom. Get stainless-steel ones and they won't galvanize in and it will go easier the next time you go in. If you want, you can polish them on a grinder with a rouge wheel and the look better than chrome.
At least you only have one to do with a Sporty. My other bike has four carbs and then you have to synchronize them.
Get a manual if you don't already have one and enjoy yourself. The "professional" at the shop probably isn't as bright as you are, and doesn't give a sh*t either.