Super E Jetting
Thread Starter
|
Tourer
Joined: Mar 2013
Posts: 379
Likes: 0
From: Tampa Bay
Super E Jetting
Well it's been a long road trying to get this bike tuned properly. I finally got it happy, but I'm really confused by the results. First, I am the third owner and have no idea what kind of build is in it. I alway believed it to be basically stock with a mild cam in it. The on-going problem was that it would run super lean on the bottom end and rich in the mid range and lean on the top. Original jetting when I first bought the scoot, was 295 and 68.
I'm going to spare you the long, long story of all the jetting changes. It now seems to be MOSTLY happy but not quite right! The largest low speed jet in the kit was 33, I had to drill it out to about a 35. The bike still seems to want a little more fuel but runs well, idles smooth and low speed cruise without hunting or popping. Exhaust is clean and smells right. I need to use the enricher for a couple minuets when first starting. A 35 jet on the bottom end would seem to indicate a large displacement. However, what has me confused is the main jet; I had to drop all the way down to 66.
The bike now pulls like a beast off the line, but the top end power curve still flattens out and run like it wants a lot more fuel. If I change to a 68 or larger, though, the bike falls flat on it's face like it's too rich, smaller than a 66 and it's definately too lean. Also, as I've given it more fuel, the charecteristics of the cam have become more pronounced. It now acts like it's a larger cam than I first thought.
How can I need such a large jet on the bottom for the bike to run properly but will only handle a relatively small one on the top? Am I missing something?
I'm going to spare you the long, long story of all the jetting changes. It now seems to be MOSTLY happy but not quite right! The largest low speed jet in the kit was 33, I had to drill it out to about a 35. The bike still seems to want a little more fuel but runs well, idles smooth and low speed cruise without hunting or popping. Exhaust is clean and smells right. I need to use the enricher for a couple minuets when first starting. A 35 jet on the bottom end would seem to indicate a large displacement. However, what has me confused is the main jet; I had to drop all the way down to 66.
The bike now pulls like a beast off the line, but the top end power curve still flattens out and run like it wants a lot more fuel. If I change to a 68 or larger, though, the bike falls flat on it's face like it's too rich, smaller than a 66 and it's definately too lean. Also, as I've given it more fuel, the charecteristics of the cam have become more pronounced. It now acts like it's a larger cam than I first thought.
How can I need such a large jet on the bottom for the bike to run properly but will only handle a relatively small one on the top? Am I missing something?
Seasoned HDF Member
Joined: Aug 2007
Posts: 8,202
Likes: 3,089
From: NW AR
The idle mixture circuit is working properly, right? Also, the later E's have one more adjustment: A jet screwed into the hole in the top of the float area. The size of that hole changes where the changeover happens from the mid range to the main jet. My vintage E has the hole, but doesn't have a tapped jet in it.
Thread Starter
|
Tourer
Joined: Mar 2013
Posts: 379
Likes: 0
From: Tampa Bay
The idle mixture circuit is working properly, right? Also, the later E's have one more adjustment: A jet screwed into the hole in the top of the float area. The size of that hole changes where the changeover happens from the mid range to the main jet. My vintage E has the hole, but doesn't have a tapped jet in it.
Thread Starter
|
Tourer
Joined: Mar 2013
Posts: 379
Likes: 0
From: Tampa Bay
Yeah, already been there. 295 is way, WAY to lean. Bike doesn't want to start, or idle and hunts and pops continuosly on a low speed cruise.
Road Warrior
Joined: Dec 2010
Posts: 1,268
Likes: 507
From: Florida
Third sentence is the million dollar question. Without knowing the build, would be hit miss on the tune.
The E might not be enough for it.
Has the whole carb been removed, completely disassembled, cleaned thoroughly, and reassembled with new gaskets?
The E might not be enough for it.
Has the whole carb been removed, completely disassembled, cleaned thoroughly, and reassembled with new gaskets?
Seasoned HDF Member
Joined: Sep 2012
Posts: 6,570
Likes: 590
From: almost there
If I go a 74 main I get blackened plugs.. ??
S&S E will handle any 80" built or not..
Trending Topics
Seasoned HDF Member
Joined: Aug 2007
Posts: 8,202
Likes: 3,089
From: NW AR
That whole air bleed thing is all new for me and I haven't messed with it. I just remember that changing the size moves where the changeover point is.
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
Jason Momoa Is Turning Classic Harleys Into PHEVs
Verdad Gallardo
Harley-Davidson Fat Boy Becomes a Dark, Decepticon-Inspired Custom
Verdad Gallardo
6 Weirdest Harley-Davidsons Ever Sold to the Public
Verdad Gallardo
7 Times Harley-Davidson Chucked Tradition Out the Window
Verdad Gallardo
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Thread Starter
|
Tourer
Joined: Mar 2013
Posts: 379
Likes: 0
From: Tampa Bay
Thats kind of what I was wondering. Is it possible that the E wont flow enough? Let's say the motor has been poked and stroked. Could it require more than the E is able to deliver? Although, 35 + 68 is only 1.03 total it should be able to flow more than that right?
Thread Starter
|
Tourer
Joined: Mar 2013
Posts: 379
Likes: 0
From: Tampa Bay
I don't know what else it could be? The carb is clean and rebuilt and no leaks anywhere.