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?
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.
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.
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.
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?
If I go a 74 main I get blackened plugs.. ??
S&S E will handle any 80" built or not..
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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?
I don't know what else it could be? The carb is clean and rebuilt and no leaks anywhere.







