carb issue?
Seasoned HDF Member
Joined: Aug 2007
Posts: 8,200
Likes: 3,089
From: NW AR
Dank u wel!
The springs on the advance unit can go weak, which changes the advance curve so that it goes advanced too soon.
Did you try a bigger main jet? Or a bigger intermediate jet? Try two sizes bigger for either one of those and see if there is any difference. At 3K RPM, I think that is pretty close to the start of the main jet. I think I would try 2 sizes bigger on the intermediate first and see what it rides like.
The springs on the advance unit can go weak, which changes the advance curve so that it goes advanced too soon.
Did you try a bigger main jet? Or a bigger intermediate jet? Try two sizes bigger for either one of those and see if there is any difference. At 3K RPM, I think that is pretty close to the start of the main jet. I think I would try 2 sizes bigger on the intermediate first and see what it rides like.
Seasoned HDF Member
Joined: Aug 2007
Posts: 8,200
Likes: 3,089
From: NW AR
The other thing to try is to go 2 sizes smaller on the jet sizes (one jet at a time) and see what it is like. That's how I do it on tuning the S&S's. Also, ride it to exactly where it is acting up and hit the kill switch and coast to the side of the road, then pull the plugs and read them.
Seasoned HDF Member
Joined: Jul 2014
Posts: 8,603
Likes: 3,374
From: Cental, MI
If it is in Fact carburetion.
Assuming the Float is set properly, and the Fuel flow is Good...ie no inline fuel filter. A real exhaust, with a 295/170-175 jetting setup, No air cleaner, [or K&N] and no Accelerator pump... The accelerator pump is to be set after the carb is tuned.
If it don't run...something else is wrong...
Shovelhead ??? Probably has an Intake leak...like someone mixed and matched oring/Rubberband Components..Not the Carburetors' fault.
Assuming the Float is set properly, and the Fuel flow is Good...ie no inline fuel filter. A real exhaust, with a 295/170-175 jetting setup, No air cleaner, [or K&N] and no Accelerator pump... The accelerator pump is to be set after the carb is tuned.
If it don't run...something else is wrong...
Shovelhead ??? Probably has an Intake leak...like someone mixed and matched oring/Rubberband Components..Not the Carburetors' fault.
Seasoned HDF Member
Joined: Aug 2007
Posts: 8,200
Likes: 3,089
From: NW AR
I'm still thinking it is carb related. You could confirm the spark is good by looking at the timing with a timing light when it is acting up, but it sounds like carb issues to me. You might try a different carb. I would guess that shovel carbs are not real common over there, but if you can find something off a mild Evo that will bolt up to the same manifold, it might be worth a try.
My old shovel went to Holland. A bunch of Dutch guys went around the US in the late 80's buying up older bikes and shipping them home for big profit. Price negotiations were very interesting. It was like I could see how their minds worked. They were trying to work me over until they found out I was Dutch also, then the deal was done as there was no point in negotiating further.
If you run across a 1979 FLH Classic cream and tan, it might have been mine.
My old shovel went to Holland. A bunch of Dutch guys went around the US in the late 80's buying up older bikes and shipping them home for big profit. Price negotiations were very interesting. It was like I could see how their minds worked. They were trying to work me over until they found out I was Dutch also, then the deal was done as there was no point in negotiating further.
If you run across a 1979 FLH Classic cream and tan, it might have been mine.
Seasoned HDF Member
Joined: Jul 2014
Posts: 8,603
Likes: 3,374
From: Cental, MI
Which Clamps?
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
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
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Thread Starter
|
Tourer
Joined: Feb 2015
Posts: 296
Likes: 40
From: Holland
Rubberbands from James with the double screw-type clamps on it.
Since I must confess it's strange that it works much better when I strangle the carb I will go up on the slowjet as that does seem logical although I can't imagine why it would need such a big slowjet...
Come to think of it: my turbo'd bike which is also in a super E did the same when the slow was to small but obviously didn't pop in the carb because of the turbo.
It did however stumble in the same fashion so...?
Since I must confess it's strange that it works much better when I strangle the carb I will go up on the slowjet as that does seem logical although I can't imagine why it would need such a big slowjet...
Come to think of it: my turbo'd bike which is also in a super E did the same when the slow was to small but obviously didn't pop in the carb because of the turbo.
It did however stumble in the same fashion so...?
Seasoned HDF Member
Joined: Jul 2014
Posts: 8,603
Likes: 3,374
From: Cental, MI
IDK what a double screw type clamp is
Note that a Rubberband intake works best [actually requires] with a Split clamp..ala the Stocker with a "space in the middle, such that it does Not clamp the Middle like an o-ring clamp...
I still think intake leak...
Note that a Rubberband intake works best [actually requires] with a Split clamp..ala the Stocker with a "space in the middle, such that it does Not clamp the Middle like an o-ring clamp...
I still think intake leak...
