Running lean
Thread Starter
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Tourer
Joined: Dec 2012
Posts: 262
Likes: 31
From: So-Cal, USA
Running lean
I have a 2001 DYNA FXDX with a 95cc, high comp pistons, and screamin eagle high comp heads, 44mm CV carb SE, SE tuner with the timing maxed out, SE heavy breather air cleaner (the forward facing cone one), SE 257 cams, I have a 48 for the pilot jet and a 250 at the main. I've also shimmed the stock needle with 2 washers.
The fuel ratio always looked good on the dyno but from time to time when I'd snap the throttle in 4th or 5th it would make a metal on metal sound almost sounds like a loose valve or a spray paint can ball, (valves and push-rods are good to go). So I'm pretty sure its spark knock from a lean condition. It doesn't happen when just cruising, only when i get on it in a high gear and I kinda forgot about it and ignored it, (I know, i know that's bad).
I recently changed the plugs because it had been quite a while since I'd changed them, I went to my HD shop and told the guy what i had (i forgot to look at the plug i had when leaving the house) and he told me to use the 10R12X plugs. It has been making more noise ever since i installed those plugs and the guy said they were colder than stock to go with my 10.5:1 compression.
I went for a ride yesterday and i was going up a hill I'd gone over a million times and it started making the noise a lot and pretty loud and felt under-powered. There was a 40mph headwind but that shouldn't matter. I turned around and immediately it felt better. It still made the sound if i pulled on it but not as loud.
I was thinking that i should throw a bigger main jet in there but i cant find anything bigger than a 230.
So now I'm at a loss of what to do. Is there a bigger carb that i can install? like the 44mm one i have i thought was pretty big for my bike. Is there a super cold plug i could throw in there? or does anyone know where i can score some massive jets?
Thanks
The fuel ratio always looked good on the dyno but from time to time when I'd snap the throttle in 4th or 5th it would make a metal on metal sound almost sounds like a loose valve or a spray paint can ball, (valves and push-rods are good to go). So I'm pretty sure its spark knock from a lean condition. It doesn't happen when just cruising, only when i get on it in a high gear and I kinda forgot about it and ignored it, (I know, i know that's bad).
I recently changed the plugs because it had been quite a while since I'd changed them, I went to my HD shop and told the guy what i had (i forgot to look at the plug i had when leaving the house) and he told me to use the 10R12X plugs. It has been making more noise ever since i installed those plugs and the guy said they were colder than stock to go with my 10.5:1 compression.
I went for a ride yesterday and i was going up a hill I'd gone over a million times and it started making the noise a lot and pretty loud and felt under-powered. There was a 40mph headwind but that shouldn't matter. I turned around and immediately it felt better. It still made the sound if i pulled on it but not as loud.
I was thinking that i should throw a bigger main jet in there but i cant find anything bigger than a 230.
So now I'm at a loss of what to do. Is there a bigger carb that i can install? like the 44mm one i have i thought was pretty big for my bike. Is there a super cold plug i could throw in there? or does anyone know where i can score some massive jets?
Thanks
Thread Starter
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Tourer
Joined: Dec 2012
Posts: 262
Likes: 31
From: So-Cal, USA
I have the SE 32702-01ASE controller. The curve is set to 4 and the spark is set to +6. It's been a good while since I've messed with timing but it goes down to -9 so I'm thinking changing it to 0 and see how that does?
And by the way the instructions are written it seems like the spark advance only controls the curve?
And by the way the instructions are written it seems like the spark advance only controls the curve?
Cruiser
Joined: Nov 2015
Posts: 204
Likes: 61
From: Arkansas
I'm by no means a expert so take this as you will. This forum has some very knowledgeable builders and perhaps your question would get more replies in the "engine mechanical" section.
I'm running a similar setup as you on my fatboy. I have a 50 idle, 235 main and 2 washers shimmed up on the needle, still running the stock carb. Don't have pinging problems unless I'm being stupid and lug it up a hill. I also run 87 octane.
My suggestion would be to ditch those colder plugs, go back with stock plugs and take some timing out. If you are at +6 try going to 0 and ride it. See if that solves your ping issue. Advance that SA timing one step at a time till it pings again then dial it back one. Before throwing more fuel at the thing I'd play with timing, just seems logical to me.
Could even try setting initial timing to 3 and SA to 0 then dial the SA from there. Write down all before and after to see how the changes feel.
What is your CCP?
How do the plugs look? A 250 main seems really big to me.
Also curious of your MPG?
I'm running a similar setup as you on my fatboy. I have a 50 idle, 235 main and 2 washers shimmed up on the needle, still running the stock carb. Don't have pinging problems unless I'm being stupid and lug it up a hill. I also run 87 octane.
My suggestion would be to ditch those colder plugs, go back with stock plugs and take some timing out. If you are at +6 try going to 0 and ride it. See if that solves your ping issue. Advance that SA timing one step at a time till it pings again then dial it back one. Before throwing more fuel at the thing I'd play with timing, just seems logical to me.
Could even try setting initial timing to 3 and SA to 0 then dial the SA from there. Write down all before and after to see how the changes feel.
What is your CCP?
How do the plugs look? A 250 main seems really big to me.
Also curious of your MPG?
Thread Starter
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Tourer
Joined: Dec 2012
Posts: 262
Likes: 31
From: So-Cal, USA
I ran 93 fuel when I lived in Italy and ran 93 in NC. Now in CA I always run 91 because there is nothing higher.
Don't know what my compression is I'll take a look tomorrow. But it's definitely still good as it barely will crank of I don't hit my compression release before I fire it.
My mpg is about 40-45 that hasn't really changed since like 2003 or so when most of the engine mods were done.
Don't know what my compression is I'll take a look tomorrow. But it's definitely still good as it barely will crank of I don't hit my compression release before I fire it.
My mpg is about 40-45 that hasn't really changed since like 2003 or so when most of the engine mods were done.
Grand HDF Member
Joined: Nov 2009
Posts: 4,315
Likes: 1,663
From: Tampa
So you're a 95" engine, high comp conversion pistons, AND the high compression SE heads?
You sure you're only at 10.5:1? I thought those pistons gave that CR with stock heads.
And yea, you definitely need to pull some timing. No **** it got worse going up hill with a gale head wind, and better when you turned around.
You sure you're only at 10.5:1? I thought those pistons gave that CR with stock heads.
And yea, you definitely need to pull some timing. No **** it got worse going up hill with a gale head wind, and better when you turned around.
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Tourer
Joined: Dec 2012
Posts: 262
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From: So-Cal, USA
I haven't gotten a chance to ride it yet but I have 155 psi in the front one and 150 psi in the back one.
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Grand HDF Member
Joined: May 2014
Posts: 3,843
Likes: 1,174
From: florida
while i agree with Matt that you should be showing higher compression numbers than that, are you opening the throttle all the way while cranking for your test, you should be.
other than that the post#4 gives you good advise.
m
other than that the post#4 gives you good advise.
m