Shorty G Issue After Rebuild

[429CV23]

Hey all
I finally got around to rebuilding the S&S Shorty G on my 2000 Bulldog with S&S 107"; Bassani 2-into-1.
It ran fine before, but leaked fuel if I left the petcock open, and was running lean on the intermediate jet; discolored headers, some popping on decel I couldn't tune out.

I increased the intermediate from 0.031" to 0.032"; I left the 'original' main jet in, an 0.082". I never had an issue with the 3000+ RPM range before the rebuild. Now it runs strong for 5-10sec, then starts cutting out. I did not adjust the float. According to the tuning guide, this condition would require an 0.004" increase, but it seems an 0.082" is fairly large to begin with.

The PO did install a spike (forward facing) which I was going to remove, but am missing some hardware to install the original filter setup, which has a K&N filter with it. The brace for the spike was broken on the forward side, so I welded it to regain support for that heavy spike.

I know the engine was rebuilt once by the original owner, and I was told it pulled 120tq on a dyno (no reported hp #), but an 82 main still seems large.

I think if the broken brace was causing an air leak, it would be running richer now, so why the higher RPM breakup?

 

[Sven]

... but leaked fuel if I left the petcock open...

Watch where I'm going with this. Seems too high is the level?

Now it runs strong for 5-10sec, then starts cutting out.

I'm going to change 'strong for said seconds' to, I want to float the valves but the plugs are too fouled to gain any rpm.

I did not adjust the float.

And here we are. I have to catch myself on the strong and petcock leak. Say, and this is all generic remember; I want the float to look horizontal to the carb's body line that the top of the bowl meets the carb's bottom... that line. Then I turn the petcock on. It starts to leak, push the bowl up higher and see if it stops the leak:
1. With bowl off, no leak, that says the petcock is not leaking.
2. Bowl rise and it stops, it says the float needle can stop the flow from leaking.
3. The float tang needs to be sent up to close the needle off. Raise the float level again and no leak. Then drop the bowl a millimeter and it should start to leak.
4. If say you see a gas etching on the float, level that etch horizontal to the body... there is your other line of no line at all and now you know what to look for level/leak wise, and etch, no etch is the float level.

I think if the broken brace was causing an air leak, it would be running richer now, so why the higher RPM breakup?

Think ~ Who fills the void faster to return to 14.7 psi before the intake valve closes. The air leak did = Less gas.
Why the high rpm breakup? Leaky carb level is so high, it runs out the orifices of the body, turns rich, loads the plugs up sooty black. But see how I'm catching myself about the level not being that far off? It's more chasing the level and leak.

Pull plugs and read it as:
a. Sooty black to wet black ~ too rich/low compression/old plugs.
b. Tan and dry looking ~ Perfect running color.
c. White porcelain nose ~ Lean is mean and without a plug reader looking deep down the bottom to read the real color, it's a more clean running carb/normal injector colors.


Say on a cold engine - brake clean at the intake boots.
On a hot engine - don't know who lights off first, b-clean or wd40?
Cold may not show up as easy as a hot engine. But then again, can't call it the float/comp/dirty carb/or leaky boots if the bike lights right off and idles cold/idles hot.

Falls on its face is dirty air cleaner/restricted air cleaner element/sooty carbs/air leak/sooty plugs for high rpm miss.

And compression test is what, before you change a jet and chased your tail no difference? And the plugs read?

Signed,
Only a few pounds off knows for sure.

 

[knothead]

Well to me the main is way to big....now with that being said i do know you live n colorado and the higher altitude will make one rich because of the thin air...but when you say its breaking up and im assuming you talking about in the exhaust popping and snapping then your main is way to big....your intermediate seems big to me also....if it was me i would go back to the 31 intermediate and a 78 main....air bleed around 1 1/2 turns out....put the accelerator pump around 2 rounds out and see what happens... but i do believe your main is killing it on the big end causing the popping your describing

 

[Sven]

knothead pointed something out... higher altitude. I'd more back off on the squirt, and drop the main down. All holes suck, but when it's big and the needle rises, that's the huge amount entering. Gotta remember too, it's linear. So fat all the way up the rpm range is the think = Sputters fat/rich.

Read the plug. Porcelain says?

And too, plug read is also at the threads is that compression in question. Wet means rings can't hold the oil back. Dry says a healthier sealing chamber.

 

[429CV23]

Thanks for all the input guys!!

I pulled the plugs; in the pic the left plug is front jug, right is rear. Those plugs are the NGK Iridiums, and had several thousand miles on them. I replaced them with Champion 404 (RN12YC) to read current conditions.
I took her for a spin last night; first few WFO pulls in 5th gave a bit of a cut out, but after 3-4 times she pulls fine at WFO. Also no more slight popping on decel. I'll put a few more miles on, then check the Champions.

 

[Sven]

Look beautiful to me. Tan, not black soot. Dry threads says the rings can keep the oil out of the chamber.

The deal with iridium is its short service life. The table top of the center electrode is so small, E wants to find the shortest path. So having that sharp edge all around when new, it's easy to jump to the side electrode. And that arc is slowly eating away at the flat surface edges, it goes round, and now the spark hunts where to jump = Misfire.

High performance wise, iridiums are replaced at every 7,500 miles. Dyno might show that small performance window v. a new set. Yes, you can toss thousands of miles on them, but... book calls the ball on the service intervals.

Why bother pulling them. Leave the threads of the head alone, leave the fresh crush of the new plug's gasket alone and all that shit. I can see the tune from here.

Signed,
Your assfactor said so WFO/WOT he said no more pop pop fizz fizz oh what a relieve it is.