Yet another single carb thread :) Dan's 1" runners from plenum to custom head flanges

[slabghost]

westgl » Sun Oct 06, 2013 5:11 pm[/url]":2cjrie2s]
What was the correct air fuel mixture setting?

I understand it could be different, but a starting point is always good

Not sure where he has it now but maybe when he get's back from his ride he'll post. I think he just adjusted it for highest idle setting. Then reset idle.

 

[dan filipi]

Just got back from a 40 mile test ride, about 10 of that on the street the rest freeway.

My original intention was to prove or disprove that 1" runners are big enough and I can say for certain that they most definitely ARE big enough to allow enough airflow.
I have proved this to my satisfaction in the way it accelerates up to 8000 rpm and above.
All I can say is WOW!

Once that secondary opens there's a nice kick in the pants.
That feeling alone makes this mod worth it!
Wide open in 4th gear it slips the clutch up around 6000 rpm Lol.
Honestly it's more power than needed up there on this cruiser but it's nice to have it when needed.

Takeoffs are a little under-powered.
I'm pretty sure that has to do with some jetting size issues, a bit too rich.
My 740 Weber/Motorcraft came with a mix of automatic trans and manual trans jets which are a mis-match according to this carb manual.

I'm happy with the way it runs from 2500 rpm and up.
I'll be tweaking to dial it in from idle up to 2500.

 

[joedrum]

cool this is big .....im liking this report :yes:

 

[Steve83]

So - you were that red streak flying down the 405! :shock: Seriously, it's sounding like you're really close to perfection...cool! :clapping: :good:

 

[westgl]

Thats Great! Dan,

Sounds like it is a whole lot better than it was.

Now just some minor tuning needed.

That secondary is fun isn't it?

Problem with me trying to get good fuel economy, by being a good boy, and staying on the Primary only, Is STDMF (Secondary Too Damn Much Fun, syndrome)

I would like to post some MPG figures, But I have severe STDMF going on, it just ain't happening.

 

[dan filipi]

West, I'm at 1-1/2 turns out on the idle jet.
I arrived at this by turning in until idle speed started to drop then backed out to smoothest idle, then 1/4 turn in for a tad lean.

The flooding problem I had earlier was caused by a piece of junk between the needle and seat.

The earlier bogging...
Was due to very small vacuum leaks.
What I had to do was turn the idle mixture screw out over 5 turns than it should be to make up for these air leaks.
Surprisingly even VERY small pinhole leaks on this setup will cause all sorts of problems.
I've found that on this carb if your not at least close to 1, 1-1/2 turns out then there's other problems.
Air leaks most likely. That's what it was for me.

I also removed the power valve to make sure it's fuel passages were clear.
They seemed to be clear but something could have been flushed out I didn't see.

Ok so we know 1" steel runners work.
We also know 1-1/2" steel runners work.
I'm not sure what size runners Jungo is using and I'm not sure what sizes West has run and if he's run any without size reducing (chokes) in the runners.

Talked to Jungo earlier. He's installing his 740 right now.

Guys this is what we do here at CGW.
Build and experiment then refine.
There is obviously (and proven) more than one way to install a single carb.

My next step is looking at ways to make my 1" runners permanent.

My plugs are tan.
Performance from 2500 and past 8000 rpm is simply amazing.
Who said you loose performance with a single carb??


All I can say is BS,

repeat, BS.

 

[dan filipi]

Something else.....

The stock carbs up at 6-8000 rpm and accelerating would start to drop off in power.
Not so bad like it was running out of gas but like the carbs couldn't keep up, can "feel" it.
Totally rideable of course but this carb keeps on going without skipping a beat.
Acceleration runs right up and keeps going smooth as glass.
I'm sure I could over rev it without it cutting out and blow the engine.

 

[westgl]

You said it all, really well Dan,

I am so glad that you have confirmed that the single 32DFT is a Performance Increase.

And Not Slug, I was getting worried, there for a while.

Before I started my Single carb conversion,

I thought for sure that i would loose all or most of my top end.

NOT!!!!!

I Gained more LOW MID Range & TOP END

So Dan the but dyno feels More power through out or is it at least the same as the stock OEM4 carb rack?

Going to a Single 32DFT does not mean you are going to have a Snail to ride around on, No, NO! AWE HELL NO!!!

Now who is going to be the first, that can make it through a whole tank on just the primary to give a good MPG rating? I dont know if I can do it

 

[badorderbob]

Great Job Dan,......but how will you get the runners off if you need too????? :hi: Bob

 

[westgl]

I am thinking there is some margin built in to the engine.

In case it is over revved, Honda over builds for this kind of thing.

 

[dan filipi]

Bob, if you read this entire thread, you'll see that this was only intended as a test for runner sizing.
I plan to mod the attachment points for easy removal.

This ride was at 94 degrees outside.
The steel runners were always at least warm and usually hot.
I feel direct head contact for heat transfer to the runners is essential.
Plenum got cool to the touch around town but warm on the freeway.
I may not need additional heat with my riding enviroment.

 

[badorderbob]

Thanks Dan,....so many threads I must have missed that one :doh: :hihihi: Bob

 

[westgl]

Building of Rev.3

It is my Best running, and Fasstest setup, that I have built yet.

This is on my bike currently, and it is made up of,

Chokes, I made them out of,
Alum. tubing 1.050" ID, x cut 3/4" long, inserted into all 4ea of the VW plenum Outlets, so they are flush with the ends of the Outlets. i put a flared leading edge to scoop mixture.

Runners
Alum. Tubing 1.250" ID x 4.250" long approximated.

 

[dan filipi]

westgl » Sun Oct 06, 2013 6:17 pm[/url]":2dqn24x7]
Building of Rev.3

It is my Best running, and Fasstest setup, that I have built yet.

This is on my bike currently, and it is made up of,

Chokes, I made them out of,
Alum. tubing 1.050" ID, x cut 3/4" long, inserted into all 4ea of the VW plenum Outlets, so they are flush with the ends of the Outlets. i put a flared leading edge to scoop mixture.

Runners
Alum. Tubing 1.250" ID x 4.250" long approximated.

West, have you done any without chokes?

 

[westgl]

Rev.1,

Did Not have chokes in the Plenum outlets.

Did not have chokes, but, the hose collapsed while riding up to 50% that could have acted like a choke.

hoses were reduced down to 1.125"ID hose
--------------------------------------------------------------------------------------------------------
Rev.2 did not have chokes, but i did not like the way it rode, with the 1-3/8" ID tubing
--------------------------------------------------------------------------------------------------------
Rev.2.2 Had same chokes but they were 1.5" long and stuck out of the plenum outlet and telescoped into the 1-3/8" ID tube.

dan filipi » Sun Oct 06, 2013 5:33 pm[/url]":752vm6rh]

westgl » Sun Oct 06, 2013 6:17 pm[/url]":752vm6rh]
Building of Rev.3

It is my Best running, and Fasstest setup, that I have built yet.

This is on my bike currently, and it is made up of,

Chokes, I made them out of,
Alum. tubing 1.050" ID, x cut 3/4" long, inserted into all 4ea of the VW plenum Outlets, so they are flush with the ends of the Outlets. i put a flared leading edge to scoop mixture.

Runners
Alum. Tubing 1.250" ID x 4.250" long approximated.

West, have you done any without chokes?

 

[82a]

any pix of those chokes?

 

[82a]

polished brass

MOEN Home Care SecureMount 18 in. x 1-1/4 in. Stainless-Steel Concealed-Screw Grab Bar in Polished Brass
Model # R8718PB
Internet # 202044132

 

[westgl]

Pix of the choke is lower left.

Upper left show the 1-1/4"ID tube, compared to the 1-3/8 tube on the upper right

P1020167

• westgl
• Oct 3, 2013

Choke is lower left, new Rev.#3 runner is upper left, Rev.#2 runner is upper right, lower right...

This pix shows the choke telescoping inside 1-3/8" ID tube

P1020170

• westgl
• Oct 3, 2013

Choke, inside of 1-5/8"ID tube

82a » Sun Oct 06, 2013 6:50 pm[/url]":uutkabzo]
any pix of those chokes?

 

[mcgovern61]

dan filipi » Sun Oct 06, 2013 6:37 pm[/url]":tdxnacxo]
Takeoffs are a little under-powered.
I'm pretty sure that has to do with some jetting size issues, a bit too rich.

Couple a questions:

Is the C5 ignition installed on this bike?

If I remember correctly, you have different transmission gears ('81?) and '83 wheels on this bike which might need more omph to get started from a dead stop?

I am only asking so that there is a fair comparison for a complete stock setup.

If there is a takeoff issue, would that be a problem if you are pulling a trailer?

 

[joedrum]

I think theres no problem at all with trailoors if it done up right ...its obvious to me the carberation is way better than stock ... especially down at tailor pulling demands