Single Carb Conversion 2 Barrel Progressive Holley,Weber 740 carb

[westgl]

Jungo,

Crank case Vent is very important you cannot just fold a hose over and block it off, this must vent, or it will build up a lot of Pressure inside the crank case, Not Good.
Best method, & cheap
I have also thought about running the crankcase vent to the air filter Like i have done, while it is the best way, cause all venting goes back into the engine.

If you cannot or do not have the spacing in the air filter to connect to it.

You could put a short hose to a small Diameter Kind of like air filter breather, down low.

Or a PVC/Check valve, a one way valve nothing goes in, only out, It would be terminated right there, no long hose to run to air filter. i would make sure this is positioned under the bike, in case of rain.

westgl » Mon Sep 23, 2013 5:04 am[/url]":28jgst2r]
Jungo

please provide a picture

I think you would have two hoses that need to be attached

1. Vacuum line for vacuum advance, this line should go to a vacuum port on your carb. It would be a port that is for Advance/retard of a Distributor Take a picture of your vacuum ports on your carb, they look like brass tubes sticking out
2. crankcase breather, run this line up to the bottom of your new air filter

I am not sure about one coming from the rear wheel

Jungo » Mon Sep 23, 2013 4:46 am[/url]":28jgst2r]
:headscratch: Guys, there's a rubber line coming from the bike's rear wheel. Where did you connect it? I supposed is a vacuum related thing, right? :headscratch:

 

[westgl]

The Crank Case Breather hose.

Some times these little details can be the night mare of the whole thing

I bought a longer 12" long piece of 1/2" hose I believe, take old one with you to parts store to verify size.

To terminate the Crank case Breather hose.

While at Napa.

I bought for less than $1.00 a Fuel proof, Black plastic barbed fitting, that has a Ring around the center, the ring is larger diameter than the barb is.

I drilled a hole in the Bottom Plate only, of the Air Filter, the size of the Barb, the ring in the middle is larger than the barb and will keep it from falling all the way through.

I also bought a hose clamp while at Napa, the size of the od of the new 12" Long 1/2" crank case hose.

Then, put your hose on the new fitting with the clamp on.

The Ring on the fitting will keep it from falling through, the hose pushed on the barb and clamped will keep it from going back up through the hole.

Remember guys, Very Important.

Anything new that you introduce to inside the Air filter that can come loose and go down inside the engine has to have a fail safe method for attachment.

I am using a large Fender washer & Nut on a piece of threaded rod as a stop for the lower air filter base plate, the Nut & threaded rod is cleaned/degreased & blue loc-tite.

The large Fender washer is large diameter I have tried to put in the throttle bores to make sure it would not go down inside, there is no way it will fall in, it is too big.

 

[westgl]

I have a Very Nice tube bender.

I also have a Very Nice Tube Notcher

That Manifold that you have Jungo,

The way the tubes insect together, and are welded together in the center section is done with a tube notcher.

Cutting the tube at the right angle with a hole saw the correct diameter, a hole saw is what cuts the hole in the tube notcher, it will get your angle correct while opening the tube up to the correct size.

Frame builders use Notchers,

I bought these tools to build my Reverse Trike project

 

[westgl]

Dan,

Try to set your idle speed at 950-rpm, and keep it in the Idle circuit, meaning less than 1000 rpm to keep idle out, of the Off Idle Circuit.

But! Not too low, as you still need adequate lubrication at idle.

Your Idle may be better there, since the Off idle circuit seems to be the Rich Zone.

westgl » Sun Sep 22, 2013 6:35 pm[/url]":36xaomq8]
I read through HP's Weber Carb. book very briefly.

I think i remember it saying Off idle circuit starts at 1000rpm,

Idle circuit is at 950rpm, and lower, so at 950rpm you are out of the off idle circuit, which may be your rich circuit

I will verify that when i receive my manual.

dan filipi » Sun Sep 22, 2013 5:53 pm[/url]":36xaomq8]

westgl » Sun Sep 22, 2013 6:41 pm[/url]":36xaomq8]
Was the bog from off idle up to 4k?

Or was it just a bog right about at 4K?

dan filipi » Sun Sep 22, 2013 5:30 pm[/url]":36xaomq8]
Not really sure about road speed I was at at 4k rpm. I tried it in first gear, in second gear, and third gear.
All times acted pretty much the same.

I would say bog was from idle up to 4k.
Good after 4k.

All plugs are dark but not black.

 

[westgl]

I hope it is just the float level is Too High,

There are Jets differences between your carb and mine.

High speed Bleeds and one of the main jets is different.

When i receive my Carb books, i hope they will proved some very good detail, as well as trouble shooting, that will give us what we want to know

I will talk to Tom at Langdons Stovebolt to see if he can steer me or provide some literature for tuning these carbs as well, just to help us out.

IMAG0352

• dan filipi
• Sep 16, 2013

The jets I have in mine.

Jet Size for Weber 740 series 32DFT

• dan filipi
• Sep 16, 2013

Top line are the jets westgl has in his 740 series weber

 

[dan filipi]

westgl » Mon Sep 23, 2013 7:11 am[/url]":3gspdr25]
I hope it is just the float level is Too High,

There are Jets differences between your carb and mine.

High speed Bleeds and one of the main jets is different.

When i receive my Carb books, i hope they will proved some very good detail, as well as trouble shooting, that will give us what we want to know

IMAG0352

• dan filipi
• Sep 16, 2013

The jets I have in mine.

Jet Size for Weber 740 series 32DFT

• dan filipi
• Sep 16, 2013

Top line are the jets westgl has in his 740 series weber

Yes, i believe my jets are larger.

 

[joedrum]

hmmm curious west what are the jet sizes in your motor craft holley weber 32-34 you got with the 24-25 chokes

 

[westgl]

Good question Joe,

I will mosey on out to the saloon, i mean the shop, (dang, a beer tap in the shop, would be nice), and check it out when I get a little more Sunshine.

Us western guys (that's why I used Mosey) dont have as much early sunshine as you guys further east do.

 

[westgl]

I am sorry,

If i seem redundant, and am repeating my self, by bringing up old already stated info, or stating the obvious, possibly going to slow for some.

I am trying to keep information that i think is currently pertinent to what we are trying to achieve now! fresh in our minds.

Also,

I want to give some insight as to my thought process along the way, for collaborative brain storming, with other thoughts from a basis starting point, even if taken a different direction, maybe that is not needed, and i am just slowing the thread down with unwanted info, that is not needed?

Until all avenues have been exhausted and Ultimate Goal is achieved we are Not finished

 

[ekvh]

For those who don't have a tube notcher, I found this site: https://metalgeek.com/static/cope.pcgi which has profiles available to print. I printed them, then cut the profile out. You then wrap the paper around the pipe to be notched and tape it there. You can use a marker to mark the notch and then have at it with your favorite cutting tool. I used spray paint to mark the pipe. It gets them pretty close. I used it for my swing arm to a monoshock conversion.

 

[westgl]

Good thinking,

Always more than one way to skin a cat.

Look at the LDwingnut Single barrel carb Manifold for the GL11/12
Then look at the Juan fernandez GL1200 Manifold

Both used a tube notcher to get that close, merged together, tube at the center/plenum tube.

This could be done, and would eliminate the need for the VW manifold, using a tube for the center plenum large enough for the 32DFT to mount to.

This would obviously be more difficult to produce, but may be the best alternative yet.

With a smaller plenum, volume wise?, (but we dont want the volume to be to small, then we are sacrificing power out) maybe flow would be more directed? in the plenum area?

The VW plenum does a pretty good job since the bottom of it is tube like, to reduce volume, and not open and flat

I could try to build several

Rev.#2, #3, #4, #etc..

To see which one i think is best?

But that did not work in a Back to Back Comparison with the butt dyno test.

Wish i had free access to a Dyno, for a day and someone that could help in the setup & record #'s phase.

Anyone have Free access to a Dyno?

ekvh » Mon Sep 23, 2013 7:13 am[/url]"kgwf756]
For those who don't have a tube notcher, I found this site: https://metalgeek.com/static/cope.pcgi which has profiles available to print. I printed them, then cut the profile out. You then wrap the paper around the pipe to be notched and tape it there. You can use a marker to mark the notch and then have at it with your favorite cutting tool. I used spray paint to mark the pipe. It gets them pretty close. I used it for my swing arm to a monoshock conversion.

 

[westgl]

Joe,

Here are the jet sizes for my 32/34DFT w/ 24/25 Chokes

Some pictures too, of top of carb showing the bowl vent screens.

With Choke on the left.
Left to Right

#1 - 70
#2 - 150, X04, 15
#3 - 180, X05, 20
#4 - 60

Those two small jets are Very Hard to See, even with a magnifier

But I have not Put this carb on yet, nor have I tried it, so i have no idea what it will run like, it could be way over rich, or too lean,

This carb. was jetted for a 1.9L engine, with, more than 100h.p. & more than 100 ft lbs of torque, so I would think it will be too rich on my engine.

How does that compare to your carb, Joe please provide your jets sizes again for reference.

Look how small the choke reduces the bore size down to,

That bore that you can see down into is the secondary, the primary has the choke plate over it, for those unfamiliar.

32DFT has a choke plate over both throttle bores,

There is nothing like Full throttle, cold start, choking to brighten your day, i guess they dropped the secondary choke plate, as the engine should be idling, or fast idling

P1020076

• westgl
• Sep 23, 2013

32/34DFT carb w/24/25 chokes top view

P1020078

• westgl
• Sep 23, 2013

32/34DFT carb w/24/25 chokes top view Jets exposed

 

[joedrum]

sheesh is the power enricher valve on that carb westgl

 

[westgl]

Yes it is,

The power enrichner valve, is on both my carbs

Joe do you have a solenoid under the the fuel inlet?

Like the 32DFT's do?

Cause My 32/34DFT does Not have a solenoid in that location.

But has a Idle cut off solenoid on the front above the idle mixture screw adjustment.

 

[dan filipi]

Interesting about the choke plate not being there on your's.
Mine has both.

When I put my hand over the secondary bore it will die.
Same happens on the primary bore.
Feeding from both?

Oh gees, I just remembered something. As I typed it jarred my memory!

When I first got the carb, the secondary throttle plate was lazy closing. Like the linkage was too tight.
Hmm.

 

[westgl]

Dan,

On my 32DFT like yours it has a throttle choke plates over both.

My 32/34DFT is only over the Primary

dan filipi » Mon Sep 23, 2013 9:26 am[/url]":26cpawxb]
Interesting about the choke plate not being there on your's.
Mine has both.

When I put my hand over the secondary bore it will die.
Same happens on the primary bore.
Feeding from both?

Oh gees, I just remembered something. As I typed it jarred my memory!

When I first got the carb, the secondary throttle plate was lazy closing. Like the linkage was too tight.
Hmm.

 

[westgl]

You may want to take one side of your throttle linkage bracket & nut off and actuate everything, to find out where exactly it is at and correct it.

dan filipi » Mon Sep 23, 2013 9:26 am[/url]":wfh0mud6]
Interesting about the choke plate not being there on your's.
Mine has both.

When I put my hand over the secondary bore it will die.
Same happens on the primary bore.
Feeding from both?

Oh gees, I just remembered something. As I typed it jarred my memory!

When I first got the carb, the secondary throttle plate was lazy closing. Like the linkage was too tight.
Hmm.

 

[Dave_J]

On the crankcase vent line, if it can not be routed up to the airfilter then get a large enough fuel filter and stick in the tube. It will allow air to flow but filters out dust and bugs. You wouldent want a VW bug getting sucked into your engine as you fly by one. :mrgreen:

Just run it up high so its out of the weather and wire tie down.

 

[westgl]

Ha ha ha !!!!!

Good one Dave, nice play on words

That vent only blows in one direction, out, I believe.

Dave_J » Mon Sep 23, 2013 9:50 am[/url]":2drv0x33]
On the crankcase vent line, if it can not be routed up to the airfilter then get a large enough fuel filter and stick in the tube. It will allow air to flow but filters out dust and bugs. You wouldent want a VW bug getting sucked into your engine as you fly by one. :mrgreen:

Just run it up high so its out of the weather and wire tie down.

 

[Jungo]

First start up (after 3-4 tries) with single carb. Advance vacuum line is too short to connect in carb vacuum inlet. Still working on this mod... :builder:

Thanks West,Joedrum, Dan and all the rest of the gang for your support and hints.

[video]https://youtu.be/h70xprLzytc[/video]