Topic: Weber Carbs fitment

[afkrejci90]

Anyone that has done this swap, how did you go about fitting up the carbs to the boots?  It seems the spacing on the carbs is a bit larger than stock.  Did you forgo using the stock rubber boots and use something else?  I am in the process of making a manifold, just have some concerns with the spacing.

[Don R]

There were two popular intakes, the RC engineering one and the MTC. I'll get a picture of the MTC one, it uses silicone turbo hose, (or at least I did) The RC uses stock rubbers.

[scottly]

There are pics of the MTC, RC, and other manifolds on this thread:
http://forums.sohc4.net/index.php/topic,68065.0.html

[scottly]

The MPD manifold mounts the carbs splayed out, while the RC manifold mounts the carbs in line, as you have pictured.

[afkrejci90]

The MPD manifold mounts the carbs splayed out, while the RC manifold mounts the carbs in line, as you have pictured.

This one just gave me a good idea that I didn't think of before.  I've been trying to design this all out aluminum but that requires the geometry to be very simple.  I still need a manifold plate for nitrous jets but after that I can 3D print the "nozzles" to fit up to the boots.  Heat won't be an issue since they won't be making contact with the head.

[scottly]

Somewhere in the thread I linked there is a manifold that used a flat aluminum plate with custom rubber boots to match up to the spigots; I think it was from Australia?

[afkrejci90]

Removed the butterfly shafts to move them as close as possible.  That takes care of the inner two intakes and makes the outer two less of an angle.  Maybe instead of using the #1 and #4 boots, get another set of #2 and #3 and use those on the outside.  If anything else use silicone turbo hose like Don R did.

[Don R]

 Here is mine, looks rather familiar, mine was broken and welded but didn't fit any more, I cut it apart and made it a two-piece bolt-together deal.

 Some fool sanded the numbers off of my Webers and cheap chromed them. The Webers are in the process of rejecting the plating.

[scottly]

My MPD was two-piece to begin with. With the MPD, the ends of the manifold line up with the spigots and are right up against them, so the hoses are only 1" long and straight. Also, the ID of the carb is 40mm, which has to neck down to 29mm or so to match the spigots. This hopefully smooth transition has to be done in the manifold.

[Don R]

 I learned later to roll up heavy brown paper and insert it in the hose and wind it in tightly, then you can cut it accurately in a power miter saw. I had enough hose left to do my turbo intake also. I bought aircraft hose clamps, they have an overlap so they don't dig in under the screw part.
 I bought air cleaner foam from unifilter and re-built these air filters. 

[afkrejci90]

So it looks like using just the two inner boots solves the outer intake problem, its now more inline with the carb.  Only problem I have is remembering where I got these reproduction boots from.

[scottly]

Can you reduce the size of your pics? Thanks.

[afkrejci90]

Can you reduce the size of your pics? Thanks.

Done, didn't know I could do that in the IMG tag

[scottly]

Can you reduce the size of your pics? Thanks.

Done, didn't know I could do that in the IMG tag

I didn't either, but thanks!

[MRieck]

I digress but who did work on the cylinder head. I see JB Weld around the spigots that's why I ask.

[afkrejci90]

I digress but who did work on the cylinder head. I see JB Weld around the spigots that's why I ask.

You did 

[MRieck]

I digress but who did work on the cylinder head. I see JB Weld around the spigots that's why I ask.

You did 

I thought so. That's from quite awhile ago going by the build thread. Just check your valve to valve clearance carefully with whatever cam you will be running....I recommend the Megacycle 125-70 in general as it doesn't have a ton of duration which is what interferes with the valve to valve clearance.

[afkrejci90]

I digress but who did work on the cylinder head. I see JB Weld around the spigots that's why I ask.

You did 

I thought so. That's from quite awhile ago going by the build thread. Just check your valve to valve clearance carefully with whatever cam you will be running....I recommend the Megacycle 125-70 in general as it doesn't have a ton of duration which is what interferes with the valve to valve clearance.

Ya life got in the way and motivation dropped off, but its back now.  I think I have the DP-327 cam right now.

[Don R]

  Here's a pic of the rubber mounts, the drag bike that I got had Webers before and the airbox tabs were trimmed and bent 90*.
 Since I've never mounted these, since I haven't spent the money to fix the stroker motor. I got myself curious about how they mount to the frame. I'll investigate today.

 It appears that mine is also an MPD. The center of the rubber mount bolts are within 1/4"of the width of the airbox tabs, they also have a little built in wobble, either age or to help fitment. 
 I bolted up the carbs and made a throttle cable.

[afkrejci90]

  Here's a pic of the rubber mounts, the drag bike that I got had Webers before and the airbox tabs were trimmed and bent 90*.
 Since I've never mounted these, since I haven't spent the money to fix the stroker motor. I got myself curious about how they mount to the frame. I'll investigate today.

It's going to take some custom work to mount them on the frame for sure, but I steel need to figure out the throttle cable and choke.  I do have a set Mikuni's I could throw on in the mean time until I get this part sorted out.

[Don R]

 Your post got me thinking about my set. I got them from Bill Benton a few years ago. I changed one jet in each carb after reading up on what everyone was running. I re-read all 40 pages, I have to give Scottly credit for adding a lot of info and value to the Weber information base. 

 I looked today, I went to #50 pilot jets. There are 45's in the bag that the 50's came in.

[afkrejci90]

Is there even a need for a throttle return cable with these carbs?  It's already got a decently strong internal spring.

[scottly]

My original set had strong enough internal springs, but the newer, but still old, set I'm running now needed external springs with the weaker internal springs.

[bear]

Somewhere in the thread I linked there is a manifold that used a flat aluminum plate with custom rubber boots to match up to the spigots; I think it was from Australia?

Your spot on Scottly. They can still be purchased new down here from a company called Lynx from memory.
I have a couple of sets in my container but I'm about to send one set off to Uncle Tez for one of his projects.

[scottly]

Hey Brian, good to hear from you! How are you and your lovely lady doing?