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Author Topic: Weber carb set-up  (Read 67951 times)

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Offline scottly

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Weber carb set-up
« on: March 30, 2010, 08:41:13 pm »
Just wondering if anyone running Webers would be interested in comparing notes?


With an 836 motor, 30mm chokes, 4.5 aux, F16 emulsion tubes, I recommend a 105 main, with an air jet in the 175-195 range, depending on altitude. If using 30mm chokes with 3.5 aux and F16s, or 32mm chokes with 4.5 aux with F16s, use a 110 main, with air jets in the 185-210 range.
« Last Edit: November 24, 2015, 05:39:23 pm by scottly »
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Offline Bill/BentON Racing

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Re: Weber carb set-up
« Reply #1 on: March 31, 2010, 04:09:07 am »
Pm or get w 754 Frank. He has more than one set (sold him mine last yr.) Good Luck,Bil
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Over 35 years of experience working on vintage motorcycles, with a speciality in Honda SOHC/4 with a focus on the CB750 and other models as well from 1966 - 1985.
______________________________________
1993 HRC RS125 | 1984 NS400R | 1974 Honda CB750/836cc (Calendar Girl) | 1972 CB 500/550 Yoshi Kitted 590cc | 1965 Honda CB450 Black Bomber | 1972 Suzuki T350 | 1973 88cc | Z50/Falcons Pit Bike | 1967 CA100| 1974 CB350 (400F motor)...and more.
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Offline 754

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Re: Weber carb set-up
« Reply #2 on: March 31, 2010, 09:33:44 am »
I hve already talked to Scottly a bit on the topic. Yes, I have 2 sets ready to run right now, also Dellortos I have not yet run.


If anyone needs short (double stepped) intake rubbers I found a member willing to make them.

 I will try to dig out my MPD jetting info and post it on here..
Maker of the WELDLESS 750 Frame Kit
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My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline voxonda

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Re: Weber carb set-up
« Reply #3 on: March 31, 2010, 09:46:02 am »
The short like that the one on the F2/K7????????

Rob
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Offline 754

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Re: Weber carb set-up
« Reply #4 on: March 31, 2010, 09:54:39 am »
I was talking obout 1/4 or 3/8 space between the manifold and head spigots..
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline scottly

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Re: Weber carb set-up
« Reply #5 on: March 31, 2010, 07:03:12 pm »
Hi, Frank. It was actually our "diet" conversation that lead to this topic: while going through my notes on how much weight I had added with the Kawi front end, I found my original notes on setting up the Webs in '79. I got the bike with a total hodge-podge of carb parts installed; different size venturis, drilled jets, you name it. My room-mate at the time was very familiar with these carbs, and lent me a book from BAP/GEON, that I used to estimate what I needed. It worked pretty well; sure wish I had made a copy of that book....

Venturi  30 mm
Aux Venturi 3.5
Main jet   125
Air correction 185
Emulsion tube F11
Idle 45F9 (switched to 40F8 in '97 due to move to 4500' elevation)
Accel jet  .35
Accel discharge .55

***************
Jonnycakes 836 auto, as of 9-2-15:
After much trial and error:

30mm chokes (32mm chokes too big, 28mm chokes too small)
4.5 Aux Venturi
F16  Emulsion Tube
120 main (125 main way too big)
45F8 Idle jet (40F9 Idle jet just a bit small)
35 pump jet
Pump Spill  55 (what is stamped)
.200 needle valve
170 AIR CORRECTOR JET

running 120mph on the highway, and a touch of wheel spin when i wack the throttle at low speed.

DONE
************
BPellerine 736 as of 7-16-13 (ultra rare 38 DCOE)

idle 45f9
115 main
200 air
f14 emulsion
main venturi29
aux venturi3.5
40 pump jets
50 spill jets
« Last Edit: October 04, 2015, 07:24:37 pm by scottly »
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Offline JLeather

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Re: Weber carb set-up
« Reply #6 on: April 05, 2010, 05:20:24 pm »
I got a set of the PH44's (Mikuni weber-knockoffs) waiting to go on my next cool engine after the turbo.  Dunno how they'll run, but man they look bada$$

Offline scottly

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Re: Weber carb set-up
« Reply #7 on: April 05, 2010, 07:04:15 pm »
I love my Webers!  :)
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Offline 1080

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Re: Weber carb set-up
« Reply #8 on: April 05, 2010, 08:50:49 pm »
Some old magazine info.

I think there was a better article on what work best with the Weber's on the 750's.

Offline scottly

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Re: Weber carb set-up
« Reply #9 on: April 05, 2010, 09:08:50 pm »
Thanks 1080!! I have never seen that before. Big diff between the RC jetting and MP. My manifold doesn't look like either one.... 
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Offline JLeather

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Re: Weber carb set-up
« Reply #10 on: April 06, 2010, 07:38:30 am »
Just for the sake of comparison, here are the Mikuni's on some kind of manifold.  It's a really nice manifold too.




Offline 754

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Re: Weber carb set-up
« Reply #11 on: April 06, 2010, 08:22:46 am »
JL, those would definitely be easier to build an aircleaner for, than the Webers.. wonder how easy it is to get jets?

 Pretty sure those were put out by Branch flowmetrics..
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline Ricky_Racer

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Re: Weber carb set-up
« Reply #12 on: April 06, 2010, 10:19:20 am »
JL, those would definitely be easier to build an aircleaner for, than the Webers.. wonder how easy it is to get jets?

 Pretty sure those were put out by Branch flowmetrics..

Yeah, I have a similar set of Mikuni-Solex PH40-PH44s. They have a cool "breadbox" type air filter, with a cast aluminum filter base with "Branch" molded in.

JL, have you found the proper rebuild kits for the PH44s yet?  Mine are going to get the full treatment later this year.  Thanks.  RR

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Offline BLUE71TURBO

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Re: Weber carb set-up
« Reply #13 on: April 06, 2010, 10:29:37 am »
    ;D     


             
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Offline Ricky_Racer

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Re: Weber carb set-up
« Reply #14 on: April 06, 2010, 11:46:55 am »

Yep, BT, I like that setup too!  ;D  Dude, we really do need to get together one of these days....   8)   RR



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Offline fishhead

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Re: Weber carb set-up
« Reply #15 on: April 06, 2010, 03:50:22 pm »
Here's my R.C. Engineering set up for my CB 750.
 It originally had the twin cables like the set above, but the lugs for the cables were cut off when I got them, so I made some linkage to convert them to a single cable set up. I don't have to worry about cables stretching at different rates any more.

 RR, Alpha1750 (his Ebay name) has a lot of the Solex/Mikuni stuff.

 I rebuilt my Solex 40PHH (precursor to the Mikuni-Solex PH) for my BMW with stuff I bought through him.
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Offline Ricky_Racer

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Re: Weber carb set-up
« Reply #16 on: April 06, 2010, 03:57:56 pm »

Thanks, Dan. I'll look up Alpha1750. RR

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Offline JLeather

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Re: Weber carb set-up
« Reply #17 on: April 06, 2010, 08:25:31 pm »
Ted,
  Sure looks like we wound up with the same manifold.  I haven't had to find any parts for mine yet, they were rebuilt before I got 'em and are spotless.  I did find in my travels that the Mikuni stuff was still being re-pop'd here and there because it's still popular with the offroaders and some brit car guys. 

Offline JLeather

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Re: Weber carb set-up
« Reply #18 on: April 06, 2010, 08:26:54 pm »
This place seems to have the gaskets and standard rebuild parts.

http://www.datsunroadster.com/SUB_SECTION_DIRECTORIES/carbs_2000_solex.htm

Offline Ricky_Racer

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Re: Weber carb set-up
« Reply #19 on: April 06, 2010, 08:31:26 pm »

Thanks, John. That helps, but at those prices I hope the insides look better than the outside.  :o  RR



« Last Edit: April 06, 2010, 08:34:59 pm by Ricky_Racer »
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Offline BLUE71TURBO

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Re: Weber carb set-up
« Reply #20 on: April 06, 2010, 08:52:09 pm »
Hey RR and the rest of you mikuni side draft guy's, here's a website that might be of use to ya !   ;D ;D

   http://www.wolfcreekracing.com/index.php?option=com_content&view=article&id=21&Itemid=30
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Offline Bill/BentON Racing

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Re: Weber carb set-up
« Reply #21 on: April 12, 2010, 05:52:24 pm »



Another book that may still be available.Sure helped me out.




   




You can see the straight manifold RC used.I went to a Jerry Magnusson one,angled instead of straight.Used one cable in center.Worked much better.Bill
BentON Racing Website
OEM Parts | Service | Custom Builds
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Over 35 years of experience working on vintage motorcycles, with a speciality in Honda SOHC/4 with a focus on the CB750 and other models as well from 1966 - 1985.
______________________________________
1993 HRC RS125 | 1984 NS400R | 1974 Honda CB750/836cc (Calendar Girl) | 1972 CB 500/550 Yoshi Kitted 590cc | 1965 Honda CB450 Black Bomber | 1972 Suzuki T350 | 1973 88cc | Z50/Falcons Pit Bike | 1967 CA100| 1974 CB350 (400F motor)...and more.
______________________________________
See our latest build 'Captain Marvel' CLICK HERE

Offline scottly

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Re: Weber carb set-up
« Reply #22 on: April 12, 2010, 07:03:10 pm »
My manifold is angled, with a single cable in the middle, but it is two parts, with overlapping flanges in the center, and a bolt that clamps them together, near the cable. The manifolds I've seen here appear to all be one piece. There are no numbers or logos, either.
Don't fix it if it ain't broke!
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Offline 754

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Re: Weber carb set-up
« Reply #23 on: April 12, 2010, 07:26:58 pm »
The angled ones come in 1 pce and 2pce, otherwise pretty much the same.
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline scottly

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Re: Weber carb set-up
« Reply #24 on: December 10, 2010, 05:26:39 pm »
Here are some pics of my setup. Rob, I have been using them on an 836 motor. If I'm not mistaken, Frank has used them on several different configurations...
« Last Edit: December 10, 2010, 06:42:19 pm by scottly »
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....

 

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