Author Topic: Weber carb set-up  (Read 151851 times)

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Offline BPellerine

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Re: Weber carb set-up
« Reply #550 on: June 23, 2015, 06:48:43 PM »
way to go jonny!
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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Weber carb set-up
« Reply #551 on: June 23, 2015, 08:33:16 PM »
You'll have this down pat by the time I get my 1000 up and running then we can start on my Weber setup.  ;D

I have NO clue whatsoever about them except that they are in a box awaiting use. 
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline jonnycakes

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Re: Weber carb set-up
« Reply #552 on: June 23, 2015, 10:25:11 PM »
BTW, the cover for the cold start can be removed; the springs keep the valves seated.

I got little aluminum covers to replace the cold start assembly
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Offline scottly

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Re: Weber carb set-up
« Reply #553 on: June 23, 2015, 10:30:07 PM »
That 150 air jet still bugs me, but hey, if it works, it works! 8) 8)
Don't fix it if it ain't broke!
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Offline jonnycakes

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Re: Weber carb set-up
« Reply #554 on: June 23, 2015, 10:47:15 PM »
The Automatic seems to want leaner main jet, but richer when it finally hits the upper RPM. 
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Offline Bill/BentON Racing

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Re: Weber carb set-up
« Reply #555 on: June 24, 2015, 04:58:46 PM »
K, keep us posted, thanks,  Bill
BentON Racing Website
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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 BPellerine

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Re: Weber carb set-up
« Reply #556 on: June 24, 2015, 05:24:46 PM »
what change did you notice when you changed emulsions,there does not seem to be a standard setting that works with similar engines with these carbs.billp
1978 CB 750K ard and webers
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Offline 754

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Re: Weber carb set-up
« Reply #557 on: June 24, 2015, 06:13:36 PM »
The Automatic seems to want leaner main jet, but richer when it finally hits the upper RPM. 
Something wrong there should be able to work it out with jets.
 I don't have the manuals, but they point you toward which jet. You should work with sometimes.
When you say seems to want a leaner main, it sounds like you are not on the main yet..
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 #558 on: June 24, 2015, 09:21:42 PM »
The Automatic seems to want leaner main jet, but richer when it finally hits the upper RPM.
You may be on to something, Jonny; with 125 mains, 185 air corrections, and foam air filters my bike is rich at WFO from 4500 RPM up, measured with a sniffer on the dyno. Are you running open stacks?
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....

Offline jonnycakes

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Re: Weber carb set-up
« Reply #559 on: June 25, 2015, 06:19:45 AM »
3" open stacks......I went from 115 to 120 main jet last night and the burble came on the highway. No noticeable change at the top end.

When I used the 125s, the carbs were soaking wet with gas when I pulled the apart and my milage was 20mpg which is really bad even for a hondamatic


I also tried 35f9 idles...way too lean, 40f9 were much better, I couldn't feel any difference when I went to my 45F8

With the matic, there's no slipping the clutch to get past any flat spot
« Last Edit: June 25, 2015, 08:44:28 AM by Jonnycakes »
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Offline jonnycakes

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Re: Weber carb set-up
« Reply #560 on: June 25, 2015, 08:59:42 AM »
The Automatic seems to want leaner main jet, but richer when it finally hits the upper RPM. 
Something wrong there should be able to work it out with jets.
 I don't have the manuals, but they point you toward which jet. You should work with sometimes.
When you say seems to want a leaner main, it sounds like you are not on the main yet..

If I was smarter Id have this by now
I'm using this:
http://www.lainefamily.com/images/WeberTuningManual.pdf
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Offline BPellerine

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Re: Weber carb set-up
« Reply #561 on: June 25, 2015, 10:21:31 AM »
how about a pic of your bike with the webers,must look cool,when I firs got my webers I was told that the 115s may be too lean but they work okay,200 air,f11 tubes,bill
1978 CB 750K ard and webers
another anfob

Offline scottly

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Re: Weber carb set-up
« Reply #562 on: June 25, 2015, 10:21:42 PM »
3" open stacks.....
When I used the 125s, the carbs were soaking wet with gas when I pulled the apart and my milage was 20mpg which is really bad even for a hondamatic

The carbs shouldn't be soaking wet with 125 mains??? Do you have the proper stacks? I noticed in the tuning guide you posted that there were two different style aux venturi; one for stacks and one without. Bill P's 38 carbs didn't need the stacks to lock the aux in place like my carbs. Do your stacks look like mine on the left side, or do they have a flat flange with two mounting holes like the ones I sent Bill?
« Last Edit: June 25, 2015, 10:27:31 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....

Offline jonnycakes

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Re: Weber carb set-up
« Reply #563 on: June 26, 2015, 05:13:36 PM »
3" open stacks.....
When I used the 125s, the carbs were soaking wet with gas when I pulled the apart and my milage was 20mpg which is really bad even for a hondamatic

The carbs shouldn't be soaking wet with 125 mains??? Do you have the proper stacks? I noticed in the tuning guide you posted that there were two different style aux venturi; one for stacks and one without. Bill P's 38 carbs didn't need the stacks to lock the aux in place like my carbs. Do your stacks look like mine on the left side, or do they have a flat flange with two mounting holes like the ones I sent Bill?

yup, only my stacks are longer..........
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Offline BPellerine

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Re: Weber carb set-up
« Reply #564 on: June 26, 2015, 06:17:07 PM »
this is what I mean when two engines are far apart on jetting,yours 849,scottlys 836,both with cams,frank and scottly get good mileage I thought.but who knows for sure.do you have a good mid response compared to stock carbs?bill
1978 CB 750K ard and webers
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Offline Bill/BentON Racing

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Re: Weber carb set-up
« Reply #565 on: June 27, 2015, 09:13:17 PM »
32mm chokes installed. Hardware polishing almost finished,Thank you Bill Pellerine, they've turned out well, Bill  ;D
BentON Racing Website
OEM Parts | Service | Custom Builds
BentON Racing Facebook
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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See our latest build 'Captain Marvel' CLICK HERE

Offline Medyo Bastos

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Re: Weber carb set-up
« Reply #566 on: June 28, 2015, 03:49:17 AM »
you get those out my garage billy?


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Offline Bill/BentON Racing

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Re: Weber carb set-up
« Reply #567 on: June 28, 2015, 05:39:21 AM »
Nah, but the RC chrome ignitignition....well that's another story. ;D
BentON Racing Website
OEM Parts | Service | Custom Builds
BentON Racing Facebook
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 Medyo Bastos

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Re: Weber carb set-up
« Reply #568 on: June 28, 2015, 07:54:09 AM »
that was actually polished


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Offline 754

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Re: Weber carb set-up
« Reply #569 on: June 28, 2015, 09:34:23 AM »
Big mean looking carbs.. I love em........go under the heading of exotic parts..
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 BPellerine

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Re: Weber carb set-up
« Reply #570 on: June 28, 2015, 09:35:22 AM »
32mm chokes installed. Hardware polishing almost finished,Thank you Bill Pellerine, they've turned out well, Bill  ;D
now they look NEW! polished screws too,they must be as close to new as you can get,you have 170 air,f7 emuls,105 main in case you were wondering.could   not get the stain from boots off but there will be others on there,would have polished the stuff too but we know why not!haha .also new pump o rings on there billp
1978 CB 750K ard and webers
another anfob

Offline BPellerine

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Re: Weber carb set-up
« Reply #571 on: June 28, 2015, 09:39:00 AM »
Big mean looking carbs.. I love em........go under the heading of exotic parts..
everything else looks ordinary after having webers!
1978 CB 750K ard and webers
another anfob

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Weber carb set-up
« Reply #572 on: June 28, 2015, 10:56:34 AM »
32mm chokes installed. Hardware polishing almost finished,Thank you Bill Pellerine, they've turned out well, Bill  ;D

There you go again Billy Bling  ;D  yeah yeah I'm jealous but I need to finish the engine before I'm NOW forced to bling up mine too  ;)
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline Bill/BentON Racing

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Re: Weber carb set-up
« Reply #573 on: June 28, 2015, 02:23:50 PM »
Nah, just send them this way!   ;D
BentON Racing Website
OEM Parts | Service | Custom Builds
BentON Racing Facebook
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 Jerry Rxman Griffin aka MuthaF'er

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Re: Weber carb set-up
« Reply #574 on: June 28, 2015, 02:35:08 PM »
Don't have time! Just torqued the head and gathering up the little odds and ends. Cam time  ;D
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)