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Author: Subject: Weber 45 tuning
Bigkiltedwarrior

posted on 13/2/15 at 07:00 PM Reply With Quote
Weber 45 tuning

Hi,

Following fitting a Burton stage 2 big valve head and Kent FR30 hi-torque cam to my 2 litre pinto already on Weber twin 45s, I have finally fired her up and have her idling nicely with the idle speed screw in about half a turn after contact with the throttle lever and the idle mixture screws out 2 turns from gently seated. RPM is sitting at about 1100. I have 12 degrees of advance BTDC.

Chokes are 36
Main jets are 145
Emulsion tubes F16
Air corrector 155 (180s on order)
Idle jet 55F6 (55F9 on order)
Pump jet 45

She seems to die a fair bit on rapid throttle whilst not under load. I haven't taken her out yet for a spin.

Anyone see anything obviously needing adjusted?

Cheers
Stewart

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coozer

posted on 13/2/15 at 07:11 PM Reply With Quote
They are a pain in the arse to keep balanced and in tune.

Sell them on, buy some bike carbs and have a nice holiday!





1972 V8 Jago

1980 Z750

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Bigkiltedwarrior

posted on 13/2/15 at 07:16 PM Reply With Quote
hi Coozer, thanks but I like my Webers and they were running great on the old setup. More than happy to persevere fiddling with them as its all part of the joy of owning one of these.
S

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cliftyhanger

posted on 13/2/15 at 07:25 PM Reply With Quote
Have you asked Burton? they may well have specs they can supply. But ideally a session on the rollers.

I still do not understand why so many people have issues with keeping twin chokes in tune. My dellortos were really reliable once set up, and would return 35mpg on a zetec. It is only a few things that could go out (balance, idle screws etc) but should be fine unless fiddled with??

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perksy

posted on 13/2/15 at 07:57 PM Reply With Quote
Dave Andrews's Weber jetting program is usually not a million miles away and is worth using.
I had a 2 litre zetec on 45's and using Dave's program it wasn't far off when visiting NMS for final set up.


Nowt wrong with with a pair of well set-up Webers, Their old school

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Angel Acevedo

posted on 13/2/15 at 11:26 PM Reply With Quote
Aarrrgghhh...
Here we go again...
I think 1100 RPM is a little bit too high.
First adjust Idle Speed screw to provide Idle slow, but enough not to stall engine.
Then adjust Idle Mixture Screws so speed increases, this a quarter of a turn to half a turn at a time....
Whenever Idle speed increases, bring back with Idle Speed adjustment screw...
Keep doing so until you have reached a point where no increase in Idle speed is noted and back off a little Idle Mixture Screws.
Adjust Idle Speed Screw.

Something else may be the Enrichment Pump Cam adjustment. (I don´t remember if these carbs have them,
I have a Weber manual near by if you want me to review what I wrote above...
HTH
AA


ETA: You may want to use a Carb balancing tool to get the best results......

[Edited on 2/13/2015 by Angel Acevedo]





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BaileyPerformance

posted on 14/2/15 at 06:28 AM Reply With Quote
F16, main and corrector not far off, (the ones you ordered)55F9 maybe abit big, 45/50F9 mite be closer.

Where in the world are you?

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jollygreengiant

posted on 14/2/15 at 06:40 AM Reply With Quote
quote:
Originally posted by BaileyPerformance
F16, main and corrector not far off, (the ones you ordered)55F9 maybe abit big, 45/50F9 mite be closer.

Where in the world are you?


Possibly Scotland judging by the username.





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Bigkiltedwarrior

posted on 14/2/15 at 03:31 PM Reply With Quote
jersey, Channel Islands. Originally Aberdeen

Productive day today in garage and have got it running pretty good with no hesitation or backfire through exhaust or carbs. Idle speed screw out half a turn, idle mixture out 3 turns (45 152s) and timing advanced about 16-18 btdc at 1000.

Drives very well and should do me until I can get to a garage to balance fully or a RR over in the UK.

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Paul Turner

posted on 14/2/15 at 05:56 PM Reply With Quote
quote:
Originally posted by coozer
They are a pain in the arse to keep balanced and in tune.



No they are not.

OK, they do go out of balance eventually but I bought one of these http://www.ebay.co.uk/itm/like/290682796527?limghlpsr=true&hlpv=2&ops=true&viphx=1&hlpht=true&lpid=108&chn=ps&device=c& ;adtype=pla&crdt=0&ff3=1&ff11=ICEP3.0.0-L&ff12=67&ff13=80&ff14=108 many years ago and simply checked and adjusted as necessary, probably a couple of times a year. Still use it to check the Jenveys.

If they are jetted correctly for your engine tune they will not require tuning again. The only moving parts are the needle jets and floats which will eventually need replacing but in 15 years of Webers I did it once.

Problem with Webers there are many "specialists" out there who know fek all, all they know is how to fek them up. Find a good tuner and they are basically fit and forget.

The other problem is the Webers available on e-bay, most are sold because they are knackered or off old cars such as Alfas etc with fixed jets. They are cheap for a reason.

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Andy D

posted on 14/2/15 at 07:06 PM Reply With Quote
quote:
Originally posted by Paul Turner
quote:
Originally posted by coozer
They are a pain in the arse to keep balanced and in tune.



No they are not.

OK, they do go out of balance eventually but I bought one of these http://www.ebay.co.uk/itm/like/290682796527?limghlpsr=true&hlpv=2&ops=true&viphx=1&hlpht=true&lpid=108&chn=ps&device=c& ;adtype=pla&crdt=0&ff3=1&ff11=ICEP3.0.0-L&ff12=67&ff13=80&ff14=108 many years ago and simply checked and adjusted as necessary, probably a couple of times a year. Still use it to check the Jenveys.

If they are jetted correctly for your engine tune they will not require tuning again. The only moving parts are the needle jets and floats which will eventually need replacing but in 15 years of Webers I did it once.

Problem with Webers there are many "specialists" out there who know fek all, all they know is how to fek them up. Find a good tuner and they are basically fit and forget.

The other problem is the Webers available on e-bay, most are sold because they are knackered or off old cars such as Alfas etc with fixed jets. They are cheap for a reason.


+1 Couldn't agree more. I get mine set up by Ron Harper, (near Middlesbrough) proper old school. I occasionally put the ballancer on them, but it's just more of a check than anything.. properly set up they do not go "out of tune".

As said, I think the problem is these old guys are retiring, and their knowledge is dissapearing..

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Angel Acevedo

posted on 14/2/15 at 09:01 PM Reply With Quote
Bigkiltedwarrior
Good to hear you´re sorted.
The aaarrgghhh at the beginning of my post is due to my connection crashing when I pressed the reply button.
And believe it or not happened again replying to this.
I will revert back to editing my (almost nil) posts in woed so I don´t lose whatever I have written.
Best regards
Angel Acevedo





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