[Roadsters] Carb tuning (And the winner is)

[stan]

Dashpot oil!
Don't I feel like a fool.  Now my motor hums like a (I won't say it).

Anyways, thanks to John and Keith (hope I didn't forget anyone)for their
suggestions and especially Keith who set me up with his website
detailing
Tuning of SU's. 
I can really see how fun it can be when you start fiddling around with 
Carbs.  Especially when you start to tweak them here and there.
You almost feel in tune with them.  No pun intended.

Cheers!
Stan

-----Original Message-----
From: datsun-roadsters-bounces+stathy=shaw.ca at autox.team.net
[mailto:datsun-roadsters-bounces+stathy=shaw.ca at autox.team.net] On
Behalf Of stan
Sent: Saturday, July 26, 2008 9:53 PM
To: Datsun Roadster List
Subject: [Roadsters] Carb tuning

Hello all!
Note I will be using spell check with this email.
 
Anyways, I have been trying to tune my SU carbs for my 69-1600 and seem
to have hit a stumbling block.
 
I understand how to set the idle screws for each carb, as well as sync
them using a syncronometer.
I've don't that successfully.
As far as setting the jet height under each carb I haven't figured that
one out yet.
I turned the mixture screw in all the way and then turned it out 2 turns
as suggested on several of the websites.
>From there no adjustments have been made.
 
Here is what I've run into so far:
 
*	the motor fires up fine and idles so-so
*	when I rev the motor slowly the rpm's increase nicely
*	when I punch the motor at low rpm's the motor gasps for air and
several backfire pops occur
 
What I cannot figure out is that at high RPM's I can punch the throttle
and it will respond quite well.
 
What would cause it to backfire so heavily at low rpm's?  I would assume
non-sync'd carbs but as I stated I balanced them out
quite well.
 
If anyone can help me out I would greatly appreciate it.
 
Best regards
 
Cheers from sunny Vancouver, BC
 
Stan
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