Hi all.

I'm still trying to tune my hs6. For the sake of this thread most other aspects of the carb are ok. I've got an ao6 needle.

WOT my afr is about 12:5 - 1 . Light throttle is around 15,16 -1. Cruising is spot on at about 14-1.

But sitting at idle, let's say I set the mixture at around 15- 1. I take it for a run then bring it home. The rpm stays the same but the afr goes backwards and forwards from about 13, to 17 -1...

I can't find any obvious vacuum leaks...... I've got a brand new dizzy.

Im also having trouble getting enough timing into it. It's just freakin doughy. Can't get it to crispen no matter how good the fuel mixture is.

I am unable to advance the timing far enough to get it to ping. Even with my dial back gauge set at 50 degrees advance.


Any help,will be greatly appreciated.

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where is your afr bung/attachment.
if at tailpipe , at idle there is too much atmo air to get an accurate reading.

it is my opinion if your exhaust is too large ( say more than 1.75inch) , then it is harder to get a spot on AFR measurement at low revs also.

Doe your changing in timing do anything to idle? tuning roughly by hand turning of dizzy back and forth to get stumble, climbing revs etc) if not then your dizzy/timing needs looking at.... this FIRST and then Fuel.

In regard AO6 etc... should be about right... but check WOT after 20 or so seconds, it could be starting to lean off,

The OA6 sounds OK in your case. And I've found it works fine with an HS6 on GR's RE7 manifold.
But I've seen 2 motors recently (1360 and1380) running a Minispares manifold and HS6, which needed a KV needle to stop leaning out from 1/2 throttle up.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I'm going to replace my main jet. It's the only thing I can think of. My wideband sensor is about 6 inches back from the firewall...... I might try and raise the idle up and see if it smoothes out ...

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im starting to think the dougyness down low is just the nature of the beast.....

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spot on... its just the way they are, trying to fix that will make a mess everywhere else

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did I tell you that I won a trophy?

With an HS6, try running with NO oil in the dashpot... I've seen this improve low down response on a couple of cars.
BTW this oil does not lube the piston rod, it's purely there for damping (= a proxy accelerator pump) when you open the throttle.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

As for the afr hunting I will just up the idle a bit... Thanks for your imput

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