While measuring the air flow on my carbs the motor would want to die when we put the meter on the stack feeding the #1 cylinder. All the others were fine.

Any ideas???

are you using a SynchroMeter? contemporary UniSyn's seem to be junk...

sounds like all the others have their idle air bleeds opened up a lot.

at least one should always be closed all the way - sounds like it's your #1.

can't speculate further without knowing what kind of induction you've got ...

QUOTE (Headrage @ Dec 18 2005, 12:10 PM)

While measuring the air flow on my carbs the motor would want to die when we put the meter on the stack feeding the #1 cylinder. All the others were fine. Any ideas???

when you say air flow, do you mean vacuum?

QUOTE (rogergrubb @ Dec 18 2005, 11:17 AM)

[when you say air flow, do you mean vacuum?

What the carbs are sucking in. All the air flow valves were open around 1/2 - 3/4 turn.

QUOTE (Headrage @ Dec 18 2005, 03:21 PM)

All the air flow valves were open around 1/2 - 3/4 turn.

well, that's just wrong.

one school of thought says there's no real reason to use any of the air bleeds - you're just building in a vacuum leak on purpose. if one cylinder breathes better, so be it...

so step one - close ALL the idle air bleeds and get a Synchrometer.

check for a bent butterfly shaft.

there's a proper sequence for dialing in Webers and MFI (i assume you've got one or the other...) and starting in the middle trying to chase symptoms just leaves you chasing your tail and frustrated.

sounds like a vacuum leak at the vacuum access point.

the only reason i know to have air running past the butterfly is to tone down a radical cam. radical cam = less vacuum. less vacuum =less air/fuel at idle. some guys drill a very small hole or two in their butterflies. i do not suggest you do this.

most likely the butterflies are worn and metering ways gummed up a bit.

are they old/worn carbs?

my last carb was setup that way buy it was old and needed a rebuild. i got a new weber and she runs like a top.

upon furthur inspection ans speaking with the PO, i found air and fuel metering was fine but the butterflies were not sealing very well and PO has jetted up on the transition circuit trying to get it to idle right.

He just traded (yesterday) his 46s for a set of 40 IDA3C on the 2.7 Kotex motor.

Is this the kind of syncrometer to get?

If your ears are good, a rubber hose works too!

You know Allan, being your friend, I can't stand to see you suffer this way.....

So,

Just bring that unreliable, nasty 2.7 down to the shop and I'll swap in a sweet running '73.5 2.4 CIS motor...no leaks, starts and idles smooth, altitude compensation.....

And


I won't charge you anything for the swap....

Killer deal.......................

QUOTE (SLITS @ Dec 18 2005, 12:40 PM)

You know Allan, being your friend, I can't stand to see you suffer this way..... So, Just bring that unreliable, nasty 2.7 down to the shop and I'll swap in a sweet running '73.5 2.4 CIS motor...no leaks, starts and idles smooth, altitude compensation..... And I won't charge you anything for the swap.... Killer deal.......................

When can I come down????

As soon as you can get a trailer....I wouldn't want you to tempt fate with that unreliable 2.7.