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Posted by: ! Oct 11 2004, 11:04 AM

My triple throat Webers on Franky sneeze and cough while at mid range cruise speed. They sound fine at idle and WOT.....

Any ideas?

Posted by: Lawrence Oct 11 2004, 11:05 AM

Allergies?

Posted by: Toast Oct 11 2004, 11:05 AM

Is one of your venturies clogged or got fine dust in it?
Just a thought.

Posted by: ! Oct 11 2004, 11:06 AM

Nah...Frank's had all his shots.... :finger2:

Posted by: SLITS Oct 11 2004, 11:08 AM

Oh, pharts at midrange just like you - one of the family.

Posted by: Toast Oct 11 2004, 11:10 AM

Damit Slits! Dont encourage him to post of picture of his ass.

Posted by: Aaron Cox Oct 11 2004, 11:12 AM

are they sync'd perfect left to right? mains to small/large?

Posted by: J P Stein Oct 11 2004, 11:30 AM

Sure, lots of em'.

If by mid range you mean 2500-3500 rpms, you're still on the idle circuit or transitioning to the main circuit.....a typical problem for Webers. The "cure" (assuming all else is right) is to richen the idle circuit. Then you're over rich and have other problems which you then have to cure.....which is doable.

All this is pretty general cause you were pretty general with your discription....no details like ignition system, cams, jet sizes, motor size......how the carbs were tuned....float level checks, balancing (the biggest single item that is screwed up...IMO).

Anyone that has a good running 9eleben motor with Webers has gone thru this or hired it done.
Long distance tuning is a bitch.

Posted by: HarveyH Oct 11 2004, 11:39 AM

Remember, the idle jets control your mixture from just off-idle to 3000 - 3500 RPM. The idle mixture screws adjust the mixture only at static idle, so you can get a decent static idle mixture and still have jets that are too rich or lean for low and mid-range running. Of course since the main jets tend to control the range from about 2800 RPM up, (notice the overlap) changing the idle jets may make it necessary to change your mains. Air correction jets further modify the fuel delivery curve from about 4000 RPM and up, and emulsion tubes are some mystical force of nature that do magic.
I need a beer
Harvey

Posted by: Toast Oct 11 2004, 11:45 AM

with HarveyH

Posted by: J P Stein Oct 11 2004, 11:49 AM

As I suspected, he's also posted this Q on the 9eleben birdboard......and hasn't collected so much BS

Posted by: HarveyH Oct 11 2004, 01:44 PM

When it comes to 914's, we know our BS
Harvey

Posted by: givory Oct 11 2004, 05:25 PM

Mike - I had a similar problem with my 40 IDA's. I was pushing fuel through a dirty filter, clogging one or two idle jets regularly. Seemed to go weak just where the idle jets handed-off to the mains. A shot of compressed air worked for me.
Gavin

Posted by: ! Oct 11 2004, 09:28 PM

Thanks givory....

BTW, JP...no answers either....at least any worth a shit.