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> can somebody give me a crash course on carbs
bd1308
post Jun 28 2005, 07:04 PM
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Just some pointers, and how to adjust different stuffs. I dont know which carbs are being installed, just that some are and it will be ready by friday.
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IronHillRestorations
post Jul 5 2005, 12:13 PM
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ummmmm, back on topic anyone?? Now that's a thought (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif)

Here's the post I made back in Sept of last year when Trekkor was having carb tuning problems, now he's a carb GURU!!!

Also note these instructions were for the 3 barrel Webers, so you'll have to adapt & survive.



Assumptions: the carbs have the optimum jet and venturi package (good luck on this one), the float level in the carbs is correct, the cams are correctly timed, the valves are properly adjusted, the ignition timing is dead on, you have the proper spark plugs for your engine, the linkage is good, the fuel is good, the engine is good.

Remember that the mixture and air bypass adjustment screws are precision needle valves, not head gaskets. Use your fingers to tighten them, not your fist.
Start and warm up the engine.
Make sure the two drop links for the throttle linkage are exactly the same length, and disconnected. You can use a 8mm thin igntion wrench to snap them off.
Turn the mixture screws all the way in and then 5 half turns out.
Turn the air bypass screws all the way in.
Turn the idle speed screws out til it just touches, and then in 5 half turns.
Put on your hearing protection and start the car.
Use your STE and find the barrel that pulls the most. We'll call this one baseline.
Balance the barrel in the other carb that pulls the most with the idle speed screw. (if you have a Uni-syn, give it to someone you don't like and purchase a STE airflow meter)
Go back to the other carb, with the baseline barrel. You will have one all the way in, then use the air bypass screws and balance the other two barrels.
Go to the other carb and do the same thing.
Snug the jamb nuts on the air bypass screws.
All six barrels should pull the same amount of air at this point, if not repeat air adjustment proceedure.
Snap the throttle linkage drop links back on the carbs. If the idle changes then you need to barely adjust the linkage mounts so snapping the drop links on, doesn't change the side to side idle balance.
Use the hand throttle or a vice grip and rag to lock the linkage between 1400 and 1800 rpm.
Start back at the baseline barrel and adjust the mixture screw in or out, to get the smoothest running and highest idle, then turn it in 1/4 turn.
Do the same with the five other mixture screws.
If you have to turn the mixture screws more than two turns either way, you've got the wrong jets.
Recheck side to side and individual air balance, adjust as needed.
Road test the car.
If you get snapping and poping out the intake, it's generally a lean condition.
If you get heavy exhaust fumes, or pboofing out the exhaust it's probably too rich.
If you get a flat spot or popping out the intake at between 2800 and 3200 rpm, you probably need larger idle jets.

That's a rough, five minute draft of my carb tuning proceedure, hope it helps!

If it goes good it should take about 45 minutes, if not about three years.

PK (IMG:http://www.914world.com/bbs2/html/emoticons/cool.gif)
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bd1308   can somebody give me a crash course on carbs   Jun 28 2005, 07:04 PM
firstknight13   http://www.914world.com/bbs2/...   Jun 28 2005, 07:27 PM
bd1308   will the whatyamacallits stay put when adjusted......   Jun 28 2005, 07:30 PM
Rouser   School Up; all installs are different, few standar...   Jun 28 2005, 07:34 PM
bd1308   http://www.914world.com/bbs2/ht...   Jun 28 2005, 07:37 PM
Mueller     Jun 28 2005, 07:41 PM
bd1308   no double checks....what about a CO2 reading....of...   Jun 28 2005, 07:43 PM
J P Stein   Go watch an expert tune the carbs & have him expla...   Jun 28 2005, 07:45 PM
Rouser     Jun 28 2005, 08:19 PM
flesburg   My opinion, which is worth not much! Do not d...   Jun 28 2005, 08:23 PM
bd1308   well it is a reversible process....so I could go b...   Jun 28 2005, 08:27 PM
Rouser     Jun 28 2005, 08:35 PM
bd1308   it's easier said than done. this is my D.D.......   Jun 28 2005, 08:39 PM
grasshopper   I agree with flesburg, If you need to do it now, i...   Jun 28 2005, 08:41 PM
Rouser     Jun 28 2005, 08:43 PM
tat2dphreak   tuning carbs is a lost art, FI is much more a scie...   Jun 28 2005, 08:45 PM
bd1308   yeah but these arent gonna be brand new webers.......   Jun 28 2005, 08:49 PM
Aaron Cox   dude... Carbs on a FI cam suck..... dont half ass...   Jun 28 2005, 08:50 PM
bd1308   if ya know latin (or lets say italian to be more a...   Jun 28 2005, 08:52 PM
bd1308   this guy surprises me all the time. For all i know...   Jun 28 2005, 08:53 PM
Rouser     Jun 28 2005, 08:57 PM
tat2dphreak     Jun 28 2005, 09:01 PM
bd1308   http://www.914world.com/bbs2/htm...   Jun 28 2005, 09:07 PM
MattR     Jun 28 2005, 09:21 PM
bd1308   it's definately NOT single carb setup...it...   Jun 28 2005, 09:28 PM
Rand     Jun 28 2005, 09:35 PM
Gint   You are soooooo screwed... Take the money you...   Jun 28 2005, 10:05 PM
bd1308   i know....but when its all said and done and i die...   Jun 28 2005, 10:10 PM
Rand   ...and a girl from the sandbox.   Jun 29 2005, 06:19 AM
Pugbug   I don't understand why you guys are so anti ca...   Jun 29 2005, 07:20 AM
Joe Ricard     Jul 4 2005, 07:14 PM
trekkor   Scotty, go easy... http://www.9...   Jul 4 2005, 07:25 PM
nebreitling   i don't know what bowlsby charges for a harnes...   Jul 4 2005, 09:53 PM
bd1308     Jul 4 2005, 10:10 PM
trekkor   No flames here. Remember the goal is to enjoy dri...   Jul 4 2005, 10:17 PM
bd1308   i dont know any better than what i have....and HOL...   Jul 4 2005, 10:23 PM
nebreitling   good deal. not driving your car sucks. glad it...   Jul 4 2005, 11:07 PM
dwillouby   Britt, Good luck with the carb setup. Best to be...   Jul 5 2005, 05:53 AM
bd1308   that 350 setup looked wild. And you even kept the ...   Jul 5 2005, 06:49 AM
tat2dphreak   http://www.914world.com/bbs2/...   Jul 5 2005, 08:02 AM
Joe Ricard   Britt are you still planning on coming down here f...   Jul 5 2005, 09:32 AM
bd1308   joe i'm up to it. I have to find a day when i ...   Jul 5 2005, 10:30 AM
dwillouby   I might be able to scare you in my car. I could sc...   Jul 5 2005, 11:35 AM
bd1308   http://www.914world.com/bbs2/ht...   Jul 5 2005, 11:58 AM
bd1308     Jul 5 2005, 12:06 PM
Joe Ricard   pboofing out the exhaust Is that a technical term...   Jul 5 2005, 01:24 PM
bd1308  

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