 Carb syncing question |
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| Cevan |
 May 13 2010, 05:39 PM
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#1
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Senior Member  Group: Members Posts: 1,079 Joined: 11-December 06 From: Western Massachusetts Member No.: 7,351  |
I'm trying to sync the carbs (Weber IDFs) on my new engine. I warmed it up and then let it idle at about 800 rpms. I disconnected the linkage and used the synchometer. On one carb, both barrels were very close to each other (5 and almost 5), while the other carb read a 5 and a 3. Is this indicative of a bent shaft or some other problem, or can this be adjusted?
I do recall removing the throttle plates from one of the carbs while I was cleaning them. I was going to remove the shaft but decided against it and put the plates back on. Might I have changed the position of one or both of the throttle plates in relation to the bore? Would this cause the problem? Also, fuel seems to be almost weeping in the area of the brass bolt and washer (#5 and 6 in the picture) directly under where the feed line connects to the carb. I used a new washer and tightened the bolt real good. Any ideas?  |
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| 70_914 |
May 13 2010, 07:43 PM
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#2
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Member Group: Members Posts: 395 Joined: 4-December 09 From: Roy, WA Member No.: 11,096 Region Association: Pacific Northwest |
QUOTE(Cevan @ May 13 2010, 04:39 PM)  I'm trying to sync the carbs (Weber IDFs) on my new engine. I warmed it up and then let it idle at about 800 rpms. I disconnected the linkage and used the synchometer. On one carb, both barrels were very close to each other (5 and almost 5), while the other carb read a 5 and a 3. Is this indicative of a bent shaft or some other problem, or can this be adjusted? I do recall removing the throttle plates from one of the carbs while I was cleaning them. I was going to remove the shaft but decided against it and put the plates back on. Might I have changed the position of one or both of the throttle plates in relation to the bore? Would this cause the problem? Also, fuel seems to be almost weeping in the area of the brass bolt and washer (#5 and 6 in the picture) directly under where the feed line connects to the carb. I used a new washer and tightened the bolt real good. Any ideas? 1. There should be an adjustment screw for each venturi that you turn to get the #'s equal, looks like #41 is it. My carbs are Dellortos so I am not sure on the Webbers... 2. Get a new copper sealing washer and heat it with a torch, let it air cool and then put it on. |
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| cgnj |
May 13 2010, 08:00 PM
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#3
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Senior Member Group: Members Posts: 678 Joined: 6-March 03 From: Medford, NJ Member No.: 403 Region Association: None 
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Hi,
Fully seat air bypass screws. Use bypass screws to balance throats one carb. No worries about the number as long as they are the same. Do the same to the other carb. Now use idles screw to make left and right even. Spend the next 3 days noodling with linkage. You're done. Except for the fuel leak. Carlos |
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Posts in this topic
Cevan Carb syncing question May 13 2010, 05:39 PM
9146986 Chris, unfortunately there could be a few other fa... May 13 2010, 06:22 PM
r_towle
Hi,
Fully seat air bypass screws. Use bypass scr... May 13 2010, 08:53 PM jt914-6
I'm trying to sync the carbs (Weber IDFs) on... May 14 2010, 06:39 AM Cevan Perry, I found your writeup. I will go through th... May 13 2010, 07:57 PM 9146986 Yes, there should be a gasket at the velocity stac... May 14 2010, 05:29 AM Vacca Rabite :agree:
#48 is air bypass. Loosens the lock nut a... May 14 2010, 06:57 AM jmill Sounds like a vaccum leak or a plugged idle jet. ... May 14 2010, 07:34 AM jmill :stooges: Double post. May 14 2010, 07:36 AM ME733 ......AFTER removing the throttle plates.."on... May 14 2010, 03:51 PM Cevan I recall putting the plates back on the way they c... May 14 2010, 08:22 PM ME733
I recall putting the plates back on the way they ... May 15 2010, 05:52 PM |
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