Home  |  Forums  |  914 Info  |  Blogs
 
914World.com - The fastest growing online 914 community!
 
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG. This site is not affiliated with Porsche in any way.
Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners.
 

Welcome Guest ( Log In | Register )

> any tips for tuning weber 34ict?
JOE M
post Aug 28 2009, 03:49 PM
Post #1


Member
**

Group: Members
Posts: 293
Joined: 27-August 07
From: N.H
Member No.: 8,042
Region Association: None



Curious about how to set the carbs up.The timing is close but may be out slightly.I started by turning the air mixture screws all the way in and than backing both off by 2 1/2 turns to start. I let the car idle and than I move 1 side until the car runs rough than back off the other way about 1/2 turn.I did the same for the other side. It runs ok but pops through the exhaust every now and than.It gets better when I take the throtle linkage off.I think my biggest problem is seting the idle speed screw. Is there something I should do prior to starting any other alignment?I read the procedure but I am stumped. What typically causes it to pop through the exhaust?I did check the vacum on both sides and they are real close ( within 1 of each other).
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
 
Reply to this topicStart new topic
Replies
aircooledtechguy
post Aug 28 2009, 05:38 PM
Post #2


The Aircooledtech Guy
***

Group: Members
Posts: 1,966
Joined: 8-November 08
From: Anacortes, WA
Member No.: 9,730
Region Association: Pacific Northwest



Here's how I sync duals. . .

First ensure all your linkage is connected and symmetrical (cross bar type linkage) you want your drop links to be as close to straight up and down as possible as well as even between the left and right side. If one is at a severe angle compared to the other, you will have problems because one carb will always lag or lead the other later.

Then, with engine running, disconnect one of the linkage arms so that the carbs are totally separate and sync the air flow through them with a syncrometer.

Then reconnect the linkage arm and tighten it into place. I find it better to do this with the engine idling so I can hear changes as I connect the link. Re check with a syncrometer to ensure they are still even at idle and exactly where they were before the linkage was attached. If anything has changed, adjust the linkage arm to get it even again at idle.

Then put your finger on one carb throttle arm and closely watch the other while you gently blip the throttle with the other hand where the cable attached (that is really important because if you use another part of the linkage to blip the throttle, it could be twisting and flexing the linkage in a way that it does not normally flex while driving). See/feel that both arms are beginning to move at the EXACT same time. This will ensure that you have a smooth throttle response off idle.

Next with the engine OFF, ensure that at WOT both throttle arm hit their stops at the same time. If they don't, the Geometry of your linkage arms is off and you will need to re-adjust things so that they can both get to WOT at the same time AND idle at the same time.

Once you have the linkage perfect, then you can move to the mixture screw fine tuning. I prefer to do this with my eyes closed so that I can concentrate on the engine speed better, but that's just me (IMG:style_emoticons/default/smile.gif)

Hope this helps. . .
User is offlineProfile CardPM
Go to the top of the page
+Quote Post

Posts in this topic
JOE M   any tips for tuning weber 34ict?   Aug 28 2009, 03:49 PM
JOE M   By the way it seems to smoke through the breather....   Aug 28 2009, 03:52 PM
neil30076   By the way it seems to smoke through the breather...   Aug 28 2009, 04:20 PM
jmill   What typically causes it to pop through the exhau...   Aug 28 2009, 04:03 PM
McMark   Make sure to sync the airflow for the left/right c...   Aug 28 2009, 05:01 PM
JOE M   Make sure to sync the airflow for the left/right ...   Aug 28 2009, 06:25 PM
aircooledtechguy   Here's how I sync duals. . . First ensure al...   Aug 28 2009, 05:38 PM
McMark   I think this is a slightly improper description,...   Aug 28 2009, 06:43 PM
JOE M   I think this is a slightly improper description...   Aug 28 2009, 06:52 PM
aircooledtechguy   I think this is a slightly improper description, ...   Aug 29 2009, 10:14 AM
JOE M   [quote name='McMark' post='1208515' date='Aug 28 ...   Aug 29 2009, 10:31 AM
904svo   Try this. Just had a crazy problem an this fix ...   Aug 28 2009, 07:11 PM
JOE M   Try this. Just had a crazy problem an this fix...   Aug 28 2009, 07:46 PM
904svo   Try this. Just had a crazy problem an this fi...   Aug 28 2009, 11:18 PM
JOE M   [quote name='JOE M' post='1208536' date='Aug 28 2...   Aug 29 2009, 08:24 AM
904svo   [quote name='JOE M' post='1208536' date='Aug 28 ...   Aug 29 2009, 08:35 AM
McMark   Jake Raby sells a breather box. Chris Foley sells ...   Aug 28 2009, 07:32 PM
McMark   The exhaust can seem tight and still have a leak. ...   Aug 28 2009, 07:38 PM
McMark   The port with thr red cap should NOT be used for v...   Aug 28 2009, 09:40 PM
r_towle   if you exhaust is leaking, get a small 2*4 and hol...   Aug 28 2009, 10:53 PM
JOE M   Easy enough--how about for the vacum advance. Shou...   Aug 29 2009, 08:44 AM
McMark   Yup. VW did it with their dual single throat Sole...   Aug 29 2009, 11:11 AM
McMark   Oh, just remember to pull the balance tube and plu...   Aug 29 2009, 11:27 AM
hi4head   I installed a set of the Weber 34 ICT's last y...   Aug 30 2009, 08:48 PM
JOE M   I installed a set of the Weber 34 ICT's last ...   Aug 31 2009, 11:12 AM
McMark   You don't want to T your vacuum lines to atmos...   Aug 31 2009, 01:38 PM
r_towle   Two type of vacuum ports bud. the manifold vacuum ...   Aug 31 2009, 05:02 PM
hi4head   Joe, Rich is right on with his comments. If it he...   Sep 1 2009, 07:39 PM
jcd914   Finally, I have a short length of hose connected ...   Sep 2 2009, 01:43 PM
JOE M   Thanks for all your help. I installed all the conn...   Sep 2 2009, 05:02 AM
r_towle   Flip the carbs side for side and flip the linkage ...   Sep 2 2009, 06:59 AM
JOE M   Flip the carbs side for side and flip the linkage...   Sep 2 2009, 11:08 AM
r_towle   You can get what you have to work fine...really. I...   Sep 2 2009, 12:33 PM
hi4head   Joe, Sorry if this is hijacking your thread a litt...   Sep 3 2009, 06:55 PM
JOE M   Joe, Sorry if this is hijacking your thread a lit...   Sep 4 2009, 07:21 AM


Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



- Lo-Fi Version Time is now: 11th July 2025 - 04:14 PM