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BNE (northside) carb setup
binner - March 12th, 2013 at 12:36 PM

well engine is running kinda, is anyone out there willing to help me out setting up a set of 40 IDF's with jet doctors ...got all my timing n such sorted out but be dammed if I can sync or tune these webers.Iit's running and idles ok but I seem to be getting some backfiring thru the muffler (unburnt gas,correct?) when its under load.
I have set timing at around 28 deg @3000 (009 dizzy) points are gapped correctly, no air leaks and everything is new.
Could this also be fuel psi related?

willing to pay in beers or similar.....

Cheers Binner


Sides - March 12th, 2013 at 01:25 PM

What size engine with what size jets & venturi's ??? You sure no exhaust leaks ???

Backfiring often means lean, which suggests you're not at a good starting point with the jets rather than just balance issues.

Once you are at a good starting point, things I'd be doing in order are:
1. Fuel pressure (3.5 psi MAX).
2. Bench set carbs, balance & adjust linkage
3. Timing and point gap
4. Balance while running
5. Idle speed while running
6. Idle mix adjustment while running (lean best idle)
7 Repeat 4 through to 6 until a nice stable idle

Otherwise happy to take a few of those beers in a week or two if you're still having probs !!!


vassy66T1 - March 12th, 2013 at 05:07 PM

Give us engine and carb details i.e. capacity, cam, compression, exhaust (just as an idea what kind of motor it is) and carb details of venturis, idles, mains, emulsions etc.


Bizarre - March 12th, 2013 at 05:38 PM

If it is a "bang" through the exhaust - my guess is rich

A "snap" or "sneeze" out the carbs - indicates lean

Idles I would start with 50's
vents are what they are - assuming you have a 2L or something, I would be expecting 32's
mains - 4.2X the vent = 135's
Airs - 180's
Mixture screws - 3 turns out

have a read here
http://www.aircooled.net/vw-carburetors-jetting-102/ 

and here

http://www.aircooled.net/synchronize-dual-vw-carburetors-103/ 


binner - March 13th, 2013 at 11:40 AM

2027cc
C35 cam
los panchito heads
40 idf webers, rebuilt, floats set as per weber specs
fuel is running at around 3psi
no leaks that i can find

i have installed the CB perf weber upgrade kit which includes the below

34 Venturis
1.80 Air Correction Jets
1.60 Main Jets


thanks for all the responses, I do appreaciate it

Cheers binner


matberry - March 13th, 2013 at 12:09 PM

Ring me whilst your in front off your engine, if you'd like my help Ian.

No probs


vassy66T1 - March 13th, 2013 at 02:59 PM

Idle jets??
Mains seam large to me.
Matt's offer is good:tu:


Bizarre - March 13th, 2013 at 05:11 PM

160 is too large for 34's in my opinion and would be causing the backfire

140 or 145 would be better


Bizarre - March 13th, 2013 at 05:11 PM

Quote:
Originally posted by vassy66T1
Matt's offer is good:tu:


best offer you will get :tu:


Bizarre - March 13th, 2013 at 05:17 PM

does the upgrade kit have a spray bar instead of the normal set up??

cause that mucks things up for opinions on jetting - well it certainly did on my dells
you run a fatter main - so my opinion above may mean jack


binner - March 13th, 2013 at 06:40 PM

Quote:
Originally posted by Bizarre
does the upgrade kit have a spray bar instead of the normal set up??

cause that mucks things up for opinions on jetting - well it certainly did on my dells
you run a fatter main - so my opinion above may mean jack


spray bar and they supply you with new jets to fit, I put these in the last set of webers I rebuilt (40 IDFs) on a 1641 engine and they were fine. I was running this with electronic ignition and standard coil too.

**N E W S F L A S H**

I may be getting somewhere, the points (brand new) are already pitted after only running for about 1.5 hrs in total. I replaced them with new ones and it ran sweet for about 10/15 mins then started backfiring so I took out the points and BAM pitted to high hell.
I'm running a mallory MSD blaster 2 with a ballast resistor and standard 009 points dizzy. Maybe this is not the setup to use with standard points, anyone?

zapzap


binner - March 13th, 2013 at 06:42 PM

Quote:
Originally posted by matberry
Ring me whilst your in front off your engine, if you'd like my help Ian.

No probs


thanks fella, I'll keep persisting until I'm spent :fakesniff: then will give you a call when I'm knackered. :lol:


matberry - March 13th, 2013 at 07:18 PM

No worries, sounds like it could be rich with the 160's if it's not ignition


binner - March 16th, 2013 at 06:05 PM

ok, so I swapped the coil for a 3 ohm standard coil and B A M ! it runs perky!!!!! (yeah I'm a crack head) I bought all this gear so long ago I can't remember whats what, so I just went ahead and shoved in the master blaster coil for electronic ig only which I was going to purchase but instead for some dumb reason I bought a points dizzy and just installed it without thinking and hence it was running like shit!!!.
So all I need now is to actually sync the carbs and I'm there. Been tearing round the neighbour hood all arvo and its running nice, just fine tuning now.

also had TACH BOUNCE so I installed a 1 amp diode inline and now it reads fuggin perfect!!! i likr it when things work :smilegrin:

Thanks for all the replies and I'm just glad it's almost ready for rego :D


tar76 - March 16th, 2013 at 06:10 PM

Nice man!


h - March 16th, 2013 at 06:50 PM

good to hear mate :tu:

n matt your mood script is gay.. xxx


binner - March 19th, 2013 at 08:05 AM

ok ,so now a step further...pulled out the EMPI fuel pump (noisy) and bought one of these http://www.fuelflow.co.nz/FF_cms_03/eshop?page=shop.product_details&flypa... and one of these http://www.ebay.com.au/itm/Mallory-Ignition-4309-Aluminum-Fuel-Pressure-Regul...

3 year warranty, super quiet pump, mallory reg with bypass getting bang on 3.5 psi and able to adjust up to around 4 if needed. So after all that it finally runs nice and now just gotta get some help on the fine tuning and synching. Is it really worth buying a snail sync to tune or is a piece of pipe and good ears just as good?

cheers Binner


matberry - March 19th, 2013 at 08:10 AM

i don't ecommend a snail, thee is usually no gasket between the elocity stack and ai-ilte bottom plate so it is meaningless imO. Just get each cylinde esponding the same to idle mixtue adjustment and you'll be in sync.


binner - March 21st, 2013 at 12:35 PM

Quote:
Originally posted by matberry
i don't ecommend a snail, thee is usually no gasket between the elocity stack and ai-ilte bottom plate so it is meaningless imO. Just get each cylinde esponding the same to idle mixtue adjustment and you'll be in sync.


i figured they would be a bit of a waste, I kinda trust my ears more but I am going a bit tone deaf so we will see :lol:

So I am right in saying that I am bringing the highest down to the lowest, is this correct?
Is this sequence correct?

1> throttle linkages off
2a > idle screw just touching then dialed in 1 turn
b> mix screws dialled in to just touching then turned out 2.5 turns
3> set at static timing and adjust barrels with 12.5 mm hose pipe n tone deaf ear (car running obviously)
4> reattach linkages and make sure they move in synch
5> set 009 30-32 BTDC @3500 REVS
6> let it fall to wherever and note BTDC @ idle 900+/- REVS
7> fine tune timing on the road
8> pour a Sailor Jerry and sit back thinking about how much money has been spent on the project :crazy:


Just fitted electronic ignition too so lets see how that goes.....


matberry - March 21st, 2013 at 02:54 PM

^^ yep, my version

2a. 1/2 turn on idle stop screw
b. 1 3/4 turn for the mixture
3 adjust carbs using mixture screws to also help with balance, as you said, screw that makes most difference down idle speed or up other carb depending on where the speed is at first.
8 Bundy not SJ


binner - March 21st, 2013 at 07:26 PM

Quote:
Originally posted by matberry
^^ yep, my version

2a. 1/2 turn on idle stop screw
b. 1 3/4 turn for the mixture
3 adjust carbs using mixture screws to also help with balance, as you said, screw that makes most difference down idle speed or up other carb depending on where the speed is at first.
8 Bundy not SJ


unkzzzz maaate... im on it this weekend, I may just make it to Al's open day.....:cool: