Running issue

[69 panel porn]

Ive had a running problem for a while now and still struggling to get to the bottom of it and it's seems to be taking all my time and still not getting any where
Here we go

I have a 1641 with twin 40 drla carbs with electric ignition

Last summer I drove my van as much as possible and it was mint then just a couple of weeks befor I wanted to put it away it started to miss and fart abit then every so often it would back fire, thought it was timing so I took it off the road and started to investigate
I had it timed up and still no better
Changed the dizzy no better
Changed the ht leads no better
New rota arm and dizzy cap no better
Changed the spark plug
Changed the coil
So though it was fuelling problem so
Flushed the fuel tank and changed the fuel lines and changed the filter no better
Changed the fuel pump no better
Took the carbs off and rebuilt them 1 of the jets was clogged up so cleaned it all up no better
Checked valve clearances no better

So had a week off to think and try and find so things out and came back to it and it wouldn't start turned over but never fired but today it fired up sounded abit better but still lumpy as
1 of the old boys at my unit was there as he use to race beetles had a look and he seems to think the rod that connects my carbs together is all out he said it's opening 1 set of the carbs befor the other and this is why is farting and banging does this sound like it could be or could it be something worse any help please :?: :?: :?:
Thanks sam

 

[dubs and classics]

It will run like a bag of cak if one carb is opening before the other..it certainly needs sorting before you go any further.

Not sure what linkage you have but the principle is the same for all of them really, slacken the lock nuts on the rods and adjust them so that they both start to move at the same time...then make sure they both reach full throttle at the same time. if they open at the same time but don't reach full throttle together you need to see why, check for bent rods or arms on the hex bar at different angles (CB Performance type set ups), or slop in the joints.....most of the time though its just the drop arms have adjusted themselves because the lock nuts where not tight...

 

[montypsx]

HI pal i had same problem bus would miss and pop a little but generally run ok then my mate the aa man said do a compression test i did and i was down on 1 pot so found out it was valves i reground them all and it was brill :mrgreen: . but the thing that amaized me the most was the increase of power :shock: . try doing a compression test see what happen's. cheers phil