DRLA 45 backfiring out of carb and exhaust (SOLVED)

[txoval]

What idle jets are you running? Maybe you have done so since the start, but if you haven’t sync’d the carbs yet, that needs to be done...remove the linkage and sync at idle first.

[74 Thing]

If you have the timing set up correctly now then do what Phil said above synch the damn carbs without the linkage then with the linkage hooked up.

And change the damn oil and filter you have to get the break in crap out!

[evanfrucht]

alright I changed that damn oil and the frickin' filter. Checked valves for the fifth time too.

I've only run it for maybe hour total at this point

Right in the middle of various diagnostics... then starter died on me.... oh, the suspense.

What I'm starting to think now is that I have some kind of blockage in my idle jet circuit on only the 1/2 carb (could be stuck soda somewhere from when I blasted them) that is atleast my theory at this point. I cam to this conclusion becuase when I spray carb cleaner into the 1/2 carb it seems to increase idle speed and fix the backfiring upon acceleration into the mid to lower rpms. However when I spray carb cleaner into the 3/4 side the idle will actually slow down.
_________________
1967 Bug ( the daily rod )
1964 Fury Wagon ( the pavement shredder )

[evanfrucht]

[evanfrucht]

[jpaull]

After the cam break in the engine should go directly in the car asap to put a load on it. Your sharpest cross hatch is going away fast as you try to dial in your engine on the stand. How fast you put a load on it sets the tone for how good those rings will ever seal.

[evanfrucht]

[74 Thing]

It should be easy to clean out the idle circuit if the carbs are on a stand. Circuit means from the idle air hole to the idle jet to the flow path to the mixture screw to out the progression ports. Carb cleaner and air are your friends.

[Ohio Tom]

This sounds simple enough to me..
Your idle mixture screws need to be adjusted.

Popping at idle is a sure sign they are set too lean.
Open up the screw on the offending cyliders a fuzz until the popping is gone.
Done...

That's what they are for...

[evanfrucht]

[74 Thing]

You may have an intake leak on the 1/2 side if it is happening to both barrels when you spray down it speeds up.

[Ohio Tom]

OK, good info.
Already at 4 turns out (with Dellorto is getting close to maximum).

Either you have a plugged idle jet, or a vacuum leak.

That's a great way to diagnose where your issues are.

I sometimes do the "hand choke" trick.
Just cover the stack with your hand for a quick second. If she picks up and runs for a few seconds, you know it's lean...

[FreeBug]

[evanfrucht]

[Wreck]

If you can remove the progression cover screw and squirt carby cleaner down the passage from the idle jet and make sure it’s clear .
I had similar issues with a pair of 48 DRLA’s , When I first got the engine running ,one cylinder needed the mixture screw out a lot further , like twice as far . I cleaned and cleaned . Checked for air leaks , compression tests showed even compression . It ran like that for a while , then what ever was restricting it cleared itself and now the mixture screws are reasonably even .
Never did work out what or why , one of life’s mysteries!

[mark tucker]

Ive never seen or heard of a billet 09. dist. what a waste of$$.and aluminum. I was refering to the 09...bosch.germany. and since you swaped side with the crabs you know witch crab isant working right so,,, FIX IT , OR SEND TO SOMEBODY WHO CAN OR REPLACE IT.

[txoval]

2000-2500 is still the idle circuit.

65 idles seems large for your engine (could be wrong), which seems to indicate an idle circuit clog issue as most are pointing too

[evanfrucht]

[modok]

I think it helps to understand where the fuel goes. And check the sizes of all the holes. I don't actually know the size of the little feed hole in the side of the main well, but it's probably somewhere around 1mm. Not much you can do for that one. Hook a piece of mig wire into it and wiggle. The main well itself should be 8mm. Progression port sizes are known, and where the idle needle seats is a calibrated hole too. And there are lots of places for air leaks also at the plugs, at the o-rings.

[FreeBug]