Slight Engine Popping

paslow22 Seriously Crusin Dubber

109 posts · joined Oct 2015 · 1 Dec 2018, 7:32 pm

#1041459

Hi,
When I come off the throttle down a hill for example the engine gives out some slight popping noises.
My idea would be carb mixture settings.

I'm running a 1915, and twin 40mm Empi's.

What do others think????
Thanks.

beetleboyjeff Custom Title Time!

1,790 posts · joined Feb 2009 · 2 Dec 2018, 7:59 am

#1041460

An exhaust leak will often cause that

From your ole' mate Jeff

paslow22 Seriously Crusin Dubber

109 posts · joined Oct 2015 · 2 Dec 2018, 8:41 am

#1041462

beetleboyjeff wrote:An exhaust leak will often cause that

Thanks,
I'm pretty sure there are no leaks but I will double check.

REDKG Officially Full-On Dubber

327 posts · joined Aug 2002 · 2 Dec 2018, 2:12 pm

#1041466

Inlet leak

paslow22 Seriously Crusin Dubber

109 posts · joined Oct 2015 · 2 Dec 2018, 3:57 pm

#1041467

REDKG wrote:Inlet leak

When I changed the manifolds using new gaskets I'm sure I tightened them all up tight, I'll double check.
Hope not, because it's a bugger to get to No.3 nut.

Thanks

vw54 Administrator Always Waiting 4 Friday

16,723 posts · joined Aug 2002 · 2 Dec 2018, 3:58 pm

#1041468

if its popping it is unburnt fuel in yr exhaust I would be checking the jetting

I read it on FACEBOOK so it must be true

http://forums.aussieveedubbers.com/viewtopic.php?tid=91278&page=1#pid848630

http://forums.aussieveedubbers.com/viewtopic.php?tid=63561&page=1#pid624099

http://forums.aussieveedubbers.com/viewtopic.php?tid=4832&page=1#pid452603

http://forums.aussieveedubbers.com/viewtopic.php?tid=60650&page=1#pid574409

paslow22 Seriously Crusin Dubber

109 posts · joined Oct 2015 · 3 Dec 2018, 5:48 pm

#1041473

vw54 wrote:if its popping it is unburnt fuel in yr exhaust I would be checking the jetting

To rich or lean?

vw54 Administrator Always Waiting 4 Friday

16,723 posts · joined Aug 2002 · 4 Dec 2018, 7:55 am

#1041476

I would say rich

You need to have an analyzer up the exhaust

the EMPI carbies are not very good as well.

I read it on FACEBOOK so it must be true

http://forums.aussieveedubbers.com/viewtopic.php?tid=91278&page=1#pid848630

http://forums.aussieveedubbers.com/viewtopic.php?tid=63561&page=1#pid624099

http://forums.aussieveedubbers.com/viewtopic.php?tid=4832&page=1#pid452603

http://forums.aussieveedubbers.com/viewtopic.php?tid=60650&page=1#pid574409

grumble Son of Jim - Creator of Good

2,672 posts · joined Jun 2008 · 4 Dec 2018, 12:27 pm

#1041479

An exhaust system with insufficient back pressure will also cause popping on deceleration, this was fairly common on the extractor systems with the hot dog muffler which would do a couple of pops and then an almighty boom and flame out of the pipe. Very effective at night.

paslow22 Seriously Crusin Dubber

109 posts · joined Oct 2015 · 4 Dec 2018, 7:19 pm

#1041482

vw54 wrote:I would say rich

You need to have an analyzer up the exhaust

the EMPI carbies are not very good as well.

Ok Thanks, The empi's were on the car when purchased.

paslow22 Seriously Crusin Dubber

109 posts · joined Oct 2015 · 4 Dec 2018, 7:23 pm

#1041483

grumble wrote:An exhaust system with insufficient back pressure will also cause popping on deceleration, this was fairly common on the extractor systems with the hot dog muffler which would do a couple of pops and then an almighty boom and flame out of the pipe. Very effective at night.

Car has a Fatboy muffler, maybe the cause?, I guess I have a few things to check up on. Keep me busy anyway.
Thanks,
Darryl

paslow22 Seriously Crusin Dubber

109 posts · joined Oct 2015 · 6 Dec 2018, 8:23 am

#1041490

paslow22 wrote:
grumble wrote:An exhaust system with insufficient back pressure will also cause popping on deceleration, this was fairly common on the extractor systems with the hot dog muffler which would do a couple of pops and then an almighty boom and flame out of the pipe. Very effective at night.
Car has a Fatboy muffler, maybe the cause?, I guess I have a few things to check up on. Keep me busy anyway.
Thanks,
Darryl

Latest, Disconnected all carb linkages and re set carb and air/ mixture and it seems to have solved the popping.

Thanks for all the input.

Darryl