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Wed Sep 17, 2008 6:16 am

with it being in the upper 50's to low 60's this morning i went out and started the bus to let her warm up. it sputtered a little then the idle finally sped up so i went inside. when i went out to leave i heard a strange popping noise coming from the exhaust. almost as if it was a slight backfire. i have new boots, new carb gaskets, new intake gaskets. there are no vacuum leaks, when i put my hand over the carb it tries to suck my hand off.

i know it has established that my bus is running a tad rich. could this be a combination of no humidity, cold temps, running rich and fuel burning off in the glasspack? it never did this when i had the stinger on it, nor did it do it with the glasspack on it in warmer temps.

here is the video i took with the ol' camera phone, not the best quality but you can here the pop pretty good.

oh yea, and incase you can't tell in the video, it's a 1600dp with a webber progressive carb, merged header and a glasspack. nothing to special

http://www.youtube.com/watch?v=LqMp5C319Mk

also, how in the heck do you embed video on the samba?

Wed Sep 17, 2008 6:27 am

see the little buttons above where you post a message? use the YouTube and /YouTube tags before and after the link.

when my bus starts getting that 'harley' popping sound, i reckon im way beyond time for a tune up. adjust valves and timing. valve adjustment can make a world of difference.

Wed Sep 17, 2008 7:58 am

It is more likely due to the fact that the heat risers are inoperative even though they are needed with the center mounted carb. The heat risers have to be there to keep the air: gas mixture in a "vapor state" as opposed to a "liquid" when it gets to the cylinder.

I am surprised the bottom of the carb is not icing up. It may be.

Wed Sep 17, 2008 8:05 am

Randy in Maine wrote: It is more likely due to the fact that the heat risers are inoperative even though they are needed with the center mounted carb. The heat risers have to be there to keep the air: gas mixture in a "vapor state" as opposed to a "liquid" when it gets to the cylinder.

I am surprised the bottom of the carb is not icing up. It may be.

the heat risers work fine...trust me, i burnt my self on them the other day.

my merged has the mounts for the risers so they are used.

one thing that was suggested by a friend of mine is the jetting is to fat. i have a 160/165 so i am getting a 145, 150 and 155 to try and see if i can lean it out enough to stop the popping.

and per the recommendation of the other guy that posted on here i will check my valves tonight, although they should be good since i adjusted them about 1k ago. if they are not you will see the post of "i'm about to drop a valve what do i do" :wink:

Wed Sep 17, 2008 11:49 am

Didn't sound that bad. Matter fact it sounded pretty good.

Wed Sep 17, 2008 12:59 pm

... it is poppin' alright. It is either ignition or valve train related. I would suggest a valve adjustment, you may likely find a tight intake valve.

Spark plugs, wires, cap or rotor could cause this pop.