Topic: Popping on decceleration

[kach_me]

Anyone have any idea why I'm popping on decceleration?  I've been riding this way for a couple of years, but seems to be getting slightly worse.  OR it's starting to get on my nerves a bit...

I'm wondering if my exhaust needs new seals or if there is something else that may cause this... Any thoughts? 

thank you,
Shannon *pop pop pop* 

[Wayne Meuir]

Check your timing.  If the timing is good, its probably a little lean on the slow speed circuits in the carbs.

Wayne

[mattcb350f]

Now I thought popping was because of a rich condition 

.....Hmmmmmm [scratching head]

 Matt.

[Johnie]

So is that adjusted by the air screws? 

[kach_me]

Damn...  You guys are full of questions for my question!  *pop*


                  *pop*

                                                     *pop*

[mattcb350f]

So is that adjusted by the air screws? 

Yeah, or by changing the slow speed jetting.

Remember, if they're air screws than turning them out will lean and turning them in will richen.

If they're mixture screws, than the opposite will occur.

If I remember right from one of TwoTired's carb sermons, mixture screws are located in front of the slides (closer to the engine) and air screws are behind (closer to airbox) on the carb.

My 350f has air screws, not sure about the other SOHC/4's  

 Matt.

[TwoTired]

Check timing is a good idea, especially if its tuneup time, (every 3000 miles).

Air ingress from leaky exhaust gaskets.
And a lean condition.  So lean on decell, that you get a misfire, push all the charge into the exhaust, and the next firing hot exhaust lights off the charge in the exhaust.

Would have been nice to know if the bike in question was stock or had any modifications from stock.  But, then I guess accurate responses aren't really wanted.

Cheers,

[mattcb350f]

So lean on decell, that you get a misfire, push all the charge into the exhaust, and the next firing hot exhaust lights off the charge in the exhaust.

Noted. Thanks TT 

......I now think I'm a little lean too 

 Matt.

[kach_me]

Check timing is a good idea, especially if its tuneup time, (every 3000 miles).

Air ingress from leaky exhaust gaskets.
And a lean condition.  So lean on decell, that you get a misfire, push all the charge into the exhaust, and the next firing hot exhaust lights off the charge in the exhaust.

Would have been nice to know if the bike in question was stock or had any modifications from stock.  But, then I guess accurate responses aren't really wanted.

Cheers,

Damn, no need to get testy! Are you sure you're not tired AND grouchy?   

Of course I want accurate info... but I live with three women (well one woman and two girls) and I am expected to read minds, aren't you?  Just assumed you'd know what I meant... OH GOD! I sound like them! help! please help?!

Seriously, Sorry I left out the pertinent info... Stock '76 750 complete with airbox not pods.  No major mods at all.  Tune up done last spring new wires, new plugs.  Been popping since I've had the bike approx. 2 years. 

[kach_me]

Little update...

Took a nice long ride yesterday.  200+ miles with 1/2 being at highway speeds 65mph to 85mph.  Popping seems to have improved a bit.  Is it possible that I have build up somewhere?  Or dirty carbs?  Whatever it is, it seems to have improved quite a bit with the long ride. 

Side note:  Had a guy on a big Suzuki try to catch me  .  That was quite fun. 

[scondon]

 The popping will usually improve the hotter the engine gets. Popping on decel? lean condition as stated earlier. Air leaks at the intake rubbers and/or exhaust must be ruled out first before changing air mixture settings. Air mixture starting point is 1 turn out on each carb, I believe. Adjust each air screw,one at a time, with engine running for highest idle(this can take patience and a trained ear). Turn air screw in 1/8 turn from highest idle(tad richer) and your popping should disappear.

    Often times it is just one carb that either has gunk in the idle circuit/pilot jet or has leaky mixture screw port due to worn o-ring or over tightening of mixture screw when seating before turning out. Do not be surprised if one or more carb mixture screws end up adjusting a bit different than the others(not even turns out across the bank).

[kghost]

Check timing is a good idea, especially if its tuneup time, (every 3000 miles).

Air ingress from leaky exhaust gaskets.
And a lean condition.  So lean on decell, that you get a misfire, push all the charge into the exhaust, and the next firing hot exhaust lights off the charge in the exhaust.

Would have been nice to know if the bike in question was stock or had any modifications from stock.  But, then I guess accurate responses aren't really wanted.

Cheers,

Damn, no need to get testy! Are you sure you're not tired AND grouchy?   

Of course I want accurate info... but I live with three women (well one woman and two girls) and I am expected to read minds, aren't you?  Just assumed you'd know what I meant... OH GOD! I sound like them! help! please help?!

Seriously, Sorry I left out the pertinent info... Stock '76 750 complete with airbox not pods.  No major mods at all.  Tune up done last spring new wires, new plugs.  Been popping since I've had the bike approx. 2 years. 

Dude...

If you want accurate, solid, dependable information...Ask Lloyd.

Just don't get your pantys in a bunch when he spanks ya because you gave him nothing to work with.

Get the idea?

[Spikeybike]

Dude...

If you want accurate, solid, dependable information...Ask Lloyd.

Just don't get your pantys in a bunch when he spanks ya because you gave him nothing to work with.

Get the idea?

ain't that the truth ,   he's like the oracle of carbs (think "the matrix") .
if you don't ask the right question, in the right manner. you might not like the answer

TT has gotten all of us out of trouble at some piont, i know for sure he has for me

[kach_me]

Damn fellas... relax... unbunch your own panties... That was my (obviously poor) attempt at self-deprecating humor.  Note the part where I compare myself to the women in my life who expect me to be a mind-reader...

*kicks the dirt* 

Again, thanks for the help.  I appreciate your input and I'll be more specific on my next questions.  *panties are now unbunched* 

[kghost]

Most of us are pretty protective of Lloyd.....

I want him around when I have a question 

[andy750]

I had popping on deacceleration when I switched to 120 main jets on my CB750K2. I checked the plugs and #3 was running a tad rich. I turned #3 airscrew out 1/4 turn and replaced ALL spark plugs with Denso Iridiums.....popping has gone completely. I took it for a 300 mile test ride yesterday to Laconia Bike Week, hitting 90mph in the highway for about 50 -60 miles.

Bike idles smoothly and has great power delivery.

good luck
Andy

[paulages]

Would have been nice to know if the bike in question was stock or had any modifications from stock.  But, then I guess accurate responses aren't really wanted.
Cheers,

Most of us are pretty protective of Lloyd.....

I want him around when I have a question 

few other people could get away with such constant condescension and seldom get flack for it... he's like a grumpy professor whom you're glad you're learning from, but wished he would just be nice every once in a while.

[scondon]

Would have been nice to know if the bike in question was stock or had any modifications from stock.  But, then I guess accurate responses aren't really wanted.
Cheers,

Most of us are pretty protective of Lloyd.....

I want him around when I have a question 

few other people could get away with such constant condescension and seldom get flack for it... he's like a grumpy professor whom you're glad you're learning from, but wished he would just be nice every once in a while.

    If you could put a face to the posts I think you'd find that TT is anything but grumpy, just talks like a typical engineer(retired). Plenty of humorous, light-hearted posts unless it's hashing over the same old stuff with a stubborn newb( and sometimes old-timer).

   Note to TT: next time you school someone use more smiley's