Poppin and Snappin

[SpiritofNY]

Ok, here goes nothing. Please keep in mind that this is coming from a total newbie who couldnt change the oil on his lowered Spirit wihout a trip to get Band Aids!

I've had my wheels for 1 1/2 months now and I notice that my bike is popping and backfiring more frequently now on decel. When I first got the bike it wasnt as much. The bike has 2" Cobra slashcuts but i dont know if it has been jetted. I recently changed the plugs and air filter, could this have something to do with it? Can I ride like this without hurting the engine, i really dont want to lay her up in a shop, at least until the first snowfall!

Thanks,

All thumbs in NY!

[navillustoo]

SoNY,
The popping can occur whether the carbs were rejetted or not. If the idle mixture screws are not adjusted properly,(and it sounds as though they are not) the Air/Fuel mixture at idle will be lean and the engine will pop on deceleration. You will not be hurting anything when the engine is popping, but if you are running the engine lean, you are not doing it any favors!
To just get rid of the decel. popping, you only have to adjust the mixture screws out a bit. If the plugs covering the screws have not been drilled out, it's very likely the carbs have not been rejetted. If they have been drilled out, you can make the adjustments easily. But, this does NOT mean that the carbs have been rejetted. Many people will drill out the plugs to richen up the idle circuit, but won't do the rejet for various reasons.
Once the weather won't permit you to ride anymore, it'd be best to determine if the carbs have been rejetted or not, and if not, git 'er done!

Brian

[rickbb]

This happened to me on my 96 1100, turns out it was no back pressure on the exhaust. (Bubs Big Willys).

The rear cylinder exhaust had cracked where it bolts to the engine, wielded it up and the pops and backfires on deceleration went away. Not to mention made it a lot quieter.

Rick

[hotrod10]

My bike pops on decel also I had it re jetted and have vance hines pipes do I turn screw in or out to enrich?

[Paradox]

This happened to me on my 96 1100, turns out it was no back pressure on the exhaust. (Bubs Big Willys).

The rear cylinder exhaust had cracked where it bolts to the engine, wielded it up and the pops and backfires on deceleration went away. Not to mention made it a lot quieter.

Rick

That's a different issue noob, if you have a exhaust leak it will draw in enough oxygen to reignite the exhaust and cause popping.

Sheish! noob's leading noobs, kinda like the blind!

[woodytick]

Sheish! noob's leading noobs, kinda like the blind!

hey for once they are helping one another, lets not mess up the flow here.....:crazy3:

[hotrod10]

I checked for exhaust leaks and all the usual problem's. I read that you can put a thin washer under where the jet is it will not let it close completely and remove the pair valve that Honda put on these bikes for clean air?

[Paradox]

I checked for exhaust leaks and all the usual problem's. I read that you can put a thin washer under where the jet is it will not let it close completely and remove the pair valve that Honda put on these bikes for clean air?

Ohhh lordy a 9 poster handing out perls of wisdom...

Noob news flash, jets don't open and close like valves.

BTW I dare ya to show me a pair valve on my 06, a pair of valves maybe but no pair valve. Keep stumbling along Skippy, someday you will lean to walk.

[hotrod10]

yea I realize a jet and a valve are different. But Honda put the so called valve on for emissions. I have read to drill out pilot jet to 1/8" also. I just it would quit popping on decel

[hotrod10]

I read to drill out the pilot jet inside the float bowl, to cure the poppin and backfirinf on decel. Has anybody else done this? After aftermarket pipes and Dyno rejet kit my 07 honda shadow vt1100 pops some but not a lot. just enough to get on my nerves. Any advise?

[mcvierh]

Yes it's possible to drill out the pilot jet, but for that you need machinist drill bits, and thats not cost efficient, i.e. it's cheaper to just buy pilot jets than it is to buy the individual drill bits for drilling the PJ, besides if you fuck up drilling your out the pilot jet but if you buy a few different sizes of PJ's then if you find you were wrong you can just go back to stock.

[Paradox]

Go ahead and drill it out with that 1/8" it'll cure the popping because the bike won't run.

[soxOZ]

Most precision jets are formed during manufacture or blanked, and NOT drilled.
They are then checked for there volumetric flow rate and stamped accordingly to this flow... The size doesn't always indicate the hole in the jet.

It's common knowledge amongst tuners and is a proven fact that if you drill out a jet by even as little as a few thousands of an inch, it will have a 99.9% chance of flowing less than the undrilled size even if the hole is larger than stock and causing it to run lean...
The reason is that you change the entrance path of fuel into the jet and create fuel turbulence caused by the rifling made by the drill bit.
If you look through the orifice of a standard jet, you will see the finish on the walls is super smooth and the finish on a drill jet is far from this... It does make that much difference in fuel flow...

Just something to consider if you ever think of drilling out your jets...

[JayT]

Go ahead and drill it out with that 1/8" it'll cure the popping because the bike won't run.

I also hear that if you drill a few 1/4 inch holes in your heads it allows the engine to breath better!

(that was a joke folks!)

[hotrod10]

http://www.hondashadow.net/forum/viewtopic.php?p=603956&sid=6b44bb1794e6efa2d07bc947c772974a (http://www.hondashadow.net/forum/viewtopic.php?p=603956&sid=6b44bb1794e6efa2d07bc947c772974a)
Here's where I read the info about drilling out the jet's.

[hotrod10]

Go ahead and drill it out with that 1/8" it'll cure the popping because the bike won't run.
You sound like you know what to do fix this problem. It is a 2007 Shadow Spirit VT1100. Is there a simple fix? I do work on cars but new to working on bike's. I have read to shim jet where it won't close. The airinjection control valve cause's this. I am trying to cure the poppin. It is not bad but enough to want it to stop. I have installed vance hines classic II exhaust and had it rejetted. What do you suggest? Other day I was on interstate and as long as I run over 70 mph and let off it doesn't pop til it decel's below 70 mph . Thanks for any help !!

[mcvierh]

it's just a lean condition......could be that the folks that did the re-jet for you didn't bother to put it on the dyno to see what your circuits were doing from idle, to midrange to mains. (in fact I'd be willing to bet all the money in the civilized world they didn't dyno it, just threw the jet kit in) now it's up to you to do a plug chop to determine where your lean and correct the problem, you say your popping, thats an indication of a lean condition, it's up to you to isolate the circuit and deal with it.

[hotrod10]

it's just a lean condition......could be that the folks that did the re-jet for you didn't bother to put it on the dyno to see what your circuits were doing from idle, to midrange to mains. (in fact I'd be willing to bet all the money in the civilized world they didn't dyno it, just threw the jet kit in) now it's up to you to do a plug chop to determine where your lean and correct the problem, you say your popping, thats an indication of a lean condition, it's up to you to isolate the circuit and deal with it.
Your right he didn't dyno it. I also read that the injection air contol valve pushes freah into the exhaust for emission's. Damn government regulation's !! I will adust the air/gas mixture if that don't fix it I am going to try to find the injection air control valve and plug it. I called Dyno company today and they said that will make it pop. Just not sure where it is. I have worked on cars, but not motorcycle's. They sure make the stuff hard to get to. You have any idea where the A.I.C.Valve may be. Thanks

[soxOZ]

Ya think it might be worth while getting a workshop manual to show you where to find it...
Might be easier and quicker than just guessing and asking everyone... Then trying to figure out what they describe too do....
BTW, there's a bunch of other worth while info in that book that you might need to know... :grin3:

[hotrod10]

Ya think it might be worth while getting a workshop manual to show you where to find it...
Might be easier and quicker than just guessing and asking everyone... Then trying to figure out what they describe too do....
BTW, there's a bunch of other worth while info in that book that you might need to know... :grin3: Manual has been ordered thanks

[Paradox]

You sound like you know what to do fix this problem. It is a 2007 Shadow Spirit VT1100. Is there a simple fix? I do work on cars but new to working on bike's. I have read to shim jet where it won't close. The airinjection control valve cause's this. I am trying to cure the poppin. It is not bad but enough to want it to stop. I have installed vance hines classic II exhaust and had it rejetted. What do you suggest? Other day I was on interstate and as long as I run over 70 mph and let off it doesn't pop til it decel's below 70 mph . Thanks for any help !!

We've told what not to do and you keep talking nonsense like you understand what your talking about. There is a lot of crap out there but you keep hanging on what you read. Why should we help when you don't listen.

[hotrod10]

We've told what not to do and you keep talking nonsense like you understand what your talking about. There is a lot of crap out there but you keep hanging on what you read. Why should we help when you don't listen.
I like your bike, guess I 'll just have it put on a dyno? I just don't have a lot of money. I was hoping for a quick simple fix. No I don't believe everything I read. Just hoping someone such as yourself with bike expierence might tell a person what you suggest. If not I will figure it out sooner or later. Thanks

[gb6049]

Not that I am any means an expert, still in the rejet process myself, but I have read enough on here to know that most folks when they have gotten the jet right and still had popping, they adjusted the AF. Some more searching for jet setting will show what most have found works for them.

[Paradox]

I like your bike, guess I 'll just have it put on a dyno? I just don't have a lot of money. I was hoping for a quick simple fix. No I don't believe everything I read. Just hoping someone such as yourself with bike expierence might tell a person what you suggest. If not I will figure it out sooner or later. Thanks

It does not look much like that now, that picture is a couple of years old. Now it's got different pipes and such. If I could ever decide on what art to paint on it It's getting torn down and rebuilt with the JJ Diablo that's sitting in the garage right now.

[mcvierh]

If your getting decel popping, then adjust your A/F mixture hotrod.........simple as that. If your getting midrange pop enrich your needles by lowering the stay 1 notch, but with that said, you need to know that it's possible to be lean in any, or a combination of any of your circuits, only a dyno will pinpoint that,( there are 3 circuits by the way, idle, midrange and main jet and each crosses over to the other) but if you can't afford a dyno then a plug chop is the next best thing and it will get you so close you really won't need to pay for the dyno.

[hotrod10]

If your getting decel popping, then adjust your A/F mixture hotrod.........simple as that. If your getting midrange pop enrich your needles by lowering the stay 1 notch, but with that said, you need to know that it's possible to be lean in any, or a combination of any of your circuits, only a dyno will pinpoint that,( there are 3 circuits by the way, idle, midrange and main jet and each crosses over to the other) but if you can't afford a dyno then a plug chop is the next best thing and it will get you so close you really won't need to pay for the dyno.
Appreciate the advise I will do as you say. Thanks