pop pop pop pop bang bang

[Anonymous]

I have a gs 1000 l , ive changed the air filter box to kn individuals, replaced the jets. When i go out for a run the the throttle rather responsive, the only thing is that it pops and farts when i let off the throttle , and when i apply the throttle, once the engine has warmed up.
One thing i have found is that the plugs are ngk bs7es, i believe they should be bs8es plugs, also two of them are white, one perfect in colour, one black.. the screws on the side of the carb are wound out 1 1/2 turns, i havent touch the screws on the base of the carbs. What could the popping be? would the change in plug type sort it all out.

All help would be appreciated. thanks.

 

[RJ]

I had the same problem with my 1100E and it only stopped when I replaced my worn out header with a new one. Check the condition of your exhaust. If you change out the exhaust you need to make sure that you put in new exhaust gaskets.

 

[Jethro]

Make sure you don't have intake leaks. That will do it big time.

 

[rosco15]

Popping off the gas is lean. Richen the idle circuit up a bit.

 

[KEITH KRAUSE]

Re: pop pop pop pop bang bang

I have a gs 1000 l , ive changed the air filter box to kn individuals, replaced the jets. When i go out for a run the the throttle rather responsive, the only thing is that it pops and farts when i let off the throttle , and when i apply the throttle, once the engine has warmed up.
One thing i have found is that the plugs are ngk bs7es, i believe they should be bs8es plugs, also two of them are white, one perfect in colour, one black.. the screws on the side of the carb are wound out 1 1/2 turns, i havent touch the screws on the base of the carbs. What could the popping be? would the change in plug type sort it all out.

All help would be appreciated. thanks.

Sounds like you're lean on both the pilot and needle circuits.
The K&N pods will require larger mains but you mention no full throttle complaints.
The pods will require AT LEAST raising the jet needles one position, possibly more. Your needle e-clips are in position 3 stock. So be sure they're at least in position 4 from the top. Test/plug reads at 1/3 throttle position for the needles. If still lean, a jetting spacer can be used to make "1/2" position changes. The spacers are .022" thick. To go from position 4 to "4 1/2", you need to put the e-clip in position 5 (the bottom) and place the jetting spacer directly on top of the e-clip. If still lean, then remove the e-clip and that would then be the richest setting your stock needles can acheive (position 5). Be sure the two jet needle plastic spacers are re-installed in correct order. Thicker one goes above the clip (or jetting spacer if used), thinner one below the clip.
For the pilot circuit, try an additional 1/2 turn out on the pilot fuel screws (underneath) from where they are now, if the bike was running well before the pods install. Turning them out richens the mixture. The pilot fuel screws are very sensitive to adjustments. So keep a record and fine tune them between tests at mimimal throttle openings. The side air screws MUST be set using the highest rpm method. Use very good fitting tools on the screws or stripping the heads is easy.
With pods, REMOVE THE TWO FLOATBOWL VENT LINES and leave the ports open to avoid fuel starvation.
Whenever the VM carb jet needles are disturbed, you MUST bench synch and follow this with a vacuum tool synch. VERY important.
For most accurate vacuum synch, the ignition timing and valve clearances must be correct first.
Also, be sure the manifiold o-rings are good and the manifolds themseleves. Also, the exhaust header gaskets. Carbs must be clean inside and floats adjusted. I set them to .94" exactly.

 

[KEITH KRAUSE]

By the way, your plugs should be NGK B8ES. No hotter/colder plugs should be necessary for all around riding.

 

[RJ]

As far as the lean condition, yeah that could be your problem. You might check the intake boots for cracks. That will lead to a lean conditionl. Also, since you have different color spark plugs with the same mixture screw settings, you're probably due for carb rebuild/synchro deal. In fact, if the carbs haven't been gone through recently, you need to do it before any other tuning issues can be addressed. You may also consider a Dynojet kit. They are designed for pods/header combo.