Delkevic 1TX 84-88 Slip On 13.5″ X-Oval Stainless Exhaust

[5speed]

Anyone running these slip ons?
According to their web site you don't need to rejet your carbs using these but mine is snapping and crackling when I let off the throttle.
Not outrageously loud but it's there.
the sound is growing on me.
It sounds like  Dean Harrison's ducati super bike. 

[Pat Conlon]

There is an ignition advance that happens upon closed throttle. This spike in timing flash burns off any unburned hydrocarbons left over in the cylinder from the open throttle conditions. This is a US EPA smog feature, not all FJ models have this vacuum advance. If you do (look for a vacuum line to your ignition box) try disconnecting this vacuum line, remembering to plug off the source vacuum from the intake port.
Capping off this advance function will not affect performance. Again, this advance action only happens at closed throttle.
For more reading: https://fjowners.com/index.php?topic=11690.0

It's simple to do, totally reversible. Try it out.

Please report back to see if your snap, crackle and pop goes away. I'm curious if this will fix this.

Cheers

[5speed]

Thanks Pat. I will try that and let you know.