Phantom 85v3 spark knock and Backfiring

[Coubob]

The time before last when i was riding my phantom it ran fine except i noticed a slight spark knock. Then the last time i was on it, it started

backfiring. It would do it only once after letting off in mid throttle. I was told to retard the timing and to raise the cylinder. How much do i
retard it? The mag thats on it is very tight against the key. I was going to switch it out with the mag thats on my zeda80. Reason being the

slot for the key on it is wide, i can turn the mag 4-6 degrees each way. But with me putting the phantom mag on my zeda80 make it to

advanced? or i was hoping, put where its suppose to be? or should i just grind down the key on the phantom?

 

[Mike Cyanide]

The time before last when i was riding my phantom it ran fine except i noticed a slight spark knock. Then the last time i was on it, it started

backfiring. It would do it only once after letting off in mid throttle. I was told to retard the timing and to raise the cylinder. How much do i
retard it? The mag thats on it is very tight against the key. I was going to switch it out with the mag thats on my zeda80. Reason being the

slot for the key on it is wide, i can turn the mag 4-6 degrees each way. But with me putting the phantom mag on my zeda80 make it to

advanced? or i was hoping, put where its suppose to be? or should i just grind down the key on the phantom?

Are you sure of all of this first of all condition of motor. Is it stock? How many miles? Are you positive of spark knock? Backfire like thru the carb? Or after fireworks thru exhaust? Most phantoms with 4 stroke a bit which may seem like an afterfire(a bump thru the exhaust) which is completely normal for them. Check out some videos of ppl riding phantoms. They sound very different then the usual China doll. I could be wrong but I was also very off put by the sound of my phantom initially.

 

[Mike Cyanide]

The time before last when i was riding my phantom it ran fine except i noticed a slight spark knock. Then the last time i was on it, it started

backfiring. It would do it only once after letting off in mid throttle. I was told to retard the timing and to raise the cylinder. How much do i
retard it? The mag thats on it is very tight against the key. I was going to switch it out with the mag thats on my zeda80. Reason being the

slot for the key on it is wide, i can turn the mag 4-6 degrees each way. But with me putting the phantom mag on my zeda80 make it to

advanced? or i was hoping, put where its suppose to be? or should i just grind down the key on the phantom?

I would really wait for further input from a senior member of the forum. Also details in the motor go a long way. (Ie. Mileage,any aftermarket parts,previous owners and such)

 

[Coubob]

Are you sure of all of this first of all condition of motor. Is it stock? How many miles? Are you positive of spark knock? Backfire like thru the carb? Or after fireworks thru exhaust? Most phantoms with 4 stroke a bit which may seem like an afterfire(a bump thru the exhaust) which is completely normal for them. Check out some videos of ppl riding phantoms. They sound very different then the usual China doll. I could be wrong but I was also very off put by the sound of my phantom initially.

I'll leave it be. It's new and has maybe a tank through it. All stock. It was backfiring through the exhaust a burb ss ya said.

 

[Chainlube]

The time before last when i was riding my phantom it ran fine except i noticed a slight spark knock. Then the last time i was on it, it started

backfiring. It would do it only once after letting off in mid throttle. I was told to retard the timing and to raise the cylinder. How much do i
retard it? The mag thats on it is very tight against the key. I was going to switch it out with the mag thats on my zeda80. Reason being the

slot for the key on it is wide, i can turn the mag 4-6 degrees each way. But with me putting the phantom mag on my zeda80 make it to

advanced? or i was hoping, put where its suppose to be? or should i just grind down the key on the phantom?

Check the width on the key, should be 2.5mm.

 

[Mike Cyanide]

I'll leave it be. It's new and has maybe a tank through it. All stock. It was backfiring through the exhaust a burb ss ya said.

Yup that's fairly normal. Its need 20:1 conventional. That's crucial and go easy on that throttle. Safe way is run her alittle rich. Gonna get some more bumps out ehaust and 4 stroking rich but it's safer that way. Do not race around on yet and watch that temp. 15min ride max. Then full cool down and make sure your head studs are at 12 ft lbs. All of this is very important. I learned the hard way. So you don't have to.

 

[Mike Cyanide]

I'll leave it be. It's new and has maybe a tank through it. All stock. It was backfiring through the exhaust a burb ss ya said.

Check your spark plug color. Again 20:1,fairly rich,correct heat cycles and do not rev the hell out of it.

 

[Mike Cyanide]

And head bolt torque. They WILL come loose.

 

[Coubob]

Yup that's fairly normal. Its need 20:1 conventional. That's crucial and go easy on that throttle. Safe way is run her alittle rich. Gonna get some more bumps out ehaust and 4 stroking rich but it's safer that way. Do not race around on yet and watch that temp. 15min ride max. Then full cool down and make sure your head studs are at 12 ft lbs. All of this is very important. I learned the hard way. So you don't have to.

I`ve been running 24:1. and i have the needle a little rich trying to keeps the temps down and it does 4 stroke. it usually runs 325F. I dont race around on this one i like torque and to casually cruise around town on it. But it does have alot of vibration starting in the midrange, I can feel the vibration though the peddles mostly.

 

[Coubob]

Check the width on the key, should be 2.5mm.

Thanks