Jetting 101 - Everything Explained!

[Blaaster]

Mainly correct, but when checking plug insulator colour, remember it must be done with a new plug of the correct heat range using a plug chop procedure.

Before you make the plug chop run it is important that the float level is correct, the idle is set correctly and there are no air leaks in the system, otherwise the smoke ring may lie about the AFR.


WHEN ALL OF THE ABOVE ARE CORRECT PROCEED WITH THE FOLLOWING.


Warm up motor to operating temp.

Fit new B8ES plug, ride WOT through the gears and hold WOT in 5th or 6th gear for 10 seconds, or as long as you can safely.

Switch off the motor and pull in the clutch, apply brakes to come to a stop quickly.

Take the plug out and replace the old one for the ride home.

Carefully cut the threaded end off the plug to expose the insulator.

There should be a smoke ring of a cardboard or biscuit colour around the insulator.

If it is non existant or a very light colour, you are lean and require a larger main jet.

If it is a lot darker you are rich and may go down a size in main.

I prefer to run a little on the darker side, I may loose a little power but it is worth it for the peace of mind that I won't need a rebuild so soon.
']You have to get up a reasonable speed so that you can get the motor to pull strongly.
']']Then hold it Wide Open Throttle (WOT) for 10 secs or as long as you can.
']']The idea is not to get speed but to make it pull strong at full throttle to get onto the main jet circuit.
']']I find I can safely do it on a short run by applying the brakes some.
']']If you have not enough room you can use 4th or 5th gear with good results.

 

[Blaster Nation]

Mainly correct, but when checking plug insulator colour, remember it must be done with a new plug of the correct heat range using a plug chop procedure.

Before you make the plug chop run it is important that the float level is correct, the idle is set correctly and there are no air leaks in the system, otherwise the smoke ring may lie about the AFR.


WHEN ALL OF THE ABOVE ARE CORRECT PROCEED WITH THE FOLLOWING.


Warm up motor to operating temp.

Fit new B8ES plug, ride WOT through the gears and hold WOT in 5th or 6th gear for 10 seconds, or as long as you can safely.

Switch off the motor and pull in the clutch, apply brakes to come to a stop quickly.

Take the plug out and replace the old one for the ride home.

Carefully cut the threaded end off the plug to expose the insulator.

There should be a smoke ring of a cardboard or biscuit colour around the insulator.




If it is non existant or a very light colour, you are lean and require a larger main jet.

If it is a lot darker you are rich and may go down a size in main.

I prefer to run a little on the darker side, I may loose a little power but it is worth it for the peace of mind that I won't need a rebuild so soon.
']You have to get up a reasonable speed so that you can get the motor to pull strongly.
']']']Then hold it Wide Open Throttle (WOT) for 10 secs or as long as you can.
']']']The idea is not to get speed but to make it pull strong at full throttle to get onto the main jet circuit.
']']']I find I can safely do it on a short run by applying the brakes some.
']']']If you have not enough room you can use 4th or 5th gear with good results.

When I ran a bigger main jet than it has now, It ran way worse and was cutting out pretty bad. Now it has tons of power all the way through 6th but right before Im totally topped out, its like I shut off the key. Then 2-3 seconds later, it starts snapping and popping. If I pull in the clutch right after this happens, it is idling really fast for 4-5 seconds before it dies down. Im thinking the float height is off. Im usually really good with jetting these by feel and have never seized a single blaster Ive ever ridden. This blaster is however not even close to stock. Stroked, big bore, v-force4, 34mm pwk, Vito Fat Bastard pipe. When I first got it together, I had to go way up with the pilot jet. I started with a 165 main and kept coming down until I was at 145. Its run the best at this point but something still isnt right. I just dont want to drop another jet size until I cover any other possibility. It pulls like a freight train until the very top of 6th then stalls. Im ganna check the plug right now. I do notice that it has a lot more unspent gas and oil coming from the header and tail pipe than any of my other blasters. Like that black wet sludge. None of my other blaster do that.

 

[Blaaster]

Buy a few b8es plugs and plug chop.

Does the header pipe leak at the cylinder?

 

[Blaster Nation]

Mainly correct, but when checking plug insulator colour, remember it must be done with a new plug of the correct heat range using a plug chop procedure.

Before you make the plug chop run it is important that the float level is correct, the idle is set correctly and there are no air leaks in the system, otherwise the smoke ring may lie about the AFR.


WHEN ALL OF THE ABOVE ARE CORRECT PROCEED WITH THE FOLLOWING.


Warm up motor to operating temp.

Fit new B8ES plug, ride WOT through the gears and hold WOT in 5th or 6th gear for 10 seconds, or as long as you can safely.

Switch off the motor and pull in the clutch, apply brakes to come to a stop quickly.

Take the plug out and replace the old one for the ride home.

Carefully cut the threaded end off the plug to expose the insulator.

There should be a smoke ring of a cardboard or biscuit colour around the insulator.

If it is non existant or a very light colour, you are lean and require a larger main jet.

If it is a lot darker you are rich and may go down a size in main.

I prefer to run a little on the darker side, I may loose a little power but it is worth it for the peace of mind that I won't need a rebuild so soon.
']You have to get up a reasonable speed so that you can get the motor to pull strongly.
']']']Then hold it Wide Open Throttle (WOT) for 10 secs or as long as you can.
']']']The idea is not to get speed but to make it pull strong at full throttle to get onto the main jet circuit.
']']']I find I can safely do it on a short run by applying the brakes some.
']']']If you have not enough room you can use 4th or 5th gear with good results.

Ok. I pulled the plug and its wet and as black as used motor oil. Even the threads of the plug was soaked. I guess Im ganna go down another jet size and try that.

 

[Blaster Nation]

Buy a few b8es plugs and plug chop.

Does the header pipe leak at the cylinder?

It has the o ring and springs at the cylinder but it seeps out