Sparks Key Rejet?

[Newrider08]

Hey guys I ordered my sparks timing advance key tonight and will have it in a couple days

I see the tutorial you have here on the forum and it is great, my only question is, Do I need to rejet my carb after installing the key?

[tri5ron]

If your jetting is already correct before installing the key,
Then it will still be correct after you install the key.

advancing the timing by 6 degrees, has no effect on your jetting.

[dunatic]

Originally posted by tri5ron
If your jetting is already correct before installing the key,
Then it will still be correct after you install the key.

advancing the timing by 6 degrees, has no effect on your jetting.

thats true but then again NOT true.

The stock or even aftermarket CDI boxes retard the timing slightly at the top end. The key advances that, so your top end jetting could be lean.....very lean, if you are already lean on the top end.

the key does no change your jetting, but by advancing the timing, you can now run more fuel to compensate for more timing.

[Newrider08]

what are you guys that have the key running as a main jet?

I have a white brothers e series, a uni filter, and lid on, my elevation is around 800 feet

[gojk]

Originally posted by dunatic
thats true but then again NOT true.

The stock or even aftermarket CDI boxes retard the timing slightly at the top end. The key advances that, so your top end jetting could be lean.....very lean, if you are already lean on the top end.

the key does no change your jetting, but by advancing the timing, you can now run more fuel to compensate for more timing.

I am not sure I follow. How does advancing the timing allow you to throw more fuel into the cylinder?

Originally posted by Newrider08
what are you guys that have the key running as a main jet?

I have a white brothers e series, a uni filter, and lid on, my elevation is around 800 feet

HMF slip on, K&N air filter, Open airbox. 42 pilot (3.25 turns out on the fuel screw I believe), 158 main, needle in the middle or 3rd slot. Plug check could not get any better unless you made custom jets for inbetween sizes and dyno tuned.

[dunatic]

Originally posted by gojk
I am not sure I follow. How does advancing the timing allow you to throw more fuel into the cylinder?

just that, you are advancing with the spark is ignited. if it burns too quick BTDC it will detonate so you have to either retard the timing or give it more fuel to burn longer.

[Wheelie]

Timing can affect jetting. I'm installing my advance key on Saturday and I'll be surprised if no tuning is required after the install.

[dunatic]

Originally posted by Wheelie
Timing can affect jetting. I'm installing my advance key on Saturday and I'll be surprised if no tuning is required after the install.

unless your running really FAT now, youll have to bump up the main jet.

especially with a +6 key, maybe not so much with the +3 key

[Newrider08]

I will have to take it for a long run to see how the jetting is up top but the thing is running great