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Adaptive timing advance.


the boris

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What would an ideal curve look like? I recently bought an aftermarket programmable ignition for my "bike".  I realize every combination is different and i would have to rent a dyno to get it perfect, bu that's not in the cards currently. As of right now i have a stock banshee timing curve loaded, but i can change it however i want. I am not vary familiar with 2 stroke timing theory and just need a little guidance.  

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So, I'm not an expert, but basically I run flat timing from just above idle to through the dead spot in the power band. You can extend the off idle ramp up a little to smooth the throttle off idle.   I keep raising the timing here until I can't tell a difference.  In my case I hit the limits of the Dynatek Ignition at 27*.  Just as the pipe comes on I drop the timing to stock and add back until I can't tell a difference again.  Then at peak power I add until I have signs of light deto then back the timing back down a degree or two.  After peak power I drop the timing to about 5 degrees to allow for increased overrev.  The dropping of the timing after peak power transfers heat from the cylinder to the pipe allowing for a broader powerband.

I mainly run curve 3, but will run 2 sometimes if its super hot out or bad fuel.  My setup is a Pump Gas Ported 421 Serval with 24cc domes, PWK 33s, and SBIF Shearers.  Throttle response is pretty good and I can overrev to about 11.3K to 11.5K rpm in 6th.  This curve hasn't been dyno'd but I've been happy with it for the last 2 years or so. I could probably hold a little more timing between 10-11K but this has been a safe setup and I like it better than the stock curve or a +4.

Gas Setup.png

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46 minutes ago, Keno said:

So, I'm not an expert, but basically I run flat timing from just above idle to through the dead spot in the power band. You can extend the off idle ramp up a little to smooth the throttle off idle.   I keep raising the timing here until I can't tell a difference.  In my case I hit the limits of the Dynatek Ignition at 27*.  Just as the pipe comes on I drop the timing to stock and add back until I can't tell a difference again.  Then at peak power I add until I have signs of light deto then back the timing back down a degree or two.  After peak power I drop the timing to about 5 degrees to allow for increased overrev.  The dropping of the timing after peak power transfers heat from the cylinder to the pipe allowing for a broader powerband.

I mainly run curve 3, but will run 2 sometimes if its super hot out or bad fuel.  My setup is a Pump Gas Ported 421 Serval with 24cc domes, PWK 33s, and SBIF Shearers.  Throttle response is pretty good and I can overrev to about 11.3K to 11.5K rpm in 6th.  This curve hasn't been dyno'd but I've been happy with it for the last 2 years or so. I could probably hold a little more timing between 10-11K but this has been a safe setup and I like it better than the stock curve or a +4.

 

 

Thank you for the reply. Exactly the kind of info i was looking for. Trying to learn more theory than specifics. The bike is actually an RD400. Similar to a banshee but nobody has done much with ignition, other than bolt on an off the shelf ignition with limited to no adjustability.  I'm running a Ignitech ignition and have limitless control over the timing map. Looking at other "similar" engines, the timing curve varies drastically. From banshees, rz350, tz250s, rd500s, etc. They all go about it differently. I like the look of he Dynatek curves. I'n my mind, it makes more sense to not pull timing until the bike comes on the pipe, but all of the maps i have looked at peak at 3500rpm. I am trust trying to learn where it is safe to add timing and what areas i should avoid. 

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So, I'm not an expert, but basically I run flat timing from just above idle to through the dead spot in the power band. You can extend the off idle ramp up a little to smooth the throttle off idle.   I keep raising the timing here until I can't tell a difference.  In my case I hit the limits of the Dynatek Ignition at 27*.  Just as the pipe comes on I drop the timing to stock and add back until I can't tell a difference again.  Then at peak power I add until I have signs of light deto then back the timing back down a degree or two.  After peak power I drop the timing to about 5 degrees to allow for increased overrev.  The dropping of the timing after peak power transfers heat from the cylinder to the pipe allowing for a broader powerband.
I mainly run curve 3, but will run 2 sometimes if its super hot out or bad fuel.  My setup is a Pump Gas Ported 421 Serval with 24cc domes, PWK 33s, and SBIF Shearers.  Throttle response is pretty good and I can overrev to about 11.3K to 11.5K rpm in 6th.  This curve hasn't been dyno'd but I've been happy with it for the last 2 years or so. I could probably hold a little more timing between 10-11K but this has been a safe setup and I like it better than the stock curve or a +4.
1960940546_GasSetup.thumb.png.645f33dd0a8a951286c9ae0fd8bf3e50.png
Sick mate, this is very informative.
Thanks.

Sent from my VOG-L29 using Tapatalk

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5 hours ago, 13B-RX3 said:

 

Thank you for the reply. Exactly the kind of info i was looking for. Trying to learn more theory than specifics. The bike is actually an RD400. Similar to a banshee but nobody has done much with ignition, other than bolt on an off the shelf ignition with limited to no adjustability.  I'm running a Ignitech ignition and have limitless control over the timing map. Looking at other "similar" engines, the timing curve varies drastically. From banshees, rz350, tz250s, rd500s, etc. They all go about it differently. I like the look of he Dynatek curves. I'n my mind, it makes more sense to not pull timing until the bike comes on the pipe, but all of the maps i have looked at peak at 3500rpm. I am trust trying to learn where it is safe to add timing and what areas i should avoid. 

Is that your RX3 in your avatar?

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I cant figure out how to post a picture, but the map i was leaning towards would be the equivalent to a banshee map that was +2 from 0-2000, +7 from 2000-5500, +4 from 6000-9000, then back to +0 at 10000. Interestingly enough, that map is very similar to an 84 RZ350 map except for -3 from 6000-9000.  The RZ map is much more aggressive.  I wonder if it's because of the PV?

3 hours ago, specialblend07 said:

Is that your RX3 in your avatar?

Yes it is. That's the weapon i choose if i really want to roll my socks up and down.

 

Edited by 13B-RX3
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10 minutes ago, specialblend07 said:
Download tapatalk for posting pictures. It's easier
 
Also, this thread is the most advanced banshee related talk we've had in years

Perfect, thank you!e0b741261387dcd7c77ac909b90844cc.jpg

 

Blue line is the map i'm leaning towards, red is stock banshee +2 from 0-2000. Any suggestions, advise?

Sent from my SM-G965U using Tapatalk
 

Edited by 13B-RX3
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