thank you, do i need to divide the rpm by 2?
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Ignition timing for modified engines
- Thread starter zrx1100
- Start date
No, in the program you enter the rpm and the advance or just pull the points with your mouse. When you get something you like program by pressing the tab up the top of the page and its done.
I have innogntion on the way. Looking forward to playing with programmable advance. Expect more dyno charts 
We're you able to find different tension springs anywhere?
Back in the day, cars used a combo set of springs to achieve the "step or dog legged" curve. Soft initial spring combined with a loose fitting stiffer rate spring to slow the rate of advance until the weights hit the max limit.
I have a Mallory spring kit for car diz, but they're much lighter than the 650 springs.
Back in the day, cars used a combo set of springs to achieve the "step or dog legged" curve. Soft initial spring combined with a loose fitting stiffer rate spring to slow the rate of advance until the weights hit the max limit.
I have a Mallory spring kit for car diz, but they're much lighter than the 650 springs.
So, I'm trying to understand this. XS650's, as far as I know, are not really "performance bikes". Yes of course there's the Kenny-esque 750's but they still don't produce today's horsepower. Hell, all of us have probably owned motorcycles that have 2x+ or 3x the HP of an XS650.
My XS-2 back in the day was not as fast as a CB750, but I wanted to pretend it was.
So ... I don't understand this discussion of advance curves. If you get the perfect advance curve, will it give you what, another 0.5 HP? Or better? Not trying to be a downer, just don't get it.?
My XS-2 back in the day was not as fast as a CB750, but I wanted to pretend it was.
So ... I don't understand this discussion of advance curves. If you get the perfect advance curve, will it give you what, another 0.5 HP? Or better? Not trying to be a downer, just don't get it.?
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There's a certain satisfaction making something OLD just work.
A higher level, is making it work optimally. Beyond that (inexplicably) is whipping all the other "Mitty's" butts with your antique. Its not logical, and maybe not ego driven. Its simply knowing you can do it.
We all own faster bikes. Its just fun.
A higher level, is making it work optimally. Beyond that (inexplicably) is whipping all the other "Mitty's" butts with your antique. Its not logical, and maybe not ego driven. Its simply knowing you can do it.
We all own faster bikes. Its just fun.
i did look into that. and ordered some springs as well. in the end it is was a bit of a challenge to find springs with not only with the target constant, but also the right preload. so to avoid a lot of trial and error, i looked for a programmable igition. @vexsed suggested innognition, which seems to be pretty impressive. @vexsed has had good success with these. I will see.
it is the journey
that said, on the dyno sheet, my bike keeps up with ducatis scrambler until ~ 6K rpm
https://www.xs650.com/threads/just-ride.54772/post-853241
what i will try to do is to put in more advance at 2200rpm to compensate for the poor mixture due to the timing of the pressure wave coming back withile valves overlap. Also, will retard the iginition a bit under load. Going uphil at part throttle my AFR is in mid 13s. Innognition allows for two curves and has a vacuum sensor.
I entirely agree for a road bike there is little to be gained.
I also have the opinion why not, some people me included like doing this sort of thing.
Keep us posted Zrx1100.
Yes, I think the answer is "because I can".
Objectively, to me, it makes no sense at all really chasing a fraction of a horsepower. But I have done it in the past. Because I could.
I put a lot of effort now into the near fifty year old bike hoping it will get me home again when I go out on it. That's a challenge enough.
Yes it's not just power but running well and efficiently at all operating RPMs a worthy goal?
it is the journey
that said, on the dyno sheet, my bike keeps up with ducatis scrambler until ~ 6K rpm
https://www.xs650.com/threads/just-ride.54772/post-853241
what i will try to do is to put in more advance at 2200rpm to compensate for the poor mixture due to the timing of the pressure wave coming back withile valves overlap. Also, will retard the iginition a bit under load. Going uphil at part throttle my AFR is in mid 13s. Innognition allows for two curves and has a vacuum sensor.
View attachment 365482
Thanks! Makes sense; nice dyno.
It will be interesting to see your results with the Innognition...to me, the biggest/best improvement might be the vacuum sensor's effect(?).
With a vac. sensor(MAP) everything is possible.it is the journey
that said, on the dyno sheet, my bike keeps up with ducatis scrambler until ~ 6K rpm
https://www.xs650.com/threads/just-ride.54772/post-853241
what i will try to do is to put in more advance at 2200rpm to compensate for the poor mixture due to the timing of the pressure wave coming back withile valves overlap. Also, will retard the iginition a bit under load. Going uphil at part throttle my AFR is in mid 13s. Innognition allows for two curves and has a vacuum sensor.
View attachment 365482
Software have 3D mapping?
For wide open throttle(WOT):
As i know, the mechanical advance stops short of detonation, just prior to peak pressure/torque.
It's way under advanced in the beginning of RPM sweeps, safe at peak torque and somewhat under advanced at higher RPM's.
Care to comment?
the ignition allows for two curves depending on threshold vacuum level. So not an extensive map
