HPI Ignition Advance

[Mexicano]

How do I know my advance is O.K. with an 2005 HPI ignition?

I mean, if I follow the instructions, which is best in your experience 3 or 5 m.m.? Where is MORE advance, 3 or 5 m.m.?

Thanks,

 

[Joël]

How do I know my advance is O.K. with an 2005 HPI ignition?

I mean, if I follow the instructions, which is best in your experience 3 or 5 m.m.? Where is MORE advance, 3 or 5 m.m.?

Thanks,

Well, with HPI you never can be sure.
Only if you use a strobo to check the position of timing marks.

5mm is more advance than 3 mm, my HPI is at 1.8 mm by the way.

 

[pr0ve]

Well, with HPI you never can be sure.
Only if you use a strobo to check the position of timing marks.

5mm is more advance than 3 mm, my HPI is at 1.8 mm by the way.

Which version do you use of hpi? at 2003 you can have less advance right?
But anyway why use so little advance ignition? Isnt it better to get the fuel burning for as long as possible without "knocking"?

 

[Browni]

Well, with HPI you never can be sure.
Only if you use a strobo to check the position of timing marks.

5mm is more advance than 3 mm, my HPI is at 1.8 mm by the way.

Never can be sure? You can be 100% sure!

This is very easy! You can adjust exactly the same as on the HPI original curve!
Cause the reference point is correct I checked it wit strobo! So you know where is the reference point from the TDC. So just see the ignition curve! For example on the 2004 version the maximum advance is 30 degree, so you have to adjut the ignition to 30 degree. You can convert the degree to mm if you know the stroke and the connecction rod length for a 39,2 mm stroke and 80 mm conrod it is 3,22 mm from the top dead center. If you adjust this you will have the same values as on the curve! If you need fine tuning you can rotate it + 2 degrees maximum (in my opinion this is the max what is still good for a high compression race engine) so you can adjust it to 3,65 mm.

For a 44 mm stroke engine with 85 mm conrod the 30 degree is 3,65 mm too.

That 5 mm is for different strokes..
For example on a 180 cc Runner, the 30 degree is 4,3 mm, etc..

5 mm for a 70 cc bike is a killer!! It's 38 degreem high torque at the bottom but will die at high rpm, or if the compression is too high it will damage!!


BUT AS YOU SEE I TALKED ABOUT THE 2004 HPI's CURVE!


However that 1,8 mm from the (TDC) is seems to be a very bad choice!

Joel

Or do you use another reference point, not the TDC??

1,8 mm is ~22 degree it isn't bad, but the 2004 HPI decrease the curve very intesively, so if it starts from 22 instead of the 30 you will have 8 degree less everywhere, this mean at 13000 you will have 0 degree ignition,a nt at 14000 you will have spark after the TDC??



Mexicano

How much is your stroke and your connecting rod?? Cause teh 2006 model has 30 degree max too!

 

[Mexicano]

Browni: My stroke ia 48 m.m., con rod is 80 m.m.

Thanks,

 

[Browni]

Browni: My stroke ia 48 m.m., con rod is 80 m.m.

Thanks,

48 and 80?

Than start from 4,1 mm fromTDC, this will give you the standard 30 as a base ignition curve!

 

[ABT]

Probably Joël's marks on his HPI aren't right or he uses a 001 CDI (no curve) instead of an 068 CDI (curve)

An '04/05/06 HPI must be at 2,8 to 3,2 mm, that's what i've seen with different mopeds on the Dyno

 

[Joël]

Never can be sure? You can be 100% sure!

This is very easy! You can adjust exactly the same as on the HPI original curve!
Cause the reference point is correct I checked it wit strobo!

With your HPI this may be the case, but with many others it isn't. The problem is they differ from eachother!

However that 1,8 mm from the (TDC) is seems to be a very bad choice!

Joel

Or do you use another reference point, not the TDC??

1,8 mm is ~22 degree it isn't bad, but the 2004 HPI decrease the curve very intesively, so if it starts from 22 instead of the 30 you will have 8 degree less everywhere, this mean at 13000 you will have 0 degree ignition,a nt at 14000 you will have spark after the TDC??

Of course the 1.8 mm I use is not just "taken out of the blue" :|
I've made several runs on the dyno and measured the under spark temperature.
I started out with 3.8mm and got a little more power and lower temperature every time I retarded the timing a little bit.
I use the same marks as seen on the picture, and I have a CDI with curve (both model 2001 and 2003 tested).

What I try to say here is: in my case it's quite obvious the timing marks don't match the real spark point.

 

[Eoin70]

thats for sure
my HPI model 03 needed 8mm

 

[Browni]

With your HPI this may be the case, but with many others it isn't. The problem is they differ from eachother!



Of course the 1.8 mm I use is not just "taken out of the blue" :|
I've made several runs on the dyno and measured the under spark temperature.
I started out with 3.8mm and got a little more power and lower temperature every time I retarded the timing a little bit.
I use the same marks as seen on the picture, and I have a CDI with curve (both model 2001 and 2003 tested).

What I try to say here is: in my case it's quite obvious the timing marks don't match the real spark point.

OH I see it! I thought all of the HPI has an accurate marking!

Our two 2004 type are accurate, and also checked with strobo!

We also cheked the ignition timing with softwer and we have to push the curve with 500 rpm! And we also checked it at the real too!

 

[Mexicano]

Thanks to all!!