Scooterotica

byron wrote:

Bufficus wrote:I'm using 7000 units on both. Set at 24 degrees at idle they retard to 18 degress.

these are the bits I'm still unclear on ~

does the timing stay at 24º BTDC all the way up 7000 revs, and then changes immediately to 18º BTDC from then on to whatever max revs are achieved ? or is the difference more graduated ? I'm guessing the instant switch.

What I see from the strobe is a gradual retardation. At 7000rpm it doesn't retard any further.

and
if the initial timing was set at say 25º BTDC, would it switch at 7000rpm to 19º BTDC ?In other words is the change a fixed number of degrees.

In my experience yes.

However, I think its important not to get too hung up on what unit is fitted. It states in the instructions that different stators can react in different ways as there are several different manufacturers there may be some difference in the number winds on the coils. Some stators will need the slot filing to allow more movement to achieve the required timing range. A 7000 unit may work better on any given engine than say a 6000 unit. But as long as the timing moves between the range that you want it doesn't matter whether its a 6000 or an 8000 fitted. If you have enough clockwise/anticlockwise movement it doesn't matter what is fitted.

Also I have found that I have one degree more range with my Indian stator than I have with my BGM stator.

Wayne Miller wrote:Its a gradual advance, all of the units 6000, 7000 and 8000 are fully retarded at tick over. They all advance as the revs increase. However they advance at different rates, the 6000 will return to your BTDC setting before the 7000 and 8000. A few more revs and the 7000 returns to its BTDC setting and a few more revs and the 8000 reaches its BTDC setting.

Wayne has just beaten me to a much simpler and probably more accurate explanation than mine.

Wayne Miller wrote:Its a gradual advance, all of the units 6000, 7000 and 8000 are fully retarded at tick over. They all advance as the revs increase. However they advance at different rates, the 6000 will return to your BTDC setting before the 7000 and 8000. A few more revs and the 7000 returns to its BTDC setting and a few more revs and the 8000 reaches its BTDC setting.

aren't they fully advanced at 24º BTDC or whatever the initial setting is at idle , then retard nearer to TDC as revs increase ??
or am I getting my terminology mixed up

.

byron wrote:

Wayne Miller wrote:Its a gradual advance, all of the units 6000, 7000 and 8000 are fully retarded at tick over. They all advance as the revs increase. However they advance at different rates, the 6000 will return to your BTDC setting before the 7000 and 8000. A few more revs and the 7000 returns to its BTDC setting and a few more revs and the 8000 reaches its BTDC setting.

aren't they fully advanced at 24º BTDC or whatever the initial setting is at idle , then retard nearer to TDC as revs increase ??
or am I getting my terminology mixed up

Correct. Wayne must mean retards instead of advances.

Yes Byron, your right. I always get that wrong and have been corrected many times . To the back of the class for me

Bufficus wrote:Correct. Wayne must mean retards instead of advances.

ok, think I'm getting it now.
thanks for your patience.

excuse the crude drawing, but it helps me to understand


A is the initial setting eg 24º BTDC
B is the rpm that the unit is made to operate at.

from revs A to B the timing will retard in a linear fashion, from B onwards the timing will be remain fully retarded. correct ?

so if A is moved, does B also move correspondingly ?
or will B remain where it is [18º BTDC?], and only the rate of retarding is affected ?

I'm asking all this as my setup tended to pink until i retarded the timing a tad to about 17ºBTDC

cheers again guys

Looking at your diagram I thought A would have been @ 18* BTDC and B would have been @ 24* BTDC. Fook me Im sending myself mad thinking about this now. I'll give challkie a bell tomorrow and pester him to explain it to me again

Wayne Miller wrote: Fook me Im sending myself mad thinking about this now.

me too. maybe my best bet is just to get one, slap it on and see what it does