Smoking on the right

[Slymo]

Vast progress in a number of areas other than smoke. Went for a 200 mile ride the other day and on going up the BIG hill on the ride I found that the bike was still pinkng like a bugger. Lifting the needle valve to notch four cured the flat ride pinking but clearly there was more to be done. I retarded the bike far more than usual and suddenly gained about ten horsepower and the pinking was gone. Got home and measured the full advance position with a stick down the plug hole and foumd it was the best part of 3/4" btdc. The sweet spot (surprise surprise) was about 3/8". Resetting the timing was interesting because about six times I reset the position to 3/8" only to discover that once tightened it had shifted to between 1/2 and 3/4". Finally got it set right and crikey what a difference! This old machine has some go. I've ordered a new set of rings and will pull the top end apart again when they arrive but until then I will contine to strop around making smoke.

[Swarfcut]

G'Day Slymo.
    From the way you described adjusting the timing it sounds as if you have a manual magneto. For those of us with the ATD, you have to consider the backlash in the gear train and it was always a case of setting the piston height as usual, then moving the idler gear and cam wheel backwards against their usual direction of rotation. Then add the ATD, set and wedged at full advance again ensuring that it is turned with a clockwise bias against the cam wheel teeth. This means that all the teeth are set in light contact  on their driven sides at rest and the variation in timing due to  backlash is eliminated.

  You know this, just posted for the benefit of those folks who perhaps have never considered this variable and wonder why the timing seems to have moved. Obviously this is not so critical with a manual maggy.

 Smokin' on.

 Swarfy.

[muskrat]

G'day Sly.
With the timing that far advanced she would have detonated like a Vietnamese rice paddy! Which may explain your smoke issue. Broken rings!
Yes fudging the timing so it's right when the nut is done up. Hands up who gets it right the first time?????
Cheers

[Slymo]

Pretty sure I haven’t broken any rings as I have a fairly gentle throttle hand. Also it’s smoked since day one. However I do think the rings are under par tension wise so a new set beckons. The nuisance is that the market seems crowded with “NOS” Hepolites which I don’t intend to purchase as I have severe doubts about the sudden influx to the market of sixty year old piston rings and if that is bollocks what else is. Gandini are proving elusive but Hastings Rings appear to be available. Does anyone have any experience with these?

[ironhead]

g'day slymo.
Hastings rings have a very good reputation, I wouldn't hesitate  to use them.

[Slymo]

Finally found a source of Gandini rings so those are on order.