Varitronic Timing

[Magalluf]

Can anyone tell me what degree to set my varitronic to. I phoned CamLam and they told me 17º and then in a local shop they said thats mad it needs to be set to 24º. I have a 186 mugello with 60/107 crank, Chiselspeed ADS3 and 30mm TMX.

Thanx

Steve

[mick1]

Cut and pasted from the Camlam site:

On some cylinders and some types of tune, power may not be gained, but you have the benefit of a high quality reliable system that is not prone to the failures of Indian systems.
Basically an overall view of how the system works is as follows, which can also be seen in the fitting instructions :-
Timing when the stator is positioned fully advanced will give you around 21 to 22 degrees when the engine is not running (you cannot check this). When you scooter is at fast tick over it will advance around 2 degrees to 23 to 24 (you can check this with a strobe. When fully retarded, depending on how hard your scooter revs, this figure can go as low as 12 to 14 degrees. The thing to remember with the Varitronic is by setting much lower timing, you may loose some top end power, but by running this far retarded your engine will run cooler and safer. The reason we prefer to be this far retarded is the Varitronic by nature of its twin spark system can run hotter, thus the need for more retard. Regarding the possible loss of top end power, you should bear in mind by the time the Varitronic system retards further then 17/16/15 degrees (it does most of its retard at between 4 to 6000 rpm), most expansions will have given up making peak power, so we feel it is not worth trying to hang on to a higher state of degrees as the end result probably will not work with most expansions and gear ratios. The gain in terms of power from the Varitronic is a good increase of power in all bar the top end, so some trade of in terms of power output will be needed in most cases.

[garry inglis]

what is the ads3 like with the186 kit does it give low to mid power

[Magalluf]

I´m none the wiser with the cut and paste. It seams to say 24º for power and less for reliability.

I can`t tell you how the ADS3 works with the Mugello as I still havn`t ridden it.

[mick1]

I take it to mean set the Varitronic to 21/22 degrees for it to retard to 12/14 degrees, which is roughly an 8 degree difference.

When running at full throttle you may lose a slight bit of power with the timing retarding to 12/14 but it will run cooler/safer.......


Setting it to 24 degree would mean it would retard to 16 degree at full throttle which may be ok, but when not at full throttle (or easing back off the throttle) you may be cruising without the main jet and be running @ 20/19 degree which may be an issue.....food for thought

[Muppet]

ign spark timed earlier raises the cylinder pressure (expanding gasses) which should increase peak power; the earlier spark creates heat for longer on each stroke; if the engine revs beyond the pipe it creates more heat but no more power; retard the spark the cylinder creates less pressure and less peak power; the less advanced spark at all revs spreads the power and drops peak power lower cylinder pressures also reduces heat in the cylinder as each spark happens later; more of the heat (expanding gasses) escapes into the exhaust

[Magalluf]

I think I´m going to give 21º a go to see what happens. Better safe than sorry.

Thanks

[psychedelicropcircle]

I've been considering the casatronic version, always ran static ignitions, does anyone run one on a TS1 if so wot degree did you set up on? < unsure if that's the best wording having never used a variable setup.

[Padge]

I toyed with the idea of fitting a varitronic when I built my engine, but initial cost and cost of replacement parts (and the fact that on the way to a rally a mate using one had a failure and no one had any spares) swayed me away.
what I ended up with was a standard SIL electronic setup, (k2 pickup and Ducati cdi) mid weight flywheel and an Augusto 7000 set at 23 static retarding to 16 (on a high revving Imola) gives almost same results (i.e. gives me back some of the low down "off pipe" grunt you lose with static timing of 16-18 degrees) but a lot cheaper and if I did have a failure I (and most of my mates) carry spares, so 20 mins at side of road and i'm up and running again

personally I think at 21 degrees it will retard too much (12-13 degrees) and you will lose quite a bit of top end power

[mick1]

probably better starting at 21 then moving it up to 22/23 than starting high and popping a piston.

Personally though I agree that 21 is too low and 22/23 would be ok