Ignition advancer?

Johnny, was the bike stock otherwise when that dyno run was taken?

Thats a lovely lump of torque all over the range.

[johnnyrod]

Pretty much - had a new pipe but no dyno setup so no advantage

[northwind]

Originally Posted by johnnyrod

Before and after...

http://www.johnnyrod.co.uk/dyno.gif

onna curvy

Were those 2 done on the same day? The "before" figure's weak for what looks like a DJ machine. The lines do show the difference well, you can see the difference in the overall curves brilliantly, but I think the advancer's a little flattered by the first run.

[johnnyrod]

Yep, they were immediately before and after fitting the advancer key. This was doen at JHS, the bike had the Akrapovic pipe but no carb mods at all, also a knackered chain and a GSXR600 shock which made the back wheel bounce up and down at high speed, so the top end probably isn't that accurate. Also James was trying to sell me an M4 pipe so I'm not totally convinced, knowing now the variations in DJ dynos, that this is that accurate a figure - once I got a K&N filter and Dynojet kit and setup it jumped up to 73bhp (corrected, at PDQ). Anyway, like you say you can see the difference it bottom end. And it makes it a little louder, as if that were needed.

[Sid Squid]

Just in case anyone is in doubt about what the ignition advance key does:

Originally Posted by I Previously

The ignition advancer - unsurprisingly - advances the ignition, that is to say it makes the spark occur ever so slightly earlier in the process, (4 degrees, in this case). Why? When the spark ignites the mixture, it takes a certain amount of time for the flame to pass through the gas and the cylinder pressure to rise to it's maximum, the most advantageous point for the pressure to be at it's maximum is just as the piston passes over top dead centre, so to arrange this the spark is timed to happen before the piston reaches the top of it's travel. The ignition timing of the SV, (actually just about all Jap bikes), is actually set quite conservatively, this is to ensure that it will run acceptably using just about any old fuel you are ever likely to encounter, however here in Blighty fuel quality is generally fairly consistent, and better than the minimum grade that the SV was constructed to run on, in this happy circumstance you can usefully advance the ignition, (4 degrees is a very common figure), to take advantage of that.
As such it shouldn't really be considered tuning, more setting up taking account of local conditions.

[johnnyrod]

spot on - I asked James at JHS at the time if I had to use super unleaded or an octane booster and he said it's not necessary for this much advance - can't say I've noticed any problems and I've had it a long time, as have many others.

I've just ordered two of these from JHS, one for my SV and one for my girlfriends.

I wonder if anyone on this forum has bought an ignition module to go with their power commander. It certainly would give a lot more tuneability, but at a price...

I fitted one to my k2.

A word of caution, for the butter fingered of motorcycle mechanics like myself. In order to get the one way bearing back on to the shaft (its part of the starter mechanism) you will need to turn the primary drive (large cog) as you mount the bearing back on. Now this step is not emphasised enough in any down loadable picture "how to" guide. If you do what I did and simply place it on the shaft and then torque it up, you destroy the bearing! After all it takes a hell of an effort using the puller to extract it doesn't it, so me thinks need a big wrench to put it back on. Wrong!! Then you replace the bearing, but put it on the wrong way round and destroy the rotor. All embaracing and expensive.

To turn the primary, remove the starter motor, which stops you doing this otherwise. This is not mentioned, but definately works.

Just some advice - if you want to avoid a long wait on some expensive parts.

My bike is now back on the road, but my pride and bank account took a dent.

[northwind]

Oh yeah, and if you do it on the sidestand instead of a paddock stand, the rotor can fall out when you finally get the bolt undone- I just caught it, but it's not something you want to drop on a hard surface.