Doing a plug chop

[slopster]

I've never done a plug chop before - seems like a major hassel on a modern inline 4 but I need to do it to make sure I'm not too lean as I play with my jetting.

Can someone correct me if I'm wrong here. Find a quiet road where I won't draw undue attention to myself. Go like a bat out of hell for a couple of mins then stop by switching the ignition off without backing off the throttle. Pull my plugs out there and then and compare them to the photos that seem to be all over the net showing different fueling conditions.

Do I need to clean the plugs between runs or do they pick up the new colour pretty quick.

What does a dyno run or two cost (so much easier).

[Pwalo]

FWIW I'd try and get some dyno time. Plug chops on a two stroke are pretty easy, but I can imagine they'd be a major pain on the GSXR. From memory w always carried at least one spare set of plugs for testing.

I'm sure some of the racers can give you some idea of costs involved.

[paturoa]

Go for a blast and then hit the kill switch and at the same time pull in and hold the clutch so that the motor stops. Coast / brake to a halt and then burn your fingers.

Before you go fo a blast take the plugs out and write on a piece of paper what each plug looks like, cos you will forget in the inverviening few minutes. Then compare to what you see after the full throttle blast.

If you are going to play a bit with anything, get a little note book and always write down what they look like before, after and what you did.

Edit - i'm not a racer (more of a nanna) but have used this a bit over the years.

[slowpoke]

Mate, any GSXR is a complex bit o' kit, tuning it by such a subjective method as plug chopping is doing it a dis-service.
The variables in trying to repeat a test scenario at anything other than a race track are huge and unless you are experienced at "reading" plugs then I wouldn't even attempt it. This method is for easily accessed plugs on racing two strokes, where all they are worried about is wide open throttle readings.
For any real world bike where you are worried about performance through the whole rev range you've got to get it on the dyno.
The seat of the pants method is for mugs too. It may "feel" like it makes more power but I've been in the situation where my bike actually felt flatter even though it was making more grunt because they filled in a "hole" in the mid range. As a result I no longer had that "kick" when it came on song, it was just seamless grunt from low down.
Tune it on the dyno. Time is money, and the hours/days you spend trying to tune it any other way (unless you have a portable exhaust analyser/oxygen meter) will make the money spent on a dyno well worth it.