Plug chop advice / reading for WOT

[JonnyC]

Yes, another plug chop thread. I'm a masochist, and my GS650G has 4-into-1 exhaust, K&N "lunchbox" filters (dual filter), and a Dynojet jet kit. Currently DJ160 mains (the largest that come with the kit), unknown clip position (rebuilt these a long time ago and didn't take notes), and pilots 2.25 turns out. I will be attempting velocity stacks later for the hell of it (please, I don't need warnings about them being bad for my engine), but that's for another time.

I attempted two WOT plug chops. Distance is short of 3/4 of a mile. The first chop was on cylinder #4, I ran high RPM WOT in every gear, which meant that I got up there in speed. Second chop was on cylinder #1, I banged through the gears as fast as possible until 5th, WOT the whole time. Bike was warmed up, swapped in a brand new plug, did the run, clutch in, killed ignition, swapped old plug back in for the ride home.

Here are the plugs...



They are just barely starting to get any color.

Was it not a long enough run? Or is it really that lean? Any advice? Go easy on me...

[hannibal]

I've never seen a plug like that. What did you do to them?! But yes, they look like brand new plugs to me.

What do you mean you did one chop on cylinder 4 and a second chop on cylinder 1??

[JonnyC]

I just chopped the threads to see the base of the porcelain. The first run I did was with a new plug on cylinder 4. The second run I did a few weeks later I tried it on cylinder 1 instead.

[mnferwerda]

Re: plug chop advice...

LOL, nice troll!

Took a look at your build thread. Looks like you know what you are doing. Very nice!

I just chopped the threads to see the base of the porcelain. The first run I did was with a new plug on cylinder 4. The second run I did a few weeks later I tried it on cylinder 1 instead.

[JonnyC]

LOL, nice troll!

Took a look at your build thread. Looks like you know what you are doing. Very nice!

Hmm? This is actually a serious question. Maybe I just fake like I know what I'm doing?

I've read a ton of info online about plug chops. Some say you only need to do a quick WOT run in one gear. Some say you need to get into top gear and do a run for 30 seconds+, uphill, maybe even dragging the brake. Some described even pulling plug wires and just running it on one cylinder, WOT, while the bike is parked.

Anyways, with 160 mains I fully expected rich readings WOT. I'm just wondering if these really do indicate lean, or if I'm just not running the bike WOT for long enough.

[AMK]

I've never seen a plug like that. What did you do to them?! But yes, they look like brand new plugs to me.

What do you mean you did one chop on cylinder 4 and a second chop on cylinder 1??

Looks like he literally "chopped" them.

[tkent02]

Probably building a chopper.

[JonnyC]

Ha, I get it. Looks like I just "chopped" brand new plugs and was asking why it didn't work.

But seriously...

[AMK]

I think leaving the plug intact would give more surface to evaluate the condition. And studying all four cylinders would be good too.

[AMK]

Ten characters

[JonnyC]

The rest of the plug looks almost brand new as well.

I was going off of all of this information...

http://kawtriple.com/mraxl/carb/plugchop.htm

http://www.braigasen.com/howtoread.htm

image002.jpg

[Nessism]

Chef Bill is good with jetting. You might want to PM him for advice.

[mnferwerda]

plug chopping

Seems like I was mistaken. I've never seen photos of plugs actually cut. I thought "chop" meant cutting the power to the engine at WOT.

See, you do know what you are doing... and I keep learning new stuff at this site.

Hmm? This is actually a serious question. Maybe I just fake like I know what I'm doing?

I've read a ton of info online about plug chops. Some say you only need to do a quick WOT run in one gear. Some say you need to get into top gear and do a run for 30 seconds+, uphill, maybe even dragging the brake. Some described even pulling plug wires and just running it on one cylinder, WOT, while the bike is parked.

Anyways, with 160 mains I fully expected rich readings WOT. I'm just wondering if these really do indicate lean, or if I'm just not running the bike WOT for long enough.

[hannibal]

I've never seen that either. I just assumed he was kidding. I will be watching the thread cause I'll need to do plug chops soon too.

[ddlaz]

I've been dealing with this myself...
It was not run long enough. even if it was extremely too lean, you'd have a permanent discoloration of your spark plug tips vs just being able lightly wire brush the carbon off.
If you're just doing a chop for sizing your mains, do your second method of going through the gears quickly WOT until you get to 4th and continue to redline and kill the engine. going WOT in high RPM in 5th for a mile is tough without breaking some laws.
It'd also help if you were going uphill, you'd accelerate slower and puts extra load on the engine.


BTW - I ended up with DJ126 mains with mac 4-1 and KN dual pod filters. The dynojet stage 3 kit comes with DJ155 and 160. WAYYYYY too big for my mild setup...