Best RPM to use for throttle-chop?

[Rema1000]

I'd like to look at the plug color, and see if I have the right size main jet.  

I understand that I need to hold WOT going up a small incline for 10 seconds or more, then pull the clutch and hit Kill.  But if I crack open the throttle from (say) 5k RPM (or just roll to WOT slowly), then I'll end-up at redline in seconds.  Unless I'm in 3rd gear, there aren't any roads I can go that fast on around here.

On the other hand, if I crack the throttle to WOT while at (say) 40mph in 4th gear (4500 rpm?), then the bike will make a BRRRRRAPPPP sort of noise (like a thumper) and accelerate slowly.  That would give me 10+ seconds at WOT, and the bike probably wouldn't top 60mph.  Is that what I should do?

[The Buddha]

No No No ... full throttle after steady state ... Your slides will keep climbing as the rpms climb ... so what will run great at 5K full throttle doesn't neccesarily run right at 10K ... Agreed ... that's what needle taper is for ... but well ... you can do it by feel ... if you wanna be that approximate ... IN any case You cant use an O2 sensor with ethanol ?? if you can ... just do that ... less chance of killing yourself ...
Cool.
Srinath.

[scratch]

You really need to find a nice long straight (or relatively straight) section of road that is light on law enforcement and traffic (and lights). Uphill is ideal. I ride the bike to my testing ground (2 minutes away) and get it up to speed in top gear, tailoring the rpm to range that I want to test, and kill the bike. Luckily, the road has ample space on the side of the road, and I can pull the plugs right then and there.

Edit: Okay, I realize that we are testing for WOT, in which case I would test in 5th gear (I'm used to when bike's didn't have 6 gears. When was that, the early '80's?).

[Rema1000]

No No No ... full throttle after steady state ... Your slides will keep climbing as the rpms climb ... so what will run great at 5K full throttle doesn't neccesarily run right at 10K.

OK; so I need to hold steady at 5k RPM for a minute, then should I whack WOT, or slow roll to WOT?

...then hold at WOT for 10 seconds and kill.

[Rema1000]

Hm, looks like you can get a wideband sensor for $60? http://store.yahoo.com/machv/plxmwio2seki.html

Then I'd need a 5v regulated power supply, some small capacitors and a multimeter to read it?

[scratch]

No No No ... full throttle after steady state ... Your slides will keep climbing as the rpms climb ... so what will run great at 5K full throttle doesn't neccesarily run right at 10K.

OK; so I need to hold steady at 5k RPM for a minute, then should I whack WOT, or slow roll to WOT?

...then hold at WOT for 10 seconds and kill.

Nope, wot he's sayin' is that 5k rpm is not going to give you the same reading as 10k rpm. If you want to test WOT, you need to run, under load (in gear), at WOT.

[The Buddha]

Yea you need to stay at full throttle till you reach steady speed ... OK fine gradual throttle till you hit full throttle and then you need to wait to stabilise the speed, and that for 5 seconds ... Not easy ...
Now Wide band ... 5 watt relay ... WTF ... get a simple Chevy cavalier O2 sensor (I use that ...) and just damned ride it ... when you see it blipping down into the 200's ... take note and see if it happens often and under what circumstances ... then iron it out.
Cool.
Srinath.

[natedawg120]

just being curious but one should put in new plugs or clean the current plugs before the test right?  May be a dumb question here, I know how to read the plugs, but I was new to the term 'throttle-choping'.  I inspect the plugs I pull out of my cars but I am still new to the motorcycle world.

[The Buddha]

Nope ... old plugs read better ... new plugs self clean too well ... Now the plug can be cleaned before the start ... but I dont believe it will make any diff ... you're going to have to warm the bike - 10 mins of riding and then hit the high revs ... trust me by then the plug is dirty ...  :lol:
Cool.
Srinath.

[natedawg120]

cool thanks Srinath