Grey Wire mod = heat
Posted September 23, 2001 - 12:51 PM
Posted September 23, 2001 - 04:05 PM
The WR250F gray wire retards the ignition timing by as much as 30 crank angle degrees - at mid throttle and engine speed greater than 7000rpm. Retarding the ignition timing from its optimum point delays the combustion process. This does two things: 1) The engine produces less brake power and 2) The lost brake power is dumped down the exhaust as heat - the flame front may actually propagate out through the open exhaust valve during the blow down process.
Your bike would tend to have much higher exhaust gas temps with the gray wire CONNECTED. It is the exhaust gas temps that are causing the header to glow.
Elevated exhaust gas temps may or may not raise the coolant temp - this depends on cooling jacket design in the exhaust port area.
I believe the night time exhaust header after glow is common, at least it is on my bike - especially at idle where the ignition timing is very retarded relative to optimum.
Posted September 24, 2001 - 05:06 AM
Originally posted by *mike68*:
The WR headers glow red from stock.
I concour. It is not from the mod. It is just that way.
If life is not a blur. You aren't going fast enough
Posted September 27, 2001 - 01:46 PM
My V-Twin Suzuki TL1000R has the same problem. My buddy and I noticed it while riding at night. Come to find out, it is normal. Thinner wall header construction for weight savings and bare metal instead of matt black finish probably make it more noticable.
White Brothers E Series Full exhaust
YZ timing I think (bought used)
Grey wire mod
Posted September 27, 2001 - 10:35 PM
just for me, would you tell me your needle code, PJ, PAJ and PScrew how many turns out?
Posted October 03, 2001 - 04:06 PM
I have heard the mod actually advances timing in midrange. Sounds logical to me that it would run hotter. Anyone else have this experience?
Posted October 03, 2001 - 06:20 PM
Posted October 04, 2001 - 04:49 AM
Originally posted by Ga426owner:
you guys are touched............the grey wire has nothing to do with heat BUILD UP......
If YZ timing is used at slow speeds it will cause more heat. Straight from Randy Hawkins.
Posted October 04, 2001 - 07:55 AM
Posted October 04, 2001 - 01:39 PM