white bros. "tork" vavle insert
Posted May 29, 2002 - 10:13 AM
I'm not saying that on a dyno/flowbench you wouldn't see a diff at the top, it is just not appreciable
Posted May 31, 2002 - 06:25 AM
Now I have a stock yz exhaust and haven't tried the valve. I have to figure that to gain something you will loose something. Since I am interested in top end power, I am thinking that I will loose top end. Also it is so hard to tell how much you are loosing. unless you try top speed up a hill or you are racing someone. Percieved power is so much different than real power. I would sure like to get better mid punch but the first time my buddies modified 660 xr beat me in a drag, things would have to change!!
Posted May 31, 2002 - 04:43 PM
Posted May 31, 2002 - 11:46 PM
When you actually see the thing, you appreciate the R&D WB put into it, it is NOT simply a plate to restrict the opening, in actual fact it is an insert to re-shape the opening, and where as the hard facts of a flow bench MAY show a decrease in flow at high RPM, the on board diagnostics, show no problems at all.
WB are not noted for their B.S. and their "Bumph" quotes a 1 BHP increase accross the range, whilst 1 full BHP may be optomistic, there certainly is a noticable boost to the bottom and mid,
And for those who still ponder the top end, I can hit the Rev Limiter in top with an indicated 110mph(on the speedo)
Just my 50cents worth....(long post LOL)
Posted June 02, 2002 - 06:28 PM
Posted June 03, 2002 - 04:28 AM
In addition I was able to go from 5 discs to 8 with a noticable improvement in mid & top end. Overall I'm happy with the way the bike feels now. Very good investment. No increased heat.
I do notice a little more of a tendancy to hick up if I open the throttle suddenly at low RPM, which I rarely (never) do...in fact I even got the bike to cough and die once...which has never happened. I adjusted the koboda air tool out 2.5 turns or so and it did seem to help a little.
As far as the valve itself, I would agree the front end is easier to bring up. Racing my brother's 426 however, I was a few bike lengths behind after the mod, which would lead me to believe it may rob a little power up top. Despite all the hype over the 426, we're typically pretty even in a drag race, however the 426 pulls considerably harder off the bottom.
I guess I just wanted a little of that...any other sauggestions out there to give the 400 a little more bark of the bottom??
Posted June 05, 2002 - 01:17 AM