Posted February 12, 2000 - 04:47 AM
Posted February 14, 2000 - 09:42 PM
Do you think you had it jetted correctly in both cases ?
I ask because I was about to make the change to YZ timing, but I've been hesitating because of exactly what you reported. I've always loved the fun to ride mid-range hit of the 250's I've ridden for years. But then I've usually tuned them for the low-mid grunt and smooth power because that's what turns the fastest laps and is the least fatiguing.
From the many volumes of reports on this site, it sounds like I'd be trading a very smooth and strong low-mid motor (that I really like) for a possibly less efective yet harder hitting mid-top powerband - might be fun.
So what do you really think ? - Maybe peak HP is not always best ?
In the end, I will have to try the YZ timing just to end the curiosity...since I already bought the jets.
Posted February 24, 2000 - 05:22 AM
Denver, Colorado, USA
Posted February 25, 2000 - 06:34 PM
Posted February 26, 2000 - 03:13 AM
This describes the WR to YZ process in terms of the number of cam chain pins between two marks on the cam sprockets. Print it out and follow it through without actually changing the timing. Then work through backwards to end up with 13 chain pins betwwen the marks, you will start with 12. Just be sure to lock the cam chain tensioner "off" so the chain is quite loose. When you go to lift the cam shaft cap off be aware that there is a bearing retainer under the cap. It can fall out and drop into the guts. I grab it with a magnetic rod as I lift. Otherwise lift the cap off and AWAY from you so it falls where you can get it. It is a good idea to stuff clean rags into the space used by the cam chain under the cam shaft sprockets. Clark suggests removing the cam shafts and recording the numbers on the shims while you are in there. It helps later. If the cam chain tensioner is off properly you should be able to rotate the exhaust cam sprocket without much trouble. You may need to have someone hold tension on the screw driver in the tensioner. Thats about it.