from: http://www.performanceoiltechnology...._and_trail.htm

HOW TO MEASURE CORRECT TRAIL

Raise the bike to an upright position, using a tape measure, hold the tape straight down from the front axle to the floor. Put a mark on the floor at that point. Then place the tape parallel to the steering neck, following the angle of the steering neck all the way up to the floor. Put a mark here also. Now measure the distance between the two marks and you have your trail measurement. It should read between 2 and 4 inches. Note: If your bike is equipped with a rear suspension, have someone sit on the seat when you make the measurements to simulate your actual riding condition.

TOO LITTLE OR NEGATIVE TRAIL

With too little or negative trail (steering axle mark behind the front axle mark), the bike will handle with unbelievable ease at low speeds, but will be completely out of balance at high speed. It will easily develop a fatal high-speed wobble. EXTREMELY DANGEROUS!

NORMAL TRAIL

Normal trail is somewhere between 2 and 4 inches. The bike will handle easily at both high and low speeds. Flowing smoothly through curves without swaying or wobbling. If you use a very fat rear tire, you should keep the trail as close to 4 inches as possible.

TOO MUCH TRAIL

If the trail is more than 4 inches the bike will handle sluggishly at high speeds. It will seem almost too steady. You will have trouble balancing the bike at lower speeds or on winding roads. It will feel generally sluggish and clumsy.

 

I think I put the Kouba links that lowered mine 1.5 and then raised the bars which feels better to me and slid my forks up 3/4" to the taper and This is what Norm Kouba recomended to me to make the bike handle correct.... I also replaced that floppy Big front fender and that made a big change in High speed riding I have had the bike at around 85 mph and it is stable for a lite weight bike with knobby tires.....I also reset the rear spring load for the changes.....

 

You know this rake and trail stuff got me thinking back in the "day" early 80s when a group of us were desert racing out here in CA. Alot of the theory makes sense, I recall if you owned a Husky it had more rake than a Honda or a Yamaha which made it more stable in the high speed stuff (less head shake) but if you had a Honda, you could always corner faster if we we racing a grand prix........ Then Scotts started selling the stablizers ....Just my 2 sense!

 

If you look at the link below you will find the factory settings for the rake and trail are 26.5 degrees (Rake) and 4.2 inches (Trail). I compared my stock DRZ400S and attempted to measure both bikes and they were very similar. I just need to find a better more accurate way to measure now but as long as they were so similar I feel fine...

http://www.kawasakimotorcycle.org/klx250.php

hth,
db

 

When I lowered the rear 1.5" and raised the forks .5" up front I measured over 5" of trail. I put electrical tape on the floor and made marks for 1", 2" and so on with silver sharpie. Then I sat on the bike and used a tape measure as a straight edge, lining it up with the steering neck. I also got 3.5" of trail after I set it all back to stock so maybe this method isn't accurate since the stock should be 4.2". It was the best I could do by myself. I'll have to find a helper to get more accurate measurements...

 

You americans worry too much, get out and ride [8D]

 

Funny thing is that I came up with measurements over 5" on both my bikes too! I sat on the bike and had a helper too and used a couple of straight sticks. So until we can get a repeatable way of measuring the stock setting at 4.2", we won't know what we really have. Look at it this way, I would rather have too much trail than not enough because a high speed wobble would be worse than harder slow speed steering. Besides, the wife would drop the bike cause it was too tall and her feet didn't touch and since I lowered it she hasn't dropped it once. We are going riding. [sm=itsok.gif]
db