www.zxrworld.co.uk

I got the question of:

A steering geometry check shows a motorcycles rake angle is incorrect. State two causes of this fault.

Any ideas??

whats a rake angle??????????? i bet its somet like an impact/pot hole. thats a wild guess lol

basically the rake angle or castor angle is "the angular displacement from the vertical axis of the suspension of a motorcycle measured in the longitudial directection. It is the angle between the pivot line and vertical."

Oh i C now i get it.

head on impact could alter the geometry or a cracked headstock. basically its the angle of the forks from horizontal.

masterofinsanity wrote:basically its the angle of the forks from horizontal.

generally stated as an angle from vertical not horizontal, but yeah.

1) pot hole/crash/other impact leading to bent frame/yokes/forks

2) rear ride height is wrong (adjusted wrong, collapsed shock, anything like that. Even a flat tyre will change it slightly )

3) forks are clamped at wrong height in yokes (lifting the forks through the yokes is a fairly common mod to speed up steering on slow steering bikes. reason it works is that it decreases the rake angle)

i knew it was either horizontal or vertical should have gone 50/50.

well i believe the zxr has a rake angle of 23.5 degrees.

If that was from the horizontal....hmm anyone?

i was just trying to point out that it was the angle of the forks

you mean you haven't memorised the rake angle of the ZXR400?

yes mate its 23.5 degrees

I was looking at a photo the other day from someone at work of their 1920's (I think) Norton, and commented that the rake angle was pretty extreme!

It's got to have been around the same as a ZXR - which was considered pretty extreme on a road bike until the last 5 years or so! No wonder the fkrs were so good in the TT races!

But they were made of pig iron Jamz

Could also be a flat front tyre, tread has worn on either front or rear tyre. Rear ride height adjusted. The bike could be on a hill?