Changing Steering Stem Angle

All,

So I am into my "Sanctuary" type build of my '76 KZ900. Welding and fabricating the frame with a "Leon" (thanks guy!) gusset kit and redoing rear set mounts, moutning up my new suspension, new upper shock mounts, oil cooler mounts, GSXR steering damper integration, etc.. My question is, should I steepen the steering stem angle in order to improve turn in? Has anyone else performed this modification? If so, how did you jig up the head stock to prevent misalignment during the fabrication? Did it end up being worth it? Any input would be appreciated.

Cory

If ur taliking about raking the frame Les raked his and for the ney sayers who say long and low wont wont turn in I highly reccomend climbing on les' bike.

Give Les a shout out he may be able to Stear you in what needs to be done

Thanks for the info, but I was actually thinking about less rake and steepening the angle of the head. Eitehr way, his experience and feedback would still be beneficial.

Cory

the offset of the trees pulls the forks closer to the stearing head I'm sure the other guys can give you a more technical aspect of the swap as I am learning it all myself

Do some homework on rake and trail! It will give you a better idea of what your going to get when you start playing with rake. Going with the newer front ends reduces offset alot of times which slows steering a little but improves stability a higher speeds. There is no free lunches when it comes to this. Watch the road racers, they are experiencing head shake when they upset the chassis even a little, they run a compromise of quick turning and high speed stability. They actually change this depending on the course they are running. Where do you want to be needs answered.

Les

I would expect you can accomplish something similar by sliding the front forks up in the trees (have to watch for clearance!) and putting longer shocks on the rear. However, it makes more sense to have a target geometry before changing things up - there are many rake/trail/offset calculators out there. You don't want to de-rake the head and then find out you have massive stability issues.

Understood. The unfortunate thing about this, is that you won't truly know what it will be like until you ride it! Then everything is PC'd and pretty and you hate to cut into it to make changes. I have several books and articles specifically geared aroound motorcycle frames and their geometry. If this was a car, I would be up-to-snuff to make this type of change and know what to expect. Will continue to keep reading and make an a more informed decision or guess.... Ultimately, looking at bring the level of handling to where my SV's and ZRX's are at.

Cory

Hit Mark1122 up, I think he's got a pretty good handle on making one do the twisties which is where I assume you are going.

Les

DrWhizBang wrote: I would expect you can accomplish something similar by sliding the front forks up in the trees (have to watch for clearance!) and putting longer shocks on the rear.

That's where I am now and it's too squirrely at speed, feels like I'll get a slapper any minute.

what r your intentions for the bike when done, road race track, drags, or street?

That's a direct result of reduced trail. Going with a newer style inverted front end corrects some of that by having a lower offset in the trees. The ZX's have around 26mm offset, The GSXR's have around 30mm offset, Stock KZ's have around 60mm offset. Find a rake and trail calculator and punch in those numbers and you'll get the picture.

Les

I am using ZRX1200 front forks and rear suspension. As far as application for the bike, looking for a nice street going, canyon carver. No racing will be in the cards for this one.

Cory