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A-arm modification


shoopie

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Im starting a new thread to make this just a project thread instead of the "planning a project" thread that the other one was.

 

anyway, here are some pictures of my progress. i also got my ball joints today (ES2074R special ordered from NAPA) and reamed out my spindles to fit. my reamer wasnt big enough so i may have to grind down the castle nuts so the holes line up.

 

first thing i did was grind out the back of the shock mount to accomodate for the yfz shocks im getting.

 

2010-12-16135844.jpg

 

i ground out the welds on the lower mounts to pop out the cast ball joint tabs.

 

2010-12-16135904.jpg

 

i then cut off the top tabs and ground the arms clean.

 

2010-12-16135824.jpg

 

i marked out the lines and cut for where the new joints were going to be installed lined up with the original ones.

 

2010-12-16141439.jpg

2010-12-16141453.jpg

 

here are the 3" x 1" steel slugs im going to be drilling and tapping for the new joints. i went with 3" because i want to widen my front end a little bit. it should be about 1.5" wider on each side

 

2010-12-16135941.jpg

 

hope you guys like my progress and i will be updating tomorrow.

 

also: do you guys think extending them like that would throw off my geometry? also, because im using yfz shocks should i kick the angle of the bungs up a little bit to help the ball joints sit even when not under load? or should i move the shock mounts down a little bit?

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also: do you guys think extending them like that would throw off my geometry? also, because im using yfz shocks should i kick the angle of the bungs up a little bit to help the ball joints sit even when not under load? or should i move the shock mounts down a little bit?

 

I love home fab!

With this set-up the ride height will be higher: The YFZ shocks are longer and stiffer, that plus the extension will lift the bike up. Move the tabs outboard to set your preferred ride height.

 

The angle of the ball joint at ride height is not the issue, preventing the ball joints from binding at the upper and lower extremes of suspension motion is more important. IOW, the shock should be the limiting factor in suspension travel, not the ball joints. Angle the threaded slug to achieve this.

 

Now is also a good chance to set camber.

 

Read up on the Lonestar website on camber recommendations for your type of riding.

http://www.lsracing.com/img/Guide_21.pdf

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I can set camber with the ball joints when I'm done.

 

Sure you can, but ideally you want as much of the balljoint thread to be inside the slug when all is set and done.

It would be a bit silly to end up with 2.5 inches of thread outside the slug and 0.5 inch inside the slug, wouldn't you say?

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bumping this up. AKHeathen: in response to your request on the other thread: Hard pack, loose gravel, mx, sand pit, trails/woods, little jumping, whoops. Pretty much anything I can get at. I ride pretty aggressive and fast but i like to just mess around sometimes. It was about 1/2" of negative camber on each side

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you measure at the tires, and take into account what the toe adjustment was at the time of measurement? the toe will effect your reading because of the knuckles SAI ("kingpin angle") the sai you cannot change, unless you run the reamer at an angle, instead of strait out, but that runs a high chance of snapping the bit, or at least one or 2 cutting edges. with the new ball-joints, you will be able to adjust the camber, but what you really have to get more precise is the caster. usually, 3-4 degrees is a good all-around dirt, but you can go as much as 7 if you ride more low-speed technical turning and such. it will ba a little harder to turn, but bite better it sounds like you may like it set at 5 degrees.....

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you measure at the tires, and take into account what the toe adjustment was at the time of measurement? the toe will effect your reading because of the knuckles SAI ("kingpin angle") the sai you cannot change, unless you run the reamer at an angle, instead of strait out, but that runs a high chance of snapping the bit, or at least one or 2 cutting edges. with the new ball-joints, you will be able to adjust the camber, but what you really have to get more precise is the caster. usually, 3-4 degrees is a good all-around dirt, but you can go as much as 7 if you ride more low-speed technical turning and such. it will ba a little harder to turn, but bite better it sounds like you may like it set at 5 degrees.....

 

yea i measured the camber at the tires. caster will be whatever it was when it was stock. i didnt measure the toe angle but it was about 1-2 degrees of toe-in.

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It would be a bit silly to end up with 2.5 inches of thread outside the slug and 0.5 inch inside the slug, wouldn't you say?

 

 

It won't hurt anything though. Once you have at least one diameter of the bolt threaded in nothing gets stronger.

 

ex. a once a half in. bolt has a half of an in. threaded in, it isn't getting stronger.

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It won't hurt anything though. Once you have at least one diameter of the bolt threaded in nothing gets stronger.

 

ex. a once a half in. bolt has a half of an in. threaded in, it isn't getting stronger.

not true. the bolt can, and does rock in the threads, and it will chew them up and wiggle loose. if anything is extruded more than the head of a screw, you want 2x diameter, or at least 2-1 on the point of force with deflection, which is what we are talking about there. i would find out what the caster is going to be before welding it all

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  • 2 weeks later...

Welded up the bottom arms today. Not as clean as it would be if I used a tig but I think they came out alright. The way i set them up at the right angle is i installed the shocks and arms and set the front end down on blocks at the right ride height so i would have the standing weight on the shocks and i just welded in the bungs level with the ground. So there should be more than enough travel in both directions for the ball joints.

 

If anyone knows where I can find a tap that is the right size for those ball joints please let me know. I have been to every hardware store and autoparts store in my area and no one has one. I an going to go to the local machine shop later to see if he has one that he will let me use or will do it for me.

 

aefc0532-ee84-23d3.jpgaefc0532-ee90-81c8.jpgaefc0532-ee99-f7b9.jpg

 

I also indented the shock mounts for the yfz shocks.

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