Yamaha upper A-arm bolt bending

[dawnchris]

Who's had trouble with this? We run arms with adjustable hiems on top, and keep bending the top bolt. Happens on Banshee, Warrior, and Raptor so far. It's not bad, but it shouldn't be happening. We are currently building arms for a YFZ, and have added tabs to the frame so the arms mount like a Honda. No more long bolt, no more problem.

[dawnchris]

hello?

[Pappy]

there is quite a few of the yammies running around with a tweaked bolt or two.

the bad part is mainence comes dead last on alot of machines so i doubt many even know they have a problem:p

welding the honda style mounts on is more then the average rider can do

[dawnchris]

At least I know it's not just us!
Anybody try to go 1in. forward with YFZ arms? I'm thinking of trying it.

[465Stroker]

In the past 2 years we have been thru 6 YFZ's with over 400 hours between on all of them with Leager, ArsFx & Lonestar A-arms without a single problem. The Leager & ArsFx were fixed caster A-arms which used the stock bolts and the Lonestar's come with there own bolts that thread into the sleeve / space that goes between the heims.

I have never heard of this problem before..:confused:

[dawnchris]

It's pretty darn common when running caster adjustable uppers. If you really think about it, it's not a great design. There is no support whatsoever for the bolt other than the far mounting tabs. When you run in the big rocks as much as we do, the upper arm can and does take alot of load. Look at the newest ATV mag that shows Farr in the rocks doing a "How to". That is the type of stuff we race through at every race.
We decided on my latest quad to add another set of upper tabs ala-Honda. It should take care of the problem completely.

[muff]

walsh has been makin adding the "4 mount" to their frames as well. it happens to many MX riders

1" forward is popular for mx as well, i'm not so sure what works for desert

http://www.wrcracing.com/shop/images/gk-yfz-4mount-onsite.jpg

[dawnchris]

Muff, yur always good for some info!
I'm going to make the arms +3 and +1. Should be nice, similiar to the Hauser, but with a captured nut at the front and no hole, so nothing gets in there. Probably have integrated skids under the shock mount as well. Thanks guys!

[muff]

I like the sound of havin the nut captured up front. are you going with the regular 18.5" shock or are ya goin longer?
what type of ball joints are you usin?

[dawnchris]

Yea, gonna use the regular 18.5 shock. Thought about going bigger, but want to be able to sell the arms easier, so decided to stay with the 18.5. We usually use the moog 2074. They hold up well, have one of the better degrees of angle movement for the money.

[muff]

you should talk with sickmojave, hes built some crazy custom a-arms for his mojave :cool:

[dawnchris]

Here's some pics of the new arms in the works. +3 and +1. Lowers use .120 wall thickness for better rock damage resistance, and .095 for the uppers. With the setup as seen, there is 12.9 inches of front wheel travel. This may change as we finalize settings. Note the upper arm mounts ala Honda. No more long bolt to worry about. These will be set up for 18.5in. shocks.
...and yes, thats a modified shopping cart the bike is on.
http://img.villagephotos.com/p/2003-7/269162/HYVCG-arms001.jpg
http://img.villagephotos.com/p/2003-7/269162/XDZPU-arms005.jpg
http://img.villagephotos.com/p/2003-7/269162/YYPIX-arms004.jpg
http://img.villagephotos.com/p/2003-7/269162/OPQHT-arms003.jpg

[muff]

looks good so far. but 2 things caught my attention

1. the lower ball joint looks very weak. i dont know much about them so i cant say if it is or isnt. but i think you shouldnt have gone with a ball joint setup like that
2. the other is the location of the grease fittings on the lower a-arms, sure looks like they'd hit the frame and bust off

what kind of design do you have for the lower shock mount?

you are using the 18.5" shock correct? you say 12.9" of travel, did you make sure the frame will go down far enough, so it ends up close to the ground when bottoming?

[dawnchris]

The balljoint is a Moog 2074. Probably one of the strongest out there. Larger than many companies use. Really not anything better.
The grease fitting you see is on the stock a-arm, so it would be fine, though we don't use grease fittings. We dissassemble the front every couple races to check it out and to grease.
As stated earlier, the lower shockmount will be much like the Hauser arms, but with a captured nut in front, and no hole.
Still working on setting up mount points and such to ensure proper clearance when bottomed. Trying to get a happy medium.