Yamaha Truly Unlimited UTV - Rustfish Racing 2921

motive

Active Member
Jan 12, 2014
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Pleasant Grove, UT
Hey Reid, Motive = Zane. geez man, can't even keep your friends straight? haha Ryan owns and drives the car. I'm just one of the CAD junkies/suspension geeks on it.

He can call me a member of the peanut gallery all he wants but if he is trying to show something important with that level then he needs to explain some details. Is the upper a arm axis (bulkhead?) parallel to the ground? Is the face of the steering arm perpendicular to the ball joint axis or something? I could bend that steering arm up/down, in and out all day (a somewhat common practice with forged spindles in the road racing world) without changing the castor or whatever he is trying to show. I was not intending to criticize by any means. Just pointing out that the info the level is displaying is useless without some explanation. If the "bulkhead" is designed at the same angle as the target castor AND the face of the steering arm is perpendicular to the steering axis then yes, it is "spot on."

In a traditional matter I would also define a bulkhead similar to how Reid does however it does not have to be a firewall per say. But a load carrying structure that is designed to take loads that are not along the axis of the main tubes (bending loads). Typically connected to other bulkheads via tubes. While a bulkhead could be laid down horizontal a typical race car chassis is build with the main tubes running front to back. If you have ever spent much time in a WWII era plane you will get a good idea of a bulkhead. Most TTs as well as the Redlands car have a very defined bulkhead that carries suspension pic up loads as well as carries the steering rack and its corresponding loads. All that being said only for the sake a sharing, I might call an apple a potato and you might call it pumking...I still got where you were going.

Telling how much anti dive a RZR has isn't a simple answer. It depends on the (sprung) center of gravity height that is going to vary from different ride heights, probably 2 or 4 seat, 1000 or turbo. I have no idea the range a stock vehicle would have. But to the best I was able to measure the chassis it is about 4.7 degrees between the upper and lower a arm axis. The whole thing is also canted up 4.something degrees.
 
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tatum

Hans Solo - 2009 UTV Baja 500 & 1000 Winner - UTVU
Feb 10, 2009
1,450
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arizona
Hey Kornfed, I'm jonesing over here. You got any new updates?
 

kornfed

Active Member
May 13, 2015
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Costa Mesa
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OMG we have SHOCKS and a Fuel Cell!!!! Finally. Here you go. Rears going in today. Will is busting ass to get this done. How many weeks to go...? YIKES...!!! If this gets finished it will be a miracle, but Will is on it. Damn, parts are always the long pole in the tent.

Oh and the see something say something is off the table. Out of time. If you have questions, Jerry will have a booth at UTV World Championships. You can ask him directly. I feel like I botched up the translation a bit, so go to the horses mouth at the race.

IMG_0918.jpg IMG_0919.jpg
 

tatum

Hans Solo - 2009 UTV Baja 500 & 1000 Winner - UTVU
Feb 10, 2009
1,450
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arizona
Keep the pics coming if possible, and ignore the naysayers. I'm pretty sure the Penhalls know a thing or two.
 
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badassmav

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Jun 11, 2013
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Jamul
Car looks awesome Dave.
I like the fact that Yamaha actually uses a separate transfer case to handle the 4wd assignments (although it seems kinda massive!). Its really the smart thing to do. I think Polaris got the whole 4wd layout wrong with the electronic push button switch, the vulnerable front differential/Hilliard thingy, and the long 2 piece driveshaft, with its flimsy carrier bearing and indifferent u-joint working angles. I think most everyone who runs a Polaris has had 4wd engagement and/or driveshaft issues at one time or another. Talk about flimsy:
I think the cluster design on your top rear shock mounts and the doubler plates on the bottom rear shock mounts look clean, are a wise choice. Those mounts will repeatedly experience a 2-3,000 lb. loading at bump, easily. Using a cluster design to spread the load on the chassis' tubing is definitely an open class fabricating discipline.
The car is really taking shape, and looks the part of it's classification as well. Hope I can make it out. Go kill it dude!
 
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bluediamond

Active Member
Jun 24, 2015
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Korrnfed you must be so stoked how this car is turning out.. I just saw the 1st weigh in. 1900 pounds with a half tank of gas is pretty amazing. I know thats minus panels and other small stuff but its a crazy number. My brother and I were saying we are hoping you guys go with a super charger instead of a turbo for phase two. It would make it even more over the top. Looks like the boys are kicking ass for you over at Penhall. This will be by far the sickest out there to date. Congrats...
 
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badassmav

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Jun 11, 2013
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." I just saw the 1st weigh in. 1900 pounds with a half tank of gas is pretty amazing."
  • All I can say is WOW! I can scrutinize a lot of things, but that aint one of 'em. With the lengthy boxed trailing arms and second set of shocks, a sub 2,000lb. wet weight is downright impressive. Your fab guys know their shit for sure, but there has to be a maintenance penalty that goes along with the light weight racer they constructed. Which is a non issue as long as you have a trained set of eyes always at hand. But in thinking about it, a heavy race car can tear shit up as much as a light race car can tear shit apart. At the end of the day, if you gotta work on the damn thing anyway, it is much easier to add support as opposed to try and find places to remove it. Good for you guys.
 
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kornfed

Active Member
May 13, 2015
153
83
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Costa Mesa
www.tetraracing.com
Korrnfed you must be so stoked how this car is turning out.. I just saw the 1st weigh in. 1900 pounds with a half tank of gas is pretty amazing. I know thats minus panels and other small stuff but its a crazy number. My brother and I were saying we are hoping you guys go with a super charger instead of a turbo for phase two. It would make it even more over the top. Looks like the boys are kicking ass for you over at Penhall. This will be by far the sickest out there to date. Congrats...
Yep half a tank and under 2k. Will and Jerry made a sick car here. We will be at the UTV Worlds with this car and the Penhall Polaris 1992 Rustfish. Testing today. I will send out pictures shortly.


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kornfed

Active Member
May 13, 2015
153
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Testing today in Barstow. The car worked really well and the new 31" STI Chicane is really nice set up.

Can't believe Will and Jerry got it done this quick. Very excited to see this at the UTV World Championships. Still waiting on a few parts and need to do some last minute electrical items, but it is a race car and it works. Phase 1 in the books.

See you all at UTV World Championships. We will be there in the Penhall Contingency booth with this Yamaha and the Polaris Rustfish 1992. So you can see both builds. The 1992 car is for sale so if you know anyone that needs a sick NA build, please send them our way.

See you at the race....!!!






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NIKAL

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May 13, 2012
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Looks really good! Front straps are tight with no droop. Assuming that will be adjusted. Also no front axles yet. Will you have 4 wheel drive by race time?

What was the deciding factor to run a 31 inch tire and not the max 32 inch allowed?
 

kornfed

Active Member
May 13, 2015
153
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Looks really good! Front straps are tight with no droop. Assuming that will be adjusted. Also no front axles yet. Will you have 4 wheel drive by race time?

What was the deciding factor to run a 31 inch tire and not the max 32 inch allowed?
Axles on the way. Should be here on Monday. The 31" Wheel and Tire combo are a lot lighter and a little narrower. Thinking 10 car style.

We will see...

You racing?


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kornfed

Active Member
May 13, 2015
153
83
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Costa Mesa
www.tetraracing.com
Looks really good! Front straps are tight with no droop. Assuming that will be adjusted. Also no front axles yet. Will you have 4 wheel drive by race time?

What was the deciding factor to run a 31 inch tire and not the max 32 inch allowed?
Oh and we had just taken the car off the jacks before this picture so the shocks are loaded. It rides a lot lower...


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NIKAL

Well-Known Member
May 13, 2012
970
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63
Axles on the way. Should be here on Monday. The 31" Wheel and Tire combo are a lot lighter and a little narrower. Thinking 10 car style.

We will see...

You racing?


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Im not racing. I claim to be retired from racing! Honestly I've been in the sport most of my life, we have pictures of me at 5 years old in 1977 sitting in the seat being pushed through contingency in Baja. I've raced Score, BITD and a few other series and won races and a Championship. I'm sure I'll race again someday??? But right now I don't have the desire to spend the time & money to race. Did I say money? I just got burnt out, plus when I race it's 110%, we don't show up if we can't win. I've still helped a few teams in resent, but not committed.

I still love doing a few Baja play trips a year, and when we bought a UTV my love for just going out to the desert with the family and friends came back. When racing, it was all about racing and going to the desert was about testing, not playing and having fun.

Plus I have this bucket list Baja trip that I want to do first.
 
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badassmav

Well-Known Member
Jun 11, 2013
1,379
182
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Jamul
Testing today in Barstow. The car worked really well and the new 31" STI Chicane is really nice set up.

Can't believe Will and Jerry got it done this quick. Very excited to see this at the UTV World Championships. Still waiting on a few parts and need to do some last minute electrical items, but it is a race car and it works. Phase 1 in the books.

See you all at UTV World Championships. We will be there in the Penhall Contingency booth with this Yamaha and the Polaris Rustfish 1992. So you can see both builds. The 1992 car is for sale so if you know anyone that needs a sick NA build, please send them our way.

See you at the race....!!!







Sent from my iPhone using Tapatalk
Man, that thing just looks Badass! Looks like the rear tires track inside of the front tires. Good deal. Hope it all holds together, and you guys enjoy a top finish.
 
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kmb760

Active Member
Mar 28, 2013
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How's testing going? Can't wait to hear a full ride report in race trim.

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