high speed trail riding is all about knowing how to move your body around. i have both my 650 and 400 set to #3 up front and #5 in the back, when i snapped my rear axle on the 650 and used the 400 during one of our outings, i kept up with a 500 and 600 polaris and we were averaging about 30mph on some very aggressive trails, u have to hang your body over to the inside of the turns to really make these beasts handle, everyone was surprised at how well our old 400 did.

 

<div class="FTQUOTE"><begin quote>Originally posted by: TRAVISM3

I just bought a brand new 2007 AC 650 H1. Ive been preparing to start a local cross country utility class for awhile. I know a pretty good deal about four wheelers but not quite as much as I see some of the people on here know. Anyways, I know that some utility racers race in 4wd and some in 2wd. I know the advantages of this and I prefer racing in 4wd in on the trails due to the ease that the quad climbs over and tackles tough terrain and on the banked and rutted out corners (it is slightly harder to turn) the 4wd hugs the corners and pulls you out faster. It also prevents the rear end from breaking loose on soft terrain. I was wanting to know if there were any differential, u joint, or any other axle pieces you guys would recommend for such high impact on 4wd. Thanks</end quote></div>

You can check out some Gorilla axles, a bit pricey but I guess that they are pretty rugged.

 

ive checked out those gorilla axles myself after i snapped one of mine last year, they are quite pricey around 300 per axle. if i ever snap another stocker than im going to get the gorillas.

 

I guess this thread would be a good one to tell about my tippy 2005 500 cat.
I had it set up for rock crawling in Colorado. Had some 6 ply 27s on it for ground clearance and puncture resistance.
It was a great machine(with the manual tranny) for going oversome pretty big rocks that other brands would try and get hung up on their frames.
Until one day when I had just went over a pass at 12,500 feet and was doing an off camber steep downhill.
The trail had been a single track until a couple years ago when it got widened out to an atv trail.
Being it was on a steep sidehill, the lower track was quite a bit below the upper one.
I was going pretty slow when my front tire on the lower track hit a small washout, the opposite back end immediately flipped right over the front and it went over the side.
I lost count somewhere around the 15th time it rolled(and many dollers later).
Luckily it went over the top of me on the 1st roll and I only had a few bruises from the rocks.
Don't quite have it all back together yet, but I am putting 25s back on it.

 

<div class="FTQUOTE"><begin quote>Originally posted by: Pitkin1

I guess this thread would be a good one to tell about my tippy 2005 500 cat.

I had it set up for rock crawling in Colorado. Had some 6 ply 27s on it for ground clearance and puncture resistance.

It was a great machine(with the manual tranny) for going oversome pretty big rocks that other brands would try and get hung up on their frames.

Until one day when I had just went over a pass at 12,500 feet and was doing an off camber steep downhill.

The trail had been a single track until a couple years ago when it got widened out to an atv trail.

Being it was on a steep sidehill, the lower track was quite a bit below the upper one.

I was going pretty slow when my front tire on the lower track hit a small washout, the opposite back end immediately flipped right over the front and it went over the side.

I lost count somewhere around the 15th time it rolled(and many dollers later).

Luckily it went over the top of me on the 1st roll and I only had a few bruises from the rocks.

Don't quite have it all back together yet, but I am putting 25s back on it.</end quote></div>

My first suggestion would have been to put 25" tires back on. You have already done that so the next suggestion I would offer is to put some 1" spacers on all four corners. Great stability and great for off-camber. Check my pictures and you can see the stability when I have had my machine over a 45 degree angle and still very stable.

 

<div class="FTQUOTE"><begin quote>Originally posted by: buckaroo50

<div class="FTQUOTE"><begin quote>Originally posted by: Junkman673



I pulled the rear shocks out and cut up a old truck mudflap to put between the spring and spring collar. It looks really good.







While I was in it I found out my rear swing arms were shot! That would be the reason why the machine kept twisting so bad and lifting the inside wheel in a turn. (even a gradual turn)</end quote></div>



Maybe some new bushings will bring her back to life - lol... Good luck and keep us posted as to how you're making out. I generally check all my bushings (especially the shock bushings) every year and replace the ones that are starting to show wear. I believe it averages out to less than $10 a year. A couple bushings here and a couple there.</end quote></div>

Everything is done..

WOW!! What a improvment. It's like a new machine now. I especially love the 1.5 inch spacers

 

<div class="FTQUOTE"><begin quote>I would like to follow all of your advice but my machine is older and not IRS. When I go into corners the inside front wheel ALWAYS lifts up off the ground and the rear will stay planted. In a tight turn it feels like the entire machine is trying to twist in two. What do you think is causing it?
(look at my pictures and you'll see what I mean by the inside wheel coming off the ground. ) </end quote></div>

not sure anyone picked up on it, but you have an articulating SRA. A lot of what this post talks about (some of it very good) taking some preload out (shocks) and stiffening the spring rate (tires). That may help your ASRA. However, this idea is only going to go so far and is only part true. As far as smooth ground, the stiffer and flatter your machine, the better it is going to handle. Race cars don't ride nice. Of course if you lose control or lose contact with 'bumpy' ground from too stiff of a suspension, you are going to be slower. Every machine, rider, trail condition combination is going to require your own experimentation. There is no secret formula. Bottom line, due to the design of your rear suspension, it is not going to corner as flat as a typical SRA, but it will articulate more and, IME, be more predictable in off camber riding than an IRS. Your biggest adjustment to get flat cornering is going to be playing with the rear. But be careful, it is one of the best riding SRAs out there. Buckaroo has done a good job at explaining some of the basics and it was worth reading. Frndinalowplace has a point too, but you can make it easier on yourself if you spend the time to learn about what you are doing with your suspension.

EDIT: did not see that last post, your swingarm bushings were shot?

 

Buckaroo. I have a Yamaha utility and a Honda sport. I never ride either even close to its limits as I am a real cautious rookie on 4 wheelers. Your tips have been a real eye opener and an education. Now I will experiment with suspension and air pressure and try out your tips.
Another technical factor not mentioned regarding tire size is that the suspension will be most compliant with light tires and wheels (unsprung weight) relative to the weight of quad (sprung weight). This is extremely important with motorcycles due to relatively lighter sprung weight than with a quad but I believe light tires and wheels will even help suspension with heavier quads. I am very happy with my 25 inch Bighorns on 700 Grizzly stock wheels. The 6 ply tires with stiff/short sidewalls handle much better than the stockers and now that I know about significance of air pressure and suspension settings I'm sure I will like them even more.
So thanks again Buckaroo from a non ACer.

 

<div class="FTQUOTE"><begin quote>Originally posted by: oldturtle

Buckaroo. I have a Yamaha utility and a Honda sport. I never ride either even close to its limits as I am a real cautious rookie on 4 wheelers. Your tips have been a real eye opener and an education. Now I will experiment with suspension and air pressure and try out your tips.

Another technical factor not mentioned regarding tire size is that the suspension will be most compliant with light tires and wheels (unsprung weight) relative to the weight of quad (sprung weight). This is extremely important with motorcycles due to relatively lighter sprung weight than with a quad but I believe light tires and wheels will even help suspension with heavier quads. I am very happy with my 25 inch Bighorns on 700 Grizzly stock wheels. The 6 ply tires with stiff/short sidewalls handle much better than the stockers and now that I know about significance of air pressure and suspension settings I'm sure I will like them even more.

So thanks again Buckaroo from a non ACer.</end quote></div>

Good point on the unsprung weight. I feel that it comes down to personal preference. I also feel that the AC's are heavy (heaviest machines in class) and can handle heavier wheels and tires. I prefer heavy steel wheels and heavy tires. The reason is traction. Like a tractor putting liquid in the tires to force the tires to sink down and dig where the traction is and not to float or skim on the surface. The tire width by comparison is very wide on a 4 wheeler. Because AC is a heavy machine and my tire and rims are heavy I have been able to find traction and get through places where others failed.

 

I don't think I made myself very clear on benefits of lighter tires and wheels. No doubt that when the most traction is needed like mud then heavier tires will sink thru the mud and find traction. I was thinking of the situation where traction is plentiful but you want the suspension to get over the bumps easier. I believe I saw somewhere that the Quad Terrain Racing Series was won the last two years by Arctic Cat 650 single with 25x8 tires front and rear. I couldn't confirm this but I would like to know for sure.