By "bleed" is this referring the through hole in the piston or something else, it seems it would have an effect on the compression as well as the rebound?

I did not word that right. I meant so we all could follow along. Pretty sure zero has a plan in place.

The bleed hole in the valve do work both ways however shaft speed is not the same bump to rebound.

I do not want to get ahead of him so I will leave that at that. I just thought with a pic of the valving we all could play along and understand what he was doing.

Also he will be using a pyramid or linear shim stack. Pyramid is easy to relate and easy to adjust. Basically large dia shim to small dia stacked. Then either all shims have same thickness or not for there dia as they stack. Some find this easier then over /under.

One final note they do make bleed shims so it can be used one way.

So for now we stick to a # then look at what shims are for that number and a pyramid stack to keep it simple for all.

Sorry for any confusion

Interesting fox sells bleed shims.

The pistons are all different. High/low flow, steel/aluminum, 0/1/2 bleeds. Lots of combos. These stocks came with low/steel/1 bleeder. I’m going back to that setup, only I’m going to start with 30/30 shims. If it’s too slow I’ll add a second 0.070” bleeder or more. Maybe I’ll look at the 0.006” shims too. They sell as individual not the full stack. I guess those would be about 20# maybe not though.

Theres always option to completely remove shims also. Like, if I remove the largest compression shim it would actually be like adding 4x bleeders. OR; removing a middle shim will make the larger shims easier to flex and flow a bit more - Eliminating a middle shim would be interesting option to try if valving in one direction is perfect but the other needs a substantial change - especially if already using the thinnest shims.

I’m going to focus on rebound a little more than compression. I’m just trying to stop mostly the bucking but if I get a little compression dialed along the way then yummy. It’s going to be about 2 weeks until I test. I may bring tools, vise, and other items to change out shims/drill to the trails too.

I got my parts in today for rebuilding and revalving. It took about 1 hour per shock to redo everything. This being a first time for me I took my time and did everything twice to be sure. 30/30 valves, low flow piston with 1 bleeder. New fox red 7w fluid. Viton seals. All done and put together. I’m just waiting on my Nitrogen fill kit to arrive but in the meantime I put 10psi of air in the chamber so that nothing moves and so I can reinstall. I should have my nitrogen fill stuff by Monday and I’ll purge the reservoir with fresh n.

Bouncing my weight hard on the rear and it’s a lot stiffer/slower than before. Even w the 30/30 valving. I guess better ride test it in about 2 weeks, but I’m already thinking I may need another bleed hole. I’ll see how much travel I get and how the rebound feels then.

Or I may try a flutter stack in rebound. Depends on how everything feels and if suspension is consumed or not.

Cool stuff
What did you set you IFP ( internal floating piston in rezzy)depth to.
Did you check before you drained it or did you set it to factory recommendation.
He may not have it set or set for a single bleed hole. With his set up hard to tell what he used. If you have the shock part number you can look up or ask kart. For base line testing short runs air up to 150 using your air compressor or 200 if it goes that high.
Don't forget to take your temp gun to measure shock body temp after hard run for HSC. With what you did your temps should go up which is a ok thing.

Look forward to your results.

Something to think about for those who are following. Look at the size of the shock body in area and rezzy in area. Then consider the area taken up in the shock body at full compression by shaft. The excess fluid needs to go to rezzy as not to hydraulic the shock. Small shock with rezzy you can set at almost zero. Larger shocks with more displacement require larger area rezzys set at a % or IFP depth. This way a MFG can use one rezzy for multi set up with on a range.

Just some food for thought. With getting into a whole lot of babble math.

So what about shocks with out a rezzy you ask. That is where you set shaft depth.

IFP is set to 8 inches. The reservoir is 11”. This is factory.

I was going to try 200psi first. It’s easier to drop quick with my mtb Fox hand pump/gauge out on the track/trail than it is to increase. I think more N might speed up rebound and slow down compression.

now you guys are going to make me rethink my setup on the rezzies, rebuilding ATV shocks you start with empty rezzy, then discharge all the pressure, and install the seal head and the bit of oil that goes in from the seal head sets the initial oil in the rezzy I do the valve adjustments without disassembling the reservoir.

My Rez is don’t have adjusters. If yours does, then you also have a shim stack in them.

I got my N tank and setup yesterday. It’s a bit crude but I was able to top up the N in shocks to about 220psi, and then with my mtb fox pump used it to bleed off a bit of excess exactly down to 200psi. Sag is set to 25%. Seems quite stiff now. Ready to test.

yes I have the adjuster for compression in the rezzie, I was told by a Fox rep that it does not restrict the rebound but I find that hard to believe.
regarding the charge pressure 150 psi is the minimum to prevent cavitation so you should be good at 200, that is where I set mine, thinking it may help with getting the oil out during rebound.

It shouldn’t restrict rebound because the shim stacks are always directional, and the DSC stack is only for compression. However, your rebound would be slowed slightly due to oil weight through the passages of the DSC, but the selector should have no affect on rebound.

If your compression is good, and rebound is close but slow, and you are using #30 shims, you can try some 0.006” shims in rebound, or remove either the second or 3rd largest shim. Otherwise it’s on to drilling the piston.

I'm not too keen on even changing shims let alone drilling the piston, it dunes great now, rebound is fast enough if I'm in the air for a landing, my issue is I have limited time out riding, don't want to spend too much time tweeking on it.

We'll see next season, I'll put the go pro on the suspension, ride hard, maybe make a change sometime between trips :)

Results of the rear Fox 2.0 valving change are in, and first let me say, I am so far VERY happy with the results of using the following setup/valving!


NEW SETUP:
Fox 2.0 7/8" shaft
175 TOP spring, 10" long
100 BOT spring, 16" long
Crossover set about 1.5" above contact point at sag
Steel valve piston with 1 factory 0.070" bleeder
#30 Rebound valving
#30 Compression valving
Nitrogen pressure at 150psi (Suspension lifted off the ground!)

ORIGINAL SETUP from Dave-Co
Fox 2.0 7/8" shaft
80 TOP spring 12" long
100 BOT spring 12" long
Crossover could not be engaged
Steel valve piston with 4x 3/16" drilled bypasses
#70 rebound valving
#50 compression valving
Nitrogen pressure at ????PSI


So, I went into this stone cold with no idea really. I'm not really a shock guy. Not really a suspension guy, but I do like to tinker. The OLD setup was very bouncy. Bottomed out really badly over almost every bump. Replacing the springs initially helped a little, but the suspension still bottomed out, bucked like a bull ride, and never settled. It was QUITE a terrible handful to say the least.

So, threw in the NEW piston and #30/#30 valving. Right off the bat, it felt SOO MUCH BETTER! Un-believable how much of a positive difference. Rebound is quite smooth and predictable, though maybe just a tad bit of a hair on the slow side. I may consider trying #25 rebound - not sure. I might just leave it alone. Compression felt great as well, but just a tad bit too hard initially, and it was only traveling about 80% over jumps. Initially, I had my crossover just 1" above sag, and N at 200PSI. I lowered Nitrogen to 150PSI, and then raised my crossover to 1.5" above sag. BINGO! Now over the same jumps it will compress down to 100% travel and un-noticably tap on the bump stop. Compression feels Perfect!

Now that jumps and big bumps are ear-to-ear, I still have to think about something. In rumbling sections, like just blazing down a rough cut trail seems the suspension it just a bit on the harsh side. I'm may keep everything as it is, because its surely so much batter than before, I'd really hate to mess it up... But I somehow just wonder if a second 0.070" bleeder would smooth out those rooted trails a bit, and also increase the speed of rebound (Which I think I need just a tad bit faster rebound). Surely though; if I add a bleed then I may need to raise compression to about #40, raise N to 200PSI, and maybe play with the crossover.

Thoughts?

A video of you running thought the woops. Would help with what direction. Do you feel it bucks or wonders after entering or at enter. Or is it speed sensitive. When you go back do some warm up runs and then tape ding runs at different speeds. Also enter at speed, enter slower and accelerate. Then I would repeat putting your cross over back where you started. This will give you an idea on what to change. Since your valving is broke up in three sections. Also do a run breaking like setting up for a turn. This will see what kind of transfer you getting. The breaking bums will see how it unloads. Maybe even run it by your shock guy.

Glad to here it's better.

Thanks. I'll consider some video next time of what the rear is doing.

To add, a couple new nuances showed up now since the rear feel so good. The front right bottomed out a good 4-5 times yesterday as well. To compensate I increased compression dampening from 3 to 6 on the both front clickers, which go from 1 to 8. Also added just 1/4" of spring preload to each. Cant check Nitrogen on the fronts as they need some kind of needle adapter.  That felt and seemed better to me. Front rebound seems to be good.

Turning is a little strange... Right hand turns at both slow, fast, and power sliding feel great. Rotates with ease. Seems nice and tight perfect for what I like. Left hand turns are a little wishy washy. I hate turning left because its un-predicible. Understeer. In-acurate at times. Tends to push when turning left; especially on the skid pad. Seems the faster I go, the less turning capability I have to the left. No so with going right. While out there I measured all sag heights with a tape measure. All are good. I did notice the rear left tire was toed in slightly where the rear right was straighter; so I tried doing in the rear right tire. It didn't help - may have made it worse actually. I tape measured some things with the rear to center-points on the frame. Everything seems square? Tire pressure is 5.5psi front, ant 6.5psi rear. Front is toed out just a tad. Caster is at about 8*. Close to zero camber at least equal on both sides.

Could it be corner weight? The rotax is biased weight to the rear right I believe. I'll get the scales out? Perhaps I can slightly adjust sag to make corner weights even if only less than 1 turn per perch? Not sure how that will work out?

Here’s a picture of corner weights, 185lb driver. 35lb in the footwell and 150lb in the seat.

I went ahead and adjusted a few of the spring perches. No more than about 1 full turn each.

FL to FR had a 12lb difference (BAD)
FL+RR to FR+LR had a 14lb difference. (BAD)
RL to RR had a 2lb difference. (OK)
10LB difference L to R

Total difference = 38lb (Added above 4 numbers up)

The front left corner weight was the worst gap of 12lb left-right, and diagonal weight had a 14lb difference. I started with the front left. Turned the spring perch about 1 full turn tighter. This diagonally also added too much weight to the RR so on that corner I took 1/2 turn out. Then the LR was a little low, so added 1/2 a turn to that corner.

This made a difference:

FL to FR now has a 4lb difference (BETTER)
FL+RR to FR+LR now only has a 1lb difference. (GOOD)
RL to RR now has a 5lb difference. (A little worse)
9lb difference L to R

Total difference now is 19lb (Added above 4 numbers up)

Hope this helps??? My understanding is the cross weight makes the most significant change in cornering capability, and now that its only at 1LB compared to before at 14lb, hope this helps?

Next time you get out tape measure. Measure from rear radius rod mount on frame to the lower ball joint center on both sides. If different than measure from axle center front to rear both sides. Write these down.
Then next time you pull tires and shocks off do the same with the axle centers at a level vertical location to frame. This may help solve. Rear axle straight out, lower arm straight out from lower frame mounts.

This will help square things out. Once your happy with shocks. I would look at changing front settings. One change at a time.

Radius rod frame mounts to front lower ball joints.. Both sides are within 1/8" of each other. Not bad. I guess one little turn of one of the hems might fix that.

Similar with the rear. 1/8" difference from the same points of the rear hub to something centerline up front. Only about 1/8" off - if that. I did spend a lot of time trying to get things square a few months ago.

Easier to measure front of rear tire to rear of front tire - shortest distance. Both are measuring exactly the same L and R.

I did mess with caster a bunch back when... Maybe I should put caster back in? I wonder if the front right caster isn't causing enough negative camber angle during left turns. That could cause push too. Actually it would be easier for me to just add a bit of negative camber to the front right.

Sound close enough. By setting the front lower arms flat you can see any change from what you have static setting there. What your looking for is the change side to side. Your at 1/8 long on ? Side.

Here's a pic to share

If I read right. 8 degrees caster and zero camber.
Tend to agree with you. Since your running pilot hubs may not be much help other then if memory serves they are set zero on caster. I'll have to check.

I use trx 05 so I'm set at 4 degree and 1/4 camber. I think I would reduce caster and go 1/4 to 1/2 negative camber. Only reduce caster to a point not to wander in woops. I say take as much out you can with upsetting it this the rough stuff. With you set up the rakes different to which impacts the caster camber setting. Basically front sitting up higher changing lower arm pivot angles. Check it compared to you other pilot maybe be an ah ha moment.
This is one reason I opted for the kpi of the 05 trx. Other have had success with 06.

Hope this helps if not be sure to give thumbs down.

There are so many angles and accountable items its much fun. Just tonight I found issue with my rear toe. I measured a difference left-to-right, where the right rear had more toe-in than the left; which causes thrust angle to bias to the right; hard to say by how much but definitely angle was there to show it. Maybe it was only 1 degree but definitely seeable when measuring. This would make sense given right turns were rotating very well; while left not so well. Yesterday I made a quick RR toe change also and I think it made the problem worse.. Thrust was helping right turns, but then hurting left turns. Adjusted toe to fix thrust, but first;

Also my rear toe in general was way WAY off - toed in at 1.25". I did this a few months back when I had the 400 mill; thinking it would loosen the rear. Nope. Instead I must have left it at 1.25" of toe-in! Holy cow! Maybe I have too many projects going on LOL.

Rear Toe-In is really bad for RWD/IRS under great power. It was probably toeing in up to 2" under heavy load! Also might have been causing and strengthening the bad left turning (thrust line) under high power as I noticed. I had to measure and remeasure 6x times to be sure. I did just fix it. Now thrust is as centered as I can measure, and the toe is set to 1/16" toe-out. Under power it will likely toe-in maybe up to 1/2".

That could fix a lot of things. Come to think of it, when I was under heavy lefts at the skid, understeering; then letting off the throttle was making understeer even worse. that's caused by too much rear toe-in (Drift car's make a heavy note of this being a problem during a drift situation; where the rear will grab and straighten the car up when lifting the throttle. Drift cars fix it by running zero or 1/8" toe-out in the rear).

Hope this helps fix it? That and the corner weight equalizing should be a plus?

I'll look more into front caster/camber later. Rear toe was very alarming tonight.

sorry about the 0 caster for stock.
looked it up this morning
The toe in # is for front

I’ll keep in mind. Pretty easy to add front toe. I made so many little adjustment that I want to check first before I go further. I don’t want to cause uncontrollable oversteer

I added an additional 1/16" bleed hole to the piston because I felt high speed rebound was not quick enough with the #30/#30 shims. The second bleed helped out a lot going down very rough trails. For now I'm going to leave the rear shocks as is and maybe play with just crossover points there. I might need to add a few shims to compression - will see.

Unfortunately, I'm still getting un-equal turning capabilities.

Right turns are great. Very even and highly controllable. Able to over-steer, etc. Feels good.

Left turns are still pushing. Unless I whip the front end left, jam the rear brakes, or mash the throttle quickly, left turns are slow and oversteer pretty heavily. A few times I almost veered off the trail due to understeer. Also the pushing gets worse and worse the more I'm on the throttle. In fact at one point it was so bad that I thought my rear right wasn't spinning!

I checked and re-checked most every way the rear is set up. Radius rods are equal length. Thrust angle is within 1/8". Rear toe is set. Everything in the rear feels equal.

Front may have an issue. My front right upper ball joint had been loose since the beginning of this machine. It adds about 1/2" of variable camber. I've ordered a new ball joint from Sikk Rides (TRX450r upper ball joint with 22* angle). Hopefully I can somehow incorporate it; maybe it will help out?

Also I'm going to swap the front drums for TRX450r disk/hubs very soon - just waiting on some hub rebuild parts. This will require a front-end re-work. Hopefully I can find and fix any issues related to camber, caster, bump steer, or toe.