350x progressive springs.

[atcmatt]

Just after a few opinions on the progressive fork springs for the 350x. My front forks are in excellent original condition with very low hours on them. I have pulled them down and changed the seals and oil in them. I run dextron auto trans fluid in them, it is a quite thin oil. I ride 99% sand dunes with a lot of vehicle ruts from 4x4s. I also do a lot of long steep dune hill climbs which require a good run up, I find when I hit the base of the dune at speed my front forks seem to bottom out and give me a good jolt on rebound.

I want to try and fix this problem. Would it be advisable to put some heavier oil in my shocks? A little more quantity of oil? Or just lash out and get the progressive springs (because they are the best thing since sliced bread?)

Thanks.

Matt

[loganm]

Get yourself some real forks up front. Inverts from a late model are what I'm talking about cuh. None of that weak outdated conventional junk

[barnett468]

Xlnt description, and although I don't have a photo of myself actually riding a 350x, nor do i wake up with grease under my fingernails [because unlike some people, i actually wash my hands before i go to bed], I did stay at a best western express hotel last night so I think i can answer at least part of your question.

how much do you weigh?

it would also be helpful to know how much your forks sag when you are sitting on it.

Since your forks are bouncing back up to quickly, increasing the weight of he fork oil will reduce the speed at which they return . atf is around 7 weight . ford type f atf has no friction modifiers but dexron does.

my guess is that you should try 15 wt oil.

if it bottoms out easily the way it currently is, i would also increase the oil level by 5/8".

if it currently sags more than 1/3rd of the total amount of travel. i would get some pvc pioe just slightly smaller than the id of the tubes and cut two pieces 3/4" long then install one on top of each spring.

i would try it like this before buying new springs.

you can also take an air tank with you and run up to maybe 6 psi in the forks, however, if you need to do that, i would eventually get heavier springs.

[atcmatt]

Get yourself some real forks up front. Inverts from a late model are what I'm talking about cuh. None of that weak outdated conventional junk

Nothing wrong with conventional forks mate. Outdated maybe, junk, no. Why would I go slapping a set of USD forks on my very nice unrestored example 1986 ATC350x? Doesn't make sense to me, USD forks have their place and it ain't on my 3 wheeler.

[atcmatt]

Xlnt description, and although I don't have a photo of myself actually riding a 350x, nor do i wake up with grease under my fingernails [because unlike some people, i actually wash my hands before i go to bed], I did stay at a best western express hotel last night so I think i can answer at least part of your question.

how much do you weigh?

it would also be helpful to know how much your forks sag when you are sitting on it.

Since your forks are bouncing back up to quickly, increasing the weight of he fork oil will reduce the speed at which they return . atf is around 7 weight . ford type f atf has no friction modifiers but dexron does.

my guess is that you should try 15 wt oil.

if it bottoms out easily the way it currently is, i would also increase the oil level by 5/8".

if it currently sags more than 1/3rd of the total amount of travel. i would get some pvc pioe just slightly smaller than the id of the tubes and cut two pieces 3/4" long then install one on top of each spring.

i would try it like this before buying new springs.

you can also take an air tank with you and run up to maybe 6 psi in the forks, however, if you need to do that, i would eventually get heavier springs.

Thanks Barnett. I weigh around 165 pounds. Not real heavy at all. Yeah I guess I will change out the oil for something a bit heavier and see how that goes. From droop doesn't seem to be a lot at all. Bike is all packed away but I could measure it out tomorrow.

[barnett468]

Thanks Barnett. I weigh around 165 pounds. Not real heavy at all. Yeah I guess I will change out the oil for something a bit heavier and see how that goes. From droop doesn't seem to be a lot at all. Bike is all packed away but I could measure it out tomorrow.

no prob, if the sag is less than 1/3rd, the spacer should just be used as a temporary fix unless you wanted the front slightly higher . this will make it a hair more stable at high speed but will "slow" the turning down a little . the difference will be small.

as far as the progressive springs go, i haven't ever used them on that bike so i can't help much other than to say that they are stiffer when the forks are fully compressed . maybe dirtcrasher or someone else has and can help you with those.

i will say that installing stiffer springs but using the same oil will definitely not stop the bottoming and it will make it rebound even quicker, so either way you need heavier fork oil, and going from 7 wt to 10 wt is a fairly small change, and since it sounds like your prob is fairly severe, it would require more severe measures to fix it.

[atcmatt]

Yep it is definately less than a 3rd of the overall travel. I'm not a heavy bloke at all so I guess that would be the reason it doesn't sag under my weight. I think, after you suggesting it may be to do with the light oil in the front. I mean if I sit on the bike and push up and down there is no chance in me bottoming the forks out. Cheers again.

Matt

[barnett468]

Yep it is definately less than a 3rd of the overall travel. I'm not a heavy bloke at all so I guess that would be the reason it doesn't sag under my weight. I think, after you suggesting it may be to do with the light oil in the front. I mean if I sit on the bike and push up and down there is no chance in me bottoming the forks out. Cheers again.

Matt

ok, xlnt, then even if they are a little light, they are not likely extremely light, therefore, my guess would be that if it still bottoms with the 15wt and higher level, you should ok with the next step stiffer springs.

race tech also sells springs and can probably tell you what the stock rate is and suggest which of theirs might be best for your particular app.

http://racetech.com/ProductSearch/3/...TC350X/1985-86

[atcmatt]

That's great. Thanks very much mate, really appreciate it.

Matt

[Dirtcrasher]

Yep, I ran progressives and a bit more and heavier oil and they worked much better; But at 220lbs. I was OBESE, lol!!.

However, since I bought an AXIS rear shock with all bells and whistles, I can tune everything in so much better with immediate results.

Your so light, just a few changes and those 350X forks will be just fine.

Onformula1 could help you immensely. And at a fair cost.........

[atcmatt]

Yep thanks guys. I am getting some help from onforumla. He is a great guy full of knowledge.

Thanks.

[jb2wheels]

My 350X has progressive springs and 20W fork oil. I never rode it with the old stuff in it but...
I let a buddy ride it after getting off his tired stocker and he says it's night and day difference.
Both of us are heavy - I'm closer to 300lbs than I care to admit to myself.
I have no issues with the front end of my X set up like this.
I ride dunes 99.9% of the time.

Also, the same Progressive part number is used in 84/85 Tecates.
My current 85 T3 had crap suspension when I bought it. No damping and worn out springs at both ends. Lots of pogo-ing and bottoming.
I set it up like my X - Progressive springs and 20W oil in the forks.
Night and day difference. The fat tired wonder has become my favorite duner.

But not a fair comparison of fresh to worn out.