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sub tanks and a 426


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ok I got the correct springs for my 426 for my weight and it doesn't bottom on the few small jumps I hit anymore :cheers: they where all flat landings to by the way

my question is should I get some sub-tanks for the ol 426 also I plan on putting in new seals and fresh oil this winter and figured why not put some sub tanks on while I am at it

this is my understanding on what the sub tanks do, you can run higher oil without the suspension getting harsh, so you get plush suspension and greater bottoming resistance basically the best of both worlds

is this correct

the sub tanks I was looking at where by tech-care http://www.tech-care.com/

if you think I should run them what oil height should I run and also what kind of fork oil weight is stock in the 426 2001 or what weight should I get I am a big boy at 285 so I was thinking of getting a higher weight oil to help with bottoming

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Sub tanks work well on the early KYB's, but they should be re-valved for their use to get the most out of them.

The problem was that if the oil level was lowered to allow a plush ride over the little stuff (slow speed compression), they bottomed on the big stuff (high speed), and worse, they were so low at that point that they worked foam into the oil and faded. If the oil was high enough to stop that from happening, the fork became intolerably harsh. The answer was to increase the air capacity with an added tank. This, in one way of looking at it, decreased the "compression ratio" of the fork. That let the rider run a higher oil level to avoid bottoming and foaming without raising the internal air pressure so high that it caused harshness. Adding the metered air flow feature later provided the rider a way to run even softer compression damping because it made the air spring component speed sensitive.

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I've used them (home made, see my garage) on my 426 with great success. Like grey said you will get the most improvement if you revalve, but you will still see noticable improvment even without a revalve.

I ran mine with the max recomended oil height. At that level, if I ran the tank valves fully closed, the forks were pretty harsh so I normally ran them open about 1/2 to 3/4 turn for moto. On the other hand if I ran the valves fully open the forks were way to soft for moto but very good for off road and trails. This arrangement was great for dialing in the plushness for a wide variaty of terrain.

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what did you use to make those

and how??

In my case I used a two tank system. A one tank system is simpler and less expensive, and has the added benefit of being self draining. I went with a two tank set up because at the time I built mine there was a lot of talk about a single tank system not draining equally into both forks. This would eventually result in uneven oil levels in your forks. I don't know if that's really a problem. It seems like a lot of people use a one tank system without any trouble. If I was doing it again I'd probably go the one tank route.

In any case here's what I used. The tanks are Bimba air reserviors and the valves I used are Bimba one-way flow controls. The tanks come tapped for 1/8 NPT fittings. I drilled and tapped my fork bleeder holes out to 1/8 NPT also. The braided hoses can be purchased at any paintball store or can be custom made. I designed and fabbed the brackets using carbon fiber plates to hold the tanks, but any number of methods will work. I've seen people just zip tie them to the forks. Simple but effective.

Here's a list of part numbers I used.

Tanks:

1.25 Diameter x 3.00 long. The Bimba part number is D-27715-A-3. They list for about $17.00 each

Valves:

Bimba part number FCP2L and list for about $13.00 each

One word of advice, when using valves like these, make sure they only restrict airflow in one direction. When you set up the system, make sure the valves are installed to restrict airflow OUT of the fork.

Hope this helps.

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thanx guys

right now the forks feel pretty good as far as not being too harsh but I hit a couple jumps by my house(flat landings) and it got close to bottming so I wanted to get some better bottoming resistance

maybe I will get them valved next summer

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  • 2 months later...
In my case I used a two tank system. A one tank system is simpler and less expensive, and has the added benefit of being self draining. I went with a two tank set up because at the time I built mine there was a lot of talk about a single tank system not draining equally into both forks. This would eventually result in uneven oil levels in your forks. I don't know if that's really a problem. It seems like a lot of people use a one tank system without any trouble. If I was doing it again I'd probably go the one tank route.

In any case here's what I used. The tanks are Bimba air reserviors and the valves I used are Bimba one-way flow controls. The tanks come tapped for 1/8 NPT fittings. I drilled and tapped my fork bleeder holes out to 1/8 NPT also. The braided hoses can be purchased at any paintball store or can be custom made. I designed and fabbed the brackets using carbon fiber plates to hold the tanks, but any number of methods will work. I've seen people just zip tie them to the forks. Simple but effective.

Here's a list of part numbers I used.

Tanks:

1.25 Diameter x 3.00 long. The Bimba part number is D-27715-A-3. They list for about $17.00 each

Valves:

Bimba part number FCP2L and list for about $13.00 each

One word of advice, when using valves like these, make sure they only restrict airflow in one direction. When you set up the system, make sure the valves are installed to restrict airflow OUT of the fork.

Hope this helps.

Is there a way i can make my own subtanks with the parts you mentioned without drilling the forks?

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  • 1 year later...

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