Very soft Enduro forks...Motocross?

[blanc]

Hi All. I have decided to keep my 1996 TM250e, its a great reliable bike! :ride: .However it bottoms out all the time and the front forks are real soft even with the compression all the way in!I think the forks are Marazochhi, the ones with compression and rebound on either side of fork leg top!
I would like to race beginner motox and enduro, how do i harden up the forks to stop the bottoming but still keep it soft enough for offroad? They were rebuilt in Dec,seals and oils and only ridden a few times since! Help is appreciated!

 

[dirt bike dave]

Raising the oil level will improve bottoming resistance, and the forks should still be plush during the first part of the travel.

 

[JTT]

Afraid your only "real" solution is a revalve, but even that will be somewhat of a compromise from MX to enduros. It's hard to have it both ways unfortunately, but being a young guy you could put up with a slightly stiffer fork in the woods (the compromise to MX type valving) I'm sure.

 

[blanc]

Cheers for the reply! AHH thought i would need to do that! Any idea as to the cost of revalve,springs, oils and bushings??

 

[dirt bike dave]

Raising the oil level 20mm or so (measured with the springs out and the fork collapsed) will greatly improve bottoming resistance, while keeping the forks plush for the first part of the travel. If you have a few ounces of fork oil, the cost is free.

Prices on suispension work can vary alot, but revalving is around $200+-, new springs around $80 - $100. Shipping and insurance (if you don't have a local shop) might be $50 - $80.

If your fork had new bushings & seals installed in December, you should not need new ones.

 

[blanc]

Yeah i think i will try the oil 1st! Cheers. I may just add heavier springs 2. Thanks

 

[dirt bike dave]

FWIW, you can stiffen your springs by cutting a few coils off (measure the gaps & mulitpy by the # of gaps to check that you will not have coil bind at full compression). If you shorten the spring, you will need to add length to the pre-load spacer.

BTW, adding pre-load can also make the fork feel stiffer in the initial part of the travel - your current trail setup may have minimal pre-load on the spring.

Removing 10% of the spaces between coils will make the spring 10% stiffer. A 5% shorter spring should make a noticeable difference.

Combined with raised oil level, additonal pre-load (you can use washers), you can stiffen your existing set-up without spending any money or losing your soft woods valving.

 

[shockdoc]

Make sure that your tuner used thick enough oil too. They can get by with thicker oil than normally used in KYB or Showa.

doc

 

[blanc]

Cheers just back from Oxegen music festival here in Ireland.Great Craic. Thanks for all the help. Do you think a heavier spring change is necessary? Front end dives under heavy breaking!

 

[DEANSFASTWAY]

On some of those older MZs we noticed that the comp cartridge was slotted and only really made much comp damping after the cart piston traveled down past halfway . On one bike we soldered up the slots but later we tried using really large electrical shrink wrap and melted it around the outside of the cartridge and it gave less bleed off , they were on heavier 410/610 huskys .Sometimes the val;ving needs to be cleaned out real well also. Lots af particulate contamination in those forks . I think we tried using showa 45mm oil seals/wipers too , We helped a kid on a Husky125 that needed fork seals every couple weeks but he rode alot and cleaned his bike alot less. He bought nice new race gear but actually got it all stained up with fork oil and it looked bad in no time . I remember the first time Ferraccis came out to Raceway this kid slid off the muddy track in practice and roosted all of us by the fence . Ferracci would have been mad but when he saw the kid was on a Husky he was stoked! You could probably use motor oil in those forks and have a pretty good ride .Think about correct springs theyre really not that expensive for the results achieved .

 

[georgieboy]

As dean mentioned, they only build up compressiom in the later part of the stroke. That's why they dive when braking.
I soldered the slot close and drilled holes every 2 inches, but then decided to close these aswell.
Now my forks are decent any have comp all the way from the top.
Valving is very upset aswell, as they work with .2mm thick shims. So invest there is also a pre.
Fiddling with these forks can be worth while. They are very strong. With a crash a bended the tripple plate not the forks. So they are very rugged.