Txt 280 Front Suspension

[davet]

hi there ive just hit a problem while out practicing the front suspension just dropped bottomed out, i can push the suspension right to the bottom,it does return but very easy to push down to the bottom, i have checked seals they seem ok,there is no sgn of oil anywhere on the forks or on the legs.

is there anyone who could advise me on the problem, and hopefully with your help i can solve it........ cheers dave....

[jse]

hi there ive just hit a problem while out practicing the front suspension just dropped bottomed out, i can push the suspension right to the bottom,it does return but very easy to push down to the bottom, i have checked seals they seem ok,there is no sgn of oil anywhere on the forks or on the legs.

is there anyone who could advise me on the problem, and hopefully with your help i can solve it........ cheers dave....

Dave,

From what you describe, especially the quick onset of the symptom, my first guess is a broken fork spring.

You didn't say what type/year your bike was (a "280", depending on model/year, could have GasGas....GasGas with Marzocchi internals....Marzocchi....or Sachs forks). If it's a fairly new model, I'd guess a construction issue with the spring, but if an older model, this is usually caused by not keeping the fork oil fresh and to the correct oil level. The forks rely on the oil for internal lubrication and bottom-out damping.

If the oil is neglected, the spring coils wear a flat spot on the outsides from friction with the inside of the upper tubes (the metal particles being rubbed off collect in the bottom of the lower tube and riders often mistake that for dirt) and this flat spot on the coil creates a "stress riser", a place for a crack to start because of the material shape. If the oil level is low, the forks are also more prone to bottom out as the oil level affects the last third of fork travel. So, poor oil, low oil level, spring shape and ease of bottoming out often lead to spring breakage.

Sounds like you will need to take the forks off and carefully inspect the internals. I'm guessing that the cause will be apparent quickly, but if not, let us know as this is only a first guess.

Jon

[davet]

hi jon

sorry it is txt 280 limited edition 03 model. i will like you say have to dismantle to check the spring. i replaced fork seals a few months ago,new oil reccomended amount, didnt notice any wear on springs. will let you know what i discover.

thanks dave.

[jse]

hi jon

sorry it is txt 280 limited edition 03 model. i will like you say have to dismantle to check the spring. i replaced fork seals a few months ago,new oil reccomended amount, didnt notice any wear on springs. will let you know what i discover.

thanks dave.

Dave,

The video: http://www.youtube.com/watch?v=AP-v_c0g0mw should help you. I'll be interested in what you find. According to your description, I'd be surprized if it was not a broken spring, but they are rare nowadays.

Jon

[davet]

hi jon

thanks for video link..i have taken fork apart the spring seems fine no marks of wear and in one piece..but the oil was black and dirty so i was wondering if that could be the problem ?

the oil may have lost its elastisity (if thats the correct term )

thanks dave.

[docheckle]

I have put an 1 1/2 " spacer at the top of the spring on my 2001 to cope with my larger frame size. Measure your static sag should be 2- 2 1/2"

[jse]

I have put an 1 1/2 " spacer at the top of the spring on my 2001 to cope with my larger frame size. Measure your static sag should be 2- 2 1/2"

I'm assuming you mean "race sag", with the rider and full gear?

I still havent figured out why, according to davet's description, the front suspension would all of a sudden easily bottom out. Is there something I'm missing? I could see that happening with a loss of fluid, but that does not seem to be the case. The dirty oil (metal particles sluffed off from the outside of the springs) could interfere with the shim stacks damping ability, but thats fairly rare and does not usually happen all at once.

davet, could you provide a little more background on exactly what happened while you were riding?

Jon

[docheckle]

race sag - static sag , you say tomatoe i say tomatoe lets call the whole thing off, song doesn't really work without accents lol

yes i think we are talking the same thing, get suited and booted and stand on yer bike in riding position and measure how much forks compress. You can use a tie wrap around the fork leg as a measurement aid.

[jse]

race sag - static sag , you say tomatoe i say tomatoe lets call the whole thing off, song doesn't really work without accents lol

yes i think we are talking the same thing, get suited and booted and stand on yer bike in riding position and measure how much forks compress. You can use a tie wrap around the fork leg as a measurement aid.

Got it!

We were talking about the same thing.

Cheers.

Jon

[davet]

hi jon

sorry its been while getting back to you.I was struggling to rectify the problem, so i took the fork to local trials shop,where the mechanic found the bolt at the bottom of the fork was rotating with fitting inside the fork,he finally released the nut and took out the bottom end,no problems found relaced all parts, and managed to tighten up the bolt at the bottom of the fork. filled with new oil checked the damper everything o k.

thanks for your correspondence.....

cheers dave

[jse]

hi jon

sorry its been while getting back to you.I was struggling to rectify the problem, so i took the fork to local trials shop,where the mechanic found the bolt at the bottom of the fork was rotating with fitting inside the fork,he finally released the nut and took out the bottom end,no problems found relaced all parts, and managed to tighten up the bolt at the bottom of the fork. filled with new oil checked the damper everything o k.

thanks for your correspondence.....

cheers dave

Cool!

Thanks for the feedback. I think you said the fork was not losing oil, just that the oil was dirty, but the "base bolt" (the capscrew with the copper washer on the bottom of the lower leg that threads into the cartridge) being loose would allow oil to drain out slowly from the bottom of the fork leg, but you wouldn't probably ever notice it. The fork would act just like a big pump and force oil out at a fairly rapid rate even if the base bolt were only slightly loose. Glad you got it taken care of.

Cheers.

Jon