fork self-servicing?

[Dozbag]

So i just bought myself a spada vt250, but unfortunately, the front forks are way too soft (you can bottom them out by pushing on the handlebars) which would make it a bit dangerous to ride due to braking and whatnot, so i resolved to not ride the bike until i get them sorted out...

so my question of course is, does anyone know anything about servicing your own forks? maybe a dumb question but i'm a total noob! any help would be much appreciated.

[ADV8]

That bike has a conventional fork so you would be fine doing it yourself with minimal tools.
Little more than supporting the front of the bike,removing the top fork nuts/caps watching out that the springs might be pushing against them.
Then changing the oil and fitting new springs as the minimum.
If the front is supported and the wheel removed you could pump the old oil out of the drain screws one at a time.
The new fork oil could be replaced via a cc measurement.

[Dozbag]

Thanks a bunch ADV8! should i be able to pick up these parts from my local dealer?

[ADV8]

No worries.

First up would be to find an online workshop manual so you can get familiar with what needs doing.
It would also give the correct viscosity fork oil and amount to get. (x 2 )
The main thing is to support the bike so there are no drama's while you are working on it.

[ADV8]

Found this on You Tube.
Shows the general idea,maybe the VT oil can be drained the same way but there is normally oil left inside the fork.

[kpt4321]

Replacing the oil will not fix an overly soft fork (yes, you can reduce the air chamber, but that doesn't sound sufficient in this case). You need springs. It is unlikely that your dealer will carry those.

[mjydrafter]

You could as an inexpensive alternative add in some spacers to increase the springs preload and add some heavier oil. I have done this, it's not the best answer, but it works if there are other repairs that need to be made.

[Dozbag]

The workshop manual seems to suggest it could be either of those issues. (weak spring or low/wrong fluid) it does however, fail to mention what type of oil is needed, or any spring ID's etc.

[mjydrafter]

Also, depending on the year of the bike, it may have air assisted forks, which if they were leaky or not holding air would seem pretty soft. My cb900 has air shocks and without air they are really soft.

I think a lot of the older Japanese bikes called for ATF for the fork fluid, and in a pinch it would probably work even if not specified. IIRC ATF is usually ~7.5wt, so a 10 wt fork oil should be pretty close.

Also if it (the fork oil) hasn't (ever) been changed in a while, it could be broken down pretty thin.

[Dozbag]

Originally Posted by mjydrafter

Also if it (the fork oil) hasn't (ever) been changed in a while, it could be broken down pretty thin.

Yeah, it's a 1990 model and I'm assuming the forks have never been looked at.

as for air assistance, i am unsure if these forks use it. are there any specific parts that would suggest air assistance? Also, is it possible to get some sort of universal springs? or do they have to be specific to the bike?

[tlartist]

A couple of comments. Best to test your suspension first to see how good/bad it is. That will let you decide on what you need to do regarding spacers and such. Do a search on the web for how to test.

You could also replace the front springs with something else if you can't get the suspension set where you want it, but start first with the stock springs.

It is best to take the forks off to get all the old fluid out. Loosen the fork caps on the bike a bit first. It is really hard to do after off the bike. You can put in a vice to hold but very hard to do without damaging the forks.

Check in advance what amount of fork fluid you will need and order beforehand. Red line is a great fluid to use. They come with different viscosity, so if not sure contact redline to see what you should get.

You will have to take the front wheel off and if the brakes are attached to the forks take those off and suspend with wire. It is a little involved so if you haven't done before best to have someone to help or a good forum to provide advice.

[tlartist]

...for how to measure sag and recommended...
http://www.racetech.com/articles/sus...andsprings.htm