Kawasaki Sportsbike Riders Club - Australia - Online Forum

gday
girlfriend just got an 89 model gpx250 and her Ls.
i rode it a few times and the front forks are really springy but there isnt any adjustment to be made.
also the clutch eases out and shes getting a warped idea of how to ride a motorbike and operate its clutch.
does anyone have any suggestions on how to make the clutch whippier?
also how hard is it to replace front fork springs and oil on such an old bike?
what size fork springs would i get and does anyone know of heavier springs that i could purchase?
or alternatively is there an online gpx250 manual anywhere?

98ninja wrote:also how hard is it to replace front fork springs and oil on such an old bike?
what size fork springs would i get and does anyone know of heavier springs that i could purchase?
or alternatively is there an online gpx250 manual anywhere?

Theres a possibility half the problem if not all of it is due to shot fluid. First thing id do is doublecheck that there's the right quantity of fluid in the forks. drain them, check how much came out, take the springs out, clean them up, flush the lowers with some clean oil, make sure they totally drain and then put the right quantity in (best way is to get an oversized syringe (without the pointy bit) and use that to measure it up.
There will be a drain bolt at the bottom of each fork, remove that and all the old fluid comes out. But first make sure that the caps come off. I cannot remember on the gpx250 how they're held in, either they are held in by circlips or they screw in. If its circlips make sure you press down on the insert a bit before attacking the circlip as you need the pressure released off it to allow it to come out. Screw out, well that's pretty easy Just bear in mind that unless its been lost, there's likely to be a cosmetic cover over the top (for looks) that'll likely flick out with a small screwdriver so you can start work on removing the fork innards.

98ninja wrote: also the clutch eases out and shes getting a warped idea of how to ride a motorbike and operate its clutch.
does anyone have any suggestions on how to make the clutch whippier?

Primary clutch adjustment is at the engine itself, to adjust it you use a pair of shifters adn adjust the bolts either side of the mounting point to move the clutch cable in and out to get your base adjustment, once the clutch actually takes up correctly then you use the secondary adjustment on the lever, which comprises of loosening the big knurled locknut off and adjusting the inner until your satisfied with the quantity of slack, then tightening off the locknut again. Sometimes you ahve to redi the bottom bit a second time slightly due to fiddling with the top adjustment throwing what you thought was right, off.

Good luck though.

98ninja wrote:is there an online gpx250 manual anywhere?

Everything you wanted to know, and more, about the GPX250 http://faq.ninja250.org/wiki/Main_Page

What do you mean by whippier and eases out? Do you mean it's progressive and has feel? Put in kevlar plates and a light flywheel if you want to throw her in the deep end?
Springs and oil are easy to change but they're meant to be soft. That's how the GPX is. I couldn't be arsed spending $200 or whatever it is for new aftermarket springs so I chopped some XJ600 springs I got at the wrecker. Worked damn well.

ok ive changed the oil finally and added 60 cents of preload to each fork.
those circlips at the top of the forks are complete bastards for a newcommer to get out.
my question that the wonderfull gpx250 site doesnt cover is
is more oil and less air in the fork make for a harder or softer feel?
at the moment we have around 1800mm of space from the top of the fork to the oil level whilst the fork is compressed
and with no spring in. its quite a firm feel now and its a good feel for 90kg me but maybe not 55kg owner of bike.
the recommended height from Kawasaki is 2000mm but i wanted to play around a little.
any suggestions?

I think you mean

98ninja wrote:those circlips at the top of the forks are complete bastards to get out.

quote="98ninja"]my question that the wonderfull gpx250 site doesnt cover is
is more oil and less air in the fork make for a harder or softer feel? [/quote]
Think this way, which compresses more easily?

and r.e. the forks, the most important mod would be the 60 cents of preload in each fork leg.
Just remember as long as it feels solid but not like sitting on a pogo stick, then it's pretty close to correct.