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Hi Jon,

I have a GAS GAS JTX370 1998. I need to top up the front fork oil, I have unscrewed top nut but will not separate from stantion to enable me to put oil in top. Am I doing something wrong? Top nut feels like it is being held by a spring and is the same both sides. Any help would be appreciated. Thanks Paula


I hope you don't mean to fill up the fork tube when you say "top off". The fork only takes 300 cc's of 5-weight fork oil after being completely drained. The drain hole is at the bottom of the lower slider and has a small phillips head screw and an o-ring for a gasket. It needs that air pocket in the top of the fork tube to allow compression of the oil and cartridge parts.

The top cap nut is screwed on to the top of the cartridge rod that has the damper piston on the other end inside the cartridge tube. After untightening the top cap, grab the fork tube and with a twisting motion, pull it down to expose the spring if the fork is out of the tripleclamps. If the fork tube is still in the clamps, push up the lower fork slider to expose the spring. After draining the forks and putting the phillips screw back, carefully add the 300 cc's by pouring it inside the spring down into the tube. Slide the fork tube back up (or if in the clamps, pull the lower slider down) and snug up the top cap. Don't overtighten the top cap, it's held tight by the top tripleclamp when the capscrew is tightened to 18-21 foot pounds of torque. Never try to untighten the top cap without loosening the top tripleclamp bolt first.

Hope this helps. Let me know.


Professional tuner and 'Trials Competition' writer Jon Stoodley has very kindly stepped up to the plate to answer your questions. If you're having problems, or need some advice just send an email to Jon. If it's something that could be useful to others, we'll post it on the site.
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