I just blew both my front fork seals at the same time getting carried away up a really disused/eroded log trail. It was a blast... Until I was riding on a mushy front. Babied it home (read rode reasonably like I should have been) and went to the dealer to order new oil and dust seals ($147!!! Why?!). Problem is, the workshop manual doesn't have it's own listed suspension sections. What oil weight and how much oil am I to use in the forks after rebuild? While I'm here, I'd also like to ask about a subtle clicking noise I hear in the front end. It almost sounds like a really loud valve or something. I've heard other people say they don't know but I'd thought I'd ask again. It was very subtle before my seals broke, and I noticed the click occurs under pretty extreme suspension compression, which is what leads me to think it's a valve... I'll be taking both tubes apart, so I guess I'll find out if something busted. For your viewing pleasure.
I am guessing that (if you have time) remove the seals and send them to a Fork Seal specialist, there would be a "generic" seal for the fraction of the price. As for the fork oil quantity, that is a mystery but you could experiment with different quantities - time consuming but not impossible. Or maybe if there is a dealer with the "full" manual (assuming one exists) can come forward with the info.
Too late on the price savings. The bike is ridden daily, and I bought them before asking around. My frugal-fu is weak. I'll ask the dealer when I go to pick up the parts. Thanks!
I hunted all over the place and finally asked the experts how much fluid to put in them. Answer was: put enough oil in both sides until 100mm below the top of the assembled fork with the cap undone and the suspension completely compressed. AFTER cycling the forks to ensure all oil had filled all cavities it was supposed to ( ie the level stops getting lower after each cycle). You can make a gauge out of flexible sheet used for kitchen cutting "boards". cuts easily with scissors and oil resistant. Cut a "T" shape that will fit down beside the spring with the top of the "T" against the top of the fork. Fully compress the forks and fill until it reaches the 100mm below THE BOTTOM of the fork cap position. Cycle the forks up and down and redo until the level doesen't get lower after cycling. That's your spot. Then just extend the forks and do up the cap. DO NOT overtighten. The cap is held locked by the top triple clamp bolts. If you are careful and measure the oil as it goes in and WRITE IT DOWN , you will just be able to put that quantity in next time. I measured how much. BUT I have shortened the internally forks by 50mm ( I use it exclusively as a road bike). That figure was 650ml each side. Std travel forks will be slightly more. Remember that the Left leg is rebound only and the right leg is rebound AND compression so you can use viscosity to help tune your forks by varying it accordingly each side. Just a thought. Forks rarely just blow seals nowdays ( as opposed to slowly wear and seep). The usual reason for blown fork seals is too much fluid in them or perhaps WAY too high viscosity in the compression side. I was told 5W FORK OIL std.( SAE viscosity for suspension oil is NOT the same as other ratings). Auto trans fluid is apparently about 30W. I am running 5w rebound/7.5w compression rebound side because of the shortened suspension.
"100mm" and "5W" was the kind of answer I was looking for. I've never heard of a different procedure for measuring fork oil levels, but then again, this is the second bike I've owned that I would be rebuilding suspension on. As for the left/right legs have different function, that's weird. I'd probably leave it where it's at, but lose 5mm of oil level and go from there. The front has been too stiff thus far off road. Thanks for you help!
I use a turkey baster with a piece of tubing on the end. Rule of thumb has always been 4" from top of compressed fork. 100mm = 3.93" . What you do is fill the fork as mentioned and make sure all air is out by stroking fork. When you get it filled you cut your baster so that tube will only go 4" down from top and suction excess oil out. This way you end up with equal oil in each fork.
I too started to notise the clicking on larger hits recently. This might seem silly but if you flex the front fender it clicks where rubber bump stomps meet the housing. I was thinking it was maybe coming from there. Its hard to tell when riding, the only clicking sound I can reproduce is from the fender. And it's loud enough to hear with the bike running and helmut on.
Different functions for left and right leg is not that unusual nowdays. It's a real bonus for fine tuning though with one side being both rebound ( only a small amount) AND compression it makes it slightly more complicated to balance what you want. You can't use a turkey baster as the springs have to be IN. The "T" piece will slide down beside the spring and the "T" bit will stop it falling in and give you a consistent stop point .
