Fork oil change on 98 RSTC

[Lug Nut]

Going to be removing front wheel to install fresh wheel bearings, repaint wheels, and sand lower fork legs. I was thinking it wouldn't hurt to drain the old 40k mile fork oil and flush it out and replace with fresh.

 

I read the 2nd gen article about removing the Schrader valve in the top of the forks and then using an air compressor to blow the remaining old oil out after letting it drain. I thought we had to be careful NOT to use an air compressor on front forks due to only running a max of 7psi?

 

So, on my bike in can refill through the air valve at the top of the shock (once Schrader valve is removed)?

 

Any thoughts?

 

Also, what brand/type/viscosity are you all using? I read that 5W was stock....

Edited June 19, 2016 by Lug Nut

[djh3]

On my RSV I went up one thickness from a 5w oem to a 10w. I just took out the schrader valves, put a pan under the forks where the lower drain bolts are. I left it drain over night. The pressure thing is because you will blow the seals out. Now with the drain bolts out the air has somewhere to escape, but would I want to risk having to reseal forks because I was in a rush to get old oil out? Nope.

[Lug Nut]

Thanks for the clarification. Are the drain bolts located up inside the lower fork tube I assume? I guess I could use my hand pump to blow old oil out. Did you bother with using anything to flush the remnants of old oul out?

[djh3]

Not sure on the earlier RSTC. The RSV and TD you remove the front wheel, and up inside the fork there is an allen head bolt. I think it is like 5mm maybe 6mm. So with the valves out of the top, the fluid will flow out pretty good. I just let it drain over night and then buttoned up everything. No flush. The bolts were a PIA to get started again as they hold some part of the spring cartridge together inside the forks. You may have to push the fork up a little to get the bolts to start.

[Lug Nut]

Ahh got it....thanks for the added info. ..in will probably do this next week. Out of curiosity why not flush them with something like MMO or another cleaner?

[tazmocycle]

when you fill it back up make sure you put right amount back in, may need to allow time for it to drain down into forks. there will be an air space in top to allow the forks to compress. the air in top will compress to absorb the bumps. 10w oil will make it better in absorbing the bumps and diving of the frontend when braking. to help get cap back on without cross-threading, I try screwing the cap on without the spring first, when the threads engage I back it up till it comes loose and then put a mark on the cap and fork so when you are starting to screw the cap on and pushing down on cap and spring, you have a starting place and if it starts to bind up within a half turn you know it's cross-threading. don't force it till you have a round or two by hand, then you can use a wrench to tighten. frontend needs to be off the ground while doing all this. hope this helps out, Don.