'07 Fork Oil Change
#22
I just got back from the HD shop and will do the job probably tomorrow. I'll be installing some SE 15w fork oil this time, as I've been told it firms up the front and reduces bottoming. The parts guy at the local HD shop, who used to be the service manager, said the top-fill approach would work but that pumping the forks to force out all the used oil was necessary. He also verified putting a little new oil in at a time so it could work its way past the damper valve, pumping the forks between fillings. Also, rather than installing the prescribed amount of new oil, put in exactly the amount drained. Makes sense unless they filled it wrong at the factory, which is doubtful.
Last edited by iclick; 08-13-2008 at 06:53 PM.
#23
Well, I didn't wait 'til tomorrow and did the fork-oil change earlier this evening. It took me about an hour to do the job using the top-fill method. It was mostly a piece of cake, and here's the blow by blow doing one side at a time:
1. Remove ignition switch and the two screws holding the inner-fairing cap. Lifting the cap out of the way gives access to the fork top plug. I tried a 36mm socket but there wasn't room, same for a crescent, but the 36mm wrench in the tool kit was the solution. The plug is not on tight and removal is easy.
Edit (07/08/11): After doing this job a second time, the 36mm wrench is actually a bit too large and 1 3/8" is a better fit.
2. I used a ½" clear plastic tube cut to about 10" in length and inserted a small funnel on one end and stuck the other end into the fork top. It was a tight fit but worked. I wire-tied the funnel to the handlebars to keep it from slipping. Put a plastic bag on the tank to protect it from fluid that might spill out of the funnel.
3. Once the top plug is removed the vacuum is released, so draining should be no problem. It indeed wasn't once the bottom drain plug was removed, and that was the biggest problem of the whole job. Those damn Phillips screws were in very tight and I almost couldn't get them off. Don't even try to remove them with a Phillips screwdriver, but instead get a #3 Phillips bit and use a 3/8" or 1/2" ratchet, putting heavy pressure on the screw while you turn it. It was close, but I got both of them without stripping the head after rapping moderately with an impact screwdriver (not an impact wrench).
3. Once this screw is out the fluid begins to drain. My right side came out slowly at first until I used a toothpick to loosen some gunk that partially plugged the hole. There is no need to pump the forks to release all the oil, as in time (about 5 min.) the oil completely drains, all 10.8 oz. of it. It is a black, smelly fluid that doesn't resemble any hydraulic or other oil I've ever encountered. It looks like it has moly or graphite in it. Once the old fluid is out, reinstall the screw, but there's no need to tighten it as much as was done at the factory. The manual says 78-96 inch-pounds.
4. I filled with SE Heavy (not the Extra Heavy variety), which is reportedly 15w (stock is 10w). Note that RK's require 11.1 oz., while EG's are 10.8 oz. Fill slowly about 2-3 oz. at a time, then pump the forks each time to force the oil past the damping valve. After about 3-4 pumps you start hearing a hollow sucking noise, which suggested to me that it had cleared the valve. RK's may not need to do this step-by-step pumping approach since they don't have the damper valve installed. That process took maybe 10 min. for each side.
5. Finally, replace the top plug, do the other side as above, then replace the inner-fairing cap and ignition switch.
This is definitely the way to change the fork oil on these bikes, IMO, and I may do this job every 10k, certainly not more than every 20k. As I said, it took about an hour, but next time I think I could do it in 45 min. now that I know the routine. Thanks to all who encouraged me to try this method.
A ride revealed a slightly firmer feel to the front-end with the SE fluid, but it is not harsh. Corners felt very secure, but my 10-mile ride didn't give it a good test for bottoming, etc. It felt taut and secure, however, and these early results are positive.
1. Remove ignition switch and the two screws holding the inner-fairing cap. Lifting the cap out of the way gives access to the fork top plug. I tried a 36mm socket but there wasn't room, same for a crescent, but the 36mm wrench in the tool kit was the solution. The plug is not on tight and removal is easy.
Edit (07/08/11): After doing this job a second time, the 36mm wrench is actually a bit too large and 1 3/8" is a better fit.
2. I used a ½" clear plastic tube cut to about 10" in length and inserted a small funnel on one end and stuck the other end into the fork top. It was a tight fit but worked. I wire-tied the funnel to the handlebars to keep it from slipping. Put a plastic bag on the tank to protect it from fluid that might spill out of the funnel.
3. Once the top plug is removed the vacuum is released, so draining should be no problem. It indeed wasn't once the bottom drain plug was removed, and that was the biggest problem of the whole job. Those damn Phillips screws were in very tight and I almost couldn't get them off. Don't even try to remove them with a Phillips screwdriver, but instead get a #3 Phillips bit and use a 3/8" or 1/2" ratchet, putting heavy pressure on the screw while you turn it. It was close, but I got both of them without stripping the head after rapping moderately with an impact screwdriver (not an impact wrench).
3. Once this screw is out the fluid begins to drain. My right side came out slowly at first until I used a toothpick to loosen some gunk that partially plugged the hole. There is no need to pump the forks to release all the oil, as in time (about 5 min.) the oil completely drains, all 10.8 oz. of it. It is a black, smelly fluid that doesn't resemble any hydraulic or other oil I've ever encountered. It looks like it has moly or graphite in it. Once the old fluid is out, reinstall the screw, but there's no need to tighten it as much as was done at the factory. The manual says 78-96 inch-pounds.
4. I filled with SE Heavy (not the Extra Heavy variety), which is reportedly 15w (stock is 10w). Note that RK's require 11.1 oz., while EG's are 10.8 oz. Fill slowly about 2-3 oz. at a time, then pump the forks each time to force the oil past the damping valve. After about 3-4 pumps you start hearing a hollow sucking noise, which suggested to me that it had cleared the valve. RK's may not need to do this step-by-step pumping approach since they don't have the damper valve installed. That process took maybe 10 min. for each side.
5. Finally, replace the top plug, do the other side as above, then replace the inner-fairing cap and ignition switch.
This is definitely the way to change the fork oil on these bikes, IMO, and I may do this job every 10k, certainly not more than every 20k. As I said, it took about an hour, but next time I think I could do it in 45 min. now that I know the routine. Thanks to all who encouraged me to try this method.
A ride revealed a slightly firmer feel to the front-end with the SE fluid, but it is not harsh. Corners felt very secure, but my 10-mile ride didn't give it a good test for bottoming, etc. It felt taut and secure, however, and these early results are positive.
Last edited by iclick; 07-08-2011 at 02:33 PM.
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#28
#29
EDIT: I too agree with the convenient use of BelRay since the wt. is evident. Takes the guess work out of the equation.
Last edited by UltraKla$$ic; 08-14-2008 at 09:07 AM.
#30
I was expecting to add only the amount what was drained, and really didn't know what to expect. I was surprised that apparently all the oil drained.
The original oil was dark gray, almost black, and had a strong odor, unlike any oil I've encountered. It's definitely not typical fork oil, and it looked like it might have moly or graphite additives in the formula.
The only trick to this whole project was getting the drain screws out of the forks and adding the oil a little at a time, pumping the forks 4-5 times in between. If you can't get the drain plugs out you should be able to extract them with vise grips, as they have a large head--then replace them with new ones. I just found the torque spec on the drain plugs, which is 78-96 inch-pounds. I didn't torque mine, but just firmed them up like I used to on my old RK. They were originally much tighter than spec, and I almost couldn't get them off.