Author |
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Oldmanriver
| Posted on Saturday, February 05, 2011 - 09:05 pm: |
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So I decided to change the fork oil as I sit and wait for the snow to melt. I did not do a full rebuild, as I have 12,500 mi and have never noticed any leaks. I pulled the cap and spring so I could refill according to the service manual, which is 3.7" to the top of the tube, no spring, after pumping the damper rod, fork assembly compressed. This was all pretty simple and straight forward, and went well. As I tore everything down I took a quick measurement for reference, it was 3.4", both forks. Pretty close I thought. It wasn't till after, when I'm dumping the oil, I realized that the 3.4" was with the spring still in the forks. In the end that's a couple inches different than what the SM calls for when refilling. So I guess I'm wondering If anyone else has noticed this when doing their forks? Is it "normal" to loose some oil over some miles? And is the fork oil a dealer setup item?(possibly not filled correct) Any insight on why the difference would be appreciated. |
Dannybuell
| Posted on Saturday, February 05, 2011 - 09:27 pm: |
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I am thinking you need to go to some of the track days as a spectator and find out from the local racers 'who is who' in your area for suspensions. In my area it is GPsuspension.com they get a lot of work this time of year as machines are being prepped for the upcoming season. |
Thefleshrocket
| Posted on Saturday, February 05, 2011 - 09:31 pm: |
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It's not normal to lose any oil. Either your fork tubes were filled with less oil than the manual specifies, or you measured improperly, or your fork tubes are leaking (albeit slowly). More fork oil means less air which essentially means more compression damping. If you felt like the bike needs more compression damping before you serviced the fork, fill the oil to the level specified in the manual. You should be able to dial out any excessive damping with the adjusters. If you were happy with it as-was, fill to the same level as before. |
Ratbuell
| Posted on Saturday, February 05, 2011 - 09:35 pm: |
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And it is NOT a dealer item. Nor is it, to my understanding, a factory item. IIRC the fork ASSEMBLIES are shipped from Showa to Buell, and bolted to triple trees. Period. "Factory set up" means *Showa* factory. |
Rodrob
| Posted on Sunday, February 06, 2011 - 02:34 am: |
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100MM from top is the recommended level. However, I was advised to try 120 or 125, when I could not get the harshness out of the forks. I am now at 120 and like it much better. My lap times have dropped as well. |
Oldmanriver
| Posted on Sunday, February 06, 2011 - 11:02 am: |
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Thanks for all the great responses and info guys! At 94mm or 3.7" it leaves very little air space with the fork fully compressed, spring and what not in place. I'm thinking I'll pull some out, go with 120 or so like you suggest Rodrob, and see how I like it. That would be much closer to what the level was when I opened them. And I was pretty comfortable with where I had the suspension setup prior. I really doubt I have any leakage as both forks were at the same level and the lower tubes look clean. And while I could have screwed up refilling them, it seems straight forward in the manual. Fork compressed, no spring, fill to threads on outer tube, pump valve assembly till no air, remove fluid down to 94mm or 3.7". Then install spring and the rest, correct? (Message edited by oldmanriver on February 06, 2011) |
Thefleshrocket
| Posted on Monday, February 07, 2011 - 08:24 pm: |
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Oldmanriver, I don't have a shop manual but the procedure you describe is what I've always used when refilling fork tubes. |
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