Guest FifeDog Posted March 7, 2007 Share Posted March 7, 2007 My bike: 2003 VFR800. I just bought the 46DR rear shock from Ohlins and the fork springs to match. When replacing the oil I am getting different opinions on what level to set the fork oil. One "expert" says 150mm and use 10w vs. Ohlins 100mm and use 10w (stock fork oil level). What is correct? Link to comment Share on other sites More sharing options...
Baileyrock Posted March 7, 2007 Share Posted March 7, 2007 Fork oil level is a tool for adjusting one aspect of the forks function of which I am No expert, but fork oil level only effects the last inch of fork travel. From what I understand in general is that lower levels are fine or desired(as long as there's enough to cover all needed pieces) and that higher levels of oil are used as anti bottoming tool if your springs aren't the proper weight. I think the less air in the fork(higher oil level) the stiffer this last and final bottoming movement(travel) of the fork. The remaining air in the forks act as a secondary spring in the latter movement of fork travel. Don't know if that makes any sense, but I would run the lower level(Ohlins) and ride the bike. If you have any harsh bottoming in certain conditions it would be very easy to add another 10cc of oils to each leg until you got the desired effect. I would imagine that you would Not experience any problems on the street running the lower level especially after changing the springs to the recommended Rates. Google fork oil level or suspension for a more knowledgeable answer. :rolleyes: :thumbsup: Link to comment Share on other sites More sharing options...
Member Contributer jstanwood Posted March 7, 2007 Member Contributer Share Posted March 7, 2007 I agree with BR, except for one little thing to keep in mind. The measurements given are typically from the top of the fork tube down to the oil level, which is also why this is called the "air gap". So, a lower number is actually a higher level. I definitely agree with the bottoming resistance aspect. Air is a compressible fluid, while oil is theoretically not. Less air = sless stuff that compresses. Link to comment Share on other sites More sharing options...
Guest Posted March 7, 2007 Share Posted March 7, 2007 Good point, I will try it at 150mm (lower level) and see how it goes with bottoming. I weigh 175, so now with stiffer (than stock) springs, I should be OK. ...Any thoughts? Link to comment Share on other sites More sharing options...
Member Contributer Dutchy Posted March 7, 2007 Member Contributer Share Posted March 7, 2007 Copied from the dutch Ohlins website: FRONT FORK OIL LEVEL First see manual. The modern front fork of cartridge type is very sensitive for oil level changes, because of the small air volume, air inside the front fork works as a spring. The different level of oil effects the spring ratio from the middle of the stroke and has a very strong effect at the end of the stroke. When the oil level is raised: The air spring in the later half stage of travel is stronger, and thus the front forks harder. When the oil level is lowered: The air spring in the later half stage of travel is lessened, and thus the front forks are softer. The oil level works most effectively at the end of the fork travel. Note: Adjust the oil level according to your manual. Also, the air gap is measured without the spring in the leg and the top part of the leg pressed fully down in the lower part of the leg. Link to comment Share on other sites More sharing options...
Guest Posted March 8, 2007 Share Posted March 8, 2007 Copied from the dutch Ohlins website:Note: Adjust the oil level according to your manual. That's exactly the confirmation I am looking for...thanks Dutchy for the cut & paste. According to the service manual it 100mm, so I will keep it at that. Link to comment Share on other sites More sharing options...
Member Contributer vfrjim2002 Posted March 8, 2007 Member Contributer Share Posted March 8, 2007 Copied from the dutch Ohlins website:Note: Adjust the oil level according to your manual. That's exactly the confirmation I am looking for...thanks Dutchy for the cut & paste. According to the service manual it 100mm, so I will keep it at that. What rate springs did you wind up with? FWIW. I recently installed .95kg/mm RaceTech springs purchased from Aftershocks. Not being a "modern suspension wizard" I asked Phil (the force behind Aftershock - who by most accounts is an MSW) who advised starting at 125mm. I settled at 120. The front end works much better than OEM. At 245 I'm a quite a bit heavier than you, but I can't say that I need or would like it firmer at the bottom of its travel. YSMV. Link to comment Share on other sites More sharing options...
Member Contributer captainchris13 Posted March 8, 2007 Member Contributer Share Posted March 8, 2007 Ok, so i ordered some fr springs in .90 from racetech to go with my 929 rear shock conversion (stock spring righ now) and for those of you who redid your forks, what is the magic change in the shim stack to make this thing smother. I found an old post by HS who said take a shim out of the comp side and put it in the rebound side, but not which one or where. Also, i noticed everyone says it has too much comp damping and too little rebound, and talk of oils and blending oils for in between weights, but has anyone just added 2 different oils to the forks? I mean, they are comp on one fork and reb on the other so why not tune with speperate oils in each but at the same height 7.5 w in the comp side, 12.5w in the rebound and leave the shims alone? maybe? they are coming apart as soon as i get those springs as the damn thing is the 30 mile wonder now, or rather its rideable for 30 mi and the the ride goes to hell ad the fr end starts shaking and bouncing and wandering. i figure its the oil foaming up or something. So should i just replace oil and springs or should i go after other things too... bike is a 99 with 10k miles on it, 6500 of those were in the last 9 months since ive owned it. Link to comment Share on other sites More sharing options...
Guest Posted March 8, 2007 Share Posted March 8, 2007 Ok, so i ordered some fr springs... Hey fella, no hijacking my topic. It's not that hard to start a new one to ask your own question! Link to comment Share on other sites More sharing options...
turtlecreek Posted March 8, 2007 Share Posted March 8, 2007 http://www.vfrdiscussion.com/forum/index.p...amp;hl=fork+oil here, use this one then....better to use open thread than start anew....lots of info for you anyways... Link to comment Share on other sites More sharing options...
Guest Posted March 8, 2007 Share Posted March 8, 2007 here, use this one then....better to use open thread than start anew....lots of info for you anyways... Yes, I actually read every bit of your thread & was tracking it to see if the information I needed would pop up before I decided to start my own topic. I'm not fond of hijacking someone elses topic. To me its like interupting a conversation, and think its best to start a new one instead. Enough said. Thanks to everyone for your input, and thanks to Hispanic Slammer for this forum and all it provides us. I am now on track! Link to comment Share on other sites More sharing options...
Member Contributer captainchris13 Posted March 8, 2007 Member Contributer Share Posted March 8, 2007 huh, a thread about forks and oil and i ask a question about forks and oil, and thats hijacking your thread? really? and then you say your done with it anyway.... :goofy: Link to comment Share on other sites More sharing options...
Member Contributer CornerCarver Posted March 8, 2007 Member Contributer Share Posted March 8, 2007 Ok, so i ordered some fr springs in .90 from racetech to go with my 929 rear shock conversion (stock spring righ now) and for those of you who redid your forks, what is the magic change in the shim stack to make this thing smother. I found an old post by HS who said take a shim out of the comp side and put it in the rebound side, but not which one or where. Also, i noticed everyone says it has too much comp damping and too little rebound, and talk of oils and blending oils for in between weights, but has anyone just added 2 different oils to the forks? I mean, they are comp on one fork and reb on the other so why not tune with speperate oils in each but at the same height 7.5 w in the comp side, 12.5w in the rebound and leave the shims alone? maybe? they are coming apart as soon as i get those springs as the damn thing is the 30 mile wonder now, or rather its rideable for 30 mi and the the ride goes to hell ad the fr end starts shaking and bouncing and wandering. i figure its the oil foaming up or something. So should i just replace oil and springs or should i go after other things too... bike is a 99 with 10k miles on it, 6500 of those were in the last 9 months since ive owned it. You do not have seperate compression and rebound "legs" with your forks. Each fork leg has an individual compression and reboud damping valve. I just completed a winter overhaul of my entire suspension and have a 5th gen with similar mileage as you. I had not noticed any of the action that you described "shaking and bouncing and wandering". I would recommend that you flush and fill your forks with a known quantity and weight of oil to start fresh and then determine what you need regarding new springs or valving in the future. When you oflush and fill, since you have not changed the valving or spring rate yet, start with the Honda recommended oil weight and level. PM me if you have any specific questions. Keith Link to comment Share on other sites More sharing options...
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