Tightwad Posted May 30, 2009 Share Posted May 30, 2009 The manual states that the Fork spring should be installed with the tapered (tighter coils) at the top. When I took the fork apart it was in the other way. I don't have reason to think the PO changed the fluid, he only had it 13K miles and didn't mention it when I purchased it. Is there a chance it was installed wrong from the factory? What would the difference be in operation? Should I put it the way the manual states it, or how it was? Link to comment Share on other sites More sharing options...
rhubarb Posted May 30, 2009 Share Posted May 30, 2009 The tighter coils should be at the top as recommended. I think I remember reading somewhere that factory springs may be the other way around. The reason given was that dual or progressive rate springs will respond better to smaller bumps if the tighter coils are at the bottom, instead of moving the whole spring. Link to comment Share on other sites More sharing options...
Forum CEO HispanicSlammer Posted May 30, 2009 Forum CEO Share Posted May 30, 2009 I just took apart my buddies vtec forks and his where oriented down! They were assembled that way from the factory, and the diameter of the small end does not match the size of the spacer washer between the spacer and the spring, the washer fits the larger diameter on top though. There is only one washer between the springs and the metal spacer too. They seem to me to face down, other than having a way of engageing a surface fully (ie the washer diameter) the orientation makes no difference. VTEC springs are different than 5th gen, since they have the tighter coils they also are smaller diameter on the tight side, my 5th gen springs are just spaced closer on one end same diameter. We replaced a blown seal and the slider bushings on his forks - we just put them back in downward cause thats the way they were when we took it apart. Link to comment Share on other sites More sharing options...
Tightwad Posted May 30, 2009 Author Share Posted May 30, 2009 I just took apart my buddies vtec forks and his where oriented down! They were assembled that way from the factory, and the diameter of the small end does not match the size of the spacer washer between the spacer and the spring, the washer fits the larger diameter on top though. There is only one washer between the springs and the metal spacer too. They seem to me to face down, other than having a way of engageing a surface fully (ie the washer diameter) the orientation makes no difference. VTEC springs are different than 5th gen, since they have the tighter coils they also are smaller diameter on the tight side, my 5th gen springs are just spaced closer on one end same diameter. We replaced a blown seal and the slider bushings on his forks - we just put them back in downward cause thats the way they were when we took it apart. I am fixing the same problem...I will put them in the same way I guess! Odd that the manual has it the other way, but good to hear it is from the factory that way. Link to comment Share on other sites More sharing options...
Forum CEO HispanicSlammer Posted May 30, 2009 Forum CEO Share Posted May 30, 2009 instead of moving the whole spring. The force of the bump acts on the entire spring - it has to have force from both ends Newtons law and all of that physics says so. When the tighter coils compress they bind up - touching the other coil when this happens the spring rate increases - thats is how a progressive spring works. I read alot about springs and found this out, the factors that change the spring rate of a particular spring is the diameter of the coil looking down from the top, the number of coils and the thickness of the spring. There is no factor for length of the coils. When a progressive spring binds up it changes the number of active coils which changes the spring rate. A spring can fatigue and it can be shorter in length however the spring rate remains the same, it will just sit lower and change the geometry of the bike. http://www.engineersedge.com/spring_comp_calc_k.htm Link to comment Share on other sites More sharing options...
V4 Rosso Posted May 30, 2009 Share Posted May 30, 2009 The force of the bump acts on the entire spring - it has to have force from both ends Newtons law and all of that physics says so. Yes, but the top end moves slower than the lower end. With the heavy part of the spring (tightly wound coils) at the top you have less unsprung weight and by that slightly better spring action. The perfect spring has no mass or inertia. Link to comment Share on other sites More sharing options...
checksix Posted May 30, 2009 Share Posted May 30, 2009 On my '07 the springs were installed at the factory with the tapered ends down. So I kept them that way, in spite of what the manual says. Link to comment Share on other sites More sharing options...
spud786 Posted May 30, 2009 Share Posted May 30, 2009 The manual states that the Fork spring should be installed with the tapered (tighter coils) at the top. When I took the fork apart it was in the other way. I don't have reason to think the PO changed the fluid, he only had it 13K miles and didn't mention it when I purchased it.Is there a chance it was installed wrong from the factory? What would the difference be in operation? Should I put it the way the manual states it, or how it was? Tight coils go down on the vfr, Stock springs are also tapered at the compressed coil end, you can put them on top if you want but they should go down. I've ran them both ways, they dont fit right coils up cause of the tapering they've done. Mine came from the factory coils down Link to comment Share on other sites More sharing options...
Tightwad Posted May 30, 2009 Author Share Posted May 30, 2009 Thanks all...this has been interesting. I hate when the manual is backwards of how they built it....hard to say "Honda wants you to do it this way" when even they can't make up their minds. On a related note....is it better to go by oil specification in ounces, or by measuring 100mm of free space between oil and top of tube? Link to comment Share on other sites More sharing options...
Forum CEO HispanicSlammer Posted May 30, 2009 Forum CEO Share Posted May 30, 2009 On a related note....is it better to go by oil specification in ounces, or by measuring 100mm of free space between oil and top of tube? The size of the airpocket is what changes the spring rate since air acts as a spring it will compress and spring back like a spring. So measure the 100mm from the top of the fork and dont worry about the volume of fork fluid. The amount of air is more important too much and your forks will feel soft too little and you could blow a seal. Link to comment Share on other sites More sharing options...
Member Contributer thx1139 Posted May 31, 2009 Member Contributer Share Posted May 31, 2009 On a related note....is it better to go by oil specification in ounces, or by measuring 100mm of free space between oil and top of tube? A volume specification would seem to be less affected by spring position. If you go by oil height, that number should be different if the springs are then reversed. With tight coils at the top, more of the measured air gap is occupied by the incompressible metal of the spring. That shoud have the same effect as a higher oil height. Link to comment Share on other sites More sharing options...
Tightwad Posted May 31, 2009 Author Share Posted May 31, 2009 On a related note....is it better to go by oil specification in ounces, or by measuring 100mm of free space between oil and top of tube? A volume specification would seem to be less affected by spring position. If you go by oil height, that number should be different if the springs are then reversed. With tight coils at the top, more of the measured air gap is occupied by the incompressable metal of the spring. That shoud have the same effect as a higher oil height. Hmmm....sounds like over analyzing it to me. I went with the measurement of 100mm, but noted the Fluid needed, which was about 1oz short of the 18.4 specified. I don't know how much of the old fluid might have still been in the damper, even tho I tried to squeeze it all out. Forks feel great, got it all back together. Realized on the second fork that I had install the seal on the first one backwards, so I had to take it all apart again! Link to comment Share on other sites More sharing options...
Forum CEO HispanicSlammer Posted May 31, 2009 Forum CEO Share Posted May 31, 2009 Bottom line is there is no way the tight end of the coil fits on top because the washer is a larger diameter, and the spacer is really thin. The washer was designed to fit the other end, tight coils go down. Link to comment Share on other sites More sharing options...
SEBSPEED Posted May 31, 2009 Share Posted May 31, 2009 On a related note....is it better to go by oil specification in ounces, or by measuring 100mm of free space between oil and top of tube? A volume specification would seem to be less affected by spring position. If you go by oil height, that number should be different if the springs are then reversed. With tight coils at the top, more of the measured air gap is occupied by the incompressable metal of the spring. That shoud have the same effect as a higher oil height. Hmmm....sounds like over analyzing it to me. I went with the measurement of 100mm, but noted the Fluid needed, which was about 1oz short of the 18.4 specified. I don't know how much of the old fluid might have still been in the damper, even tho I tried to squeeze it all out. Forks feel great, got it all back together. Realized on the second fork that I had install the seal on the first one backwards, so I had to take it all apart again! Yeah, a little, but given the volume of the slider cylinder and the relative volume the spring can take up, it actually does make a difference. If you ever get to a point in riding where you would notice the difference, then well, there is a difference to notice... Link to comment Share on other sites More sharing options...
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