JimLor
Well-known member
I wanted to update my experience changing springs and pass on a couple of things I learned (or re-learned) for those interested or those who may be considering changing fork springs. 3dogs provided much needed and appreciated guidance/counsel during this whole effort.
I went with Race Tech fork springs that were not specifically listed for the FJR. They were the 403111 (final 11 being the 1.1kg spring rate). The 4031s were recommended as they are larger and fit the 48mm FJR tubes better than the 43mm springs listed for the FJR. Another reason is that the FJR specific springs only go up to a .95 spring rate - I’m 185 and the RT calculator says I need a 1.165 rate. The 4031s go up to a 1.2kg spring rate.
I went through 3 or 4 evolutions of this process before I got it right - mostly changing spacer lengths to little avail. A math error (double subtracting the fork cap measurement), skipping a step called for in the service manual when changing fork oil, and not fully realizing and understanding the spring diameter/spring seat difference and the impact of that caused me some unnecessary frustration and “do overs.”
The OEM spring is a progressive rate spring and is wide in the middle and narrower on the ends. The 4031 is a single rate spring consistent in length from end to end (same dia as OEM center part). Within the fork tube the bottom of the spring rests on the “spring seat” that’s on top of the cartridge in the fork. Here’s a picture looking into the empty tube – you can see the spring seat at the bottom and you’re looking at the damping rod in the center (a smaller rod fits into the center hence the hole in the rod).
The spring seat is sized for the smaller end of the OEM seat. I initially had great frustration in that changes in spacer length did not result in similar changes in “sag” measurements. After several spacer changes didn’t produce satisfactory results, I started the entire process from the beginning – yup, took the whole shebang apart, drained the oil, remeasured the spacer measurement, cut the spacers (again!) and put it all back together.
During the redo I noticed that there isn’t a washer under the spring, only the spring seat and that is sized for the smaller OEM spring end. RT provides 2 x washers (same dia as the spring) and about 6 x aluminum spacers (didn’t use these at all) with the springs. I installed 1 x RT washer under the spring in each fork. I went to Lowe’s and bought 2 x schedule 8 washers of the same size and put them on top of the spring. Here’s a picture of how everything went back into the fork tube from the bottom up. RT washer/spring/RT size washer/OEM washer/spacer/nut/fork cap. You can actually see 2 x spacers. That’s because I cut the spacer a few times and wound up having to stack them together to get what I needed. As long as they’re cut square, I don’t think there’s a problem stacking them.
I followed the service manual directions for fork oil (put in before installing the above) – pour it in, cycle the damping rod at least 10 times (didn’t do that the first time), compress/release the fork a couple of times, then wait 10 minutes for the oil to settle/let air out. I measured 130mm vice the OEM 100mm oil level from the top (forks extended) due to the increase in the spring size from OEM (take up more space - ~50mm longer).
I put it together, took a test ride and lo and behold it works! Hallafrigginlullah! I “think” what was happening before was that the spring was getting pushed over the spring seat and didn’t have any support on the bottom. The spring couldn’t function as designed and was over stiff. Not sure if adding the “cycle the damping rod at least 10 times” step during fork oil loading added to the solution or not, but I didn’t do that the first time.
Lessons I learned or re-learned. A. Read the directions. B. Read the Service Manual. C. Use the FJR Tech articles as a reference. D. Repeat A, B, C until you understand as much as humanly possible about the task before you. Take your time – whatever time it takes! And, there’s never enough time to do it right, but there’s always enough time to do it again!
Here’s something that might help you and did help me in troubleshooting. I noticed when the springs were way too stiff (little sag) that I could pop ole Maxine on the centerstand without any problem at all (front wheel way to high). When, after a couple of frustrating results, I whacked a good chunk off of the spacer I found it was extremely difficult to get her on the centerstand (front wheel way to low) – way too much sag.
I am not an expert in motorcycle suspensions and this is not an effort to sell myself as such. I offer this as a means for others to learn from my experience / mistakes. I am glad I did this even with the frustration involved. I’ve learned more about my forks, spring rates, sag, taking the whole mess apart than I ever would have otherwise and Maxine does handle better than before. If anyone is considering undertaking this I would be happy to talk with you if you like. PM me and I’ll send my phone number.
I went with Race Tech fork springs that were not specifically listed for the FJR. They were the 403111 (final 11 being the 1.1kg spring rate). The 4031s were recommended as they are larger and fit the 48mm FJR tubes better than the 43mm springs listed for the FJR. Another reason is that the FJR specific springs only go up to a .95 spring rate - I’m 185 and the RT calculator says I need a 1.165 rate. The 4031s go up to a 1.2kg spring rate.
I went through 3 or 4 evolutions of this process before I got it right - mostly changing spacer lengths to little avail. A math error (double subtracting the fork cap measurement), skipping a step called for in the service manual when changing fork oil, and not fully realizing and understanding the spring diameter/spring seat difference and the impact of that caused me some unnecessary frustration and “do overs.”
The OEM spring is a progressive rate spring and is wide in the middle and narrower on the ends. The 4031 is a single rate spring consistent in length from end to end (same dia as OEM center part). Within the fork tube the bottom of the spring rests on the “spring seat” that’s on top of the cartridge in the fork. Here’s a picture looking into the empty tube – you can see the spring seat at the bottom and you’re looking at the damping rod in the center (a smaller rod fits into the center hence the hole in the rod).
The spring seat is sized for the smaller end of the OEM seat. I initially had great frustration in that changes in spacer length did not result in similar changes in “sag” measurements. After several spacer changes didn’t produce satisfactory results, I started the entire process from the beginning – yup, took the whole shebang apart, drained the oil, remeasured the spacer measurement, cut the spacers (again!) and put it all back together.
During the redo I noticed that there isn’t a washer under the spring, only the spring seat and that is sized for the smaller OEM spring end. RT provides 2 x washers (same dia as the spring) and about 6 x aluminum spacers (didn’t use these at all) with the springs. I installed 1 x RT washer under the spring in each fork. I went to Lowe’s and bought 2 x schedule 8 washers of the same size and put them on top of the spring. Here’s a picture of how everything went back into the fork tube from the bottom up. RT washer/spring/RT size washer/OEM washer/spacer/nut/fork cap. You can actually see 2 x spacers. That’s because I cut the spacer a few times and wound up having to stack them together to get what I needed. As long as they’re cut square, I don’t think there’s a problem stacking them.
I followed the service manual directions for fork oil (put in before installing the above) – pour it in, cycle the damping rod at least 10 times (didn’t do that the first time), compress/release the fork a couple of times, then wait 10 minutes for the oil to settle/let air out. I measured 130mm vice the OEM 100mm oil level from the top (forks extended) due to the increase in the spring size from OEM (take up more space - ~50mm longer).
I put it together, took a test ride and lo and behold it works! Hallafrigginlullah! I “think” what was happening before was that the spring was getting pushed over the spring seat and didn’t have any support on the bottom. The spring couldn’t function as designed and was over stiff. Not sure if adding the “cycle the damping rod at least 10 times” step during fork oil loading added to the solution or not, but I didn’t do that the first time.
Lessons I learned or re-learned. A. Read the directions. B. Read the Service Manual. C. Use the FJR Tech articles as a reference. D. Repeat A, B, C until you understand as much as humanly possible about the task before you. Take your time – whatever time it takes! And, there’s never enough time to do it right, but there’s always enough time to do it again!
Here’s something that might help you and did help me in troubleshooting. I noticed when the springs were way too stiff (little sag) that I could pop ole Maxine on the centerstand without any problem at all (front wheel way to high). When, after a couple of frustrating results, I whacked a good chunk off of the spacer I found it was extremely difficult to get her on the centerstand (front wheel way to low) – way too much sag.
I am not an expert in motorcycle suspensions and this is not an effort to sell myself as such. I offer this as a means for others to learn from my experience / mistakes. I am glad I did this even with the frustration involved. I’ve learned more about my forks, spring rates, sag, taking the whole mess apart than I ever would have otherwise and Maxine does handle better than before. If anyone is considering undertaking this I would be happy to talk with you if you like. PM me and I’ll send my phone number.
