Rides, ramblings and rants on a motorcycle.
- We are scientists, too!
11.29.2009,5:22 PM
Rebuiding Forks on the Wee-strom
Parts -springs and fork internal components- have been sitting on my living room floor for a month and 1/2. Each ride on the Whee made me think about those parts sitting on the floor. Instead of my traditional annual Turkey Day Dropout Camp Out this year, I chose rebuild the forks. It was...... interesting.
We got a late start on Friday, but......oh well. I kept hearing that it would only take a few hours at the most to rebuild the forks, so we didn't see the need for a rush. Little did we know.......
Following Ed's instruction and a thread on Stromtroooper forum, we easily removed the forks from the bike and began tearing them down. During our initial attempts to remove the bottom bolt from the inside damper, we met The Resistance (TM).
First, a long allen head wrench is required because the bolt is only accessible by going through the hole which goes through the axle hole. Then the bolt head is recessed by at least an inch. We didn't have a long allen wrench of the correct size.
Secondly, some serious oomph is required to loosen the bolts. The poster on Stromtrooper used an impact wrench to loosen the bolts on his forks. We had an impact wrench, but not the right allen wrench or extension. Ed creatively used physics to improvise with a shorter allen head wrench and found it required quite a bit of oomph to try and loosen the bolt. He felt it give, but it was not the thread that gave; it was the bolt head. It was so tight that the corners completely rounded. No way was this bolt coming off the way it should have.
Friend Bill offered his expertise and both agreed the only way to remove the bolt was to vewwy vewwy carefully drill it out. He popped over to assist, armed with super sharp drill bits. After many many minutes full of tension and drilling, a pop offered some relief for all three of us. The drill broke through, released the internal pressure, and it bled dark stinky oil all over the place. The damper rod slid out of the fork tube with the remainder of the bolt sticking in it. I threaded that out with ease and discovered a nasty burr on the end of the damper. That was not supposed to be there.
We were astonished at the condition of the copper washer under the bolt head; it was severely deformed. Only an excessive amount of pressure on that bolt head could have caused the washer to deform like that. It confirmed our suspicions that the bolt had been replaced on the damper rod with an impact wrench. And tightened waay too tight.
The fork oil was black and stinky, which should not have been considering that the fluid was changed only 2-3 months ago. The removed bushings were very worn with brass showing through the teflon coating; one was almost completely worn away.
We relaxed a bit now that the worst was over and we could now clean and assemble the fork with new bushings, seals, rings and springs. But first we needed to try and find a new washer for the damper bolt as well as new bolts. So it was off to the hardware store.
Concentrating on looking for what you really need is always hard in a hardware or tool store. I'm always distracted by looking at hardware and tools I want. Searching for the exact hardware is even worse. Tools are easier to find. We found the bolts we needed. We already knew we would have to drill the bolt out of the other fork, so we needed two bolts. Over the decades of building/repairing, I learned to always get 1-3 more than you need; you never know what will go wrong next and that miserable bloke Murphy dictates that if anything can go wrong, it will, especially when you are not prepared for it. So we got three of everything we needed.
We could not find a copper washer of the right size. Be warned that if you ever work on your forks, you won't find these copper washers at a hardware store. Or brass, or steel, or.............
We decided to get a Starbucks coffee, relax, call it quits for the day and watch a movie. Then attack anew the next day.
The next morning, this time bright and early, we reassembled the one fork with the new Sonic spring and innards. A length of hefty thick PVC was packaged with the springs to use as spacers. We liked the idea of using that for a new spacer, but the inner diameter of the PVC will not clear the clip on the bottom of the fork cap. So we had to reuse the thin stock metal spacer and the two washers supplied with the springs.
Then we attacked the other fork. This one was worse than the first fork. And it took forever to drill through the bolt head. We were both sweating it; the tension was almost unbearable. Finally, the fork tube spit out when Ed taped the bolt with a screw driver and hammer. Whew........
Ed drove over to a local bike shop to see if they had any of the right-sized copper washers. Low and behold, and darned lucky for me, they happened to have two in their miscellaneous parts box. We replaced the deformed copper washers with two new shiny ones.
Below is (from left to right) the second decapitated bolt head, second bolt after removing from bottom of damper rod, and deformed copper washers.
These are the two bushings from the second fork, which were in better shape that those removed from the first fork.
Here are all the parts for one fork, cleaned and/or new, ready to be reassembled in their shiny chrome house.
Next we tackled the steering bearings. Again, I used another thread by Black Lab on Stromtrooper as a guide. It took a bit of dismantling handlebars, etc, but we finally got to them. The top bearings didn't have much grease on them; the bottom bearings were very dry. And the entire head was too loose.
Below is the top race for the top bearings, nice and clean, waiting for the freshly greased bearings.
In all, the entire process of rebuilding the forks and greasing the bearings would have taken maybe 3 hours. But we had to deal with an unexpected issue of over-torqued bolts. Unfortunately, this is the third incident I've discovered from when the bike was worked on at a local shop back in October of 2007.
It had gone in for valve check, complete fork renewal and a few other items. the first thing we discovered shortly afterward was that the front wheel axle had been over-torqued. If not discovered so soon, I would have had to replace the wheel bearings.
The second issue, also discovered right away, was the fluid levels in the forks were off; one much lower than the other fork. And the fluid grade too high.
This is the third issue - over-torqued damper rod bolts. I am NOT pleased with the quality of the shop's work and will not take any of my bikes back there, ever. And I'm hoping real hard that there are no issues with the valves next weekend.
Lesson learned: do not use impact wrench to tighten bolts on bottoms of fork damper rods. I even called my daughter, the bike mechanic, and related this experience so she knows what can happen when using impact wrenches on these bolts.
My sincere thanks to Ed and Bill for their gracious help and patience in teaching bike mechanics to a biologist, and to Black Lab on Stromtrooper for posting the "How To..." threads.
We got a late start on Friday, but......oh well. I kept hearing that it would only take a few hours at the most to rebuild the forks, so we didn't see the need for a rush. Little did we know.......
Following Ed's instruction and a thread on Stromtroooper forum, we easily removed the forks from the bike and began tearing them down. During our initial attempts to remove the bottom bolt from the inside damper, we met The Resistance (TM).
First, a long allen head wrench is required because the bolt is only accessible by going through the hole which goes through the axle hole. Then the bolt head is recessed by at least an inch. We didn't have a long allen wrench of the correct size.
Secondly, some serious oomph is required to loosen the bolts. The poster on Stromtrooper used an impact wrench to loosen the bolts on his forks. We had an impact wrench, but not the right allen wrench or extension. Ed creatively used physics to improvise with a shorter allen head wrench and found it required quite a bit of oomph to try and loosen the bolt. He felt it give, but it was not the thread that gave; it was the bolt head. It was so tight that the corners completely rounded. No way was this bolt coming off the way it should have.
Friend Bill offered his expertise and both agreed the only way to remove the bolt was to vewwy vewwy carefully drill it out. He popped over to assist, armed with super sharp drill bits. After many many minutes full of tension and drilling, a pop offered some relief for all three of us. The drill broke through, released the internal pressure, and it bled dark stinky oil all over the place. The damper rod slid out of the fork tube with the remainder of the bolt sticking in it. I threaded that out with ease and discovered a nasty burr on the end of the damper. That was not supposed to be there.
We were astonished at the condition of the copper washer under the bolt head; it was severely deformed. Only an excessive amount of pressure on that bolt head could have caused the washer to deform like that. It confirmed our suspicions that the bolt had been replaced on the damper rod with an impact wrench. And tightened waay too tight.
The fork oil was black and stinky, which should not have been considering that the fluid was changed only 2-3 months ago. The removed bushings were very worn with brass showing through the teflon coating; one was almost completely worn away.
We relaxed a bit now that the worst was over and we could now clean and assemble the fork with new bushings, seals, rings and springs. But first we needed to try and find a new washer for the damper bolt as well as new bolts. So it was off to the hardware store.
Concentrating on looking for what you really need is always hard in a hardware or tool store. I'm always distracted by looking at hardware and tools I want. Searching for the exact hardware is even worse. Tools are easier to find. We found the bolts we needed. We already knew we would have to drill the bolt out of the other fork, so we needed two bolts. Over the decades of building/repairing, I learned to always get 1-3 more than you need; you never know what will go wrong next and that miserable bloke Murphy dictates that if anything can go wrong, it will, especially when you are not prepared for it. So we got three of everything we needed.
We could not find a copper washer of the right size. Be warned that if you ever work on your forks, you won't find these copper washers at a hardware store. Or brass, or steel, or.............
We decided to get a Starbucks coffee, relax, call it quits for the day and watch a movie. Then attack anew the next day.
The next morning, this time bright and early, we reassembled the one fork with the new Sonic spring and innards. A length of hefty thick PVC was packaged with the springs to use as spacers. We liked the idea of using that for a new spacer, but the inner diameter of the PVC will not clear the clip on the bottom of the fork cap. So we had to reuse the thin stock metal spacer and the two washers supplied with the springs.
Then we attacked the other fork. This one was worse than the first fork. And it took forever to drill through the bolt head. We were both sweating it; the tension was almost unbearable. Finally, the fork tube spit out when Ed taped the bolt with a screw driver and hammer. Whew........
Ed drove over to a local bike shop to see if they had any of the right-sized copper washers. Low and behold, and darned lucky for me, they happened to have two in their miscellaneous parts box. We replaced the deformed copper washers with two new shiny ones.
Below is (from left to right) the second decapitated bolt head, second bolt after removing from bottom of damper rod, and deformed copper washers.
These are the two bushings from the second fork, which were in better shape that those removed from the first fork.
Here are all the parts for one fork, cleaned and/or new, ready to be reassembled in their shiny chrome house.
Next we tackled the steering bearings. Again, I used another thread by Black Lab on Stromtrooper as a guide. It took a bit of dismantling handlebars, etc, but we finally got to them. The top bearings didn't have much grease on them; the bottom bearings were very dry. And the entire head was too loose.
Below is the top race for the top bearings, nice and clean, waiting for the freshly greased bearings.
In all, the entire process of rebuilding the forks and greasing the bearings would have taken maybe 3 hours. But we had to deal with an unexpected issue of over-torqued bolts. Unfortunately, this is the third incident I've discovered from when the bike was worked on at a local shop back in October of 2007.
It had gone in for valve check, complete fork renewal and a few other items. the first thing we discovered shortly afterward was that the front wheel axle had been over-torqued. If not discovered so soon, I would have had to replace the wheel bearings.
The second issue, also discovered right away, was the fluid levels in the forks were off; one much lower than the other fork. And the fluid grade too high.
This is the third issue - over-torqued damper rod bolts. I am NOT pleased with the quality of the shop's work and will not take any of my bikes back there, ever. And I'm hoping real hard that there are no issues with the valves next weekend.
Lesson learned: do not use impact wrench to tighten bolts on bottoms of fork damper rods. I even called my daughter, the bike mechanic, and related this experience so she knows what can happen when using impact wrenches on these bolts.
My sincere thanks to Ed and Bill for their gracious help and patience in teaching bike mechanics to a biologist, and to Black Lab on Stromtrooper for posting the "How To..." threads.
"Oh dear, Gromit, I think I ate a bit of moldy Wensleydale!!!"
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