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Post by steve63 on Jul 23, 2024 17:46:28 GMT 1
My Mrs is really good at detecting things going on with bikes when she's riding pillion. She's asked me if the R1 had something wrong with it when the back tyre was quite worn and tracking white lines. She said it felt odd. Last Thursday she said she didn't like the way the VFR was handling. She said she's not going back on It until it's sorted! It felt a bit off to me but then again it was the first time I'd ridden it since we got back from holiday so it wasn't loaded up but surely it should feel better? I put it down to a combination of a pretty worn back tyre making it handle oddly and a chain that needed adjusting making it a bit snatchy. I also thought the tyre pressure was down on the rear. I put the chain right and put 3 or 4 psi in the tyre back up to 42/43 and to compensate for the worn tyre I put two more notches of pre-load on. It's now on full. I took it for a ride and it feels on edge and a bit nervous so probably went too far with pre-load. Reading your post I'm now thinking I should give it a thorough good look over for anything that could have broken. My Mrs is available for testing duties 😉
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Post by vectisitch on Jul 23, 2024 19:20:22 GMT 1
My Mrs is really good at detecting things going on with bikes when she's riding pillion. She's asked me if the R1 had something wrong with it when the back tyre was quite worn and tracking white lines. She said it felt odd. Last Thursday she said she didn't like the way the VFR was handling. She said she's not going back on It until it's sorted! It felt a bit off to me but then again it was the first time I'd ridden it since we got back from holiday so it wasn't loaded up but surely it should feel better? I put it down to a combination of a pretty worn back tyre making it handle oddly and a chain that needed adjusting making it a bit snatchy. I also thought the tyre pressure was down on the rear. I put the chain right and put 3 or 4 psi in the tyre back up to 42/43 and to compensate for the worn tyre I put two more notches of pre-load on. It's now on full. I took it for a ride and it feels on edge and a bit nervous so probably went too far with pre-load. Reading your post I'm now thinking I should give it a thorough good look over for anything that could have broken. My Mrs is available for testing duties 😉 "My Mrs is available for testing duties" you say? 🤔🤔 |
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Post by steve63 on Jul 24, 2024 13:03:04 GMT 1
I can see what's happened now.
I guess when it snapped the reservoir mounting stopped it just collapsing so that was what prevented a disaster?
I know from my job that set screws and bolts have different markings to indicate tensile strength. Most common is 8.8 on steel and we use mainly A4 70 stainless. If it was an off the shelf screw or bolt then it would come under one of those standards. If this is a specially made part for the shock manufacturers then it's down to the manufacturer to decide on the material, heat treatment if needed etc. This could be the result of it being too hard.
I have seen a picture of a bolt made in China sliced down the middle and there were air pockets all the way through. The spec for the job said "no Chinese fasteners."
From time to time (far too often actually) I receive photos of problems with equipment we send out and it's awful opening the emails TBH. If I were involved in the manufacture of these parts and I received this photo I would be very worried.
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Post by Tobyjugs on Jul 24, 2024 13:27:49 GMT 1
I can see what's happened now. I guess when it snapped the reservoir mounting stopped it just collapsing so that was what prevented a disaster? I know from my job that set screws and bolts have different markings to indicate tensile strength. Most common is 8.8 on steel and we use mainly A4 70 stainless. If it was an off the shelf screw or bolt then it would come under one of those standards. If this is a specially made part for the shock manufacturers then it's down to the manufacturer to decide on the material, heat treatment if needed etc. This could be the result of it being too hard. I have seen a picture of a bolt made in China sliced down the middle and there were air pockets all the way through. The spec for the job said "no Chinese fasteners." From time to time (far too often actually) I receive photos of problems with equipment we send out and it's awful opening the emails TBH. If I were involved in the manufacture of these parts and I received this photo I would be very worried. I think you and Zed are right. The broken bolt in question is from the original shock. Not sure what material it is made from. I believe the basic design is wrong. It should be the eye of the damper fixed wit a horizontal bolt or pin. I will explain later when I have more time. It has failed once before when i went a bit to hot into a tight bend and the front end washed out. Both me and the bike hit the banked wall and bounced back into the road. |
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Post by Tobyjugs on Jul 24, 2024 13:30:14 GMT 1
Steve i know the perfect place where you and your wife can do as much testing as you like.
It's called Two4fun, close to Gouda.
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Post by steve63 on Jul 24, 2024 13:46:35 GMT 1
Steve i know the perfect place where you and your wife can do as much testing as you like. It's called Two4fun, close to Gouda. Is that somewhere I shouldn't be checking out on my work PC by any chance? I had a load of red warning windows popping onto my screen yesterday and that was only after looking into the temperature at which steel becomes malleable 😕 Don't want to have to call the IT guy over today as well 😀 |
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Post by zed1015 on Jul 24, 2024 14:11:18 GMT 1
I think you and Zed are right. The broken bolt in question is from the original shock. Not sure what material it is made from. I believe the basic design is wrong. It should be the eye of the damper fixed wit a horizontal bolt or pin. I will explain later when I have more time. It has failed once before when i went a bit to hot into a tight bend and the front end washed out. Both me and the bike hit the banked wall and bounced back into the road. If it's a Yamaha R1/R6 etc item they are usually aluminium. They are ok when used in their original application as a top ride height adjuster in compression directly in line with the direction of shock travel but when subjected to any angular force they can shear. That looks like it has been used as an adjustable shock mount on a modified swingarm at an angle to the shock travel which has caused the shear failure. It at least needs replacing with a steel one but ideally that mount should be solid and any height adjustment placed at the mount on the frame. |
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Post by Tobyjugs on Jul 24, 2024 17:14:07 GMT 1
I think you and Zed are right. The broken bolt in question is from the original shock. Not sure what material it is made from. I believe the basic design is wrong. It should be the eye of the damper fixed wit a horizontal bolt or pin. I will explain later when I have more time. It has failed once before when i went a bit to hot into a tight bend and the front end washed out. Both me and the bike hit the banked wall and bounced back into the road. If it's a Yamaha R1/R6 etc item they are usually aluminium. They are ok when used in their original application as a top ride height adjuster in compression directly in line with the direction of shock travel but when subjected to any angular force they can shear. That looks like it has been used as an adjustable shock mount on a modified swingarm at an angle to the shock travel which has caused the shear failure. It at least needs replacing with a steel one but ideally that mount should be solid and any height adjustment placed at the mount on the frame. Yes well said its getting pushed sideway in two directions. Just like if you bend sheet metal backwards and forwards. Eventually it will break. I'm not going to bother with a steel adjuster. I will change the top of the swing arm and fit a different shock. This time the right way up. |
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Post by urbantangleweed on Jul 24, 2024 20:51:15 GMT 1
Steve i know the perfect place where you and your wife can do as much testing as you like. It's called Two4fun, close to Gouda. Is that somewhere I shouldn't be checking out on my work PC by any chance? I had a load of red warning windows popping onto my screen yesterday and that was only after looking into the temperature at which steel becomes malleable 😕 Don't want to have to call the IT guy over today as well 😀 Good thing you weren't researching hot wood...... |
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Post by steve63 on Jul 25, 2024 13:01:21 GMT 1
Is that somewhere I shouldn't be checking out on my work PC by any chance? I had a load of red warning windows popping onto my screen yesterday and that was only after looking into the temperature at which steel becomes malleable 😕 Don't want to have to call the IT guy over today as well 😀 Good thing you weren't researching hot wood...... I had to use stainless pipe for the pneumatic damper actuators on a project once which is quite normal. In the spec for this job though it stated the pipe had to sheaved in tight fitting black PVC. I think it was to do with chemical resistance. Imagine the results of my searches that day?. We had less IT protection/interference in those days. |
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Post by urbantangleweed on Jul 25, 2024 13:11:08 GMT 1
Good thing you weren't researching hot wood...... I had to use stainless pipe for the pneumatic damper actuators on a project once which is quite normal. In the spec for this job though it stated the pipe had to sheaved in tight fitting black PVC. I think it was to do with chemical resistance. Imagine the results of my searches that day?. We had less IT protection/interference in those days.  |
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Post by Tobyjugs on Jul 25, 2024 14:32:23 GMT 1
Here is a picture of the first failure.  As you can see it was made for a thread or stud. It is a TZ swing arm which fitted really well almost keeping everything standard. I only added a aluminium spacer to give the stud more support. After the arm failed a much bigger stronger bracket was welded to the swingarm. |
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Post by veg on Jul 25, 2024 19:18:18 GMT 1
Too many sprinkles on your bread, me thinks a diet is required.
Glad you’re ok bud.
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Post by JonW on Jul 28, 2024 2:40:37 GMT 1
Good sleuthing Tony.
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Post by steve63 on Jul 29, 2024 13:06:08 GMT 1
Here is a picture of the first failure. As you can see it was made for a thread or stud. It is a TZ swing arm which fitted really well almost keeping everything standard. I only added a aluminium spacer to give the stud more support. After the arm failed a much bigger stronger bracket was welded to the swingarm. Classic heat effected zone aluminium weld crack. Remember the articles regarding frame life when aluminium frames first started appearing, RG250? It never really has become much of an issue has it? I have heard of the shock mountings on RGV250's failing and Hayabusa sub frames but not nothing else I can recall. I guess they got their choice of aluminium/weld material and heat treatment or not about right? Aluminium isn't my area but I know there are lots of different grades that need different welding rods and heat treatment and some don't ned treatment at all after welding. It's easy to get it wrong. In a previous life I once straightened, repaired and welded a aluminium swinging arm off an F2 Yamaha. The chain had jumped off and caused a lot of damage. I used whatever rods we had on the shelf and I knew nothing of heat treatment. I've no idea how long it lasted but it looked Ok when I gave it back  |
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