Throttle spring unwind
Posted: Fri Jul 16, 2021 4:03 pm
Back in 2010 when I learned about it, I unwound the throttle return spring on my '08. At this point that was 101,000 miles ago.
The reason for doing doing this is to help reduce right wrist pressure, especially on long rides. Many people have done this to their FJR. It has the side benefit of being a poor mans cruise control. It is done by slipping the end of spring off a '"v" notch. As it slips off, it instantly unwinds the full 360 degrees it is wound in the first place. This spring is the large spring between throttle bodies 2 & 3.
The throttle cable assembly is then the only way to close the throttle. The throttle cable assembly is a two part cable assembly, one cable pulling the throttle bodies open and the other pushing the throttle bodies closed. With the throttle spring untouched the throttle bodies close quickly under spring pressure, and the push cable is only there for insurance against a throttle spring failure.
Now to get to the interesting part. I was coming home from CFR on the 400 highway north of Toronto last Sunday. Traffic was slowing down, so I let off the throttle and suddenly felt something odd through the right grip, and instantly there was no engine deceleration as would be normal. I hit the brake to avoid a collision. I carried on keeping this in mind, and thought I should expect unusual operation once off the 400 and shifting through the gears. On my first up-shift I pulled in the clutch and the engine raced up towards redline, so I quickly released the clutch and shifted up to avoid over revving. The rest of the 300 kms of back roads going home was a careful combination of low engine speed, speed shifting and letting the engine decelerate slowly with the little bit of main spring force still available. The brakes sort of made up for loss of deceleration. Let's just say I was happy to get home later that day without having the bike on a tow truck.
Upon inspection, I found the well lubed push cable broken at the hand grip end. Without the normal throttle spring pressure keeping the push cable taut, there will be abnormal flexing at one end. It's kind of like pushing on a string, something has to give. A new cable assembly is on order for $40 Cdn, but it takes 10 days to get it. The real upshot here is that I'm leaving the throttle return spring unwound, and hope to get another 100,000 miles out of the new cable assembly. Call me crazy, I don't care, but all you guys that have done this, now have a bit of new crucial information.
You guys with the Gen3 bikes that have "throttle by wire" would never have this issue.
The reason for doing doing this is to help reduce right wrist pressure, especially on long rides. Many people have done this to their FJR. It has the side benefit of being a poor mans cruise control. It is done by slipping the end of spring off a '"v" notch. As it slips off, it instantly unwinds the full 360 degrees it is wound in the first place. This spring is the large spring between throttle bodies 2 & 3.
The throttle cable assembly is then the only way to close the throttle. The throttle cable assembly is a two part cable assembly, one cable pulling the throttle bodies open and the other pushing the throttle bodies closed. With the throttle spring untouched the throttle bodies close quickly under spring pressure, and the push cable is only there for insurance against a throttle spring failure.
Now to get to the interesting part. I was coming home from CFR on the 400 highway north of Toronto last Sunday. Traffic was slowing down, so I let off the throttle and suddenly felt something odd through the right grip, and instantly there was no engine deceleration as would be normal. I hit the brake to avoid a collision. I carried on keeping this in mind, and thought I should expect unusual operation once off the 400 and shifting through the gears. On my first up-shift I pulled in the clutch and the engine raced up towards redline, so I quickly released the clutch and shifted up to avoid over revving. The rest of the 300 kms of back roads going home was a careful combination of low engine speed, speed shifting and letting the engine decelerate slowly with the little bit of main spring force still available. The brakes sort of made up for loss of deceleration. Let's just say I was happy to get home later that day without having the bike on a tow truck.
Upon inspection, I found the well lubed push cable broken at the hand grip end. Without the normal throttle spring pressure keeping the push cable taut, there will be abnormal flexing at one end. It's kind of like pushing on a string, something has to give. A new cable assembly is on order for $40 Cdn, but it takes 10 days to get it. The real upshot here is that I'm leaving the throttle return spring unwound, and hope to get another 100,000 miles out of the new cable assembly. Call me crazy, I don't care, but all you guys that have done this, now have a bit of new crucial information.
You guys with the Gen3 bikes that have "throttle by wire" would never have this issue.