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Throttle spring unwind

Posted: Fri Jul 16, 2021 4:03 pm
by John d
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.

Re: Throttle spring unwind

Posted: Fri Jul 16, 2021 4:25 pm
by FJRoss
I never did the unwind. Never had big problems with wrist strain and never liked the thought that the throttle wouldn't default to closed if my hand came off the throttle or if something broke.
I have Throttlemeister bar ends and can fully or partially engage to give the wrist a rest if needed.

Re: Throttle spring unwind

Posted: Fri Jul 16, 2021 4:30 pm
by SLK50
I did the unwind AND my throttle still snaps shut.
Perhaps you did it more than one wind?

Oh, and I do enjoy the less effort to open the
throttle. No regrets.

Re: Throttle spring unwind

Posted: Fri Jul 16, 2021 4:35 pm
by ionbeam
SLK50 wrote: Fri Jul 16, 2021 4:30 pm I did the unwind AND my throttle still snaps shut.
Perhaps you did it more than one wind?...
John d wrote: Fri Jul 16, 2021 4:03 pm ...I unwound the throttle return spring on my '08...
Upon inspection, I found the well lubed push cable broken at the hand grip end...

Re: Throttle spring unwind

Posted: Fri Jul 16, 2021 4:50 pm
by John d
ionbeam wrote: Fri Jul 16, 2021 4:35 pm
SLK50 wrote: Fri Jul 16, 2021 4:30 pm I did the unwind AND my throttle still snaps shut.
Perhaps you did it more than one wind?...
John d wrote: Fri Jul 16, 2021 4:03 pm ...I unwound the throttle return spring on my '08...
Upon inspection, I found the well lubed push cable broken at the hand grip end...
I'll try rewinding one turn and see what comes of it. Stay tuned.

Re: Throttle spring unwind

Posted: Fri Jul 16, 2021 5:19 pm
by rbentnail
I've replaced both cables on my '07. Do yourself a favor and get long handled straight and curved needle nosed pliers. Better yet are long handled straight and curved hemostats. You'll thank me later.

Re: Throttle spring unwind

Posted: Fri Jul 16, 2021 5:40 pm
by John d
rbentnail wrote: Fri Jul 16, 2021 5:19 pm I've replaced both cables on my '07. Do yourself a favor and get long handled straight and curved needle nosed pliers. Better yet are long handled straight and curved hemostats. You'll thank me later.
I have both of the hemostats. They do come in handy.

Re: Throttle spring unwind

Posted: Fri Jul 16, 2021 5:41 pm
by Hppants
For clarity, the Gen 3 "throttle by wire" is somewhat misleading. There is still a pull and a push cable. They lead to an electronic actuator that moves the throttle plates.

Re: Throttle spring unwind

Posted: Fri Jul 16, 2021 5:48 pm
by ionbeam
Hppants wrote: Fri Jul 16, 2021 5:41 pm For clarity, the Gen 3 "throttle by wire" is somewhat misleading. There is still a pull and a push cable. They lead to an electronic actuator that moves the throttle plates.
With the Gen 3 throttle spring hangin' out there on the right side of the throttle body where you can easily reach it.

Re: Throttle spring unwind

Posted: Fri Jul 16, 2021 5:53 pm
by gixxerjasen
Rewinding is a pain in the ass.

Re: Throttle spring unwind

Posted: Fri Jul 16, 2021 8:28 pm
by SLK50
gixxerjasen wrote: Fri Jul 16, 2021 5:53 pm Rewinding is a pain in the ass.
Actually, it’s a piece of cake.
Use a loop about a foot long of soft,
flexible wire, feed it all the way
around, snag the end of the spring
and pull it back into position.
Takes longer to explain it than do it.

Re: Throttle spring unwind

Posted: Fri Jul 16, 2021 8:40 pm
by John d
SLK50 wrote: Fri Jul 16, 2021 8:28 pm
gixxerjasen wrote: Fri Jul 16, 2021 5:53 pm Rewinding is a pain in the ass.
Actually, it’s a piece of cake.
Use a loop about a foot long of soft,
flexible wire, feed it all the way
around, snag the end of the spring
and pull it back into position.
Takes longer to explain it than do it.
How many winds for stock, you figure?

Re: Throttle spring unwind

Posted: Fri Jul 16, 2021 10:40 pm
by raYzerman
The '06-'07 had high throttle effort and combined with the fueling, resulted in snatch and inability to feather the throttle.... the spring unwind was born.... I have rewound one with a zip tie...... probably the right idea is with the flexible wire.

Re: Throttle spring unwind

Posted: Fri Jul 16, 2021 11:04 pm
by gixxerjasen
SLK50 wrote: Fri Jul 16, 2021 8:28 pm
gixxerjasen wrote: Fri Jul 16, 2021 5:53 pm Rewinding is a pain in the ass.
Actually, it’s a piece of cake.
Use a loop about a foot long of soft,
flexible wire, feed it all the way
around, snag the end of the spring
and pull it back into position.
Takes longer to explain it than do it.
I'm quite familiar with that method, though it didn't go quite so smoothly for me.

Re: Throttle spring unwind

Posted: Sat Jul 17, 2021 3:04 pm
by John d
Today I got the spring wound up one turn using soft wire. I tried to wind it a second turn but it was hard to wind and slipped over the plastic guide disk on the right side and jammed up. It took while to slip the spring back into its track area, but was still jammed up. After turning the throttle linkage a few times the spring freed up and stayed wound up at one turn. I wasn't going to try a second time to wind to two turns. Once I get the new cable assembly I'll see if the one wind feels stock.

Re: Throttle spring unwind

Posted: Sun Jul 18, 2021 2:45 pm
by John d
Today I tried doing two winds on the spring again. Two winds are not possible before the spring binds on the shaft, at least on my '08. The four other coil springs on the shaft snap the throttle shut, at least when no throttle cables are present. This would mean that the friction within the cable assembly determines how much throttle snap back could be felt at the grip.

Re: Throttle spring unwind

Posted: Sun Jul 18, 2021 4:56 pm
by raYzerman
Don't quite understand why you're going two winds, when you only undid it one........ if it's binding up, then basically you can't wind it up two as you just can't get there.
There should be very little resistance of the cables, next to none. You could lube the new ones just for fun.

Re: Throttle spring unwind

Posted: Sun Jul 18, 2021 5:11 pm
by John d
raYzerman wrote: Sun Jul 18, 2021 4:56 pm Don't quite understand why you're going two winds, when you only undid it one........ if it's binding up, then basically you can't wind it up two as you just can't get there.
There should be very little resistance of the cables, next to none. You could lube the new ones just for fun.
It was previously suggested that I may have undone two winds. Yes, not possible. I just wanted to know for sure.

I agree there should be little resistance, but with a frayed cable there would have been more resistance.

Re: Throttle spring unwind

Posted: Sun Jul 18, 2021 9:04 pm
by raYzerman
Just to reassure you, if you had done two unwinds, it would not return to anywhere near zero with good cables, throttle would not close...... the single unwind on my '07 was OK, however, with the air rushing in the TB's at 5000 rpms, there was a hesitation for the throttle to close for a second or two... all good, but you had to be aware of it.

Re: Throttle spring unwind

Posted: Sun Jul 18, 2021 9:46 pm
by John d
raYzerman wrote: Sun Jul 18, 2021 9:04 pm Just to reassure you, if you had done two unwinds, it would not return to anywhere near zero with good cables, throttle would not close...... the single unwind on my '07 was OK, however, with the air rushing in the TB's at 5000 rpms, there was a hesitation for the throttle to close for a second or two... all good, but you had to be aware of it.
In my case one unwind brings me to zero. For over 100,000 miles I had zero issues until the push cable broke.