White House K10 - a story of regeneration

[GoldOxide_imp]

OK, just give us an update with pics when in progress or completed.

[url=http://cb1100forum.com/forum/member.php?action=profile&uid=3454]PB: When you get K10-Blue, can I borrow it for 'bout an hour?

[url=http://cb1100forum.com/forum/member.php?action=profile&uid=3454]PB: When you get K10-Blue, can I borrow it for 'bout an hour?
GO, you had your blue CB... it rides the same..no need for ya...and is not as comfortable as the AT

[url=http://cb1100forum.com/forum/member.php?action=profile&uid=3454]PB: When you get K10-Blue, can I borrow it for 'bout an hour?
GO, you had your blue CB... it rides the same..no need for ya...and is not as comfortable as the AT
So, is that a "no"?

[Tev62]

Yap, there she is, a blue queen
Do you want me ro rd-test it, while you doing office duty?

Gee PB, that' SO generous of you!

But talking of road tests, after the first ride out to Chester I thought the ride quality was a little harsh, at the weekend I backed off the front pre-load adjuster to the stock position (3 rings - was in 2) and also turned down the HyperPro rear shocks from mid position, 25 clicks - or 2.5 turns, to approx 30 clicks or 3 turns from max. Of course, after 5 sleeps I had completely forgotten about the change and only recalled what I had done when around 6.5 miles into my 7.5 mile commute after hitting a roundabout with a particularly poor road surface. Before I would have found it harsh, now it simply rode straight over and was completely unperturbed. Happy days. Suspension adjustment - done.

I'll be back in the garage at the weekend to have another go at the chrome grab rail brackets - had another idea to extend the bracket to incorporate the K0 indicator support so will be drilling metal again to test it out. More later.

Gee PB, that' SO generous of you!

But talking of road tests, after the first ride out to Chester I thought the ride quality was a little harsh, at the weekend I backed off the front pre-load adjuster to the stock position (3 rings - was in 2) and also turned down the HyperPro rear shocks from mid position, 25 clicks - or 2.5 turns, to approx 30 clicks or 3 turns from max. Of course, after 5 sleeps I had completely forgotten about the change and only recalled what I had done when around 6.5 miles into my 7.5 mile commute after hitting a roundabout with a particularly poor road surface. Before I would have found it harsh, now it simply rode straight over and was completely unperturbed. Happy days. Suspension adjustment - done.

I'll be back in the garage at the weekend to have another go at the chrome grab rail brackets - had another idea to extend the bracket to incorporate the K0 indicator support so will be drilling metal again to test it out. More later. How does adjusting your preload one notch change the front end from harsh to less harsh? Your spring rate is the same no matter where you set your preload. Your preload is only setting where your fork/shock sit in its stroke, e.g. 25% or 30% for example. It is there to adjust for load. I can understand the rear, sounds like you are adjusting the damping on the Hyperpros.

[Ninemeister_imp]

Reducing the pre-load does two things:
a) lowers the ride height for any given load (read weight)
b) reduces the force required to initiate compression from full droop (sag)
You are right in that the spring rate is a constant, so all this can be doing is lowering the start off force.

I'm guessing that I have noticed the benefit from the latter, the front wheel requiring a reduced load from fully extended and in simple terms letting the damper absorb more of the energy rather than the spring. If anyone else has the 2017 SDBV forks why not chime in to whether they have experienced the same?
Two more photos today in the car park.

Look at that folks - vivid clear blue skies in the UK in November!!!

[Tev62]

But once you are sitting on the bike and your weight has overcome that initial force, where the preload is, is now irrelevant. Dropping the preload has dropped your front end a little, reduced the trail a little and might make the handling a little sharper but it should have no effect on damping. The damper will be doing the same work, it has not picked anything extra up from the spring. A great read on suspension is Race Tech's Motorcycle Suspension Bible, a small excerpt here on preload. It goes into more detail than this and is a great read if that's your bag.

"Spring preload is one of the most misunderstood concepts when discussing
suspension. Often we hear riders talk about adjusting their motorcycle’s
spring preload to make the spring stiffer or softer. This is a misconception:
changing spring preload does not change the spring rate at all. The spring has
the same rate regardless of how the preload adjustment is set.
Let’s look at what really happens. When a spring is installed in either the
front or the rear suspension, the spring is typically compressed a small
amount. The length the spring is compressed is referred to as preload.
Specifically it is defined as the distance the spring is compressed from its free
(or uninstalled) length to its installed length with the suspension fully
extended, Most vehicles, including motorcycles, use positive spring preload
(negative preload means the suspension compresses before hitting the
spring). This is true even for bikes that don’t have external preload adjusters.
Even suspension with the external preload adjusters backed out all the way
commonly still have some preload".

"With a given amount of preload force on the spring, it will take that same
force to initiate suspension movement when the suspension is fully extended.
As preload is increased, it takes more force to cause the fork or shock to
begin to compress. When preload force is decreased, less force is required to
cause movement. It is important to note that when the motorcycle is resting
on the ground with the rider on board, the suspension is compressed. When
preload is changed the sprung mass is held higher or lower. This means more
preload does not require more force to initiate movement once the weight of
the bike has compressed the suspension".

[Ninemeister_imp]

We can all quote textbooks, this from "Teach me suspension/Part 3":
"By turning the preload adjuster on the top of the fork and adding another 5mm of mechanical compression, the spring would then be exerting 15kg of force back out, meaning you would need to then apply more than 15kg of force in order to begin to compress it.

While the rate remains the same, by adding preload to the spring in your suspension you are changing how the spring reacts to weight that’s applied to it. Whether it be through a rider’s movements, braking, cornering efforts, or the application of power.

By adding preload on the front, for example, in the braking zone there is going to be less of a diving effect as the weight moves forward because it takes more of yours the bike’s weight to overcome the force of the spring pushing back up.

This is why it is often referred to as making the suspension ‘stiffer’, because that’s the impression it gives."


The impression I get is that the bike is softer with reduced preload. That's good enough for me, but thanks for your input.

[PowerDubs_imp]

I haven't looked into the valving and spring rates of the stock forks/shocks- nor my upgraded to SDBV forks- but I can certainly say no -

"How does adjusting your preload one notch change the front end from harsh to less harsh? Your spring rate is the same no matter where you set your preload."

Is not true. Neither is the valving on many modern suspension.

Although the effect is probably minimal- it still has an effect.

A constant rate spring- would be constant in spacing and diameter the entire way. When they are not- part of the spring is 'softer' to compress first - either on impact- or when squeezed- as the spring doesn't know the difference. So 'pre-load' is just constant load-no different than load from a bump. The soft 'area' gives up first.

[Tev62]

We can all quote textbooks, this from "Teach me suspension/Part 3":
"By turning the preload adjuster on the top of the fork and adding another 5mm of mechanical compression, the spring would then be exerting 15kg of force back out, meaning you would need to then apply more than 15kg of force in order to begin to compress it.

While the rate remains the same, by adding preload to the spring in your suspension you are changing how the spring reacts to weight that’s applied to it. Whether it be through a rider’s movements, braking, cornering efforts, or the application of power.

By adding preload on the front, for example, in the braking zone there is going to be less of a diving effect as the weight moves forward because it takes more of yours the bike’s weight to overcome the force of the spring pushing back up.

This is why it is often referred to as making the suspension ‘stiffer’, because that’s the impression it gives."


The impression I get is that the bike is softer with reduced preload. That's good enough for me, but thanks for your input.

I haven't looked into the valving and spring rates of the stock forks/shocks- nor my upgraded to SDBV forks- but I can certainly say no -

"How does adjusting your preload one notch change the front end from harsh to less harsh? Your spring rate is the same no matter where you set your preload."

Is not true. Neither is the valving on many modern suspension.

Although the effect is probably minimal- it still has an effect.

A constant rate spring- would be constant in spacing and diameter the entire way. When they are not- part of the spring is 'softer' to compress first - either on impact- or when squeezed- as the spring doesn't know the difference. So 'pre-load' is just constant load-no different than load from a bump. The soft 'area' gives up first.

Not sure what you are getting at here but don't forget your spring length is the same length at varying preloads as both parts of the suspension can move. Adding preload does not "use up" the softer end of any progressive spring.

[PowerDubs_imp]

What? It certainly does.

Taking temporary upward movement such as a crest in the road out of discussion- a laden bike absolutely starts to compress the spring- hence preload, and will squish the soft portion. Effective spring length is NOT the same. Don't confuse spring length with travel.

[jtopiso_imp]

Yap, there she is, a blue queen
Do you want me ro rd-test it, while you doing office duty?

Gee PB, that' SO generous of you!

But talking of road tests, after the first ride out to Chester I thought the ride quality was a little harsh, at the weekend I backed off the front pre-load adjuster to the stock position (3 rings - was in 2) and also turned down the HyperPro rear shocks from mid position, 25 clicks - or 2.5 turns, to approx 30 clicks or 3 turns from max. Of course, after 5 sleeps I had completely forgotten about the change and only recalled what I had done when around 6.5 miles into my 7.5 mile commute after hitting a roundabout with a particularly poor road surface. Before I would have found it harsh, now it simply rode straight over and was completely unperturbed. Happy days. Suspension adjustment - done.

I'll be back in the garage at the weekend to have another go at the chrome grab rail brackets - had another idea to extend the bracket to incorporate the K0 indicator support so will be drilling metal again to test it out. More later.

Gee PB, that' SO generous of you!

But talking of road tests, after the first ride out to Chester I thought the ride quality was a little harsh, at the weekend I backed off the front pre-load adjuster to the stock position (3 rings - was in 2) and also turned down the HyperPro rear shocks from mid position, 25 clicks - or 2.5 turns, to approx 30 clicks or 3 turns from max. Of course, after 5 sleeps I had completely forgotten about the change and only recalled what I had done when around 6.5 miles into my 7.5 mile commute after hitting a roundabout with a particularly poor road surface. Before I would have found it harsh, now it simply rode straight over and was completely unperturbed. Happy days. Suspension adjustment - done.

I'll be back in the garage at the weekend to have another go at the chrome grab rail brackets - had another idea to extend the bracket to incorporate the K0 indicator support so will be drilling metal again to test it out. More later. How does adjusting your preload one notch change the front end from harsh to less harsh? Your spring rate is the same no matter where you set your preload. Your preload is only setting where your fork/shock sit in its stroke, e.g. 25% or 30% for example. It is there to adjust for load. I can understand the rear, sounds like you are adjusting the damping on the Hyperpros.

To add a bit to your point, check an old post:
http://cb1100forum.com/forum/showthread....#pid250414

I haven't looked into the valving and spring rates of the stock forks/shocks- nor my upgraded to SDBV forks- but I can certainly say no -

"How does adjusting your preload one notch change the front end from harsh to less harsh? Your spring rate is the same no matter where you set your preload."

Is not true. Neither is the valving on many modern suspension.

Although the effect is probably minimal- it still has an effect.

A constant rate spring- would be constant in spacing and diameter the entire way. When they are not- part of the spring is 'softer' to compress first - either on impact- or when squeezed- as the spring doesn't know the difference. So 'pre-load' is just constant load-no different than load from a bump. The soft 'area' gives up first.

If you have gas filled dampers (as on the rear), changing preload changes how the gas volume on the damper.

The gas acts as a gas-spring working in paralel with the main ride-spring. The gas-spring rate is minimal compared with the ride spring (coil-spring), but it's not neglectable. Changing preload will change the spring rate for this gas spring, but not on the coil-spring.

On the front, as far as I know, there are no gas dampers, so rate should be constant.

All the above, assuming constant rate coil-springs, which are usually the case.

[Ninemeister_imp]

And so, back to the grab rail...

It's always satisfying to make a part that does two jobs, so after playing around making the trial brackets for the grab rail I had the idea to make a "Z" bracket to also hang the indicators from. I also worked out that I wanted to use thicker material than the 3mm stainless steel, so hunting around at work I found some 20mm x 4mm black mild steel bar. Just the job.

* Stage one - how to fold a Z in the bar?
Since I didn't have a press brake, I made one from a piece of 6mm mild steel offcut, a small Vee-block and our workshop press. With a little grease on the vee-block to allow the bar to slide into the corner it was surprising how well this worked with remarkably little pressure.

* Hacksaw, grinder & pillar drill, plus less than an hour and we had a couple of prototype brackets to play with.

* The indicators have a M10 threaded stem, so I drilled out the lower holes to suit, the upper holes to the frame being 8.5mm for M8 screws.

* The brackets fit to the standard rear frame mounts, the chrome rail sitting on top (will be welded when finished)

So far, so good.
The next problem to solve was the shape of the grab rail. If you recall, the grab rail came on to the bike but was useless as it had the rear mounts cut off. It also had an unsightly bend down on the sides which made it look kind of odd in my opinion.

So the question was, now I'm at home in the garage, how do I straighten the rails without using my press? The answer came in the shape of two G-clamps, some home made wooden saddles and a cast iron table. Where there is a will, there's a way...

After pressing near straight, I used the saddles to hold the rail in the vice and gave the end of the tube a gentle tap with a lump hammer to tweek the final few mm of bend out.

Final photos show the now straight rails fitted and as desired, parallel with the bottom of the fuel tank. Finally it's starting to look like it's meant to be there.