Not understanding 500 front suspension 🤔

[K2-K6]

Used in mtb forks currently, plastic spacers to make up length as required in either screw together or some types just clip.

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A possibility to help.

[McCabe-Thiele (Ted)]

I would need something 15mm thick with a 8mm hole with an outside diameter of 22 mm or so. Any links for these sort of  items please?

[taysidedragon]

I would need something 15mm thick with a 8mm hole with an outside diameter of 22 mm or so. Any links for these sort of  items please?

If that's what you plan to do Ted, why not cut one of the 30mm spacers you have in half to make 2 x 15mm.
Make sure they're cut square and both equal.

[McCabe-Thiele (Ted)]

I would need something 15mm thick with a 8mm hole with an outside diameter of 22 mm or so. Any links for these sort of  items please?

If that's what you plan to do Ted, why not cut one of the 30mm spacers you have in half to make 2 x 15mm.
Make sure they're cut square and both equal.

The chromed thin tube that was used is IMHO mank. I had a big clear out about 3 years ago of old seat belt spacer fittings plus loads of old narrow wheel nuts - either would have done the job nicely. I know I will find something I can adapt to do a neater job.
Pretty sure I can find a pair of items that will do the job.
I have some  bush inserts that were a part of a Polybush suspension kit somewhere in my garage just need to try to remember where I stored them.
I can always resort to some brass, alloy or SS stand off spacers if I can't find anything suitable in my garage.

[McCabe-Thiele (Ted)]

Just spent an hour removing one of the fork lock nuts  - the nut will need replacing as it had been severely overtightened against the end of the thread to fit the pre-load spacers.
I'm certainly not using the old spacers - I'm in pause/thinking mode to decide if to return to standard or us a smaller spacer.

What thread is the shaft & nut supposed to be please it's an M8 but my M8 x1.25 dye is clearly the wrong pitch at first glance ?

I think it's M8 x 1.0 pitch??

[taysidedragon]

Just spent an hour removing one of the fork lock nuts  - the nut will need replacing as it had been severely overtightened against the end of the thread to fit the pre-load spacers.
I'm certainly not using the old spacers - I'm in pause/thinking mode to decide if to return to standard or us a smaller spacer.

What thread is the shaft & nut supposed to be please it's an M8 but my M8 x1.25 dye is clearly the wrong pitch at first glance ?

I think it's M8 x 1.0 pitch??

If 10 threads measure 10mm then the pitch is 1.0. 👍

[McCabe-Thiele (Ted)]

Just spent an hour removing one of the fork lock nuts  - the nut will need replacing as it had been severely overtightened against the end of the thread to fit the pre-load spacers.
I'm certainly not using the old spacers - I'm in pause/thinking mode to decide if to return to standard or us a smaller spacer.

What thread is the shaft & nut supposed to be please it's an M8 but my M8 x1.25 dye is clearly the wrong pitch at first glance ?

I think it's M8 x 1.0 pitch??

If 10 threads measure 10mm then the pitch is 1.0. 👍

Never thought of that -  I'm thinking to myself that counting threads  might be harder than it sounds - I have a little thread gauge tool but I can never decide  if the bit of metal is sitting in the threads properly or not. (Need to go to Specsavers)

Sounds daft but my method is trying a nut on a bolt of known pitch - if it spins on by hand all is good. Trouble is the pitch isn't stamped on my nuts & I soon mix them all up in my bolt box. I confuse myself with great ease - with my Dad not being around like the old days I have no one to ask except here.  (Note to self use different boxes for different pitches with label on box)

This opens up a new can of worms for me as I'm a bit old at 74 to be an Apprentice but in many ways I still am.
Back in the 1960's I was using my AVO meter almost daily - these days I only use it for the V bit A&O don't live in my brain any more.

I found myself re-learning lost skills when working on my 400 but I've been to bed a few times since then.
I realise now on the 500 not only is it a bit different but the learning curve has turned back into more of a dip!

[taysidedragon]

Stick with it Ted. There's always a few dips in the road on any journey. 👍😁

[Johnny4428]

I learn every day just reading the forum. Poor day when we stop learning Ted!🫢

[McCabe-Thiele (Ted)]

After looking at the thread damage on my fork lock nuts and one of the top threads on the long rod I have decided to not fit any pre-load spacers to the front forks - leaving it as standard as both spring legs are well within limits.

I've ordered a pair of new lock nuts from DS as there were a few other odds & ends I wanted from them - I will run a tap down the flattened thread to clean it up plus a die down one of the chromed fork top nuts on the same side.

I will fit the fork springs with the closer wound end at the bottom as this seems to be the consensus.
I also need to fit a couple of Helicoils in the right fork leg as the threads for the front fender fitting are not in great shape.

[K2-K6]

Apologies Ted as I now think I didn't understand the status of components in original question, in that the spacers fitted are Honda's original equipment. I read that the other way now, is that correct ?

If so, then agree that fitting with just the springs is correct to assess what it's like.

To expand verification, preload is used to set "sag" if the spring rate is correct to carry the mass of vehicle and rider. Sag being how much the vehicle sits down into it's suspension expressed usually as % of total travel and with 20% being fairly normal.
This can be checked simply by sitting on the bike static and measuring how much it sits below maximum extension, often done with an O-ring pre fitted to one stanchion to let you see where it was after dismounting to have a look.

Purpose of sag is that any suspension sitting right at maximum extension in normal use has no capacity to cope with any quick extension due to road surface deformity.  Usually set that way, the fork will "thunk" on minor road irregularities as it hits the top out provision and subsequently drive you nuts  you want to try and avoid thunking definitely 

Progressive wound springs will work exactly the same either way up. Pedantic assessment will have them fitted with tightening coils at the top as best positioned with any extra weight then being on the sprung mass rather than adding to unsprung mass of the wheel assembly. In reality, although correct,  it's highly unlikely anyone will be able to feel any difference as those grams have such a tiny additional contribution to wheel, brake, fork sliders etc.

The oil you use will control how quickly they respond to input. They seem to favour 5 viscosity or even 2.5 to let them move nicely on a road bike such that the fork can easily move in response to road riding (as opposed to someone that may want a more restricted control for higher pace applications) the 2.5 viscosity gives very good compliance for smooth ride in day to day riding. I like Motul fork oil as it gives that choice along with very good friction reduction to enhance that response by reducing stiction.

[taysidedragon]

Ted, instead of jumping straight in and using helicoils on the fork legs, it's worth trying a medium strength Loctite on the mudguard screws. Just nip them up lightly and let the Loctite take up any 'play' in the threads.
It'll hold them fine, unless the thread is virtually bare.

[McCabe-Thiele (Ted)]

Not sure what would happen with Locktite on the threads if I had to undo them in the future. One thread has a very short Helicoil in it already. The second thread is worn at the top but better part way down I've cleaned it out with a tap so the lower part of the thread should hold. I was going to leave it like that but it's a load of work if the mudguard shakes loose - I thought fix it once fix it right.
The spacers fitted are definitely not original.

[taysidedragon]

Use a medium strength threadlock, they are designed to be dismantled when necessary. No problem coming apart on a little screw like that.

[McCabe-Thiele (Ted)]

Purpose of sag is that any suspension sitting right at maximum extension in normal use has no capacity to cope with any quick extension due to road surface deformity.  Usually set that way, the fork will "thunk" on minor road irregularities as it hits the top out provision and subsequently drive you nuts  you want to try and avoid thunking definitely 

Progressive wound springs will work exactly the same either way up. Pedantic assessment will have them fitted with tightening coils at the top as best positioned with any extra weight then being on the sprung mass rather than adding to unsprung mass of the wheel assembly. In reality, although correct,  it's highly unlikely anyone will be able to feel any difference as those grams have such a tiny additional contribution to wheel, brake, fork sliders etc.

Interestingly there was an odd clunk on the front suspension when I rode the bike before strip down - it felt like a metal on metal clunk as if the suspension was bottoming out - it was after hard braking - it was not a good sound - it sounded like just one side but hard to be sure.
So from what you are saying about un-sprung weight the tighter coils should strictly be at the top.

As you can see in the earlier photo the coils were well distorted even at rest due to the high pre-load .

Might it be worthwhile fitting a smaller spacers in the light of your comments about avoiding thunking or have I misunderstood you?
Fitting 10 mm spacers would be quite easy as would 5mm or none.