Suspension behaviour

[NickNickleby]

Daft question alert!

A few years ago, I left a bike in for service and was told that the rear shock was suspect. Hmm, I never noticed anything wrong, although I think it may have bottomed out a bit harshly over ramps with a (very occasional) pillion passenger. At slower speeds you'd notice nothing. So, I assume THAT's how you'd know there's a problem. But if the shock was really bad, how would that manifest itself? Would it really smack down hard, or is the greater risk that it would bounce all over the place??

Now, consider the front forks. Weepy front fork seals. What's the implication of loss of fork oil? Hard bottoming out or bouncing all over the place? I ask because I'm possibly going to take responsibility for a bike that 2 years ago had weeping fork seals. If they're no longer weeping, its probably safe to assume all the oil is gone. So I need to wonder about driving it home.

This is my opening post in what I hope will become an interesting thread.

[JayZeus]

Leaking seals or low oil in the stanchions or shock body means reduced or no damping. Front end will nose dive easily and rebound too quickly. Back end will bottom out and bob. On both ends, this could allow for the tyres to loose grip if you hit potholes, small indentations, broken road surfaces, gravel etc.

The most important thing to take away from this is that the tyre contact/grip will be diminished and that’s never okay on a road bike. Unless you’re Guy Martin. And even he wouldn’t be happy riding an unknown bike with shit damping if he could help it.

Trailer or van job, IMHO. Or drain and refill the forks and swap the seals, and ride it handy if the rear needs rebuilding or replacement to get it home.

[kadman]

Dont take responsibility for the bike until its fixed....simple

[PogMoThoin22]

I thought your were fired from your job, I am disappoint

[kadman]

I thought your were fired from your job, I am disappoint

I was for years which was denied, but thats a whole other thread,on a whole other forum, that wont be fleshed out here.
If you were there, then you know, if you weren't, then you missed out

[NickNickleby]

Right , first off - Thanks folks for the comments.

The bike in question was mine for 15 years. It's a 03 Deauville and even today only has about 27k miles on it.. I brought it to a mechanic about every three years for deep dive servicing. In the meantime I did plugs, oils, filters, pads, brake fluid and coolant replacement myself. I had (have) a good selection of tools and a shed. And over the 15 years more money than sense so probably changed fluids and plugs and filters much more often than required. The fork tubes were replaced with stainless in 2015.

Two years ago I decided to pass it on to a nephew. At the time I told him he could have it to do his A test so we went out to a large no-public-access car park and I let him drive it around for a couple of hours. He owned a CBRxyz which I tried out and after 5 minutes had to get off it before my hips separated. I will say that in the week before handing it over, I'd taken it out the back roads beyond Swords and put it hard into some bends and it was solid as a rock (probably 60-80kph where permitted)

Anyway, the bike is now redundant, and is taking up room in my sister's garden. So I'm taking it back. The dream is to clean it up and make it more alluring than it ever has been ( a sexy Deauville, is my aim - go on, slag me).

So, I'll address each comment above...
Jayzeus - thanks very much for a very comprehensive description. I understand the issue in cars, but never was able to translate it to the bike. As I said, I never personally experienced handling problems on the bike - although I recall hitting a ramp with my son on the back and it definitely bottomed out, but not alarmingly so. I adjusted the preload and that seemed to take care of it. But I don't drive the bike such that there'll be much bumping - I'm an extremely sedate rider. My plan is to get the bike running and check the fork seals. And the brake calipers and the ground underneath. Hopefully there'll be no evidence of oil loss. So, if that first test is passed, I'll take it outside and see how to safely determine the level of 'diving' on the front. I'll do it with another nephew, big strong lad, I'll get him to jump up and down on it and see what happens at the front. Assuming it passes this static "test" then I'll drive up over and back on the ramp outside the gate and 10/20/30 kph and see what happens. If it behaves during these passes, then I'm going to drive it 9km home at well under 50.

Kadman, thanks for the advice, but as you can probably tell from the conversation, it really should be MY responsibility. I'll just bite the bullet.

PógMoThóin22 , I originally thought your comment was aimed at me and a reference to my dread of having to inform MrsN of my intentions. Believe me, I'm far more concerned about her reaction than any fork seals!

So, I'm going to post here about developments. Worst case scenario, I can get access to a large van or trailer. Be about a week though, I'm laid up at the moment trying to shake a dreadful chest cold. Thanks again, I genuinely look forward to comments about this.

[kadman]

I took it tye firing comment was aimed at me....maybe not, who knows.

As to the family element and the bike, yep, I totally get the responsibility aspect. So you will ALWAYS be the goto guy now for the bike upkeep
Sounds like you have kept up the bike maintenance fair play.
Its a few years now since my biking, but not too much. Was tempted recently to get back into them, but a shoulder injury says stay away.

Good luck on your test drive.

[PogMoThoin22]

The firing comment is that I thought at first glance at the headline we had another Enoch Burke, "suspension behaviour"

[NickNickleby]

Right, update !!

I said at the outset that I wanted to make an interesting thread. Here goes...
Taxed and insured the bike last month, but owing to a bereavement, everything came to a standstill.
Anyway, couple of weeks ago, Mrs N and I went out to collect it. Unfortunately, the front wheel was flat and when I went to pump it up I discovered that the valve stem was broken. Shop wouldn't do the job unless I ponied up for a new tyre.
€185 and a week later back we go. Put the wheel back on. Clean the forks, fork oil everywhere.
Pump up the back wheel. I had previously brought the battery home and nursed it back to life using a smart charger and a big old merc battery - smart charger won't do anything when you're down to 4.5v.
So, key in ignition, turn and vroom almost immediately.
Take it out on the road and go over a few ramps to see how it feels. Handles OK at 20kph, stopping power a little, ahem, suspect.
Suit up with all my lovely 4 year old but still brand new gear. Give Mrs N the admonition that her job is to hold back any traffic behind me on the curly roads behind the airport, and off we go.
After some brief experiments, it becomes apparent that stopping distance is an issue. But it's late evening and there's little to no traffic. Got up to 80 on the newly surfaced road and bike handling like a dream. Dropping down to 50 approaching side roads, but incident free journey. Mrs N was unaware of any of this and noticed nothing about my riding that suggested I was being ultra cautious. She blew gaskets when we got home though .

So, bike is home. Time to do full inventory of work to be done.
Fork seals
Brakes - pads probably contaminated, but no sponginess. However, will do full dismantle and clean as well as new fluid and pads.
Change engine oil and filter.
Check air filter and plugs.

Then the real work starts - scratches and cracks in the plastic need sorting, and all the black bits are now grey.

I took a photo for 'before' comparisons but it won't load. I'll sort that out and then put it up.

Oh, and Mrs N's gaskets are fine again. But she wants the bike gone. Well, I can only get rid of it if I make it roadworthy, so that's my current excuse