The constantly compressed forks quiz.

[NJD]

So before we go any further I should say I post this thread as a request from the Borg and also that I have phoned the shop that serviced the bike and will be taking it back tomorrow. Place your bets on (a) if I will or won't survive a 10-12 mile ride with the below issue and (b) what the cause is and or was by the time I post something tomorrow.. if I'm alive. <dramatic music>.

So the long and short of it is that last Friday I collected the bike from being serviced and rode home / to and from work with no issues. After a long weekend of work I used the bike to get to work yesterday with no issues.. this is where it gets funky. So I come to my bike after leaving work and found that my bar end / clutch lever was resting against the top long bar of one of these, basically somehow the front end had moved somewhat and it looked like the bike had slipped as the bar end / clutch lever are usually hovering over or they're more to the left than what they where. I've no idea what happened but it didn't look anything like an attempted theft because nothing was scratched or damaged and the locks hadn't been touched, in the "what grinds your gears today" thread I said it could have been someone attempted to move the front end or the side stand had slipped a little, well.. until this morning when there's a new possibility.

So I'm happy when I get on my bike to discover that the clutch lever isn't bent or damaged and everything works as it should and nothing has been touched until.. and this is where the actual issue starts.. I pull away and instantly the front end feels unstable. I'm talking it feels like the front tyre is flat and there's juddering from the front end. Anyway I make it home and do some checks and come to the conclusion that there's noting wrong. Load the bike up this morning and find that the forks, once compressed by pressing the front brake lever and pushing down, are not bouncing back.. at one point I think they didn't even want to compress.

So either something's happened that I can't figure out while I've been in work or while parked the forks have decompressed (assuming the issue had already started and I hadn't noticed) hence the slip or moved bars slightly and no signs of anything else.

In regards to the service last Friday the guy on the phone basically said that he couldn't think immediately how the service could of caused it as there's no work done on the forks during that service but was more than understanding (since I've only used them and new who I was by voice / bike) in requesting to see me as soon and wanting to get to the bottom of it.

When I was pumping the forks this morning to start out with they basically sounded solid and made a noise, I can't recall, and then I noticed that I had to grab the underside of the grips and pull them upwards to get the forks to fully bounce back <uh oh, phone shop leave bike at home moment>. The fork oil, not that I know how often it needs changing of the top of my head, has to my knowledge never been changed.. and I've owned the bike from new. 7000km and about a year and a half old? Forks show no signs of leaking oil when compressed. Fork seals, to my limited knowledge of what I'm looking at, are all firmly in place and show no signs of leakage or tears. Fork gaiters are without tears or signs of damage. Only signs of rust on the fork legs are a small amount in the very small gap between the fork gaiter and fork seal on the right leg, other than that I've noticed nothing. Issue has occurred without any pre-warning signs and as above after limited use after a service.

Over to you.. (again this thread is for entertainment purposes and not a diagnosis).

[Kickstart]

Hi

Normally it is the fork spring and the compressed air gap that extend the forks again. Springs alone should do it easily, and the chances of the fork springs snapping are slim.

Dampers in the forks couple have become blocked, hence slow return. But would probably need to be quite a blockage.

My guess would be the forks are jamming. Possibly a fork bush has managed to come out of position and is jamming the forks, or the forks are twisted in the yokes badly and binding (but the most likely way that would happen would be being knocked over, and I would expect other visible damage)

All the best

Katy
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Hong Kong Phooey]

If it has adjustables, has rebound been dialled all the way to 11?
Seems odd for both forks to fail same time.

Not likely to be fork oil degradation at that mileage imho, and they say they not touched it anyhow.

Edit after rereading. Possibly fork tubes bent, maybe hit by car reversing - pushing forks into kerb. Look down the tubes from top and inspect from the side at distance (remove gaiters), more than a couple of degrees would be visible, straight edge probably not required if that bad to cause binding.
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'81 CG125, '97 FZS600 : '99 CBR600F4, '09 KTM RC8

[NJD]

[jaffa90]

Something sounds a bit bent to me.

[Kickstart]

Hi

Suspect nothing adjustable on that.

Tbh, I would say the first thing to do is to strip the forks and check them over. Springs possibly but I suspect most likely a bush is very badly worn and is jamming the fork

All the best

Katy
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[NJD]

[Hong Kong Phooey]

[Rogerborg]

I'm struggling to picture how that would happen suddenly.

Even if the bike was dropped and picked up and the forks are twisted in the yoke, I'm not clear in my head on how that would actually stop them rebounding.

A car reversing into it and freakishly banana-ing the forks while not knocking it over is just barely conceivable. Do they look straight?
____________________
Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

[Suntan Sid]

Some has stolen the springs from one or both of the forks!
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"Everybody needs money, that's why they call it money!"

[Rogerborg]

[mysterious_rider]

Hello has the front wheel been off at all? If the spacers are wrong or missing it will lock the forks tight. Sounds silly but iveseen it happen.
Loosen the axle and bounce.
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KAWASAKIIIII

[NJD]

[Rogerborg]

£113 (retail, with gaiters) price on two new forks, plus delivery, plus half an hour independent labour? That's not actually too daft and I agree that it's better than paying for hours of labour to diagnose, strip, re-assemble and then find there's still something wrong.

It might even make sense to just replace the forks rather than even replacing the seals, which speaks volumes about today's disposable culture. <crying-indian.jpg>

Top prize would have gone to whipping them off yourself and repairing or replacing whichever one is hooky (and it's likely to be one). Mudguard off, caliper off, axle out, slacken the yoke clamps and the forks drop right out.

Ideally remember to put the bike on the centre stand first.

It is a weird problem though, I'm interested to know what's going on there.
____________________
Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

[NJD]

[bamt]

It's possible that the bike has been knocked sideways and therefore the chain has put a sideways strain on that fork, bending it outwards. Unlikely, but I guess it depends upon the weight of your bike and strength of the fork.

Chaining it up like that, I'd be tempted to loop the chain through the front wheel rather than the fork. That stops somebody nicking that wheel, whereas a single chain looped through the frame and forks is redundant through the forks (your not stopping any parts being stolen, and the loop through the frame stops the main part of the bike going - obviously subject to a decent chain).

[NJD]

[Rogerborg]

[NJD]

[NJD]

Collected today, £140.

Non the wiser as to what the issue was, can either fix in my own time (or at least attempt to) or just sell them on.. undecided as of yet.

Ride back was fine (so it was the forks) but managed to find the worlds biggest pot hole, sods law. Got back to base and since I was so tired I started compressing the forks and convinced myself I'd buggered another pair.. locked it up and left it alone, been a long week.

Only annoying thing was that by the time I'd got home (not that I checked if this was the case before setting off from the shop) the fork gaiter on the left leg was a fair way down (as in held in place by the clamp) so took the locking clip out and pushed it all the way up and then put the clip back on. Only thing is you can pull down and push up the gaiter by hand with the locking clip in place.. probably just playing too much attention to nothing. Think I've still got to move the right one up a little also. Other than that I've got to apply some ACF-50 to the bottom of the leg when I get time and jobs a gooden.

As to the old fork legs can only think internal since the entire leg (beside some small amounts of surface rust) looks fine (ie; no dents). Can only think internal.. either way was cheaper to get new legs and solve the issue than attempt to find the problem with the old ones.

Hopefully it's the end of this tale.

[Rogerborg]

You're going to have Phantom Fault Syndrome for a while. Please do pick up those old forks and figure out what's going on, I'm genuinely puzzled.
____________________
Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

[NJD]