Gen1 Rebound Damping Dilema

[know your limitations]

Had my current Gen1 1000 for about a month now and finally got round doing all my tweaks including firming up my front and rear suspension which was bouncier than a space hopper on a trampoline.


According to the owner's manual, the range of adjustment for the rebound damping on the front forks is 17 clicks.
[size=1em]I started with the adjusting screws turned fully clockwise to the firmest setting. To get to this, the left screw took at least 25 clicks and the right probably a couple less (not the most promising of starts).[/size]
I'm a big (ish) bloke but I was by no means forcing the screws to get them to the hardest setting (I stopped as soon as I encountered reasonable resistance).
Both screws were then at the same point of firmness, however.....
Whilst the right screw height was probably 1mm above flush with the spring preload bolt, the left screw was a good 3mm down inside the preload bolt.
I re-checked the right screw and there was no way it would turn enough times to get it down to the same height as the left.
With this slightly odd starting point I turned each screw counter clockwise 7 clicks to get the damping on the comfier side of firm.


I've also adjusted the spring preload and compression damping to what I think should the best balance for my size and riding style.
There is a noticeably nice firming up of the pitch of the bike when I apply the front brake but it's only been tested with me pushing the bike.
I'm hoping to test it properly tomorrow and I'm looking forward to experiencing the change in ride but I'm still a little worried about the uneven height of the rebound damping screws.


Are the screws supposed to be the same height or is it the number of clicks from the same starting point the most important factor?


Should I be worried?

[Falcon 269]

First thoughts are someone has had the fork tops off (oil change, probably) and not preset the rebound adjuster screws the same amount before refitting the caps.

They should be level ideally but if you turn them out equally from the full-in position, the results will be the same amount of damping on each side.  This assumes, of course, that there's no internal damage and the only way to determine that is to strip, inspect and rebuild.

I hope when you say 'reasonable resistance' you in fact mean 'first resistance to turning the adjuster with fingertip pressure'.

[mcyoungy]

As Mike says someone has been inside. It's probably worth taking a look in there yourself to see what's been done.

[know your limitations]

Hi Mike , thanks for the quick response  (I feel very honoured).
Loving the smiley face at the (hopefully) unlikely prospect of a strip down!
Scout's honour on the reasonable resistance. When I was turning the screws it was literally, turn, click, turn, click turn... oh it won't turn anymore and this was for both sides, so they've both experienced the same minimal force.


Oddly, the left screw did seem to go down a greater distance for each turn though.
The bike was riding fine, as was, except for the aforementioned bounciness, though of course, previously the screws were at the same height (although in theory, they mav have been receiving uneven amounts of damping)...hmm
Your response has at least given me the confidence to do a gentle ride out and test the water.
It's odd also that the number of clicks it took to get to maximum damping was way in excess of the 17 outlined in the owner's manual. Do they factor in a bit breathing space for the inept? (whoever they may be)  :o


Finally, do you know of an easy way to check if both forks are experiencing the same level of damping and would it be obvious out on the road?
p.s.
McYoungy, as my name suggests, that may not be an option. Too many things to go ping, boing, crack and drip.

[Falcon 269]

Don't get carried away, chap ... I'll talk to anybody, me. :lol

The cautionary on 'reasonable force' was aimed at the wider audience, if you follow me.  Not everyone who reads the forums understands the concept of 'gently, gently'.

The adjusters have many more clicks of movement than are actually mentioned in the Owners' Manual so your 17+ is nothing to fret over. 

Take a look at this link and in particular the re-assembly description.  It covers the process of presetting the adjuster before refitting the top cap.  Also note that if the top caps aren't installed to the same position on the damper tube it will also affect rebound damping adjustment. 

http://www.yamahafz1oa.com/ravenriderssu...rade.shtml

For the adjusters to move different distances for a given amount of rotation would mean that they have different thread pitches.  That would be most odd but might point to one fork leg being from a different bike - maybe a crash damage replacement? 

Since the damping adjustment on the Gen 1 forks is essentially 'on, off, somewhere in the middle', I wouldn't lose sleep over any minor difference from one side to the other.  There's no reliable way of comparing damping levels but since they're all clamped together firmly, they effectively act as one unit.  Indeed, that's why many modern forks have compression damping in one leg and rebound damping in the other. 

[know your limitations]

Mike (I feel comfortable using your name now  ),
Thanks a million for your info. I thought (hoped) I was probably going to be in the clear.
Whilst not being a total novice, I am still pretty wet behind the ears when it comes to bike maintenance so it's always good to get some reassurance from somebody with a much oilier rag than my own. :lol
I checked out the link you posted and surprisingly, it looks like something I'd be able to tackle in the future if required, so thanks for that too.
I'll take the bike out tomorrow and see how it feels. Unless there is something obviously wrong, I'm very much steering towards "if it ain't broke....." in relation to opening up the forks, for now
I only bought it a month or so ago from a main dealer (albeit Honda) and it was serviced and MOT'd before collection so I'm as confident as you  can be in relation to an imminent problem.
Finally, I particularly liked your pithy analysis of Yamaha's 17 adjustment settings..... on, off, somewhere in the middle.
There's probably a fork designer in Shizuoka saying, "I don't know why I fwippin bovva!"

Simon

[mcyoungy]

There's many a Fazer 1000 rider thinking "I don't know he fwippin bovvad" too!

[Falcon 269]

There was something in the latest Performance Bike mag about aftermarket suspension where the point was made (by one of the Maxton guys, IIRC) that the degree of adjustment of most standard suspension is limited to a narrow band within the middle of the normal damping range. 

It's impossible to dial in too much or too little damping and the factories supply them this way deliberately to stop the ill-informed from messing up big time. 

[know your limitations]

It's impossible to dial in too much or too little damping and the factories supply them this way deliberately to stop the ill-informed from messing up big time.

Cheers for the info Mike, that pretty much sums up what you said previously.


I've had chance now to try out my new settings and they've made a ton of difference. The bike feels much more composed, especially when "making progress" and in undulating corners. If I'm honest, I've overdone the damping at the front and rear a touch.
Up front, the bars now feel a bit vibey and you can see this effect in the reflection in the mirrors. At the rear, when I go over a big bump, the back is now a bit too unforgiving and gives me a little kick up the backside sending me forwards on the seat a couple of inches. It's miles better than the marshmallow effect of previous but a little disconcerting nevertheless.
Still, if you don't try these things, you'll never know and I reckon 3 or so clicks in "direction b" in the manual should solve it.
Thanks again from a much more dynamic (and much comfier) rider.

[tomjimtom]

Hey Simon,
Nothing to do with your problem, but I changed my fork oil last year as a total newbie
That link is invaluble and I also looked up a few videos on the internet which helped

If I can do it, you certainly can

Tom