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Discussion Starter #1
According to the Workshop Manual fork stroke is 120mm.

With the front wheel off the ground the distance from the lip of the dust seal -where it contacts the tube - to the casting at the bottom is 116mm.

So it looks like on full compression the seal will be squashed by 4mm. :eek:

Am I right or am I missing something? :confused:

I have a cable tie on the tube and it has been pushed to the bottom on occasion.
 

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Ahem!
Should I be asking how much you Gentlemen weigh? and could it be the difference between you which makes it bottom out for one and not the other or shall I just blame it on the good old British pot holes0:)
As for the missing 4mm. I haven't a clue but it seems size does matter to some of us;)
 

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Ahem!
Should I be asking how much you Gentlemen weigh? and could it be the difference between you which makes it bottom out for one and not the other or shall I just blame it on the good old British pot holes0:)
As for the missing 4mm. I haven't a clue but it seems size does matter to some of us;)
Only 107Kg (16stone 12 lbs) in riding gear and pot holes aren't so bad here
 

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When my suspension was set up by Dave Moss, he marked maximum stroke before starting to adjust it. The mark is 5mm above the top of the bottom casting.
 

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Discussion Starter #8 (Edited)
When my suspension was set up by Dave Moss, he marked maximum stroke before starting to adjust it. The mark is 5mm above the top of the bottom casting.
Thanks Geoff, how did he find/know what max stroke was, and did he measure from the seal edge like I did ?

It's Dave Moss who's to blame for my post, been watching his YouTube channel. Unless it's a different man as he's in the USA
If he is right then max stroke must be less than 120mm.
My riding weight is 168lbs (12 stone) but I'm on a diet so it's coming down.:)
 

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Thanks Geoff, how did he find/know what max stroke was, and did he measure from the seal edge like I did ?

It's Dave Moss who's to blame for my post, been watching his YouTube channel. Unless it's a different man as he's in the USA
If he is right then max stroke must be less than 120mm.
My riding weight is 168lbs (12 stone) but I'm on a diet so it's coming down.:)
Hi Dekker,

I can't precisely tell you how he did it as it was the precursor to a tuning ride with some other riders on the course and I was chatting whilst they were taking some of the initial measurements (see: write-up and photos towards the bottom of this blog post: Confessions of an Ageing Motorcyclist: A most excellent week!). To get the full extension, another guy and I angled the bike on the side stand whilst Dave measured it. He then put on a zip tie and he and the course coordinator put their combined weight through the bars. The 5mm measurement I mentioned must have been to the seal lip as that's what would have pushed the zip tie down. During the ride at various stop points, Dave would do some re-measurements when the oil was up to working temperature and make various adjustments. Not sure how much help that's going to be to you! I might add that I periodically reset the zip tie and it rarely gets any closer to the bottom casting than 20-25 mm measured at the top of the tie where it contacts the seal lip.

As an aside, the course coordinator was a guy called Chris Smith who is an IAM member with me. Chris is English and when he lived in the UK, he taught Angeline Jolie, Matt Damon and other celebs to ride for their movies! Some nice photos on his website here: https://www.passmasters.nz/gallery

Edit: BTW, my weight in my socks is 74 kg :D
Cheers,

Geoff
 

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According to the Workshop Manual fork stroke is 120mm.

With the front wheel off the ground the distance from the lip of the dust seal -where it contacts the tube - to the casting at the bottom is 116mm.

So it looks like on full compression the seal will be squashed by 4mm. :eek:

Am I right or am I missing something? :confused:

I have a cable tie on the tube and it has been pushed to the bottom on occasion.
Aside from the discussion about stroke length..how much preload are you running because if you have bottomed out it sounds like you don't have enough preload
 

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Discussion Starter #11
Aside from the discussion about stroke length..how much preload are you running because if you have bottomed out it sounds like you don't have enough preload
Thanks for the reply. My apologies for not explaining my motive for the post properly. I have no problems with my setup - other than searching for the "Holy Grail" of perfection - and yes indeed when I bottomed out I was running very little preload, deliberately.
I mentioned it just to show that the forks would in fact go that far down.
What puzzles me is the fact that the dust seal would, theoretically, using Suzuki's 120mm stoke figure crash into the bottom casting.
 

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Most modern forks use a top out spring. It works well, but it makes the 120mm stroke figure hard to calculate since the forks often times dont return to the 100% stretched out point. If you were to hand extend the fork, you might find that extra 4mm. Still, Seeing them return to only 116mm is not a real concern. The forks on my Kawasaki were also claimed at 120mm travel, but reality was way closer to 110mm.



Also, Suzuki, or anyone else specs that 120mm figure, and puts that into the spec figures.....then, they go to KYB, Showa, Ohlins, etc and orders the fork. What they get back may be slightly different than what they asked for.
 

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I'm sure the travel is spec'd without concern for squishing the fork seal. I looked at mine and it measure ~8mm, so without actually measuring how far it can be squished (I'm < 150lbs, 68 kg), it seems like it's in the ball park.

;)
 
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