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Thread: Front-end shake under braking?

  1. #31
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    Quote Originally Posted by Robert Taylor View Post
    Refilling by quantity is very inaccurate. Overfilling and then syringing back to specified oil level / tolerance range is the only way you should do this. It will be detailed in the workshop manual. Setting the oil level sets the secondary air spring volume, and that very volume determines the latter reaches of stroke progressivity. Simple way equals mediocrity, the correct way equals a better result.
    Noted.

    Quote Originally Posted by Robert Taylor View Post
    That bush should NOT fall into the fork housing.There is a problem with the bushing and / or fork leg that needs to be rectified.
    it was common to mine from memory so could be a design thing. It wasn't rattling around in there, but there was sod all holding it in... (actually the fork seal and retaining clip were holding it in...!)
    $2,000 cash if you find a buyer for my house, kumeuhouseforsale@straightshooters.co.nz for details

  2. #32
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    Quote Originally Posted by ManDownUnder View Post
    Noted.



    it was common to mine from memory so could be a design thing. It wasn't rattling around in there, but there was sod all holding it in... (actually the fork seal and retaining clip were holding it in...!)
    There should at least be a small degree of interference requiring a heat gun to preheat the alloy leg and then allow it to drop in. The passage of time ( high kilometres ) has either worn the recess or stretched it. That and the other problems have a cumulative effect.

  3. #33
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    Quote Originally Posted by Robert Taylor View Post
    There should at least be a small degree of interference requiring a heat gun to preheat the alloy leg and then allow it to drop in. The passage of time ( high kilometres ) has either worn the recess or stretched it. That and the other problems have a cumulative effect.
    Good application for loctite?

    I've done it before, where the bush internal clearance was still good. The outside diameter would still need to be no more than a few thou clearance in the leg though, and well degreased...

    I've also bored legs once and made oversized bushes (Ossa from memory), but in that case the bush OD was slightly smaller than the seal OD so there was room to play with.
    Go soothingly on the grease mud, as there lurks the skid demon

  4. #34
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    Quote Originally Posted by Ocean1 View Post
    Good application for loctite?

    I've done it before, where the bush internal clearance was still good. The outside diameter would still need to be no more than a few thou clearance in the leg though, and well degreased...

    I've also bored legs once and made oversized bushes (Ossa from memory), but in that case the bush OD was slightly smaller than the seal OD so there was room to play with.
    No, because the interference fit is also designed to firmly abut the free gapped ends of the DU bushing together to give the appropriate clearance to the chrome leg. Loctite is a wonderful product, but not here. This is a job for a very fussy machinist.

  5. #35
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    Give me a yell if you need a hand on Sunday MDU, I've had a few forks apart.
    Quote Originally Posted by Dean View Post
    Ok im coming out of my closet just this one time , I too kinda have a curvy figure which makes it worse beacuse im a guy. Well the waist kinda goes in and the bum pushes out. When I was in college the girls in my year would slap me on the arse and squeeze because apparently it is firm, tight... I wear jeans
    .....if I find this as a signature Ill hunt you down, serious, capice?

  6. #36
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    Quote Originally Posted by Robert Taylor View Post
    No, because the interference fit is also designed to firmly abut the free gapped ends of the DU bushing together to give the appropriate clearance to the chrome leg. Loctite is a wonderful product, but not here. This is a job for a very fussy machinist.
    Makes sense. Are most of them split bushes nowadays?
    Go soothingly on the grease mud, as there lurks the skid demon

  7. #37
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    Quote Originally Posted by Robert Taylor View Post
    There should at least be a small degree of interference requiring a heat gun to preheat the alloy leg and then allow it to drop in. The passage of time ( high kilometres ) has either worn the recess or stretched it. That and the other problems have a cumulative effect.
    Well bugger me. It's a tight fit but I definitely never had to use a heat gun. Sounds like a fair bit of wear there wkingham. Hopefully Nigel's got spare parts that can help. If you get stuck give me a yell. I've got a spare set down here too we may be able to cannibalise to help you out too.

    Thanks for your comments Robert. They're much appreciated. I understand that precise measurement is always a good thing to achieve precise results but I'm not sure if you totally answered my question. I guess I really wanted to know if, given that the quality of the Showas in the Suzuki is pretty ordinary, being a few mls out in each fork is really going to make that much of a difference. Either way, next time I change the fork oil I'll pay more attention to it.
    And I to my motorcycle parked like the soul of the junkyard. Restored, a bicycle fleshed with power, and tore off. Up Highway 106 continually drunk on the wind in my mouth. Wringing the handlebar for speed, wild to be wreckage forever.

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  8. #38
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    Robert--Can you explain why you Wouldn't use the old tried n true method ?
    To see a life newly created.To watch it grow and prosper. Isn't that the greatest gift a human being can be given?

  9. #39
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    Quote Originally Posted by FROSTY View Post
    Robert--Can you explain why you Wouldn't use the old tried n true method ?
    Well tried but seldom true! Refilling with a specified oil volume very rarely achieves the same oil level ( and therefore trapped air volume ) from side to side. If you are careful it can get close but there are those of us who are not content with ''thats near enough''.

    Reference to setting the oil level and a minimum and maximum range has appeared in the workshop manuals of at least the more sophisticated models for several decades now. The text is certainly not there to use a little more ink and to hasten the demise of The Amazon forest!

    Adjusting oil level is a wonderful way of tuning end of stroke air spring effect, just as useful for road going motorcycles as it is for road race and MX. If you go to www.ohlins.com there are downloadable front fork manuals that describe fork tuning inclusive of the effect of changing oil level.

    If for example you fill the forks by specified volume and you decide to change to heavier rate springs that are otherwise exactly the same, you have also changed the effective oil level and end of stroke air spring pressure rise. Why? Because the firmer springs will have ( usually ) thicker wire that will displace more oil when installed.

    For reasons such as that manufacturers high spec racing forks specify that oil level is checked with the springs installed, it removes a variable.

    When I travel to racing meetings I include in my toolkit a large oil levelling syringe and a handful of small 5 and 10ml syringes, plus hyperdermic needles for bleeding and charging nitogen. That does not mean I am taking illegal mind and mood altering drugs! Rather, optimising air spring effect, end of stroke bottoming resistance and attaining maximum available fork travel ( without abrupt bottoming ) is one of the most frequent tuning variaibles employed by top riders and their techs.

    In my workshop , be it forks for road race, mx or just a road going commuter I NEVER ever fill by volume, only by specified level and an adjustment made for the application.

    Different race tracks require different oil levels, the street circuits such as Paeroa and Wanganui require a higher oil level.

    Life can be as simple as you want it to be, but if you want to be ''closer to the front'' you have to accept embracing hard work, lots of thinking and complexity. Why accept mediocrity? Theres too much of that in everyday life.

  10. #40
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    Quote Originally Posted by Ocean1 View Post
    Makes sense. Are most of them split bushes nowadays?
    Indeed, that is so.

  11. #41
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    No doubt your method should be more accurate.What about situations where the forks give a false reading? Im thinking forks with them newfangled innner thingees
    To see a life newly created.To watch it grow and prosper. Isn't that the greatest gift a human being can be given?

  12. #42
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    Quote Originally Posted by FROSTY View Post
    No doubt your method should be more accurate.What about situations where the forks give a false reading? Im thinking forks with them newfangled innner thingees
    There are no false readings that I am aware of, I think you need to describe more accurately what you actually mean?

  13. #43
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    Where some components require filling with oil before assembily
    To see a life newly created.To watch it grow and prosper. Isn't that the greatest gift a human being can be given?

  14. #44
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    Quote Originally Posted by FROSTY View Post
    Where some components require filling with oil before assembily
    It is but a matter of ensuring that everything is fully bled and stabilised before setting the oil level, again, workshop manuals detail the procedure and those of us in the trade have streamlined ways of being able to do so quickly. But Im not crossing that line and divulging that too readily!

  15. #45
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    Sounds like we're back to 'If you don't know what you're doing, leave it the hell alone'

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