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suzuki 4ls brake on roadholders

Discussion in 'Other Norton Motorcycles' started by t ingermanson, Dec 5, 2018.

  1. t ingermanson

    t ingermanson VIP MEMBER

    Joined:
    Oct 17, 2018
    hey all,

    i've got a suzuki 4ls brake that has had the brake plates milled to fit a 7 3/8" roadholder fork. question is, the bearings in the suzuki hub seem much smaller inner diameter than the outer of the norton axle.

    how have people dealt with that? different bearings or custom axle? both?

    to that end, i'm looking for a good set of 7 3/8" yokes and shrouds.

    thanks!
     
  2. frankdamp

    frankdamp

    Joined:
    Oct 7, 2005
    Be careful about using that amount of brake power on forks that were designed for a cable-operated sls brake. It may be possible to generate enough bending moment in heavy braking to collapse the forks.
     
  3. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Plenty of folk have put in MUCH bigger and fiercer drums that that, as well as huge twin discs etc.

    I’m not aware of collapsed forks being a common issue...
     
  4. t ingermanson

    t ingermanson VIP MEMBER

    Joined:
    Oct 17, 2018
    thanks for the word of warning. it's always worth mentioning. quite sure there have been more effective brakes on these forks (yes, fast eddie, and ridden much harder than i'm going to ride!!). the fact that it's a symmetrical hub (no twisting) makes me quasi-confident. amazing what we can talk ourselves into...

    pretty sure i found bearings that'll take the axle and the hub, but the balls will have to be smaller than either norton or suzuki intended. i'd like to learn if anyone's had any detrimental effects from running either a smaller diameter axle vs smaller balls. if the smaller balls work, i'm a happy man.
     
  5. mdt-son

    mdt-son

    Joined:
    Jan 19, 2012
    The full width Norton hub uses a 17mm axle. I wouldn't consider reducing this if I were you. At the same time I am surprized a Suzi of any size used a smaller diameter axle than this? I guess your hub is from a 750 "Water Kettle" ?
    Have you looked into the possibility of turning (machining) the hub, enabling larger bearings OD / ID to be fitted? If the casting allows this, I will be happy to propose replacement bearings and a suitable tolerance for the outer race. You may send me a p.m.

    B.R.
    Knut
     
  6. marinatlas

    marinatlas

    Joined:
    Nov 4, 2007
    Hi , it looks like the kettle have a 6202 (pair of) 15x35x11 while the cdo have 6203 17x40x12, so you could fit a 17x35x10 ( 6003) , and yes you will have "small balls".........:confused:
     
  7. Dutch

    Dutch

    Joined:
    Sep 21, 2015
    I would never go smaller with a front axle.
    The axle is a critical component for the rigidity of the front suspension.
    Holding the front wheel is just part of its job.
     
  8. o0norton0o

    o0norton0o

    Joined:
    Apr 27, 2015
    I have done exactly what you are asking about to my commando. My donor wheel was a yamaha which was used with a 15mm axle. I wanted to keep the norton 17mm axle so I wouldn't have to mess with using a bushing in the norton fork sliders. The simplest solution was to swap the wheel bearings from 15mm x 42mm to a 17mm x 42mm and use the norton 17mm axle. I have been running this yamaha wheel for a while now with no issues whatsoever. I regularly do 100mph up a certain hill on the hiway nearby my home. I haven't had any issues.

    One thing of note was that I had to order the bearings 2 times as I wanted sealed bearings and I was sent sealed one side only the first time, so I actually have those as a back up pair, which so far seems unlikely I'll ever need.

    here's the result
    [​IMG]

    If you have a drum brake rather than a disc, you'll have to bore out the brake plate to the new axle diameter. There may be other ramifications to that, if there's not enough meat in the brake plate casting to support the plate with the bigger diameter hole. You have to consider that.
     
    Last edited: Dec 8, 2018 at 4:55 PM
  9. t ingermanson

    t ingermanson VIP MEMBER

    Joined:
    Oct 17, 2018
    knut and dutch, i too am nervous about reducing the axle. i'm also hesitant to machine out the bearing bore in the hub, due to concentricity issues. i'd rather run smaller bearings than eccentrically fitted bearings. it's amazing to me that the gt750 bikes ran with 15mm axles. then again, they were not known for their handling.

    marinatlas, yes, those are the ones i found as well.

    oonortonoo, that looks like a good set-up! strangely, the wheel i got has had the brake plates milled to fit between un-milled 7 3/8" roadholders, which is nice, as most who do this mill down the fork lowers as well. the plates however, were not bored for the larger norton axle. the plates have a steel bush pressed into the plate for the axle, with plenty of beef to take out what i need for the larger axle. i don't know if the person who did the previous work ran a 15mm axle or got half way through the project and stopped. the price was right though for this wheel, so i thought i'd give it a try. i've got a small machine shop, so the fabrication work is well within reach.

    on my triton (in my avatar) i've mounted twin four pot brembo disc brakes, and have gotten used to well working brakes on the narrow twisting roads in my area. this front end will be going on a faux 88ss i'm putting together right now.
     
  10. 84ok

    84ok

    Joined:
    Aug 10, 2014
    Last edited: Dec 7, 2018
  11. o0norton0o

    o0norton0o

    Joined:
    Apr 27, 2015
    In my application, I was NOT willing to mill down the faces of the norton sliders. The yamaha hub had a ridge in it's casting which helped contain the grease from the old yamaha speedometer gearbox drive. This ridge interfered with the Norton gearbox that I wanted to mount on the front wheel and the ridge made everything too wide by a little bit, so I milled down the ridge on the cast hub and the whole assembly just barely fit with only about 1/16" of space between the Norton gearbox drive (which is fixed as part of the wheel spacing assembly) and the hub face. (which of course spins) The outside face of the speedo gearbox is against the slider face. It is perfect after I milled the ridge off the hub.

    The wheel still could fit easily without milling the hub ridge, but I wanted to run the speedo gearbox off the front wheel, so there was an extra challenge there presented by the thickness of the speedo drive gearbox that made things very close to being a more involved modification to the hub.

    It sounds like you have all the issues covered. I can indeed tell you that the "small balled" bearings work fine on my bike. My bike handles really well. In fact, I swapped nortons with a friend at the norton rally this year and he liked my bikes handling very much. I wouldn't think there is an issue there from my experience but of course you could check with someone more knowlegable than I to make sure... There are plenty of those people here on the site to ask...
     
  12. t ingermanson

    t ingermanson VIP MEMBER

    Joined:
    Oct 17, 2018

    to be fair, that's a totally different mode of failure. aluminum vs steel, leading axle vs inline axle, off road vs on road, etc, etc, etc. i get the point though. the moment sustained by the forks at full braking is massive. i'll be getting brand new fork legs from andover to minimize the chances.

    oonortonoo, sounds good enough to me. i'm not sure i care about the speedo drive. there are other ways to skin that cat. your endorsement of the bearings are exactly what i was looking for. thank you!
     
  13. Triton Thrasher

    Triton Thrasher

    Joined:
    Feb 10, 2009
    Which is the most reassuring- new pattern parts or ones that have already proved reliable?

    I know that’s slightly spurious in the case of Roadholder stanchions and sliders, because most of the originals have already been replaced.
     
  14. mdt-son

    mdt-son

    Joined:
    Jan 19, 2012
    I can't see concentricity as a problem for a precision machining operator. Obviously you haven't spoken to an operator? Assuming the bearing seat was to be bored (turned) on a milling machine having a movable table, watch this video:
    All you have to do is create a datum plane each side of the hub. These may be present already (depending on the fabrication method at the factory). Fixing the hub using the fresh datum plane, perform a boring operation to, e.g., IT5/M5 tolerance according to ISO 286.
    Even if the detected center should be 5/1000 mm off, you will be well inside the tolerance provided by the sliding fit of shaft/inner race. Have you considered the magnitude of rim run-out? While I don't have ISO 6054 at hand, I am sure the maximum allowed run-out is much larger than 5/1000 mm. Even cast wheels would have run-outs larger than this - I bet they are a factor of 20 higher. The tire will easily absorb a small run-out.

    As for fitting a "small ball" bearing, usage of a non-standard bearing should be considered carefully. Decisive factors are application, dynamic load magnitude and maximum thermal load. I wouldn't rely on the experience of another fellow on this site, considering your life is at stake!

    Excuse me, but this is a non-sense question. Have you ever heard of fatigue? What has proved reliable in the past does not necessarily prove reliable in the future. This is especially true for parts made of aluminum. Provided the (new) pattern part is made to spec, I would no doubt choose the latter over a well used genuine slider whose fatigue life may be exhausted. Absolutely!!

    -Knut
     
    Last edited: Dec 8, 2018 at 12:43 PM
  15. t ingermanson

    t ingermanson VIP MEMBER

    Joined:
    Oct 17, 2018
    yes, i've got a coaxial center finder and a few boring heads for my bridgeport milling machine. it's not a lack of ability to do it, but it may take more time and effort than the "problem" is worth. i'd like to rebuild the wheel with an aluminum rim, so the brake liner should be skimmed if messing with hub centers, which needs to be done after spoke tensioning. sounds like quite a bit of a to-do list at stage of the game.

    not to sound as if safety is an inconvenience, but i don't like to get too far into the details while the bike is only taking shape, and i'd just like to get a front end on the frame. once i know everything is playing nice, i'll start taking care of all the time-toilet projects.

    i think i'll grab a couple appropriately rated bearings and give them a go as i get the bike together. who knows? maybe the two sizes are rated similarly and will work just fine?



    i'm not aware of a bunch of spectacular structural failures of roadholder lowers under normal use (filing the normal crack on the clamp side and broken/stripped fender tabs under "unspectacular"). i've only heard of fork tube failures, which, yes, i'll ride tubes built by andover all day everyday, over the ones that came on this bike. the fatigue cycles on lowers has got to exponentially lower than what the tubes go through.
     
  16. mdt-son

    mdt-son

    Joined:
    Jan 19, 2012
    ??? How do you derive at that statement, considering all loads have to pass through the sliders? Isn't it rather the opposite?
    Furthermore, I have never seen fork stanchions fail due to fatigue. It may have been a problem in the 50's as stanchions had small OD's .....

    -Knut
     
    Last edited: Dec 9, 2018 at 7:09 AM
  17. o0norton0o

    o0norton0o

    Joined:
    Apr 27, 2015
    As far as milling out the hub for a larger bearing goes, I wouldn't rely on the conjecture of another fellow on this site who thinks that it is possible to remove material from the casting without weakening the hub significantly, considering your life is at stake!

    Knut, It sounds like you're dismissing my actual tested experience in favor of your unresearched conjecture that milling the hub would be safe. You should apply the same skepticism to your suggestion as you do to mine. The difference being that my suggestion has been tested and works well.

    ... t ingermanson, what size is the existing OD of the stock bearing? My yamaha bearings were 42mm x 15mm x 13mm C3 deep ballbearings. They were changed to 42mm x 17mm x 13 C3 deep ball. If your hub bearing recess is less than 42mm, then you are breaking new ground with your bearing substitution. My bearing substitution has been tested and works well, in spite of the speculation put forth.
     
  18. 84ok

    84ok

    Joined:
    Aug 10, 2014
    info from post #6
     
  19. o0norton0o

    o0norton0o

    Joined:
    Apr 27, 2015
    I think 35mm OD donor wheel is a much different consideration than my 42mm OD wheel, rendering my successful modification irellevant to the modification T ingermanson plans to do. I'd look for a different donor wheel. there are many around
     
  20. t ingermanson

    t ingermanson VIP MEMBER

    Joined:
    Oct 17, 2018

    yes, the suzuki stock bearing bore is 35mm. not sure i'm breaking new ground, as i'm sure it's been done before, but maybe there's a lack of experienced voices, because they are all dead from front end failure! ha!

    i did a bunch of hub measuring and some bearing research. the 6003 bearing has a notably lower rating for dynamic as well as static loads, than the stock 6202 bearing. the 6203 bearing has an increase in rated loads, but has a 40mm outer dimension.

    the bore of the hub is relatively thin walled (compared to the other hubs i measured) at .250". it has stiffening ribs as well as a deserved reputation for being overbuilt, however, boring 5mm from the hub is questionable, at best. i'd rather have a failed bearing than a failed hub body.

    since the point of no return has been passed for the brake plates by their previous owner, i think i'm going to give the smaller bearings a shot and keep a close eye on them.



    yes, the loads pass through the sliders, but the distance of cantilever of the fork tubes from the yoke is considerably longer than the distance of cantilever from the axle to the lower fork bush, hence the number of bent fork tubes rather than the number of bent fork lowers. the longer the cantilever, the higher the multiplier of force. no?

    the above bmw fork failures resulted from a leading (cantilevered) axle failing at the point of attachment to the rest of the lower. norton roadholders use an inline axle, so that specific mode of failure is all but off the table.

    failure from fatigue is completely indistinguishable from a single impact failure without serious testing. most (all) guys who bend their forks, replace the tubes and get on with it.

    it would be good know the steel alloy being used for tubes these days. a DOM or 41xx alloy would be far stronger and resilient than the steel tubes of yore.