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Triumph magneto gear, no advance

Discussion in 'Triumph (Classic)' started by skipsoldbikes, Feb 15, 2014.

  1. skipsoldbikes

    skipsoldbikes

    Joined:
    Jun 3, 2011
    Hi all,
    I am sending a rebult early K2F magneto to a guy in Singapore who is rebuilding his Dads old Pre-unit Triumph. To make a long story short, I need a magneto gear (fiber) . This unit would have a steel hub with a oil slinger on the back side & the fiber (fibre) gear would be riveted on. I have 2 new fiber gears, but no steel hub.
    This is for a manual advance mag, so there is no automatic timing device on it, just a gear & a hub.
    He does NOT want an all steel, or all aluminum gear. I am sure a few of you must have an old one with brogen, or worn out teeth laying around, as the condition of the gear teeth are not important,as I will be riveting on a new gear to the old hub. I am trying to help this kid out, as he is a real greenhorn, but the joy he has received from working on his dads old bike is inspiring :)

    I would also consider an entire gear assembly brand new, but I can only find one supplier & they are out of stock:
    http://www.classicsolutionsengineering. ... 257&page=1

    Any one have any supplier they would recomend, or have an old gear to sell (or trade for Lucas magneto parts) ?

    Thank you,

    Skip Brolund
     
  2. Adrian1

    Adrian1

    Joined:
    Jun 24, 2013
    Long shot, contact one the repairers. They may tell you to get lost but worth a try? :idea:
     
  3. Triton Thrasher

    Triton Thrasher

    Joined:
    Feb 10, 2009
    If he actually wants a Tufnol mag gear, he really is a "greenhorn!"

    I think you'll have to get the hub made on a lathe.
     
  4. acotrel

    acotrel

    Joined:
    Jun 30, 2012
    Years ago I fitted the narrow gear which was used on the distributor models brazed to the hub out of the tufnel gear, on a lucas mag. Worked really well. A good engineering shop would make that hub fairly cheaply. The taper needs to be correct. If you go down to the dealer who sells old farm machinery or old boat engines, you might find and old magneto you can steal the gear off to get the centre.
     
  5. Time Warp

    Time Warp .......back to the 70's. VIP MEMBER

    Joined:
    Dec 3, 2012
    The (auto advance Lucas competition magneto) fibre gear on my 1957 TR6 needs replacing,what is the best bet to replace it with being a greenhorn also.
    TIA.
     
  6. Triton Thrasher

    Triton Thrasher

    Joined:
    Feb 10, 2009
    The Tufnol gear is a breakdown in waiting, but the alternatives are a bit tricky. Not all that many Triumphs had auto advance magnetos as original equipment. Maybe that's why nobody appears to be in business supplying good metal replacements. Such things have certainly been available for Velocettes.

    Simplest fix is to rivet a new Tufnol Gear on. Take care to put no strain on the teeth when you tighten the nut: take the strain with a lever stuck in the auto advance.

    Most reliable fix is a solid metal pinion. Apparently, however, there are alloy ones that fall to bits, on the market. Also, you are left with no auto-advance, which makes starting, idling and slow running a bit fussy.

    Cleverest fix is a steel camwheel or alloy pinion turned down on a lathe, to fit onto the auto-advance.

    I use a Tufnol gear on mine, even though it has let me down in the past. I carry a spare solid alloy pinion and nut in the toolkit. The alloy pinion has proved itself over many miles in the past, but I don't know who made or supplied it.

    Yes, I know, I've not been all that much help!
     
  7. Matt Spencer

    Matt Spencer

    Joined:
    Jul 25, 2010
    Around 56 the Bearing got Bigger , so the brass got bigger , so it doesnt split & fall off , as the steel shaft with the taper for the drive gear is a interfearance push in thing .

    [​IMG]

    So theres ' Big Bearing ' mags from 56 on . Youd inspect for cracks on a early one , at the least . Brass - shaft to face , @ the intersection . Amoungst other things .

    Theres a few types of auto advance . roller ( centrifugal ) and spring / bob weight . New Fibre gears are available . The 1948 one on the 61 FAILED for some reason .
    washed if theyre oil impregnated and look a thousand years old , it may pay to replace it . :D .

    whacking up something out of something else that bolts on a K2F in something else wouldnt be a problem . as they all have the same taper . on K2Fs . :)
     
  8. Matt Spencer

    Matt Spencer

    Joined:
    Jul 25, 2010
    Apparently this is the B.T.H. one , with the Centrifugal rollers ( 5 ) . fairly reliable .

    [​IMG]

    aparently some people have problems with nylon distributor drive gears . If you want to wreck one you put a wrench somewhere and wrench something .
    Paxalon or whatever Mag. drive gears would come into the same catagory . Throwing a cloth in the Gears , thoughtfully - to spead the loading - is about
    as far as youd strain them & expect to get away with it . So might pay to drive a remote locking tool for when wrenching nuts attached , when required .

    More pretty B.t.H. pictures .https://www.google.com/search?site=imgh ... h&imgdii=_ . for deciphering .
     
  9. skipsoldbikes

    skipsoldbikes

    Joined:
    Jun 3, 2011
    The magneto gear is available in fiber (fibre), steel, and aluminum. Eash has its own pros & cons. If your fiber gear has worn out, it ether has many miles on it & has served its purpose, is not installed properly, did not get proper lurication (dirty oil, or lack of oil), or it was made incorrectly (China/Taiwan, India).

    Fiber gears are still used today & were used on billions of american cars from the Ford model A, clear until the 1980's on timing gears, so the problem with the Lucas magneto fiber timing gear isnt the material.

    I have heard several opinions on why many motorcycle manufacturers used a fiber timing gear on the mag. Some say it is so that if the mag bearings fail, you wont strip the steel gear teeth & have the metal go through the engine. Not sure I believe that, because if the mag bearings failed, there would be no more ignition & the engine would stop. Some say it was cost, I dont think that is true either if you consider the labor cost to make the fiber gear, the rivets, the steel center hub, then pay someone to assemble the whole thing, versus making a one piece metal gear. I have heard it was to electrically insulate the armature shaft, that cant be true, as the earth brush takes care of that anyway. I can tell you for a fact, that in manufacturing , the most common use of fiber gears is because they are quieter, and they dampen vibration, that is not to say that is why English motorcycles used them though.

    I have seen the brand "Tufnol" used, do we know that that is the brand that was used originally, of is that a generic term for all fiber gears?

    For what its worth, here is a current & direct quote from the Tufnol website regarding their gears:

    "GEAR DESIGN IN TUFNOL LAMINATES

    BENEFITS
    Non-metallic pinions machined from fabric reinforced TUFNOL laminates are used successfully in many industries to reduce noise and to damp vibration in high speed machinery and equipment. This application extends from instruments to heavy-duty industrial plant.

    Long life TUFNOL laminated gears are hard wearing. They are also sympathetic to metals with which they work and this results in little or no wear on their mating wheels; often the life of the metal wheels is prolonged by the use of a TUFNOL gear in the drive. TUFNOL laminates are unaffected by oil, grease or petrol, are generally suitable for use in corrosive atmospheres and can be stored indefinitely without deterioration. Their mechanical strength, toughness, and temperature resistance exceed those of many commonly used thermoplastics materials and enable them to withstand extremely arduous working conditions, as well as the more delicate precision situations. Their resilience provides good resistance to shock loads and their light weight - one sixth of the weight of steel - reduces inertia, which leads to lower power requirements."

    I think it would be interesting to know why it was used & why some people still have thier original timing gears on their high mileage bikes & some people get a short lifespan.

    All the best,

    Skip Brolund
     
  10. Triton Thrasher

    Triton Thrasher

    Joined:
    Feb 10, 2009
    How many miles is that?

    That must happen a lot.

    Impossible in the timing chest of a working Triumph twin.


    If a fibre gear fails where a metal gear wouldn't, the material is one problem. Do a google search for Ford fibre gear and see how many results are not about chewed-up gears.

    There isn't much clearance in a mag and swollen shellac or stray foreign matter could cause a seizure where you might prefer to strip the gear teeth than try to force the mag to turn.

    The earth brush is a conductor! The paper bearing insulators take care of insulation.

    Edit: I didn't think that through, did I? The insulators prevent LT current going through the bearings, as that is generally held to be erosive to the bearings. The earth brush gives a conductive path for the LT current. With a metal pinion, the earth brush and the gears are parallel paths for the LT circuit. And the gears do not seem to suffer erosion.

    No magneto drive gear makes a noise audible over the rest of the racket from an old bike engine. And the Tufnol gear hasn't stopped my bike vibrating!


    Could be!



    Mine will never shear as long as it knows there's an alloy replacement in the toolbox.
     
  11. texasSlick

    texasSlick VIP MEMBER

    Joined:
    Jan 2, 2013
    I have a 1977 Ford service manual that states noise was the purpose for fiber timing gears. These were first used when auto engines required a complete re-build at 100,000 miles, and the fiber outlasted the rest of the wearing parts. Ford replaced fiber with alloy or steel when engines began to run 200,000 miles before major over-haul, and the fiber was not lasting that long (my '77 pickup jumped time at 180,000 miles, and the replacement timing gears were alloy).

    I agree with Triton Thrasher....with all the racket that comes out of a period motorcycle engine, noise is not, or should not be, a factor. Perhaps the engineer who first proposed using fiber came from the four wheel automotive industry....if so, he would be the "greenhorn".
     
  12. Bernhard

    Bernhard

    Joined:
    Apr 20, 2011
    1st of all I would be very wary of fitting any fibre timing/ magneto gear into any engine, the reason is I had a 500 Velo with the same and stripped two in the time that I owned it. The first time the big end went a few thousand miles later because I suspect I failed to locate and remove the stripped gear tooth from the engine, the new a/r didn’t last a whole lot longer. Why they fitted alloy gears with the manual a/r and not the automatic a/r was a moot point with me. A work collage had a 500 MAC and also stripped the fibre gear a couple of times.
    I would strongly advise you to fit the alloy gear to you’re a/r for a long-lived engine.
     
  13. Triton Thrasher

    Triton Thrasher

    Joined:
    Feb 10, 2009
    I think maybe Velocette is a good example of common use of fibre magneto wheels for (attempted) high mileage use.

    I believe that most Velo owners with experience regard the Tufnol gear as a bad joke.
     
  14. Matt Spencer

    Matt Spencer

    Joined:
    Jul 25, 2010
    [​IMG]

    this is a later Ford V4 / V6 timing Gear , Nylon Toothed Steel Center . The Flywheel effect
    as its considerably weightier ( several x the Tufnol job ) Smooths the operation .

    id think Levering on things would lead to tooth failure . no doubt theres no locking bar to avoid this .
    likely the timing Gear is supposed to be replaced at engine overhaul , but likely ommitted . older ones
    take a bedraggled appearance with the cooking & contamination in a neglected engine .

    The ' gear whine ' is / should be a distinct characteristic of the TRIUMPH engine , with its Gear Train Cam drive . Rather that buggered tappet block rattle .
     
  15. skipsoldbikes

    skipsoldbikes

    Joined:
    Jun 3, 2011
    I just dont buy into the all composite gears being bad, I mean look at how many millions of vehicles have had them without failure. Most of the vehicles I have owned have had them ( bikes & cars, including Model A Fords), and my 3 current Nortons, and I have never replaced one due to failure. I have changed them when doing a full engine rebuild, just as I replaced bearings & other parts you would normally replace on an engine rebuild. These gears were also used on all of the Lucas Magdynos, which covers the majority of all British singles. Sure they wear out over time , just like any gear of any material (like the steel gear on the Lucas Dynamo), I just have not seen a large amount of fiber gear failures. The ones that I have seen fail were in engines that had not been cared for very well with regular oil changes, or due to improper magneto clearance adjustments.

    I am sure like any product, there are some that were made poorly by some brands, and other company's that made them better, but . I can tell you that in the vintage Ford groups there are 2 main types of composite timing gears, the good ones are woven, the bad (cheap) ones are macerated, or made up of chopped up fibers & are not as strong. According to the folks who make the Tufnol brand, the gears should be made with the fibers running the correct direction as well. The end "grain" should be at the gear teeth, not showing at the face of the gear. I wonder if some of the failed timing gears were those made "on the cheap"?

    As to the "why did they use fiber gears" question, we may never know, I can only say what other industries say (automotive & industrial) and that is the fiber gears are quieter & lighter, and in some cases are used as a intentional weak point (in the case of some machine shop machines) so if the machine is abused, the fiber gear will shear, rather than expensive gearbox parts being destroyed. Being slightly abrasive in nature, you will often see fiber gears running next to steel gears.
    On vehicles that came with stock fiber gears that were used for racing, most seem to replace the fiber gears with aluminum.

    So, why did one persons fiber gear fail & millions of other gears not fail???
    a) dirty oil?
    b) improper adjustments on the gear train?
    c) harsh riding ?
    d) poorly made fiber gear?

    i'm no expert, but if all fiber timing gears were bad, you would see a lot more cars getting towed to the shop I would think. The Pre unit Triumph & am rebuilding the mag for, was nearly 60 years old with the original fiber gear. The reason we are replacing it is because it had rusted to the mag armature & was destroyed while being removed.

    Here is the mag shaft: http://s306.photobucket.com/user/skipso ... sort=2&o=4
    I replaced the entire armature, as I have a few dozen K2F armatures in stock.
    here are more mag pics of this job which started this thread : http://s306.photobucket.com/user/skipso ... t=2&page=1

    As a side note to the mag in the pics, you will note this is NOT a K2FC, but an early K2F. It used the screw on pick-ups & the same body casting as the later K2FC. Although, I did use the K2FC drilled bolts rather than the original style cheese head screw. New pick-ups are on the way, originals would have been black, un-coated on this mag, but the K2FC pick-ups would have been painted with red electrical varnish. We'll see which way the customer wants it.
     
  16. Triton Thrasher

    Triton Thrasher

    Joined:
    Feb 10, 2009
    How do you know?
     
  17. skipsoldbikes

    skipsoldbikes

    Joined:
    Jun 3, 2011
    It hasn't left the family (kinda cool actually).
     
  18. Bernhard

    Bernhard

    Joined:
    Apr 20, 2011
    This is very interesting as you must have a unique component to last that long if you have a fibre gear? I suspect you do not do a high annual mileage either.
    I have head/read that one Velo owner was so pi**ed off with the fibre gears stripping and having to strip the engine to locate the missing tooth from the engine he fitted an alloy gear from the manual a/r and drilled and riveted it on to an auto a/r.
    Correct me if I am wrong but do BSA and Norton fit steel sprockets on their chain driven a/r units :?:
     
  19. skipsoldbikes

    skipsoldbikes

    Joined:
    Jun 3, 2011
    My 3 Nortons (all mag bikes) use a fiber gear on the mag. Although it is basically a fiber ring gear with a "slipper clutch" style hub, to allow for the gear to slip, rather than strip off teeth. Some of the Triumph guys I talked to hate the metal gears, because if you loose a tooth you may seize your engine, a fiber tooth is a lot softer & would do less damage to the engine that a metal gear. It seems there are different quality's of material for some to last so much longer than others. As I have read, dirty oil seems to be death on them also.
    Who knows?
     

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