• Category Archives Tech Tips
  • Tech articles to help repair and maintain a motorcycle:

  • CARBURETOR CLEANING

    CCcC

    One of the most important jobs on any restoration is to re-build the carburetors, and before a re-build they need a thorough cleaning.  There are numerous expensive acid-based carb cleaning liquids on the market, but a cheaper method that works is as follows ;–

    1)  Get hold of an old saucepan (pot) that is big enough to enable the carb components to lie on the bottom without being on top of each other.  I have commandeered a pot that was going to be thrown out because it had been allowed to cook dry at some stage..

    2)  Fill it enough to just cover the carb parts with a third each of water, white vinegar and lemon juice, ( the kind you can buy in a plastic bottle at the grocery store called ReaLemon)

    3)  Wait till she has gone shopping, and boil on her stove for about 20 minutes.  (It must be bubbling and it stinks!)

    4)  Tip out the hot liquid and rinse several times with cold water.

    5)  Blow out excess water with an airhose through all the airways and lay out on a clean cloth and allow to dry.

    6)  The parts and air passages are beautifully clean but everything will be covered in a very fine grey powder which is easily brushed off with an old tooth brush or similar. If you want a nice dull shine, a soft brass bristle brush works fine (I bought a whole set including the brass bristle one, from Dolarama)

    A dull grey fine powder like the “bloom” on a grape!
    The bloom removed and parts brushed
    Re-built carbs with new gaskets & jets etc.

  • No Title

    FAIL SAFE ANTI WET-SUMPING VALVE

    For the un-iniated, Classic British motorcycles are prone to wet-sumping after an extended lay-over period, such as Canada’s long cold winters, and in some bad cases even after a couple of weeks. Because of their dry sump design where oil is stored in a separate tank, then fed through the engine under pressure from the oil pump and returned to the tank from the bottom of the crankcase by a “scavenger” pump or return pump, oil tends to leak through the oil pump and collect at the bottom of the crankcase.  The more worn the pump the worse the bypass leak is.  Gear type pumps (Norton and AJS/Matchless Twins) are worse than plunger type pumps (Triumph/ AJS & Matchless singles)  Whilst slightly worn pumps will deliver pressurized oil satisfactorily and not be in need of an expensive overhaul or replacement, the wet-sumping problem is a tiresome nuisance on start-up after lay-over, and in extreme cases can cause excess crankcase pressure with oil leaking all over and even blown gaskets, before the scavenger pump has time to pump the excess oil back into the tank.

    Not to mention clouds of blue smoke until the oil is cleared.  My neighbour came running one spring start up thinking my garage was on fire!

    There has been much written about solutions for curing wet-sumping.  Commercial parts suppliers offer various types of anti wet-sumping valves with prices varying from $35 to $300.  The simplest and cheapest consist of a steel ball closing on a seat under spring pressure and rely on the pumps suction to draw the ball off the seat and allow the life preserving oil to flow to the pump.  The internet is full of stories about what happens when these valves DON”T open and the spectacular melt-downs that take place between the riders legs shortly afterwards and not far down the road!

    The simplest of all is to install an on/off valve on the hose between the tank and the pump.  This of course relies on the rider/owner remembering to turn it off before lay-over and most importantly, to turn it ON BEFORE RE-STARTING!

    Therein lies the problem. Murphy always intervenes and there are as many internet stories about how he forgot and trashed a first out restored beauty that he had been restoring for the last five years!

    The most expensive valves incorporate some form of fail safe device that does not allow the bike to be started until the valve is opened.  The other option is to go the expensive route and rebuild or renew an oil pump which is still giving a more than adequate oil delivery. It is also not unknown for some rebuilt pumps to still leak oil past.

     

    Always on the look-out for a better and cheaper way I bought a ball type lever valve with hose barb on both ends from Rona for under $10 and a Honeywell model WWG24A302  3 terminal limit switch from Acklands Grainger for $4.63  I drilled two small holes in the brass valve body and tapped them to accept two machine screws. This has to be done like porcupines making love ie; CAREFULLY Not too deep so as not to interfere with the stainless steel ball or the teflon seals. A small bracket was made using 1″ aluminium angle cut to size and drilled accordingly, with slotted holes so that the switch could be positioned so that the heel of the valve lever would actuate the switch arm/roller. With one ground terminal and two other make and break terminals it was possible to wire the limit switch to cut out the ignition switch or ground out a magneto through the stop/grounding button.  Thus the bike will not start until the valve has been opened and that life-preserving golden liquid is flowing to that oil pump and giving a finger to our old friend Murphy!

    DSCN1968

    Valve open- switch arm off contact.

    DSCN1969

    Valve closed – Switch arm depressed contact made.

  • JIS vs Phillips

    JIS – or Japanese Industrial Standard – is a Pacific Rim standard used for “Philips” (cross, star,) type screwdrivers. Most people, professional mechanics included, don’t even know that such a thing exists. But every “Philips” screw on a Japanese vehicle is not a Philips screw at all, but a JIS screw. They can be identified with a small dot on the top of the screw:
    screw

    Philips screwdrivers don’t fit JIS screws, at least not properly. Because they don’t fit all the way into the screw, you tend to mangle the screw when attempting to tighten it, or loosen a tight one. If you have any “Philips” screws on your Japanese bike that are stripped or mangled, this is what has happened. The solution? A set of JIS screwdrivers.

    Some places to get JIS drivers are:

    Vessel tools 
    RJR Tools


  • Chrome Cleaning

    A tip to get those nasty burned-on rubber boot sole marks off of your exhaust chrome. Especially bad on airhead BMW’s.

    Rub with a cloth and “Ceramabrite”; the white paste your wife uses to clean her glass top stove. ( Make sure to take it when she is not looking!  My wife remains eternally suspicious after I washed my motorcycle engine halves in her dish washer!)

    For real stubborn marks grade 00 Superfine steel wool works wonders. ( Also to be found amongst her cleaning things!)


  • Screw removal aid

    I’m sure everyone has been annoyed over having to remove a screw with a damaged /striped head at least one time or another.

    To help remove a damaged screw or prevent damaging a screw head be it phillips, slot, robertson or any other type and besides giving the screwdriver a sharp rap on the end with a hammer which sometimes helps. Try dipping the screwdriver tip in some valve lapping compound. The compound gives the driver grip and prevents the “cam out” action that causes the damage, It has worked for me thousands of times and I have even tried it on hex head bolts and allens as well with success.


  • A Tip for BMW Airhead Owners

    A Tip for BMW Airhead Owners

    Only the more expensive “split” oil filters are now available from BMW, and this as a kit only for about $24 each, excluding shipping.

    The “split” filter is made for machines fitted with oil coolers which seem to be in the minority. (I’ve never seen one, but then I’m no expert!)

    The “straight” filter is obtainable from K&N Filters, Their part #  KN161, for $7.98 each.  My local Napa Auto Parts ordered in for me and shipping for two filters was a further $10. Admittedly this doesn’t include the all-important white “O” Ring. This can be ordered separately from your usual BMW supplier @ $1.97 each. Part # 11 421 337 098    According to the airhead “boffs” this used to be referred to as “the $1000  “O” Ring”, because of the rather spectacular consequences if it didn’t seal properly. Now with the passing of time and inflation it is “the $3000 “O”Ring”!

    Moral of the story.  DO replace the “O” Ring with a new one every time you change the oil and the filter.

    PS  Owners of older British bikes please ignore this advice. Your bike doesn’t even HAVE a filter and anyway, with the way they all leak oil,they don’t need a filter because the oil is always fresh!


  • Amal Concentric MK1

    AMAL Concentric MK1 Carburetor  Re- builds.       By Tom Hesom

    This is intended for those whose interest is in the restoration of British motorcycles fitted with Amal carbs, and directed more to machines built up from basket cases than to runners.  Much has been written about these often maligned instruments by more knowledgeable “wrenchers” than I, so I don’t profess to be an expert, but I have “fiddled” with the confounded things for long enough to have learned a few things, and continue to learn more.

     

    For instance my freshly restored Triumph Bonnie would only run on one side until John T found that one carb had no in-body pilot jet! More recently more trouble with my BSA Lightning only to find that one spray tube was missing from one carb. The spray tube is the brass tube visible through the bore and like the in-body pilot jet is not normally removed as it is a friction fit and has to be tapped into place.

     

    Most troubles by far however are caused by wear between the carb body and the slide.  Because Amals were built to a price dictated by the  always-cash-strapped British motorcycle industry, they used the same soft alloy material for both body and slide which they knew as well as anybody was conducive to fast wear. This wear causes all sorts of problems but mainly the inability to get the machine to idle because of excess air being drawn past the slide.

     

    Only solution is to buy new carburetors,  but if  it is a twin carb bike this can be expensive.  New Amal MK1 carbs are available from Walridge Motors, Lucan, Ontario  @ $200 each plus shipping and handling. If you have a Monobloc or an even earlier Amal, they are also available at about double this price.  email; sales@walridge.com       Web www.walridge.com

     

    In my view a better option is to have your old carbs re-sleeved.  The bore is honed out to true and the slide is sleeved with brass.  This then obviates the same- metal problem and you have a BETTER than new instrument! (With the proviso of course that you also re-new any worn jets or needles at the same time)  I sent my carb bodies and slides to Bruce Chessell in Ontario by ordinary Canada Post. Bruce did a magnificent job in under a week and returned them promptly without asking for advance payment!  Said he would email me the price and return postage and I could send my cheque!  Rare trust these days!

    Cost  $75-00 per carb = $150-00 plus postage $14-50 each way = $29-00    Total $179-00

    Plus two Carb Kits (gasket sets)  # CGS900     @  $3-00 ea                 6-00

    Plus two Tickler Conversion Kits  (no more gas on finger!)  @  $6-65 ea                13-30

    Postage and Insurance                                                             7-70

    Overall cost                  $206-00                             Bruce Chessell’s address;  314 Knightsbridge Rd,

    Woodstock, ON

    N4S 7C4                  Email; bchessell@odyssey.on.ca

     

    PS   This price was even further reduced.  The Right-hand carb body had other problems besides wear in the bore and slide and could not be used for re-sleeving.  I put an ad in our newsletter and before it even came out Dave Pritchard said “How many do you want!?!”   and for no charge!   Thanks Dave!  One of the many advantages of belonging to a super motorcycle club!

     

    Another Tip for Twin Amal Carbs

     

    If you have difficulty getting the slides to rise simultaneously by a feeling finger in each carb intake and have no-one to operate the twist-grip,

    – – Here is the answer;- – –

    Put two 1/8″ drill bits shank first into the carb mouths just under the slide cut-aways. (with air filters off of course.) Two thirds of the bits should stick out and hang down slightly. Adjust the cable adjusters until both bits drop simultaneously when you crack the throttle.

    This way you can get both slides to rise evenly on your own.  Then proceed in the usual way with both air filters back on, to set one carb idle  at a time by removing one plug on fast idle and adjusting on the opposite side until they run smoothly, then reduce the revs to a nice idle with both plugs in and both sides firing.