No replies to this topic

[LITEW8CUB]

These are some tips collected and tried during many decades of fooling with bikes, particularly Cubs. I wish to write them down while I still can, and pass them on to newbies, so they don't have to reinvent the wheel multiple times without end, and perhaps to recall some of them for us oldies.


Litew8cub's 29 Tips.


1) To properly get a good solid purchase and avoid slipping and damaging very thin nuts as found on top of fork tubes, steering stems, clutch hubs, gearbox output sprockets, etc, I have found it very helpful to grind away the ends of my sockets, removing nearly all of the radius leading to the nut cavity, so more of the socket and nut flats are in good contact.

2) BSA and Triumph factory brochures always show the kickstart cotter key nut installed towards the front of the bike. A careful analysis reveals that the heaviest kickstart load is thereby borne by the narrowest part of the cotter key flat! BAD! If the cotter is inserted from the front of the bike, with the nut at the rear of the kickstart lever, the heavy load will be applied to the wide end of the flat, thereby vastly reducing the loading, the stresses, and potential problems with loose levers. The available kickstart lever range of motion will be slightly reduced because the pedal is now rotated slightly farther back, and you must carefully check that the relocated nut does not gouge the engine side cover.

More musings---I may remember from years ago that bicycle crank cotter pins were soft and useless for us--Proper motorcycle ones were harder, and could be identified by a circumferential groove just below the non-threaded end.

Also, it is easy to make a much more durable replacement by hand- merely use a better grade 3/8 dia bolt (allen bolts are ideal-good steel, tough, properly heat treated, and may have a slight case hardening), file or grind an angled flat with the wide part of the flat right into the bolt threads- even with a portion of the thread diameter filed away, this is still a LOT stronger than the puny 1/4-26 threads of the "proper" item- now just trim the bolt to length at both ends,and you are probably done. If the nut gouges the side cover surface, just take a smaller 5/16 nut, drill & tap it to 3/8.

Always try to support the kickstart lever boss when installing or removing the cotter, and use a drift to transfer the blows to the end of the cotter and keep the hammer away from the cases. I find things tighten up really nice if you keep tightening the nut while gently tapping. You only need 3 hands and a knee on the k/start lever.

Some of my old Cub k/start assemblies are worn so that the full diameter of a 3/8 bolt just goes right through- it takes surprisingly little wear!- a shim made from a piece of hacksaw blade to fit between the flats of the cotter and the k/start spindle has served me for decades.

3) Since the previous owner did not keep the pinch bolts for your bike's finely splined gearshift, brake, or Bantam kickstart levers tight, they are now permanently floppy, even when you hack the slot wider on the non-threaded side, and use a high-tensile bolt to replace the one that broke in a desperate mending attempt. The problem is that the splines on each side of the pinch slot resist the bolt tightening forces. The cure is to file away 3 or 4 of the splines on each side of the slot, allowing proper tightening. Unfortunately the thin kickstart sleeves for the Bantam and Can-Am are crushed by now, and shift the engine into gear when you kick it!

4) I have found there are 2 types of tyre valve stem cores- long and short--I have only recently come across my first long one which was bad, but I have garbaged dozens of leaky short ones, usually very slow leaks!

5) A hypodermic needle filled with heavy engine or gearbox oil is perfect for oiling control cables (the thin needle will go right in between the inner cable and outer sheath) and it is very easy to place a minute spot of lube right where it is needed, even in very tight inaccessible places, such as control lever pivots and pull cable barrel ends. I also use them to supply a bit of fuel into the sparkplug hole or carb to start a reluctant engine-much safer than dribbling fuel from a large container! I have found that the ones using an "O" ring seal on the end of the plunger tend not to dribble or be affected by oil or fuel, whereas the ones with a rubber cap on the plunger end are problematic.

6) Years ago, even the cheapest Japanese bicycles brake levers had a little pin-hinged stirrup into which the brake cable end fitted, avoiding all bending and eventual breakage of the cable end. I use them on some of our bikes. When I repaired my own cables, I used to heat the end strands red-hot to try and burn off the oily gunge and make the strand ends easy to spread out and solder. Bad idea! The ends then break off easily because the inner strand have been burned. The best idea I have come across is to insert a small shoe tack into the cable end after the strands have been frayed out inside the end fitting counterbore, apply lots of zinc chloride paste flux (corrosive!) to the heated cable end, then solder.

7) A quick PERMANENT emergency repair insert for a stripped 5/16 or 8 mm threaded hole can be made from the threaded end of a 10 mm spark plug. Use a 9 mm or "T" drill to clean out the ruined threads in the hole, tap the hole 10×1 mm, and drill the i.d. of the sparkplug shell thread to 17/64" and tap it 8×1.25 mm or 5/16×22 (BSF) or 24 (UNF) or whatever, before cutting your new insert loose from the rest of the spark plug shell. Carefully lock the new insert in place with a thread locking compound so it does not wind its way out of the hole next time the bolt is removed and cause more problems; clean (cotton swab) all compound out of the insert i.d., and apply grease to the bolt so it does not get locked to the insert i.d.

8) A thread pitch measuring gauge from Walridge Motors or Princess Auto is a wonderful thing to have; however, the cheap gauge that came with your tap set, and which does not cover Brit 26 tpi cycle nor 22 tpi threads are still useful- use the 13 gauge to check 26, and the 11 or 44 to check 22 tpi--just use an available gauge which is a simple fraction or multiple of the desired thread.

9) Since we refuse to use girly-man torque wrenches, (even if we could find the "Factory" torque specs), very carefully checking the pitch of every thread on a bolt will soon reveal that the previous "mechanic?", STRONG LIKE BULL, has severely overtorqued the post-1960 Triumph Tiger Cub centre-split crankcase 5/16" mild cheese bolts holding the halves together, necking and stretching the threads from the standard 22 to 19 threads per inch!!! This does not do the tapped threads any good, so it is best to return each bolt to its original hole, if there is any thread left in it. The crankcase halves locating dowel in the bolt hole just below and behind the cylinder base results in a short thread in the right crankcase half, very easily stripped! That common condition requires the use of hint #7 above. The 10x1mm tap does leave slight witness marks inside the dowel hole, but does not impair its function. Some people, I suppose, would just drill the hole out to the other side and use a longer junkbox bolt and nut. Other Triumph and BSA engines use bolts of the same size, so similar problems may be expected!

10) That same "Mechanic" will have overtightened a lot of the fasteners, pulling the aluminum around the hole up above the surrounding flat surfaces. Carefully shaving the raised area down with a larger twist drill turned with your fingers will solve that.

11) ALWAYS use anti-seize compound on anything threaded into aluminium! It will lubricate the threads for good bolt clamp-up, and prevent thread seizure and stripping in the future; especially important for sparking plugs!

12) A friend has pointed out to me that Dollar store reading glasses can be stacked up in front of each other to give lots of magnification to older eyes.

13) A 10-32 bolt (.190" dia. X 32 tpi) will fit (tightly) into a 2 B.A. nut (.185" dia X 31.4 tpi), but a deep 2 B.A. threaded hole will cause binding and thread damage, even though readily available 10-32 Allan bolts are so tempting!

14) To slightly reduce unsprung weight of variable-rate suspension springs for racing, place the heavier closer-wound spring coils at the sprung end of the suspension; most of the ones I have seen are wrong!

15) Use a #6-40 tpi tap and die to clean up the nipple and spoke threads of Honda TL 125 and Yam TY 175, etc. spokes. DO NOT CUT MORE SPOKE THREADS WITH A DIE—spoke threads MUST BE ROLLED!

16) Mud and sand buildup between sprockets and chain rollers, which can cause extremely tight chains, breakage and bearing damage, can be prevented by slightly chamfering the sprocket teeth valleys with a file (aluminium sprocket) or grinder for steel and hardened gearbox sprockets. (I use a cutoff wheel worn to a size to fit my bench grinder, which is also extremely useful for general ferrous metal sculpting, shaping, slotting, etc.) Chamfer about one third of the sprocket thickness, from both sides if possible, leaving a land of about one third of the sprocket thickness between the teeth. The chain pull load is exerted on the flanks of the teeth, not the bottoms! So do not damage tooth flanks, and do not chamfer the tooth valleys to excess, to avoid weakening the teeth!

17) SEAL-ALL ™ from CTC will plug fuel tank leaks! Push an ice pick or scriber point through a corroded steel tank pinhole to give a stronger hole edge, more surface contact, and a larger hole which is easier to fill up. I have used the scummy deposit in the handsoap dish to immediately plug a running fuel leak in an emergency, but not recently with modern fuels, but it may still work.

18) Always use a small Fram #G1000($2) paper element fuel filter with old steel fuel tanks. They stop tiny rust particles, which the screen types do not.

19) Always cut the tail end where it enters the head when removing a plastic tie-wrap, so it can be re-used when you need a shorter one.

20) I knew it was bad form to check plug sparking by laying it on the engine and kicking lustily- it tends to fall off, spelling death for electronic ignitions, as emphasized by a speaker at our Paris (Ontario) Rally Seminar, because very high damaging voltages build up when the sparkplug shell is not properly grounded. My cure is to bolt 2 metal spring clamps (such as small battery clamps) together, one to hold the sparkplug shell, and the other to be clipped to a cooling fin, grounded metal frame or bolt head. Home Hardware 4”, #870491, 4 pcs/$1.99; and 2”, #869024, 6 pcs/$1.19, seem to be suitable. This works really well to check the function of a magneto being turned by hand, by either holding a good sparkplug in position, or the end of the high-tension wire close to the magneto frame! Remove the clamp’s plastisol insulation where required, and perhaps do some creative re-bending for best results.


21) NEVER use an impact driver to tighten Brit screws. The anti-sieze previously recommended will allow you to hand-tighten them properly, after cleaning out the 50-year accumulation of old gasket goo from the bottom of threaded holes. An impact driver is indispensable to remove seized-in-place screws with messed-up heads, and of course you would never reuse those, would you?

22) What look like Phillips screws may actually be Posidrive used after about the mid-sixties- look for a small radial line between each of the normal 4 existing slots. It was one of the many attempts to improve on the Phillips- the slots have more parallel flanks to reduce driver cam-out, and needs the proper Posidrive screwdriver for best effect.

23) Have your dentist save his old broken picks for you. They are indispensable for many jobs, especially to remove and instal O rings. New ones can be bought at surplus, Pricess auto, and Lee Valley. The broken ones can be sharpened to make good scribers.

24) Old dental burrs are extremely handy for metal shaping, when chucked in a high-speed rotary tool. The old-style 3/32 inch shaft types as used in the old handpieces are the most usefull, but difficult to obtain. Maybe we have a dentist CVMG member who could order some for us? (Do not examine the “cutting” teeth closely with a strong magnifying glass- they look more like sharp-edged triangular shapes than classic raked cutting edges as found on drill bits and milling cutters- no wonder they vibrate at high frequency, bounce around and create a lot of heat and pain in the mouth).

25) DO NOT EVER use a tyre valve-stem-to-wheelrim locking nut! Better to let the valve stem float in the rim hole, so it can tilt if the tyre creeps on the rim due to dangerously low pressure, hopefully warning the observant rider of a problem. A locknutted valve stem will rip out of the tube, giving an instant dangerous flat! In aluminium rims used for low tyre-pressure dirt riding, I always elongate the round valve stem hole with a file to a 5/8 inch long slot to give the valve stem even more room to indicate creep, because sometimes even 2 rimlocks won’t keep the tyre in place at 3 psi trials pressure.

26) Years ago a Vincent rider warned me against using an undersize tube- he claimed it ripped open and the high-speed blowout could have been fatal. I have since seen a magazine article with the same warning against the use of both undersize and oversize tubes- the latter leads to the tube being pinched during installation, or folding, creasing and chafing inside the tire, all resulting in problems!

27) Fine steel wool dipped in engine oil does a good job of rubbing out surface rust on chrome- a careful look reveals that the surface rust spreads from a tiny pinhole through the chrome, and the rubbed-in oil will help to retard its reappearance.

28) On Triumph Tiger Cub engines, DO NOT FORGET the thick flat washers under the head hold-down nuts, or the aluminium inside the top of the hole will be smeared into the stud threads, effectively locking the head to the stud. Subsequent attempts to remove the head will cause people to use screwdrivers and break fins! Witness the many I have, ALL from previous owners! Absent the proper washers, I make my own from 5/16 lockwashers by holding them in a vise and twisting them flat with the aid of pliers, and reducing the outside diameter slightly by allowing the washer to spin between my index fingertips against a rotating emery wheel. Do not forget to use a 21/64 inch diameter drill to clean out the stud holes in the head!

29) I have always thought it an abomination to lock a stud into a casting by jamming it into the incomplete tapered threads in the bottom of the hole- VERY HIGH stresses are created, which our old castings may be loath to resist! Much better to use a medium-strength thread-locking compound in a cleaned threaded hole- a little heat will help to eventually remove it when required in the future.


Best regards from Litew8cub.