'73 DAYTONA T100R

[Rudie]

BIKE DOESN'T LIKE HOT STARTS. IT TAKES 5 TO 10 KICKS TO GET IT GOING AND IDLE IS DIFFICULT.

Because it is hot, it could literally be anything - a hot electrical component that is heading towards failure when hot, carburation, wear in the carbs.

Substitution testing might be the way forward but I strongly advise against early substitution of new carbs for old - very expensive if it is not the solution - the fault could be in any of many cheaper components.

If the engine is hot when you try to start it, be aware failing to start could be because the mixture is too rich - carbs heated by the hot engine while the bike is parked will cause more fuel to vaporise in them, this is exactly the same as tickling the carbs when the engine is cold; however, a hot engine does not require an extra rich mixture and might fail to ignite it.

Are the carbs fitted with air slides, aka "chokes"? If they are, I assume you are not deploying them when attempting any sort of hot start?

When starting - hot or cold - is the throttle closed or a little open? If you normally hold it a little open for a cold start, experiment with holding it open more for a hot start - if the current problem is an over-rich mixture because the carbs are hot, holding the throttle open more will admit more air and weaken the mixture.

I hope you do not open the throttle more as you kick? Useless with Amals.

If opening the throttle more before kicking does not reduce the number of kicks required to start when hot, try tickling the carbs before attempting a hot start? This might sound counter-productive but the new fuel into the carbs will cool them for a short period, then holding the throttle open more to draw in more air can produce a mixture the plugs can ignite.

Ime, if the engine has not started within five kicks, the mixture is either too rich or too weak. I clear whatever remains by holding the throttle wide open for a few kicks. Then I close the throttle, tickle the carbs, open the throttle as if for a cold start and kick again.

If none of the above reduces the number of kicks required hot, I would start substitution testing with a new pair of spark plugs; however, unless the bike has thin-electrode plugs already, they are what I use - NGK B7EV, B7EVX or, if they are all you can get, B7EIX. Iirc your bike does not have electronic ignition? If not and it also does not have an electronic regulator/rectifier (instead of separate rectifier and Zener diode), try to avoid plugs with built-in resistors - BR...

adjusting the air jet

Amals do not have an air jet. The air screw (horizontal on the engine side of the body) varies the amount of air admitted from the filter through the channel in the underside of the body because the pilot jet is a fixed orifice.

bigger pilot jet

It is almost impossible to replace the pressed in pilot jet in a standard Amal Mk.1 Concentric.

In theory, it is possible to enlarge the orifice of the pressed in jet; however, in practice, as standard is 0.016" (16 thou) and the next size up is 0.018", the chances of enlarging it accurately are between remote and non existent. And, having enlarged it, if the original problem is not cured, it is impossible to reduce the size of the orifice again.

 

[Cosmic Sled]

Because it is hot, it could literally be anything - a hot electrical component that is heading towards failure when hot, carburation, wear in the carbs.

Substitution testing might be the way forward but I strongly advise against early substitution of new carbs for old - very expensive if it is not the solution - the fault could be in any of many cheaper components.

If the engine is hot when you try to start it, be aware failing to start could be because the mixture is too rich - carbs heated by the hot engine while the bike is parked will cause more fuel to vaporise in them, this is exactly the same as tickling the carbs when the engine is cold; however, a hot engine does not require an extra rich mixture and might fail to ignite it.

Are the carbs fitted with air slides, aka "chokes"? If they are, I assume you are not deploying them when attempting any sort of hot start?

When starting - hot or cold - is the throttle closed or a little open? If you normally hold it a little open for a cold start, experiment with holding it open more for a hot start - if the current problem is an over-rich mixture because the carbs are hot, holding the throttle open more will admit more air and weaken the mixture.

I hope you do not open the throttle more as you kick? Useless with Amals.

If opening the throttle more before kicking does not reduce the number of kicks required to start when hot, try tickling the carbs before attempting a hot start? This might sound counter-productive but the new fuel into the carbs will cool them for a short period, then holding the throttle open more to draw in more air can produce a mixture the plugs can ignite.

Ime, if the engine has not started within five kicks, the mixture is either too rich or too weak. I clear whatever remains by holding the throttle wide open for a few kicks. Then I close the throttle, tickle the carbs, open the throttle as if for a cold start and kick again.

If none of the above reduces the number of kicks required hot, I would start substitution testing with a new pair of spark plugs; however, unless the bike has thin-electrode plugs already, they are what I use - NGK B7EV, B7EVX or, if they are all you can get, B7EIX. Iirc your bike does not have electronic ignition? If not and it also does not have an electronic regulator/rectifier (instead of separate rectifier and Zener diode), try to avoid plugs with built-in resistors - BR...


Amals do not have an air jet. The air screw (horizontal on the engine side of the body) varies the amount of air admitted from the filter through the channel in the underside of the body because the pilot jet is a fixed orifice.


It is almost impossible to replace the pressed in pilot jet in a standard Amal Mk.1 Concentric.

In theory, it is possible to enlarge the orifice of the pressed in jet; however, in practice, as standard is 0.016" (16 thou) and the next size up is 0.018", the chances of enlarging it accurately are between remote and non existent. And, having enlarged it, if the original problem is not cured, it is impossible to reduce the size of the orifice again.

On the prem carb you can replace the pilot jet

 

[SIR LOIN]

THE CARBS ARE NEW AMAL 626 WHICH WERE PUT ON THE BIKE IN 2018 AND HAVE LESS THAN 300 MILES ON THEM. THEY DO NOT HAVE A CHOKE AND I NEVER START THE BIKE HOT WITH THE THROTTLE OPEN NOR DO I TICKLE THE CARBS. MY PLUGS ARE NEW NGK B8ES AND I'M RUNNING POINTS NOT ELECTRONIC.

 

[SIR LOIN]

If you have not changed the fork oil since you bought the bike, you do not know either the quantity or the viscosity of what is in there, either of which can affect fork action.

71 onwards, the T100 was the only Triumph to retain the old style forks that, before 71, had been fitted to all bikes. Triumph recommended 20-weight oil in the old style forks, ATF in the new style forks. ATF is only around 7.5-weight; not very clever and not very careful people (mechanics as well as owners) put ATF in old style forks, owners wondered why their T100 dived so much under braking ...

Proper fork oil has been around for years. Ime and mho, I would first locate some 20-weight proper fork oil, then empty all the old oil out of the forks, remove the sliders and dampers, degrease them and remove any sediment and/or sludge in the bottoms of the sliders, reassemble and fill with the recommended quantity of the new fork oil.

Then go for a test ride; knowing the oil in the forks is both the correct quantity and the correct viscosity you can evaluate the front suspension accurately, whether you need to make changes.

"correct viscosity" - If you do need to make changes to fork oil viscosity, know not every fork oil maker is as good as every other at matching the true viscosity of the oil in a container to the viscosity printed on the container ... Fork oil weights

So, if you need to change viscosity, try to avoid changing makes at the same time. Also know 20-weight fork oil is thick by modern standard so there are few makers and, if you want a viscosity that no one makes, you might have to mix proportions of lower and higher viscosities - e.g. if you wanted 25-weight, you might have to mix equal quantities of 20-weight and 30-weight.

Nevertheless, intermixability is one of the advantages of "proper fork oil"; also, having cleaned the fork internals once for the first fill of proper fork oil, if you do want to change to a different viscosity, you need only empty out the old and refill with the new.

I'VE HEARD THAT FOLKS USE HYDRAULIC OIL TO MATCH A 30 WEIGHT FORK OIL. IS THIS TRUE?

 

[Rudie]

I NEVER START THE BIKE HOT WITH THE THROTTLE OPEN

One reason you are having trouble starting it hot.

MY PLUGS ARE NEW NGK B8ES

They are not "new", you have started the engine and ridden the bike. Amal Concentrics are quite crude compared to most carbs. When the original carburation was tested, what passes for 'fuel' in the 21st century, particularly in California, had not been invented. I strongly advise trying the more sophisticated spark plugs I suggested, ime they are less likely to foul than B8ES.

POINTS

Another reason for difficult starting, points do not stay in tune for very long.

But you definitely need to experiment with the throttle opening when starting hot.

 

[SIR LOIN]

WELL I'M TO SAY THAT THANKS TO THIS FORUM AND A BIG THANKS TO RUDIE, ME AND MY BIKE HAVE LOGGED A BIT OF MILES IN THE MOUNTAINS AND BEACHES OF SOCAL. I STILL HAVE SOME MINOR WORK LEFT TO DO ON THE BIKE BUT JUST LAST WEEK AT OUR LOCAL WATERING HOLE IN MALIBU I WAS OFFERED NEARLY TWICE WHAT I PAID FOR THE BIKE. NEEDLESS TO SAY, I TURNED IT DOWN.

I HAVE NOTICED ONE ANNOYING ISSUE. RECENTLY, WHILE STARTING THE BIKE, I'VE NOTICED THAT THE KICKSTART SPRINGS BACK UP AND THIS LAST TIME IT HURT MY ANKLE PRETTY BAD. I WAS LIMPING FOR 2 WEEKS AND IT PUT THE DAMPER ON MY RUGBY GAMES.

I'VE READ THAT THIS COULD BE DUE TO THE TIMING BEING OVER ADVANCED. IS THIS TRUE? I THOUGHT I WOULD CHECK WITH THE FORUM BEFORE RE-TIMING THE BIKE.

 

[Rudie]

TO SAY
ME AND MY BIKE HAVE LOGGED A BIT OF MILES IN THE MOUNTAINS AND BEACHES OF SOCAL.

ONE ANNOYING ISSUE. RECENTLY, WHILE STARTING THE BIKE, I'VE NOTICED THAT THE KICKSTART SPRINGS BACK UP AND THIS LAST TIME IT HURT MY ANKLE PRETTY BAD. I WAS LIMPING FOR 2 WEEKS
COULD BE DUE TO THE TIMING BEING OVER ADVANCED.

Depends what you mean: "kickstart springs back up" and 'kicking back' because of over advanced timing are two different things:-

. "kickstart springs back up", it is supposed to when you release it. If you are allowing your foot to simply slip off the kickstarter at the bottom of its stroke, the end of the lever will whack your foot, ankle or leg. The remedy here is to keep your foot on the lever while letting it back up.

. Otoh, 'kicking back' is when the engine fires while your leg is still pushing down on the kickstart lever but, because the spark timing is too advanced for the slow engine rotation, the piston of the firing cylinder has not passed TDC (Top Dead Centre) so the explosion tries to turn the engine backwards, causing a jolt into the kickstart and then into your foot, ankle, leg.

If the latter, first use a strobe timing lamp to ascertain whether the timing is over advanced throughout the range - can simply be adjusted - or the auto-advance unit is sticking - the timing's correct at full advance rpm but is over advanced only at low rpm/starting, the a.a.u. must be dismantled to clean, lubricate and possibly install new springs.

 

[SIR LOIN]

I STROBED THE BIKE AND THE TIMING IS 2MM OFF THE 38 DEGREE MARK (BETWEEN TDC AND THE 38 DEGREE MARK) AT 2000 RPM AND ABOVE. THE BIKE RUNS GREAT SO I LEFT IT ALONE.

I DISMANTLED THE AUTO ADVANCE UNIT AND GREASED IT LAST MONTH SO I DON'T THINK IT'S THAT.

SHALL I RE-TIME IT AND GET IT RIGHT ON THE 38 DEGREE MARK?

 

[Rudie]

AUTO ADVANCE UNIT
GREASED IT

That is not the advice in the Triumph workshop manual - Section A10 ("CONTACT BREAKER LUBRICATION"):-

. Page A12 (pdf page 56):-

To lubricate the auto advance ...
... the mechanism should be slightly oiled (see arrows shown in Fig. A8) at the same interval that is given above for the cam wick.

. Page A11 (pdf page 55):-

The cam is lubricated ... with a few drops of oil ... every 5,000 miles

. The oil suggested is SAE 20 or 30 but that could be difficult to obtain - SAE 20 is similar viscosity to warm (not hot) 20W50 engine oil but, unlike multigrade engine oil, will become thinner as the engine heats up.

. The reason grease could affect a.a.u. operation is it is sticky; the springs that return the advance weights are light anyway; if you did not replace them, you do not know how old they are, springs lose their temper with both heat and age so old springs could have even greater difficulty controlling the a.a.u. weights, without also working against sticky grease.

I STROBED THE BIKE AND THE TIMING IS 2MM OFF THE 38 DEGREE MARK (BETWEEN TDC AND THE 38 DEGREE MARK) AT 2000 RPM AND ABOVE. THE BIKE RUNS GREAT SO I LEFT IT ALONE.
SHALL I RE-TIME IT AND GET IT RIGHT ON THE 38 DEGREE MARK?

Aiui, 21st century California fuel is poor compared to the fuel Triumph tuned with in 1973. If you do not have any experience of different timing, without trying it you do not know if the bike will run 'better' with the timing set correctly or not.

 

[SIR LOIN]

I WILL RELUBE THE AAU WITH SAE 20. THAT OIL IS AS COMMON HERE AS BUMS IN TENTS.

I HAVE NO IDEA WHAT YOU MEANT THOUGH REGARDING TIMING. I DON'T HAVE 1973 ENGLISH GAS SO I WILL NEVER KNOW WHAT TIMING IS?

 

[Rudie]

NO IDEA WHAT YOU MEANT THOUGH REGARDING TIMING. I DON'T HAVE 1973 ENGLISH GAS SO I WILL NEVER KNOW WHAT TIMING IS?

73 T100 might have been sold as it came from England or, if sold new in CA, it might have had altered carb specs and/or timing to suit 73 heat and gas.

What I am saying is you have to experiment a little to find the best it runs on 21st century CA gas. Timing slightly retarded might be "best", or set correctly might be "best".

 

[SIR LOIN]

I TOOK THE BIKE OUT FOR A QUICK RIDE AND WHEN I GOT HOME I NOTICED THE REAR RIGHT SIDE ROCKER CAP HAD MELTED MY CLUTCH CABLE HOUSING. I CHECKED THE TEMP OF THE ROCKER BOX AND IT WAS 209 DEGREES (191 CELSIUS).

IS THAT A NORMAL RANGE AND IF NOT WHAT COULD BE THE ISSUE?

 

[Rudie]

REAR RIGHT SIDE ROCKER CAP HAD MELTED MY CLUTCH CABLE HOUSING.

The covering of any control cable outer is plastic and all parts of an air cooled engine become very hot when it is used.

 

[SIR LOIN]

TWO WEEKS AGO I HAD A CHANCE TO GO OUT FOR AN 80 MILE RIDE IN OUR LOCAL MOUNTAINS WITH OUR RIDING CLUB. TOWARDS THE END OF THE RIDE MY OIL LIGHT BEGAN TO FLICKER AT IDLE. THIS HAS NEVER HAPPENED. I'M RUNNING VALVOLINE VR1 RACE OIL 20-50W.

A FELLOW NORTON RIDER TOLD ME I WOULD BE BETTER OFF RUNNING A STRAIGHT 40W OIL. APPARENTLY THE OIL GETS VERY HOT AND OIL PRESSURE DROPS HENCE CAUSING THE OIL LIGHT ISSUE.

I WAS ALSO TOLD THAT VR1 OIL IS NOT FOR A WET CLUTCH SYSTEM SINCE IT HAS ANTI FRICTION PROPERTIES.

DOES ANYBODY HAVE ANY INT INTO THIS MATTER?

 

[Serge1952]

Check the oil pump for dirt in the balls

 

[Rudie]

80 MILE RIDE IN OUR LOCAL MOUNTAINS
TOWARDS THE END OF THE RIDE MY OIL LIGHT BEGAN TO FLICKER AT IDLE. THIS HAS NEVER HAPPENED.

Particularly as it was towards the end of 80 miles, I suspect it was probably a combination of heat and the engine working hard climbing hills, especially if the were bigger cc bikes on the ride. How high were these mountains? Have you seen the light after less arduous rides since?

However, the only way to be sure a more serious problem is or is not developing is to connect an oil pressure gauge. I have oil pressure gauges permanently mounted on all my Triumphs.

I'M RUNNING VALVOLINE VR1 RACE OIL 20-50W.
TOLD THAT VR1 OIL IS NOT FOR A WET CLUTCH SYSTEM SINCE IT HAS ANTI FRICTION PROPERTIES.

The way to tell for certain is to look at the can for the list of specifications the oil meets, specifically for "JASO MA2"; this specification specifically excludes the additives that can promote clutch slip.

A FELLOW NORTON RIDER TOLD ME I WOULD BE BETTER OFF RUNNING A STRAIGHT 40W OIL.

Norton engine oiling systems are not Triumph twin engine oiling systems. Even when Triumph recommended monograde engine oil, 30W was the highest recommended even in ambient temperatures higher than 90 degrees Fahrenheit. However, when they recommended multigrade, it was always 20W50 in all ambients higher than 32 degrees Fahrenheit.

If you want to know when oil pressure is a problem, fit a gauge.

If you do not know several other owners of late sixties/early seventies Triumph twins who have all used other than 20W50 for some time without problems ...?

However, one other possibility is a good-quality 20W60?

Check the oil pump for dirt in the balls

One reason for the bike to be fitted with a proper oil filter - I use OIL FILTER KIT ( PRE-OIL MODELS) | Tricor Andy - fits in the space in front of the battery, clamped to the vertical frame tube behind the engine.

Other reasons are: it adds a little extra oil capacity, it has a large cooling area.

MAP Universal Oil Filter Kit - Black in the US.

 

[SIR LOIN]

THE MOUNTAINS GO FROM 2K FT. TO 5K FT. I KEPT THE BIKE IN 3RD AND RPM'S BETWEEN 5K AND 6K. THE LIGHT HAS NEVER COME ON BEFORE. I STOPPED AND CHECKED THE OIL TANK AND IT WAS CIRCULATING NICELY. THE LIGHT NEVER CAME BACK ON AFTER WE STOPPED FOR LUNCH. THAT'S WHY I CHALKED IT UP TO A HEAT AND NOT PRESSURE ISSUE.

WHAT BRAND OF OIL GAUGE DO YOU RECOMMEND RUDIE?

IF SINGLE GRADE 30W WAS RECOMMENDED WOULD CAR OIL BE THE SAME OR DID THEY MAKE BIKE OIL IN '73? A WELL RESPECTED TRIUMPH ENGINE BUILDER HERE IN LA (FAGENGINE.COM) RECOMMENDS PENNGRADE 1 SINGLE GRADE OIL.

I WILL ALSO PURCHASE THE OIL FILTER KIT YOU RECOMMENDED. I LOVE RIDING THIS BIKE AND I MAINLY FLOG IT IN THE MOUNTAINS SO I DON'T WANT TO DAMAGE THE MOTOR.

 

[Rudie]

CHECKED THE OIL TANK AND IT WAS CIRCULATING NICELY.

That actually does not mean much. If the crankshaft seal in the timing cover inverts or splits, all the pumped oil runs straight to the bottom of the crankcase, from where it is scavenged back to the tank as normal ... however, the oil is not being pumped to the big end bearings, one or both of which will sustain major damage, before seizing ...

Obviously this has not happened, just be aware seeing oil returning to the tank confirms very little apart from the oil pump is working ...

IF SINGLE GRADE 30W WAS RECOMMENDED WOULD CAR OIL BE THE SAME OR DID THEY MAKE BIKE OIL IN '73?

In 1973, Triumph recommended 20W50. However, it is irrelevant, a good quality modern "4T" or "Vee Twin" oil is likely to have a superior additive package to anything in 1973; ime monograde oil development has not been the same as multigrade development simply because the market is much smaller.

A WELL RESPECTED TRIUMPH ENGINE BUILDER HERE IN LA (FAGENGINE.COM) RECOMMENDS PENNGRADE 1 SINGLE GRADE OIL.

I know of F.A.G. They are in California too, I would not argue against their recommendation.

BRAND OF OIL GAUGE DO YOU RECOMMEND

No one particular brand, it depends on the bike; e.g. best for T160 or 79 on twin is the L.P. Williams kit, because founder Les developed the complete kit for T160 based bikes he built, 79 on twins use the same speedometer/tachometer mounting.

When fitting a gauge to any Triumph twin, the only possible connection to the engine is the oil pressure switch port in the front of the timing cover. On your bike, the thread should be 1/8"NPS - National Pipe Straight - but never assume without confirming, there are some early timing covers with 1/8"NPT - National Pipe Tapered - thread.

NPS/NPT is a vexed problem - there are very few NPS fittings and, of the gauge kit suppliers I have suggested below, Triples Rule could well supply a 1/8"NPT connection to the engine. Such a fitting must be fitted in the timing cover very carefully, because the timing cover port wall is thin and the fitting is tapered, it is very easy to split the port wall. PTFE plumbers' tape might well be necessary for an oil-tight seal between fitting and timing cover without applying much force to the fitting.

If your bike has the standard T100 speedometer, tachometer and mounting, your gauge choice is probably between:-

. One of the Triples Rule "Solo Mount" gauges - be aware standard 73 T100 speedometer and tachometer mounting counts as "1970 & earlier Triumph";

. Morgo - Morgo offer more options (e.g. the "Multi Point Pressure Adaptor Kit") if you want to keep the oil pressure warning switch and light.

I LOVE RIDING THIS BIKE

 

[SIR LOIN]

A FELLOW TRIUMPH OWNER TOLD ME THAT I SHOULD ALWAYS START MY BIKE EVERY WEEK AND LET IT IDLE FOR A FEW MINUTES TOOK KEEP THE OIL CIRCULATING. MY BIKE SITS FOR A FEW WEEKS SINCE I HAVE 2 OTHER BIKES I RIDE.

WILL LETTING THE DAYTONA SIT FOR 2 TO 3 WEEKS CAUSE ISSUES WITH THE OIL PUMP?

 

[SIR LOIN]

THANKS FOR ALL THAT HELPFUL INFO RUDIE. I WILL LOOK INTO GETTING AN OIL GAUGE.