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splash Offline OP
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Brand new points there Allen G. 🤷🏻‍♂️


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Brand new points but who made them? The cost of all parts for these things keeps going up while the quality keeps going down.


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Originally Posted by splash
Brand new points there Allen G. 🤷🏻‍♂️

As Desco said...

Originally Posted by desco
Brand new points but who made them? The cost of all parts for these things keeps going up while the quality keeps going down.

Brand new or otherwise, the points still need to have good closure on the contact faces. If you don’t create that good contact the points may spark until that contact face is eroded away enough to give a better contact, even then you’ll need to sand the surface clean to remove any pitting. The other thing is you’ll be for ever adjusting them and very frequently until this is done. I had a set of points on a D14 at one point, only part of the heel was on the cam, I was adjusting these weekly as the heel wore (with such a weedy engine you soon found when performance was falling off from timing adjusting) eventually the heel wore square, by that time I’d wore the threads out for the screw that you had to slacken for adjusting the points and had to tap the thread to a size bigger. All fun and games.

Unless your prepared to accept that “Lucas repop” points are made of pretty poor quality compared to anything else on the market for jap bikes etc and put that time in to adjust them, you’ll be better spending a few quid and getting electronic ignition, at least then you’ll enjoy riding the bike and not be getting wound up with it.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

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splash Offline OP
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This is a pure frustrating mess.
3 adjustments and trying to align all up is like trying to create a solar eclipses. Adjusting one forces to adjust all others then back to adjusting first one.
I follow directions and still come up with FUBAR chasing my own tail.


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Why I went to EI. Have not messed with points in 33 years.

Last edited by desco; 03/17/21 7:09 pm. Reason: addition

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I’m just about f’n convinced!


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Hi Splash,
Points and EI both have their pros and cons.
Points assembly all in good condition and set up well will work just fine for thousands of miles between adjustment, but does require a good understanding. No-one was born with that understanding, you are learning as you go.

Just an observation from your pic, the solder blobs at the ends of the points wires appear to allow collision with the moving point when at full lift. This is not healthy, and may explain why the meeting of the points surfaces seems to be off-flat (the points arm has been distorted).

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Yes, if you compare the pic in
https://hermit.cc/tmc/technote/igtiming/index.htm

to your pic, you will see that the wire collars in your intallation straddle the spring, whereas they do not in Hermit’s pic. This produces the problem I pointed to in my previous post.

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If you get stranded with an EI because of a low battery it's your fault not the EI. I keep my batteries on a battery tender at all times. I check the battery voltage before each ride and check it again when I get back. If it is not higher when I get back the battery or the charging system is suspect. Act accordingly.
Again, never stranded, points or EI. Time saved not screwing with points, priceless.


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I am thinking the cam may be worn. The primary plate has to be set to the maximum counter clockwise position for line to match up near pointer when strobing. I don’t know what else can cause for max tolerance fully deflected all the way like this. Maybe the auto advance?


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Hi splash, It is very common to have back plate at or near limit of travel. It doesn't matter. Getting the timing correct is what matters. You can/will compensate with the sub plates.

Trust me a worn cam will not cause this.

You need a cam advance holding tool. Take a piece of bailing wire. Bend into washer shape that will fit over end of points cam, yet clear center shaft.
Remove AAU bolt. Place your bailing wire over end of AAU. Place larger flat washer over wire. {ut bolt back in finger tight. Hold cam clockwise to stop. Snug bolt & cam will stay at advance.

Don't use thin paper or cellophane. Get an ohm meter. You can use test light if you don't have ohm meter.

Remember you want points opening. Opening is what triggers spark.

Rotate motor until 38b mark lines up on rotor. Note, there are 2 marks on rotor. Only one is for you motor. If you have TDC tool use it to find 38b. Look in spark plug hole. If tool goes in & piston is at top that's TDC back up motor a little. In any case the TDC tool will go into slot at one of the marks. Put X through unused mark on rotor so you know that's wrong mark. The TDC holes in crank are actually slots. You can see them with flash light & mirror & feel them with screw driver. Just so you'll know.

I always start with front points (L cyl). Doesn't matter, but I like to. Turn motor until it looks like front points are ready to open. Hook up ohm meter with alligator clip to the curved points spring. Other lead to head fin. Now, this is important. Read meter with points closed. Record reading. Now turn motor until you see points open. Record reading. Notice you'll see about 3ohm & 70 ohms give or take a lot... the point is you want to see the change when points open. So memorize what meter does when points open. That's what you want to recognize, the moment points open.

Now back up motor & come forward rotation. Turning rear wheel on center stand is easy way. Spark plugs out. You always want to measure with motor rotating forwards, never backwards. If you pass the opening too fast. Back up motor a lot, then come at it again. This compensates for backlash in timing gears.

So AAU locked in advance. Ohm meter hooked up. Rotate motor forwards until meter shows points just opened. Go easy it happens quickly when you're at the sweet spot.

Look at line on rotor. Remember your sub plates & slot are centered. Your gap .015". Now move back plate until you are on time or close as you can get.

It can take several trial & error adjustments at first. If you run out of slot, then move sub plates. However double check point gap first as it can change moving primary plate. It just does...

Now go back & turn motor until points open again per meter. Move sub plate to trim the timing until you see meter read points open at same time line is on pointer.

Now move to rear points. Again verify gap. Now, trim timing on rear points my moving sub plate.


Expect to take a few hours until you get the hang of it. Probably all day Saturday actually. Takes time & practice. I can do all this in about 10-15 min. Like riding a bike or surfing. Looks easy & it is once you get the hang of it.

After all this cut some strips of copy paper. Dip in gas or carb spray. Place between point faces & clean off any oil or grease residue. Dry with dry strips of paper. Put a dab of point cam lube on the rubbing block. Lubricam SL-2. Ebay if local parts store doesn't sell it. This is very important. Or rubbing block will get hot, melt/wear quickly & gap will change. Properly serviced the points will last many thousands of miles & should cover 3k miles between servicing without problems. I do it all the time. Have for years.
Don


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So I finally figured out the points with timing light. Fires right up on first kick. Still have low idle issue when from high RPMs then to pulling clutch in to coast or put in neutral to coast to a stop. Usually by bumping the throttle it will settle at idle OR if I leave it in gear to slowly whin down the RPMs. Is this common?


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Sounds like your running Concentrics with screw in pilot jets for that last one splash.


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Tell me more. Is there a page in the repair Manual? What does running Concentric mean?


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Your carb is an AMAL Concentric ( model name), early concs had a pilot jet screwed into the roof of the float bowl, this gives poor idle. later concs have a fixed bush jet which lives directly behind the pilot air adjusting screw. Either way the idle jet is tiny ( 0.016") and is the first to block. Clean with a #78 drill.

i am struggling to understand Allans advice to set the points gap when they are closed, how does that work?


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Originally Posted by splash
So I finally figured out the points with timing light. Fires right up on first kick. Still have low idle issue when from high RPMs then to pulling clutch in to coast or put in neutral to coast to a stop. Usually by bumping the throttle it will settle at idle OR if I leave it in gear to slowly whin down the RPMs. Is this common?

If we can assume that the points gaps and timing are now correct and equal on both cylinders (I’m dubious of that, after reading your previous posts) and the engine has warmed up, then an engine that slows down too much when you shut the throttle, then picks up slightly, can be a sign of a rich pilot mixture.

Last edited by triton thrasher; 03/21/21 11:45 am.

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Triton with the forever inviting posts once again. Thanks for your help. I’m running short straight pipes where it needs to be somewhat rich.

Last edited by splash; 03/22/21 6:56 am.

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Originally Posted by gavin eisler
Your carb is an Amal Concentric ( model name), early concs had a pilot jet screwed into the roof of the float bowl, this gives poor idle. later concs have a fixed bush jet which lives directly behind the pilot air adjusting screw. Either way the idle jet is tiny ( 0.016") and is the first to block. Clean with a #78 drill.


Those screw in pilot jets are troublesome when shutting off throttle and coming to a stop, there just isn't enough fuel at the right point when you need it most. by having the pressed in bush (or a premier carb with a screw in jet directly opposite the pilot air screw) there is, and you don't get the suddern engine dying.

Just adding on from Tritons comment, the same instance wouldn't happen above if you were stationary and revved the engine up and let it fall to idle as the fuel isn't being moved back and forth in the bowl. If it does it here then the idle mixture most likely isn't set correctly and the slide probably is too lean also.

Originally Posted by gavin eisler
i am struggling to understand Allans advice to set the points gap when they are closed, how does that work?

Ha! you got me, Id like to say i was testing folk to see who was reading what I wrote, but no I was just having a dopey moment.

Yes, set the marker on the points cam to the heel of the points and set the gap there. Its advisable to remove the screw and using a soft punch, give a few light taps to ensure the AAU has seated square and isn't running off centre.


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Hi Splash, A ‘70 Tiger would have come with AMAL MKI. A round float bowl, with pressed in .017 pilot (idle) jet, behind mixture screw.

If you remove mixture screw, look in hole with flashlight you’ll see tiny brass bushing with .017 hole in it. Strip back some 18g stranded wire a few inches. Stick 1 strand into hole. You have to be steady as hole is tiny. This will push dirt into passageway. Shoot carb cleaner into hole & it usually will blow dirt back into float bowl. Remove drain from bowl first. Open fuel tap & let some fuel flush bowl.

A newer premier version Concentric will have a cross head brass plug on opposite side of mixture screw. This brass is head of removable pilot jet. The very first version had removable pilot jet inside above float bowl. Highly unlikely you have earliest carb.

There is also new non premier Concentric with silver cross head screw. It has pressed in jet. The silver cross head can be removed to make jet cleaning easier.

Lots of changes & carbs shaped the same.

MKII Concentric has square bowl & looks Japanese like Honda carb. No tickler.

To check for worn out carb/slide bore, heat soak motor. Pull over & let motor idle 5-10 seconds. Open throttle slowly as possible. No matter how slow you open throttle motor should not falter or die. Some wear will falter, bad wear will die. This is tiny opening only .005” or so. You can pass the bad spot by opening more quickly, then motor will rev as expected. Don’t jump to conclusions. Do this test several times over a few rides. Cheating mixture about 1/4 lean (out with screw) will make idle feel worse, but improve dying somewhat. New carb is best cure. New slide may help temporarily.

Make sure idle is not too low in every case.

Street bikes tend to not like straight pipes. Not to mention peace of the island. Emgo repro original mufflers work well & not too costly. The motor is sensitive to air filter changes also. Paper elements can make make mixture do odd things.

Factory settings only work for factory stock bike & ‘70s fuel.

You have much going on at the same time. Will take some sorting to work this out.

Remember the basics start with good reliable power to both coils, good points & point wires to coils. Good condensers, good plug wires & good coils. Good advance unit & timing.

On paper it’s easy. Real life is lots of hard work, often frustrating if you don’t have experience.
Don


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Hi Splash,

You said “I’m running short straight pipes where it needs to be somewhat rich.”

This is not quite right.

A free-er flowing exhaust system (and/or a free-er flowing inlet system) will allow more air through the engine.
That will often require larger main jets and possibly adjustments to the needle position, needle jet itself (uncommon), throttle valve cutaway (uncommon).

These adjustments (correctly done to compensate for the increased air flow) will result in a correct mixture, NOT a richer mixture. On a single carb engine like yours, this will be correct for both sides.

If you are still seeing big differences between the 2 cylinders in sooting of plugs, and you are sure that the mechanicals (compression, valve condition/clearances, rings) are good, then all that is left is ignition timing.
A spark firing at the wrong time on one cylinder could produce sooting on that cylinder.
If you have strobed one cylinder to be correct, now try the other cylinder (the other plug lead).

It takes 2 cylinders to tango!

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Hi Splash,
If you remove the centre bolt of the AU unit a larger washer can be temporarily fitted, this can be used to wedge the cam in the fully advanced position which will free up one hand and make it easier to set the points opening at 38degrees BTDC.
This is the full advance position, the AU retards the timing for starting and low revs timing
(Don't forget to remove the washer when finished setting the timing)
The mark on the cam looks like the max opening, lined up the the rubbing heel of the points is where you set the points gap

John

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Plugs now look the same after running for a few days after setting timing. Electrode is burnt toast color but arm and circumference where threads begin is black carbon.

Will try cleaning out behind mixture screw as Don explains above.


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Arguing about points vs EI is about as senseless as arguing about religion or politics. You believe what you want.. No one is going to change your mind.


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Plugs now look the same after running for a few days after setting timing. Electrode is burnt toast color but arm and circumference where threads begin is black carbon.

That sounds good enough Splash, no need to mess with it further. Ride it and enjoy!

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It’s just another option that’s all, Desco. I can go EI one day soon or later 🤷🏻‍♂️. Just a different way to skin the cat. After a fresh rebuild I gotta go the inexpensive route for now and learn.

Last edited by splash; 03/23/21 6:30 am.

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