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71' TR6C Trophy Carb Spitting

3K views 38 replies 7 participants last post by  jackdawack 
#1 · (Edited)
Hey Guys,

Finally got the bike back together and running good enough, however there is still an issues I am tracking down.
With an single AMAL 930 premier carb and #19 pilot

I am trying to tune the carb spitting that occurs from idle with a quick snap of the throttle. Sometime's it flames out, other times if i release the throttle it will stay running. While moving the bike rips, no spitting or anything that I can tell. Yet, once i stop and give it a blip before taking off again it will spit. If i check the plugs from idling they look slightly rich. Which tells me my carb settings are decent enough and not lean on the idle circuit. Yet, spitting is said to be from a lean condition. Any time I open the throttle with ease the bike runs like a champ.

I'm curious if this is normal, or if there is something I need to look at next. I checked for air leaks around the carb, and didn't find any with a butane torch.

My valve's were checked and theyre set correctly.

I have not checked the ignition timing, if i start down that rabbit hole im probably going to go with a boyer system(if anyone has the correct system i would appreciate that info too)

Otherwise, the bike idles nicely and rides great... which makes this tough because i dont want to make anything worse.

Hoping that someone else might have had a similar issue..

Thanks
 
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#2 ·
Sorry, but retarded timing will cause the carb to spit, so it’s one thing to check.
Wrong slide cutaway or leakage around the slide can cause it.
Advance unit not functioning correctly can cause it.
A valve leaking might cause it to spit .
Is a #19 pilot normal for your bike ?
Are you running mufflers ? Air filters ?
If your cutaway or pilot is leaner than what is normal , I’d suggest trying what others use with the same bike.
 
#4 ·
FWIW the last 3 reuilds I have done have needed 1/2 smaller slide cutaway to get rid of hesitancy coming off tickover, and that with new concentrics. I guess you are running the standard 3 1/2 now, I'd go down to a 3. Fuel is very different now than back in the day (even though different again from UK to USA)
HTH
Mick
 
#6 ·
Yes, the "correct" size was the 3 1/2" for my model. I will consider this as an option once I go through the ignition timing and everything else.

Hi Jackdawack, Where do you live? Fuel can make huge difference. As Mick found I also find Tigers tend to like #3 slide better. The can also prefer .1065 needle jet. Amal sells this special size.

Overall E10 Unleaded fuel in USA, motor likes about 5% richer jetting across the board.

You have premier. Good! They work great. .019 pilot (idle) jet is correct & works better than .017 like old carb had. Many internal changes in premier so they require different settings.

Float setting for premier is very different. Just above gasket surface & level. This is correct! If you lowered float level, raise it back up. then road test before moving on.

As was stated, timing is critical. It must be checked. You may find bike works better 3/32" retarded. I'd do that. I do that on my bike as well as others I tune. Looking at pointer in timing cover. Hash mark on rotor will end up 3/32" closer to front wheel from pointer.

On occasion the rotor alloy can slip on the steel center hub. That will throw timing marks off. Good plan to verify the rotor hash & pointer with TDC tool in 38b slot in flywheel. Note position & compensate with the hash/pointer relationship. Timing is very important. Even left to right is important.

Well serviced points are very reliable & allow starting with dead battery. Key work: Well serviced. Taking half a turn of end of advance spring & smoothing any flat spot worn in fly weights is good idea. Smooths idle & just above idle.

On the other hand, Boyer has a much more desirable advance curve. Gives perfect timing left to right. Tends to reduce the shake in motor just off idle that points AAU may cause. The down side of Boyer or any other electronic ignition is low voltage will make impossible or hard to start. So if you choose electronic be sure your battery & charging system is always well maintained & electrical output is to specs. In every case poor charging system is no good, so in many owner's mind, electronics advantages far out weigh the negative of low volts. The single biggest advantage of electronic ignition is the desirable advance curve with modern fuel. Substantially reduces pinging & holed pistons, but if mixture or timing is not properly set it cannot compensate for that.

Regarding getting slide & all the other mixtures correct, it will take some practice, experiments & very important to mark your grip in 1/8s. Use masking tape on grip & throttle housing. Take up cable slack very gently, twisting grip. Mark that zero. Turn to full throttle. Verify slide is full up. Mark as full. Then divide marks in halves. The eye can find center points fairly well. Use dividers if/as needed. Be accurate on marks! Adjust throttle cable, idle rpm as needed before marking grip.

Often needle will want full up, meaning clip on bottom groove. Main jet one size lower than 8 stroking. This will go a long way in preventing melted pistons on hot days up hills. Remember unlead fuel plug readings are really tricky. Not like '60s & '70s. When it looks a little too rich is probably just right. However, go more by road tests than plug reading.

You'll soon learn how little throttle is used. Seldom more than 1/16-1/8. The needle will wear flat spot here. That skew mixture into being rich at worn point. So watch out for that. If you lean it there to just right, it defaults to lean when jet is on unworn part of needle. If in doubt replace needle & needle jet. Jet wears oval. Even .0005" wear is a decided change in mixture. Sometimes.... a worn jet with new needle is just right. Trial & error. Try each one & see.

Again, worn needle is always problematic.

Slide size is found at snap throttle test. Sometimes (often??) you'll be right between #3 & 3-1/2 cutaway. Default to richer #3 if you find this.

Since bike runs good you're not far off. Start with main jet then work with needle clip, then slide. Your pilot get of .019 is good. It will have 3 small rings machined into the silver tip of jet.

Print the road test part of John Healy's tuning guide. Put it in your pocket, you'll need to memorize it.

8 stroking is an odd misfire that sounds like ah ah ah ah ah at full or just shy of full throttle. Backing off goes away. cranking on comes back. High gear 65 mph up a moderate hill or head wind is easiest.

To rich if slide can 8 stroke on snap throttle. But you need to really listen & know what 8 stroke sounds/feels like.

Too lean the bike will gain very slight power when you back off throttle, like 1/32 turn. Very hard to feel until you understand it. Easy to smoke piston when lean. Better to go too rich, then back off going leaner a little at a time.

Again start with main jet. If main jet is not right, it can/will confuse the needle clip position.

I don't know what air filter or exhaust you are using. That will make a difference in mixture.

I've chased my tail for days (a few months actually) with paper elements in air filter. Don't use them. The original type wire/gauze is better. They clean fine & don't mess with air flow at different RPM. Or should I say, Triumph must have designed carbs to complement them.

Find a road test route that has all the conditions of testing you need. Use same route every time. Then you'll feel changes much more readily. It takes a good 10-15 miles to get motor/carb to minimum temp to set mixtures. After 50-60 miles you may need to trim idle mixture idle rpm. You'll learn to find the happy medium.

There is no provision for cold fast idle, so motor will not idle on cold mornings & in hot weather take a good 2-3 miles before idle is to be trusted. If bike runs really well cold, idle mixture is too rich. Some Electronic ignition has idle stabilization by changing idle timing. They idle great no matter what unless really cold like <40f. That's another story.

What sucks about our bikes is you must remove carb to access slide. Makes the job very time consuming. Just have to accept that. If you have stock air filter, the boot is a pain. 750 Tiger is worse with offset boot hole.

Here's the tuning guide. NOTE the float level of .080" is for older carbs, NOT premier. They demand much higher to achieve the correct liquid level in bowl.


Don
I am in Northern New Jersey.
If anyone knows a specialist in the area I am interested since my time is limited right now.

Thats really funny!!! I did in fact lower the float bowl and it did come set above the gasket.
Yes, I have had to remove and re-install the carb probably 4 times already and with the 2 stock airboxes it has to be the biggest pain in the arse. I will reset the float level and then move on.

Next.
I am going to see if i can sort out the timing and check to make sure it is set correctly. I have the TDS flywheel tool because I knew i was going to have to deal with this at some point. I am a bit worried about screwing this step up, but I will make all my measurements before taking anything apart.

From there I will work through everyones suggestions.
 
#5 ·
Hi Jackdawack, Where do you live? Fuel can make huge difference. As Mick found I also find Tigers tend to like #3 slide better. The can also prefer .1065 needle jet. Amal sells this special size.

Overall E10 Unleaded fuel in USA, motor likes about 5% richer jetting across the board.

You have premier. Good! They work great. .019 pilot (idle) jet is correct & works better than .017 like old carb had. Many internal changes in premier so they require different settings.

Float setting for premier is very different. Just above gasket surface & level. This is correct! If you lowered float level, raise it back up. then road test before moving on.

As was stated, timing is critical. It must be checked. You may find bike works better 3/32" retarded. I'd do that. I do that on my bike as well as others I tune. Looking at pointer in timing cover. Hash mark on rotor will end up 3/32" closer to front wheel from pointer.

On occasion the rotor alloy can slip on the steel center hub. That will throw timing marks off. Good plan to verify the rotor hash & pointer with TDC tool in 38b slot in flywheel. Note position & compensate with the hash/pointer relationship. Timing is very important. Even left to right is important.

Well serviced points are very reliable & allow starting with dead battery. Key work: Well serviced. Taking half a turn of end of advance spring & smoothing any flat spot worn in fly weights is good idea. Smooths idle & just above idle.

On the other hand, Boyer has a much more desirable advance curve. Gives perfect timing left to right. Tends to reduce the shake in motor just off idle that points AAU may cause. The down side of Boyer or any other electronic ignition is low voltage will make impossible or hard to start. So if you choose electronic be sure your battery & charging system is always well maintained & electrical output is to specs. In every case poor charging system is no good, so in many owner's mind, electronics advantages far out weigh the negative of low volts. The single biggest advantage of electronic ignition is the desirable advance curve with modern fuel. Substantially reduces pinging & holed pistons, but if mixture or timing is not properly set it cannot compensate for that.

Regarding getting slide & all the other mixtures correct, it will take some practice, experiments & very important to mark your grip in 1/8s. Use masking tape on grip & throttle housing. Take up cable slack very gently, twisting grip. Mark that zero. Turn to full throttle. Verify slide is full up. Mark as full. Then divide marks in halves. The eye can find center points fairly well. Use dividers if/as needed. Be accurate on marks! Adjust throttle cable, idle rpm as needed before marking grip.

Often needle will want full up, meaning clip on bottom groove. Main jet one size lower than 8 stroking. This will go a long way in preventing melted pistons on hot days up hills. Remember unlead fuel plug readings are really tricky. Not like '60s & '70s. When it looks a little too rich is probably just right. However, go more by road tests than plug reading.

You'll soon learn how little throttle is used. Seldom more than 1/16-1/8. The needle will wear flat spot here. That skew mixture into being rich at worn point. So watch out for that. If you lean it there to just right, it defaults to lean when jet is on unworn part of needle. If in doubt replace needle & needle jet. Jet wears oval. Even .0005" wear is a decided change in mixture. Sometimes.... a worn jet with new needle is just right. Trial & error. Try each one & see.

Again, worn needle is always problematic.

Slide size is found at snap throttle test. Sometimes (often??) you'll be right between #3 & 3-1/2 cutaway. Default to richer #3 if you find this.

Since bike runs good you're not far off. Start with main jet then work with needle clip, then slide. Your pilot get of .019 is good. It will have 3 small rings machined into the silver tip of jet.

Print the road test part of John Healy's tuning guide. Put it in your pocket, you'll need to memorize it.

8 stroking is an odd misfire that sounds like ah ah ah ah ah at full or just shy of full throttle. Backing off goes away. cranking on comes back. High gear 65 mph up a moderate hill or head wind is easiest.

To rich if slide can 8 stroke on snap throttle. But you need to really listen & know what 8 stroke sounds/feels like.

Too lean the bike will gain very slight power when you back off throttle, like 1/32 turn. Very hard to feel until you understand it. Easy to smoke piston when lean. Better to go too rich, then back off going leaner a little at a time.

Again start with main jet. If main jet is not right, it can/will confuse the needle clip position.

I don't know what air filter or exhaust you are using. That will make a difference in mixture.

I've chased my tail for days (a few months actually) with paper elements in air filter. Don't use them. The original type wire/gauze is better. They clean fine & don't mess with air flow at different RPM. Or should I say, Triumph must have designed carbs to complement them.

Find a road test route that has all the conditions of testing you need. Use same route every time. Then you'll feel changes much more readily. It takes a good 10-15 miles to get motor/carb to minimum temp to set mixtures. After 50-60 miles you may need to trim idle mixture idle rpm. You'll learn to find the happy medium.

There is no provision for cold fast idle, so motor will not idle on cold mornings & in hot weather take a good 2-3 miles before idle is to be trusted. If bike runs really well cold, idle mixture is too rich. Some Electronic ignition has idle stabilization by changing idle timing. They idle great no matter what unless really cold like <40f. That's another story.

What sucks about our bikes is you must remove carb to access slide. Makes the job very time consuming. Just have to accept that. If you have stock air filter, the boot is a pain. 750 Tiger is worse with offset boot hole.

Here's the tuning guide. NOTE the float level of .080" is for older carbs, NOT premier. They demand much higher to achieve the correct liquid level in bowl.


Don
 
#7 ·
Hi Jack, Put your mind at ease. The procedures are not hard. Just takes a little practice. I'll send you a cheat sheet tonight after 10pm pacific time tonight.

You will not screw this up, trust me!

Good to have a spare gasket on hand for the access cover with the 3 screws. The gasket will sometimes tear on removal.

You must have a timing light of course. A separate 12v battery to power the light. Spare bike battery or park you car close enough. Or remove car battery. Also a box fan placed in front of bike is a very good idea. Motor will get quite hot without fan during setting. NEVER power timing light from bike's battery. Some timing lights have internal battery (mine does) so it's self powered. In that case you don't need extra battery.

You'll also need feeler gauges .014, .015, .016". Easier to set points.

Some very fine sand paper/emery paper, or wet or dry paper, or fine thin emery board to file points if/as needed or dedicated points file or points emery board.

Tube of Lubricam SL2 points cam lube. May find local, ebay has it. Points lube is a must!

Don't mess with timing until you have items needed to do good job. Resetting float level will change things. Luckily the bowl is easy to remove.
Don
 
#8 · (Edited)
I raised the float bowl, didn't do much of anything. Still wants to flame out if i crack the throttle quickly. I will consider purchasing a Boyer system after reviewing some more info on the timing procedures on the stock unit. I would need a timing light and the point lube, should have everything else. I might look for a #3 slide as well.
 
#9 ·
jack, just learn how to check the timing.

its a five minute job and takes zero brains.

youll need a timing light anyway if you want to keep the bike.

points are another ten minutes.

these things require 1930s technology. dont overthink it.
 
#10 ·
Gonna order the light tonight, and if I get an hour Im gonna put the original carb back in and see tomorrow if the issue changes. This way I can isolate the carb. The original was rebuilt anyway prior to getting the premier, I just liked the idea of putting the premier on. If the problem disappears I will go down that hole of a new 3# slide etc. I will check the timing regardles, and It would be a nice skill to add to the basket.
 
#11 · (Edited)
Hi Jack, Just get an inexpensive simple timing light. No need for fancy degree reading or the like. No need for RPM reading. You only need those features for getting into special timing curve tuning or advance unit diagnosis.

Start by looking at points wires. Black/white wire goes to front set of points. Look at coils. Black/white should go to left coil.
Black/yellow wire goes to rear points. Looking at coil, it should go to right coil. This is the factory way it was done. Notice the black/yellow wire is longer to reach to the rear points.

The power wire to coils is white/yellow. Notice it connects to one coil, then goes to the other. We won't think about this wire. Just so you know what it is though.

Look at screws on points plate(s). The pillar bolts allow the entire assembly to rotate. The screw on points allows points to adjust. Notice the eccentric screw in the slot. You rotate it to change point gap. One way wider, the other closer. Practice that... Notice you must loosen points screw a little to allow points to move freely, but not too much. All 4 eccentric screws are very weak/flimsy. If you force it at all it will break or strip slot. So practice how much to back off points screw to get eccentric screw to move things. Just takes a little practice to get this right.

Now move to sub plates. They are secured by the screws that hold the lube felt bracket. As you can see there are 4 screws total. 2 for each side. Obviously you loosen screws on side you want to adjust. However sometimes you need to loosen the other 2 slightly to relieve tension on the bracket. Again practice moving the sub plates using eccentric screws. Notice how the sub plates move in arc. Make a cheat sheet so you know which way to turn eccentric to move sub plate the direction you want it to move. The sub plates allow you to set timing on left & right sides individually.

File tit off point face if they have one. Clean off any filing dust 100% if any dust is left behind it will wear cam & rubbing block. Again folding emery paper or wet/dry about 400 grit. Wet or dry works quite well used dry.

Set rubbing block to hash mark. Gap points. Rotate motor. Gap 2nd set. No matter which set you do first. I start with right set just because I do.

To gap points use .014" & .016" feeler gauge. .014 will feel sloppy. .016 will feel snug. Don't really need .015, but fun to see how it feels.

Clean point faces well with strips of copy paper using alcohol, parts wash, or gasoline. Dry with dry strip of paper. Clean until paper comes out clean. Again verify not a trace of sanding dust on rubbing block or cam.

Place a very thin smear of points lube on cam. Place dab of grease size of paper match head on rubbing blocks. You see my grease is green. Lubricam is brownish. Put only one drop of motor oil on felt lube pads if they are still there. Not there, no matter. Grease alone will work perfectly. Do not forget the grease! Notice side of rubbing block grease is on. this way rotation pulls grease onto cam.

Mark the points sub plate with marker pen L & R so you don't forget which points is for which side of motor.

Now you are ready to set timing. Remove cover on primary cover. Hook up timing light to left cylinder (spark plug wire). Turn on fan to cool motor.

Start motor, rev motor to approx. 3500-4000 or until you see hash mark on rotor stop advancing. Very easy to see this. Idle it's not near pointer at all. Rev motor & it moves right around to pointer area. When mark lines up with pointer at above RPM it's 38B, which is spec.

If hash mark doesn't line up look at cheat sheet. Move points sub plate according to cheat sheet until hash mark lines up to pointer. Once you have the left side timed, you'll move to right cyl.

Move timing light to right cyl spark plug wire. Star motor, rev it as before. Adjust the left points sub plate as you did for they other cyl until hash mark lines up with pointer. Remember this time, you'll move the left point sub plate.

Once this side lines up with pointer your done. Both sides are now timed.

That is done. Disconnect timing light, install covers for primary & points.

If you hear pinging you can retard the timing, but when you are learning just use the 38B mark.

Since you are still learning it will take some time. Budget a few hours. Once practiced it takes 10 min. But not when you are figuring all this out.

There is a lot of oil flying around in primary. It is messy job & expect oil to blow out when you start & run motor. Consider putting cardboard on floor. About 3x3' sheet.

You can make a plastic window for opening screwed in place of cover to get no mess. It will condensate bad for a few minutes until it heats up. That's another subject. Just deal with mess for now.

Looking at pic of my points you can see the grease. Don't confuse hash mark with the large square slot. Put rubbing block on hash mark, not slot when setting gap.
Don
 

Attachments

#12 ·
Timing similar to this on eBay is good enough. The pickups for plug wire are quite fragile to shock. Don't drop them. Zip tie wire away from heat. Try to keep pickup off fins so it doesn't vibrate pick up.


Many of these lights are not very durable. Even the costly ones aren't much better (often worse). Bulb in the light is fragile also. So be gentle with any of them. You want one that says good to about 7-10000 rpm max. The really cheap ones cut out at the higher rpm that we need to set our timing. They crap out around 2000 or less!
Don
 
#13 ·
Timing light came yesterday, new battery today. Waiting on the gasket for the inspection cover and will work through getting all the timing checked and adjusted if necessary. I went with a slightly costly light 100 bucks due to a lot complaints I read about them being cheap, came witha nice storage case too. Unfortunately, a lot of deliveries lately are coming damaged, and in soft packaging. So I opted for something a bit more durable.

I ordered a spotting scope for my shooting hobby, 500 bucks and they slapped a shipping label on the product box and just shipped it in original packaging. Needless to say the box was crushed becuase it was never designed to be shipped like that.

Anyway I will read through all the above and report back.

Thanks for all the help.
 
#14 ·
i uze a simple dial back to zero light for timing everything. ignition timing makez a big difference in how well your motor works, and if your elevation or fuel grade isnt the same as it wz when and where your bike was made (and it wont be), you can make it run better by advancing or retarding the spark a bit from the factory setting. i have TDC marked on my front pulley and i can set to any number i want to try.
 
#15 ·
Ok so, I started messing with the points and actually opted for a static timing set up before strobe checking and fine tuning.

I set the points gap, that was easy enough. However, when I went to auto advance the timing something seemed odd.

The "brass" cam with the scribe mark on it. I can rotate it about 20 degrees(just a guess) forward and back with zero effort, and it will stay in what ever position I leave it. Am I correct that there should be a spring behind the points unit that holds it in place? Shouldn't it spring back from the auto advanced positon?

I have not removed the plates yet, it was like 1am when I discovered this last night, but wanted to get an opinion before I went back out tonight.

If i end up pulling the entire ignition system out im gonna put a damn boyer in.
 
#16 ·
Am I correct that there should be a spring behind the points unit that holds it in place? Shouldn't it spring back from the auto advanced positon?
Yes it should spring back. There should be two weights which move outwards against their respective springs as the revs rise, when the revs drop the springs pull the weights back in retarding the ignition.
 
#18 ·
I pulled the timing unit out. The cam now rotates into auto advance, and will spring back on its own.

First off, is there a way to clean the auto advanced assembly with out removing it? To remove it do i just pull the cam bolt out? The entire assemby feels sticky like bearing grease.

Second, the springs for the unit feel "weak" im not sure how much tension there should be, but the weights move outward with minimal effort. Is this normal? If I put a flat head in the cam notch it takes zero effort to push it into the advanced positon. I have s feeling its normal but just want to check.
 
#21 ·
Hi Jack, Sorry I couldn't reply earlier. The cam will most of the time not spring back with tension of the points rubbing block on it. That is common & normal. At the same time the springs can weaken over time & the grooves in weight get worn as does the pegs on back of cam plate.

During starting & lower RPM the drag on the cam pulls it to retard so they don't have such a bad effect as you'd think. Shortening springs tends to make bike run a little better just off idle. I don't know it would make a big difference on spitting back from carb.

Also factory sent out a bulletin that shorter/stiffer springs were available. These had different part #s. I've not been able to find genuine Triumph ones so far. Various people are selling repro springs under this & former part #, However a real crap shoot as to how these repro springs fit & work. You can bend spring end to make it shorter. This tends to work quite well.

Using small file with emery paper under it you can smooth out wear on weight grooves. Also same method round off the flat edges worn on pegs.

However!! Before taking the AAU cam off or apart very carefully scribe witness marks on cam part & the main backing where you see springs hooked. If you install anything 180deg out, you can't set timing. Mark the springs where they were & which way, mark the weights also. If it all fell apart there is a way to know, but marking simplifies things.

You'll find one spring often fits looser than the other. This is normal.

You want to shorten springs by about 1/2 an end hook. A little more than 1/16". Compare the spring back. The springs are hard & fairly stiff for being so skinny. I have a set of spring/wire bending pliers which works really well. Small needle nose will work ok though. After re bending you may have to shorten the tip of wire hook slightly. Always make sure spring can swivel as needed on the posts. I wouldn't bend the posts to tighten springs. They can snap off.

Yes you must remove center bolt to cam. But, the AAU assembly will be tight in it's taper. There is peg in cam & slot at back of taper to align AAU into cam so it should be easy to reinstall correctly.

The AAU can be fairly easy or quite tight in cam. Factory makes a puller 60-0782 '69 & up is the tool for your your year. Under $15 eBay or parts sellers have them. I don't like the slide hammer. I don't like hitting them sideways with hammer. The tool just removes it, not pain, no damage. Just screw in tool finger tight. Turn with wrench a few turns & pop it's loose.

With AAU in hand very easy to unhook sprigs & remove.

However with your points plate removed to one side you can see the posts that hold springs. Unhook springs & the cam simply slides off. Actually the cam can get stuck with hardened grease & rust. You may have to spray with penetrating oil & work it off. Only the springs are holding cam to back plate. Don't stretch springs during removal.

Going back together put thin smear of wheel bearing grease on spindle. A trace of grease on slots in weights, pivot pins.. That's what I do.

If you remove AAU from cam, before install look closely inside exhaust for burrs or damage to round peg. Look closely at taper of AAU for burrs & damage to slot for peg. Once all ok, look at peg. Install AAU into cam such the slot sides smoothly over peg. Slightly wiggle AAU & feel with it's centered evenly on taper. Hold tightly into taper. Install washer & bolt & final tighten bolt. You will remove bolt later for static timing, but we want AAU seated in cam tightly so it doesn't fall loose during static timing.
Don
 
#22 ·
Hi Jack, If you don't want to learn to work with AAU or service points then Boyer is excellent choice. Good availability & warranty support in USA.

I doubt if your cam not springing back is cause of spitting back in carb. I doubt Boyer will cure carb problems.

Boyer will have full advance in practice at about 3500 rpm compared to 2000 rpm with points. This is very desirable for USA fuel & reducing ping. Boyer will hold timing basically indefinitely & is service free. You will only have to reset timing if you remove pickup plate or Boyer rotor for some reason. New Boyers have made some changes, so full advance may be even higher. That is not bad thing.

Be most careful that every wire connection is perfect. #1 Boyer failure is actually installer's fault do to poor wiring. Timing will still be set with your new strobe light. It is still wise to verify 38b mark on alternator rotor is to pointer with TDC tool. Boyer rotor doesn't have a slot for round peg. You must line rotor dot up through a hole in pick up plate. Then tighten center bolt. Simple! Then strobe time. Sometimes you won't have enough slot on plate to set timing. Then you must clock Boyer rotor to compensate & reset strobe timing. We'll get into that only if needed. Just don't think your crazy if it happens.

Stuart has a different way of wiring Boyer for better reliability. I suggest contacting him for exact details should you chose Boyer.


Boyer demands good battery & charging system. Charging system should be kept good anyway. Points let you cheat a little on charging system. But making charging proper & fitting Boyer is what thousands have done to very good results.

I've only worked with Boyer Micro MKIV (it has black box, meaning the case electronics are in). Part # KIT00052.
It basically replaces your points & AAU & gives a much more desirable advance curve. Boyer says MKIV works better on lower volts than the old MKIII. That's good. If I was buying, this would be my choice. I don't care about idle stabilization. You make your choice.

Boyer Micro Digital (red box) adds idle stabilization & rev limiter. I've never seen one of these..

Boyer Micro Power (blue box) adds more sophisticated timing control & use less electricity. I've never seen one of these either.

I know probably 30 guys with Boyer black box. Some MKIII, Some MKIV. I've ridding several bikes with black box. It works really well & only cost about $145.00. (MKIII is no longer made for Triumph twins. MKIV is an improved MKIII).

I don't know if the Micro Digital or Micro Power are worth the extra cost or not.

You may need new coils if what you have now is not compatible with Boyer. You may need new plug wires and or plug connectors as well. Just keep that in mind. Look over Boyer site. Can be confusing. Look at instruction sheets they have additional info.

If possible post some clear photos of you coils, condensers, battery & batter connections. Will give us an idea of where your at now.

If you want to try points for now, why not? It's free & you'll learn some things. If your done with points, $145 Boyer you can't go wrong.
Don
 
#23 · (Edited)
I put a new MotoBatt battery in recently, and have a podtronics regulator coming in the next few days. I rewired the entire bike last year with a new harness and went through all the electronics. I haven't checked the voltage of the stator at speed, but it's reading fine at idle. I did not upgrade the coils, they are 12v, though I did put new plug wires in. I think i'm set up for an EI system, but I don't ride it long enough to justify dumping more into the bike to "upgrade" it. I go for like 20 minutes rides every week or so.

I think I got the points set tho!

So my fault, I my brain misplaced a zero. I was trying to set the 38BTD point gap to .015, its .0015. So once i figured that it all fell back into place. The needle lines up near perfect at the scribe with the flywheel, so that was very nice to see. Now I Should know my 2 sides are near each other to strobe.

Should i keep it at 38BTC or should I expect to decrease the angle? I saw read something about 35 with newer fuels.
 
#24 ·
Hi Jack, I'm not familiar with the .005" gap at 38b.

I've always used .015" gap at the hash mark on cam. Then lock the AAU full advance. The rotate motor normal running direction with rear wheel high gear, bike on center stand, spark plugs removed. Points just opened check mark on rotor. It should be lined up. I use ohm meter to check when points just open, but test light works good also. Finally use strobe light.

If you are just replacing points. Set gap to .015". Then strobe light. The static setting is more useful after taking the points plate or sub plates off. It you put accurate witness marks on these, you can often (but not always) then set gap to .015" & go straight to strobe.

Issue is if timing is very far off, it can kick back violently or not start at all.

To lock cam at full advance you need a large washer. A flat washer to trap large washer. Remove AAU bolt. Install washers & trap them bolt just snug. Hold cam full advance (clockwise) with a small tool or screw driver. Lock bolt. The idea is to lock the cam. If you feel it want to spring back, it's not locked. Static set as above. Static carefully done can be quite accurate. It at least gets you within a few degrees. Close enough for getting started to strobe time.

Wire tool is made from coat hanger. Flatten end to fit. It must be thin enough to not get trapped by washers.

I find the bikes ping less with timing a little retarded. 1/16 to 3/32". Depends on your fuel & ambient temperature. You can try it both ways. In every case use the highest octane fuel even if it has ethanol you can get. If you have 93 that would be good.

Did you re bend the AAU springs a little shorter?
Don
 

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#25 ·
Sorry edited my response, its a .0015 gap to set the secondary plates at 38BTD with auto advanced engaged. I was Able to hold the auto advance with a flat head like you did, the bolt and washers would have been useful but i actually used the motion of advancing to pull my feeler gauge through from "closed", got a nice feel for when it opened and let go.
 
#26 ·
Hi Jack, That's the cigarette wrapper method. It should be close enough to get started to strobe time.

Not really one to one, but .001" change of gap changes timing about 1 deg. So if rubbing block wears closing points .001", timing will be retarded by 1deg. I think this is why some bikes ping worse after tune up. The points may have closed by .003-.004". I'm nearly due to service my points. I'll check timing before I touch points to see what it is. Lubricam lube is very good. Rubbing block lasts really well with no wear.

The points face develop a tit & pit as they wear/burn. This is normal. I'm curious to see if the tit has changed timing & how much rubbing block has worn. Might be more than a month before I get to it though.
Don
 
#28 · (Edited)
well, for what it's worth you have the nicest-looking points setup that i have ever seen. most of have the screw heads buggered up and the threads stripped.

your springs might and probably are just weak from age. you can get new ones or you can try to get more tension by bending the posts that attach them to the backing plate out a bit. or wedge a small piece of beer can underunder the spring loop to stretch it out a bit.

you have th e6CA lucas points. that hash mark isnt for ignition timing, its just to mark the highest point on the cam lobe for when you set the points gap. some cams dont even have it

set the gap using the hash mark for both sets of points. then set the timing fir one cylinder to 38btdc by rotating the entire points plate by loosening the pillar bolts. that 38btdc is unrelated to the mark on the points cam.

leave the points gap adjustment alone, and set the timing at 38btdc for the other cylinder by rotating just the other set of points on its own little adjuster plate, without mezzing with the gaps

use a static method to get the timing close enough to stzrt the bike, then use the timing light to set it precisely

Locking the cam in advanced, does that mean when timing with light I can do it at idle?
yes
 
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#29 ·
Hi Jack, Unlock cam when you use strobe. Bike will be hard to start when locked 38b. Do not attempt to strobe with cam locked.

The method of static timing light I said is shop manual way. There are other ways that work.

When checking/setting timing with strobe, you rev motor to about 3000 ish. You clearly see mark move at lower rpm. As you rev, mark moves, then stops. When mark doesn't move anymore that's full advance. Spec is 2000 rpm full advance.

If your springs are weak it will reach full advance at lower rpm say... 1800 rpm. But I wouldn't give that a worry. Just rev high enough get to full advance, then see where mark is.

Be accurate to left & right sides. Take your time to get it even as possible left to right.

Again motor will overheat quickly. Use fan in front of motor.
Don
 
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