Topic: CB750 advance unit - sloppy springs- full advance constantly -Huge Progress!

[PeWe]

I verified a problem and solution today.
My ignition timing was at full advance constantly. Searched the forum and found advice to shorten the springs on the advance unit.
When taking the unit out from the engine I saw that the arms could be moved rather much until the springs were working. Really sloppy springs with huge play. How could I miss that before??

I shortened the springs on the side mounted into the arms. Mounted them and found that the arms now have spring force from the very beginning. I shaped the springs when mounted with a plier when the spring itself blocked complete retraction of the arm.
EDIT: I turned the springs around which can be seen where the springs are attached around the fixed pin. It felt better that the springs enter the holes in the arms from beneath. Visible if comparing first photo with last

One more thing if somebody has seen that there is one part missing. I use PAMCO electr ignition and therefore removed the cam that earlier moved the points, (center concentric shaft).

WOW! Now correct timing possible. 
'F' at ~1200-2000 rpm's no problem, turned to '' full advance at about 2800-3000 rpms.
I did not check very exactly when I have to jet the carbs correctly which is possible now when the timing is OK.

[lucky]

I verified a problem and solution today.
My ignition timing was at full advance constantly. Searched the forum and found advice to shorten the springs on the advance unit.
When taking the unit out from the engine I saw that the arms could be moved rather much until the springs were working. Really sloppy springs with huge play. How could I miss that before??

I shortened the springs on the side mounted into the arms. Mounted them and found that the arms now have spring force from the very beginning. I shaped the springs when mounted with a plier when the spring itself blocked complete retraction of the arm.
EDIT: I turned the springs around which can be seen where the springs are attached around the fixed pin. It felt better that the springs enter the holes in the arms from beneath. Visible if comparing first photo with last

One more thing if somebody has seen that there is one part missing. I use PAMCO electr ignition and therefore removed the cam that earlier moved the points, (center concentric shaft).

WOW! Now correct timing possible. 
'F' at ~1200-2000 rpm's no problem, turned to '' full advance at about 2800-3000 rpms.
I did not check very exactly when I have to jet the carbs correctly which is possible now when the timing is OK.

The springs are supposed to be loose.
As the engine speed increases those"arms" fly outwards from centrifugal force and  advance the timing. Make sure timing is advancing at 2500 rpm to the double hash marks. That is about 45º

You do not want the timing advancing too late with springs so tight.

I think you need to buy two new springs, and throw the old ones away that you shortened because they are probably too tight now.

You said the timing is advancing at 2800-3000 rpm which is too late.
Caused by the springs being shortened and too tight.

I have never know anyone to do what you have done to those advance springs.

[PeWe]

It works much better after springs are  adjusted
Before constant full advance, not possible to adjust less than 5mm before full adv. I'll check when it reach the full advance. I think it's within the range. I saw that it moved when twisting the throttle and reached full advance marks. I did not check exactly when it changed to full advance. I saw it was at 2800 rpm. Might have changed earlier.
The Honda book say full advance after 2500, F mark on idle 850-950. I do not know if the CX-7 cam will have stable idle at ~900rpm. I measured stable idle at 1000-1200 rpm at F mark.
I'll know when I have got my carbs better jetted.

[lucky]

Do you know what the advance marks look like? Just asking.

[Kickstart]

Do you know what the advance marks look like? Just asking.

Um... that sounds a little condescending. 

I thought I remember Hondaman suggesting cutting off one loop on each spring and doing exactly what PeWe did... but I don't have the book in front of me right now.

PeWe, I think the springs have more slop in them when the eccentric cam is removed, but I could be wrong.  It would be interesting to know what your actual RPM is when advanced is reached... I was thinking about doing the same thing.
 

[PeWe]

Yes, exactly, no cam sloppier springs which most likely is one part of the explanation.
I think the Pamco rotor affect the advancer unit different when there is no points that have a counterforce when pushing them. The springs need to do that job.

Yes, I read the Hondaman's hint to fix the springs. There are some threads discussing it.
I'll check at which rpm  the full advance marks are reached and update this thread that can be something for others with same "problem". Important that it happen AFTER 2500rpm.  F was very stable around 1000-1200 something.

[PeWe]

Do you know what the advance marks look like? Just asking.

I'm very sorry that I did not explain that.
Marks will be visible thru the hole in the plate when using a timing lamp
Hole visible here, same location as the OEM point plate.
http://forums.sohc4.net/index.php?topic=110188.msg1237386#msg1237386

Yellow/white arrows - F mark that should be rather stable at idle.

Black/white arrows-  Full advance. AFTER 2500 rpm.

Lets see at which rpm it start to move and reach full adv. The curve might be something to fiddle with if idle and full adv are OK.

[lucky]

Do you know what the advance marks look like? Just asking.

I'm very sorry that I did not explain that.
Marks will be visible thru the hole in the plate when using a timing lamp
Hole visible here, same location as the OEM point plate.
http://forums.sohc4.net/index.php?topic=110188.msg1237386#msg1237386

Yellow/white arrows - F mark that should be rather stable at idle.

Black/white arrows-  Full advance. AFTER 2500 rpm.

Lets see at which rpm it start to move and reach full adv. The curve might be something to fiddle with if idle and full adv are OK.

Yes thats it exactly.
Very good photo with the arrows too.
Very good for beginners to see this photo.
Good luck with your experiments.

During the time this motorcycle was manufactured the advance was not as critical as on a modern engine where a computer controls the injection and the engines are run at extreme temps. Some direct injection cars now  are running
variable valve timing and 65:1 air fuel ratios!

[PeWe]

EDIT: In all manuals I see now has this data about timing of an OEM CB750. I do not find AFTER 2500.
”F” Mark              10* BTDC
Max advance       35* 
RPM from  “F” to max.  1.200-2.500 rpm

Update!
I checked the ignition again, this time to make sure when the full advance was reached.
~2600rpm, (not less, max 2700) between the marks l l, tricky to check tachometer and timing lamp at the same time. Maybe I should have spent some additional $$ for a timing lamp with rev counter.

I remember a thread about different ignition advance curves and carb jettings. I noticed that the ignition make a difference on idle. I set to 'F', not where the engine ran smoothest.
This might have to do with the current jetting that I'm also working with.

Very interesting thread, Hondaman (of course):
http://forums.sohc4.net/index.php?topic=7401.msg67248#msg67248

I'll change the plugs, to the other NGK Iridium plugs with now increased gap according to Pamcopetes recommendation 0.035" (0.9mm). Now NGK D8EA with std gap ~0.75mm. I have to verify the ignition again, just for sure so I can get the thoughts out of my head.
I start to understand why ignition systems with fully adjustable advance curves exists.

[MCRider]

ITs been known for decades that sloppy springs as you describe affect timing. Irregular distance between coils, overall weird look, means you won't time up right.

As to new parts, AFAIK springs were never available and advancer units are NLA. I've bought up a bunch as I run across good looking ones.

I didn't know it was possible to get good results from cutting the spring. I'll need to read my HondaMan's book on the subject.

"323" advancers fit CB750s and I think perk up the timing a bit.

OCICBW

Not discussed here, but good to know. When swapping cams for other ignitions, DYNA, Prestolite in my case, etc. you can accidentally pin the advancer so it stuck in place. Put it on with the point plate or substitute off. Then put the nuts on. Grab the cam and see that it turns smoothly and snaps back. It might need some emory, or light lube.

[Black 750K8]

"323" advancers fit CB750s and I think perk up the timing a bit."

MC perk up in what way? what do you mean?

[MCRider]

"323" advancers fit CB750s and I think perk up the timing a bit."

MC perk up in what way? what do you mean?

I'm not really sure. The 323 is from the 550/500 lineup. I think if you put it on a CB750 it gives the impression, at least, of quicker throttle response. There is no obvious visual difference other than 323 stamped on the face.

[PeWe]

I'll continue with the advance springs I have now. Engine is not spitting fuel out from the carbs as with the sloppy springs and too early advance. The PAMCO rotor moves free and snap back when turning clockwise and release, better after adjusting the springs. Lubed with thin Lithium grease.

Next is to change plugs as I wrote in earlier post and check/change timing.
I'll adjust timing a little to get smoothest idle,"F" mark is currently not giving smoothest idle. After reading car tuning threads I understand that the timing can (should) be more advanced at idle with a hotter cam. This will change full advance rpm too.....  Good idle first for outside garage revving, singing for my neighbours.   Later verify full advance while driving without pinging and good power all the way.

I work in 2 threads when my Mikuni VM29 carbs are involved in this. http://forums.sohc4.net/index.php?topic=114046.msg1465903#msg1465903
The ignition advance setting/curve and Pilot air/fuel mix affect each other and I hope to find the synergy setup. I think that the carb jetting is OK.

One interesting question I have is: which advance curves that you guys with modified engines have found work well on a street bike from idle up to full?
- Idle setting, exact at F mark or..?
- At which RPM is full advance marks reached?

I doubt that the HONDA OEM settings is the best choice for high CR and cam with higher duration, later inlet valve closing.

[bjbuchanan]

I have reworked the springs with good results. I didn't just cut one coil and say good enough tho. I cut off a little over one and reshaped then popped the whole assembly back on and verified timing. Get yourself a timing light with rpm or check if you have a decent reading tach (if possible, borrow friends tool, get creative) and have fun. It is a little fiddly but rewarding in my case

After the reshaping I got consistent 2600~rpm full advance with a smooth movement. I worked mine a little bit so that it wasn't snapped shut at idle tho. It starts to overcome springs force around 1300 or so

This fixed up after long last my hanging idle. I had ruled out everything and this really helped with smootness and the engine going right back to idle at a stop

[HondaMan]

When the cam timing is wider than OEM, or earlier opening of the intakes before 5 BTDC, it is always helpful to retard the spark advance. The reason: the waste-spark during overlap between exhaust-intake strokes causes some of the leftover fuel to ignite, which makes it "spit" back into the intake tract toward the carbs. This slows down the velocity in the intake tract. When the air moves slower, the carb "thinks" it is in "Idle speed" mode, where it also mixes very rich (12:1 A/F ratio until 1/8 throttle on the typical carbs). This makes the low RPM range difficult to adjust, as there is too much fuel everywhere.

If the spark advances later, as from tighter springs, this "spitback" is greatly reduced. Even with the stock K0-K5 cams, there is some advantage to retarding this timing. I usually set one spring back 1/2 turn at least, and find that both springs cut back 1/2 turn is almost perfect for the Megacycle 125-00 cams. My own bike has a stock K2 cam (now a K4 cam) with 1/2 turn from each spring cut off and slightly extended. It starts advance at 1500 RPM and tops out at 2800-3000 RPM. The difference in clean sparkplugs from this is dramatic! the improvement in MPG around town was also a great benefit, and the engine runs much cooler in heavy commuter traffic.

The torque in the 2000-4000 RPM range is also better, because the bottom end is 'cleaner' and the leftover fuel does not have to be ingested (or wasted) above 3000 RPM: it was already mixed better and burned more completely (yeesh...now that sounds like an EPA ad...   ).

[PeWe]

When the cam timing is wider than OEM, or earlier opening of the intakes before 5 BTDC, it is always helpful to retard the spark advance. The reason: the waste-spark during overlap between exhaust-intake strokes causes some of the leftover fuel to ignite, which makes it "spit" back into the intake tract toward the carbs. This slows down the velocity in the intake tract. When the air moves slower, the carb "thinks" it is in "Idle speed" mode, where it also mixes very rich (12:1 A/F ratio until 1/8 throttle on the typical carbs). This makes the low RPM range difficult to adjust, as there is too much fuel everywhere.

If the spark advances later, as from tighter springs, this "spitback" is greatly reduced. Even with the stock K0-K5 cams, there is some advantage to retarding this timing. I usually set one spring back 1/2 turn at least, and find that both springs cut back 1/2 turn is almost perfect for the Megacycle 125-00 cams. My own bike has a stock K2 cam (now a K4 cam) with 1/2 turn from each spring cut off and slightly extended. It starts advance at 1500 RPM and tops out at 2800-3000 RPM. The difference in clean sparkplugs from this is dramatic! the improvement in MPG around town was also a great benefit, and the engine runs much cooler in heavy commuter traffic.

The torque in the 2000-4000 RPM range is also better, because the bottom end is 'cleaner' and the leftover fuel does not have to be ingested (or wasted) above 3000 RPM: it was already mixed better and burned more completely (yeesh...now that sounds like an EPA ad...   ).

Thanks for the encouraging guidelines!
I noticed yesterday that the engine had better idle when retarded. Iridium plugs with 0.035" gap was not a success either, sooty from earlier tests.
 My engine has never liked anything else than std NGK despite others talking about magic plugs that usually foul after a few minutes. NGK 8DEA and everything is fine

I cut the springs 1/2 turn as visible in the earlier photo with plier. 2 cut-off pieces beside the advancer.
Spot on F at idle, within advance marks at ~2600-2700 rpm.

Next will be a few degrees retarded idle which will make the full advance earlier in rpm if I understand everything correct.
I'll change to new std NGK 8DEA, not sooty as all my other plugs and avoid problems caused by the sooty plugs. Just ordered 8 D8EA plugs from eBay. Maybe I'll buy locally too if I cannot wait

[PeWe]

Huge progress!
- New plugs, NGK D8ES 0.7mm gap (0.0275")
- Ignition very close to line up with F at idle. Just line beside line towards retarded.
The ignition is more retarded in general since the modified springs hold back better.
- Full advance marks reached at 2600-2700 rpm, not less or more (still no exact measurement when I have no rev counter beside timing lamp and ignition)

The markings in case and advance units very close to each other when I timed the cam and checked the true TDC. Line beside line as most deviation.

The springs have good pretension since I cut them and formed them with a plier to ensure the weights to go all the way back with a more distinct snap, without the cam which I do not use since I have replaced it with a Pamco rotor.

The engine ran nice with very close to smooth idle. The pilot jet is probably too big when air screws 2 turns out did not help the accumulative rich idle that had to be cleared by revving the engine with black smoke.

I'll downgrade pilot jets to 20 from 22.5 which hopefully will be the end of ignition and carb tuning.

Finally: The spring advancer spring mod was a clear improvement on my bike when the advancer did not work properly. The higher tension will keep the ignition back at lower rpms which seems to be fine for my cam. Maybe for my high CR pistons too. I'll know next spring when I can drive the bike on higher rpm's and check if it pings when accelerate on high gears from low rpm's.

[70CB750]

I cut my advance springs too and she felt like a new bike; it was very effective for the simplicity of the task.

[AJK]

Hi Pewe,

Lucky is right, your springs are too tight. I too have the pamco and discovered that i was getting timing jitter, especially at idle. This had the effect of an idle that i wan't happy with, but the overall bite the pamco gave me 'feel wise' was good above idle, so i persist. End result, i'm real happy, but read on ...

Before going on, i really like the pamco unit! I found out that you may need to make some tweaks to your pamco rotor to bring it inline with the Honda rotor which is machined to a very high spec.

Ok. The description & pictures are in the following order.

(1) Measure the diameter of the base of the honda advancer rotor. Do this with verniers or micrometers. Honda has seemed to have factored in the spring pre-load in their design, so at idle, your timing doesn't jump around. Honda has also likely factored in points drag which also keeps things stable. See 1st pic and note your measurement.

(2) When you move to the pamco rotor, you no longer have points drag and you may not have the same base diameter. What you need to do is make the base diameter of the pamco the same as the honda one. That way, when you re-install it, the spring preload becomes what honda intended.
  The way i fixed this was to add some high temperature epoxy to the sides, then after it sets hard, used a small file to get the overall base diameter close to the original honda's rotor. This way, your advancer weights will be positioned as honda intended, correcting the springs pre-load.
   This is all in the 2nd & 3rd pics.

(3) The gap in the slot has to be the same as hondas.  The gap I'm refering to is the gap that slots into the advancer lugs (3rd picture). I.e. a tight tolerance when the weight lugs are engaged into the rotor slots. This gap has to be the same as the honda's rotor, so measure the honda's gap and fill the pamco's gap and file until you make it the same as the honda's one. Take your time and get both of them right. What you should end up with is a pamco rotor that upon the slightest of rotation, should contact and engage both weights evenly and immediately from the rest position. In other words, there should be no slack when you begin to move the rotor from its rest position.
  Again, i built this up with epoxy and I ran masking tape on the inside of the rotor to hold the epoxy neatly in place until it set. I used jbweld. Measure your honda's gap (pic 5) and make the pamco's the same.
  The 4th pic in just another angle. Notice how i made a mod to the rotor - see also my other link http://forums.sohc4.net/index.php?topic=113480.0;all

(4) When you rotate your pamco rotor, it must rotate freely and without being notchy, from the initial to total advance positions.

My advice is, put your springs back to how you had them and follow my suggestion. Your end result should be that you get full/total advance at the correct RPM (not at excessive RPMs like i think you have now). On my advancer (early K2, its at full advance at 2000 rpms). You will have to check what yours is, but make sure it follows the factory advance profile, whatever it is for your advancer.

After you do all the work, ensure that your advancer is operating smoothly and freely, with no notchy feel to it.

My bike is running beautiful now. The timing is dead steady at idle (no more jitter) and works smoothly all the way to full advance (when checked with a timing light). The idle and tractibility of the bike up to 2000rpms is so much nicer now its not funny & really enjoyable to ride. After 2000rpms for me, its at full advance just as before.

PS: I know hondaman recommends a sping (half cut) modification, but thats separate to whats being discussed here. Hondamans mod will make your bike run nicer, but what you have done with your springs may potentially ruin your motor.

Hope this helps.
Alex

[AJK]

 Just a correction to my last statement here about potentially ruining your motor with tighter springs. I typed it up too quick without giving it better thought, so forget about that part. To better explain it, if your motor is stock and you have the stock advancer that comes with the bike, if you have tight springs, all that will happen is that it will cause the total advance to come in later in the RPM range. This is because the total advance is governed by the advancer stops. You don't run the risk of over advancing because the stops are fixed at the total advance angle, so there is no risk to the motor in that sense (e.g. pinging, holes through pistons, etc).  (This assumes that your total advance is at the || marks). All that happens is that the timing is more retarded than it was designed at the lower rpms (until it hits the || marks), so until then you will be down on power and generate more waste heat as a result and your economy will go down (I.e. until the weight hits the stop). Not optimal and you will feel it.

  If everything is stock, then the 'F' (initial advance) and || (total advance) marks are all you need to work with. With the timing light, you can either set it at 'F' at idle, then rev it to say 4000 and check that the mark falls between the || marks, or, you can do the opposite which is to raise the RPMs to say about 4000 to be safe and set the mark at ||, then let it idle to make sure its around 'F' (which is the method i use).

So say TDC ('T' mark) is 0 degrees, the initial advance angle is at 'F' (say 10 degrees BTDC), with the total firing angle (say 35 degrees BTDC) at the || marks. This gives you a mechanical/centrifigul angle of rotation of 35 - 10 = 25 degrees which is how far your advancer unit will turn from its rest position (at idle) to its total advanced position at say 2000, 3000 or 4000 rpms, whatever it happens to be for your advancer. The revs at which total advance occurs is advancer dependant, so you will need to check yours.

The spring tension controls the 'gain' of the advance profile graph, so this affects how quickly the ramp/transition occurs from initial to total advance as the revs climb.

So looser springs have the opposite effect, they get you to the stops quicker (steeper graph). On hotted up motors (cams, porting, pipes, carbs, etc), you usually need less total advance because the motor is breathing better at those higher revs (better combustion), so you can bend the stops in (or fill with epoxy) so that you have control over where it stops (earlier), but you want to increase your initial advance to overcome poor breathability down low. So in effect, your mechanical advance needs to be reduced to give you a bike that works nice down low as well as up top.
  Unless one only races at the strip and only really care about total advance, you should give consideration to your advance springs and stop positions if you want to get the best torque out of your rpm range across the board. I.e. Get to understand the concepts.

I've provided a graph below on what i've mentioned above, so hopefully that should help you visualise things better.

As an aside, i'm a firmware engineer with 20+ years experience, so i'm looking at bringing out an ignition system that will let you do all this in software and save it into the flash storage of a microcontroller. That way, one can do away with the advancer plate all together and tune the parameters on your PC to your hearts content (using a serial cable from the PC to the module). Modified bikes would benefit most from such a system. The s/w would work as analogously to the actual mechanical unit in every way so its easy to visualise, with controllable dwell and other goodies. In short, it would be an electronic advancer, but with total control in your hands if you wished. Just an idea i have for 2014 & beyond. The module would be small and located underneath the seat somewhere (away from heat) and would likely have a multi-point reluctor setup on an ignition plate with a single pick-up (which i personally think is the best automotive setup). I'm aiming at 0.5 degree resolution control in the s/w. Of course there will be other features in there like optional anti-theft (keycode), auto-coil switch off (anti-burn), on the fly tuning with your PC, RPM tach output and very low power consumption.
  The system won't be for everyone, but a few tech's out there who like such things can enjoy armchair tuning their machines. Hopefully i can find the time to make it happen, but don't hold me to it. Still toying with the idea at the moment. Until then, cycle-x or boyer would be the closest mechanical advance free systems available for the cb750 that i can find.

Hope this makes sense
cheers
alex

[Kickstart]

Shouldn't your graph have a curve?  I believe spring force is linear but centripetal acceleration force is squared (if that's the correct term - velocity squared).
http://en.wikipedia.org/wiki/Centripetal_force#Formula

Hmm.. I wonder what affect the shape of the advance curve has on performance.

[AJK]

Your right, depending on how the software is implemented, you can have many adjustable points on that slope, so you can effectively create a curve from it. This is like having a distributer with 1 weak spring and 1 stronger one. What this does is get a steeper curve happening off idle, but as the rpms increase, the stronger spring takes over and gives you get a less steeper slope.

Here is an example
http://www.gofastforless.com/ignition/advance.htm

On our bikes, it doesn't have to be that complicated, but can be put into the s/w at not too much added cost if the rest if it is there. Our bikes have 2 springs that are identical, so the spring rate will be the same/uniform as the rpms increase. But sure, you can even put in a true curve (like a polynomial) function to get it to the nth degree once its in sofware. There is so much you can to these days with modern microcontrollers.

To be honest, i have a lot of these fundamentals already in place as i write controllers for hydraulic control systems, so i can borrow a lot of my own work from controllers i have written in the past to build one of these.


Here is another article.
http://classicinlines.com/IgnitionTiming.asp

Keeping it simple for now. F=Kx, where K is spring tension, x is displacement & F is force on spring. Thats pretty much how the graph looks.

PS: i am ignoring vacuum advance  for now. I bikes dont make use of it.

cheers

[HondaMan]

Honda used a balanced mechanical design of points feet to set out the lateral forces and hold the alignments as the cam advanced. The points feet push the advancer back when on the curve at the 1200 RPM point as they also push the slack out of the inner bearing: you can make the bike (with points) slide right past the 1200 RPM point quickly by having enough grease on the feet and (inner advancer shaft) of the points. Without the points to slow this initial advance (which shows up on an old-style Sun Tach Tune machine as a preliminary shallow ramp, followed by a steep one to 1500 RPM), the Dyna S advances too quickly in this region. I suspect the Pamco creates this same quirk, as does the old opto-driven units like Pertronics and Boyer-Brandsen.

Once you get (got?) the "feel" of the 750's advancer, you could tell if the cam/advancer was greased enough (or not) by slowly turning up the throttle through this range, presuming the timing was correct, gap was right, and carbs were set. If it stutters for a second at about 1250 RPM, the cam needed grease. If not, it was OK. If the plugs were clean and the cap resistances right, it pops right up to 1500 RPM like it's aching to rev.

When switching to non-points-driven units, the points cam must be held square to the shaft by some other means, or the advance curve 'teased' to be a little slower in the initial stages. What you don't see in the standard shop manuals is:

they show an idealized linear advance ramp from start-of-advance to end-of-advance, but what really happens is:
it begins advance of a couple of degrees at about 1100 RPM, slowly advancing it to about 1250 RPM with around 2 degrees movement (75 RPM per degree), then advances linearly and quicker to the end at about 50 RPM/degree, with RPM.

For high-revving engines with wide cams, this 50 RPM/degree rate can continue to about 4000 RPM and 45-ish degrees BTC, after which it should back off to about 100-150 RPM/degree to about 10,000 RPM: this becomes impractical for street bikes with normal fuels, though, because they don't burn slow enough.

This low-end sluggish advance is very important for the clutch engagement phase, when you want the torque to not advance suddenly at low bike speeds, least the bike stall or the clutch slip and 'lunge' in RPM, then grab hard at the clutch. Honda was (is?) the King of making these little things work rather invisibly, and in the 'old days' it showed clearly as the driveability difference between a Honda Four and, say, a Kawasaki Z1.

[AJK]

Thanks Hondaman,

You certainly know these units well. After playing with the advancer myself, I'm convinced of Hondas high quality & ruggedised engineering in these advancers (actually the whole bike). Given that it was back in the day & high production runs, its still impressive.
  I can picture a group at Honda making all the components gel together in an integrated way with their ignition system, so the unit behaves correctly on the whole (as i mentioned about points drag and the collection of things). Sometimes you don't realise how nice this integration is until you start to alter their original design (or even a small part of it), and then things don't quite work as expected (or as well).

  I think anyone wanting to beef up their existing ignition would do well buying one of your transistorised units. The reason i say this is mainly for the fact that you get to retain the tried and true high precision honda advancer with the points as an integrated unit, and thus, the advance profile characteristics remain unchanged and as honda intended. As mentioned, the moment you alter their integrated unit by introducing other components into the mix and removing others, you can no longer expect it to behave the same. I have absolutely nothing against points by the way and i used to run a transistorised unit in an old 76 Ford Escort I owned for years, worked a treat. I always run a smear of high temp ptfe grease on the rotor and also on the weight hinges, even though they could run dry.

 I have a pamco unit and don't get me wrong, I'm happy with it, but experience has told me that if you retain honda's very well built mechanical advancer you won't have some of the issues I've come across. Perhaps i'm the exceptional case, but the mods i have made mentioned above can be felt. It can be difficult with these things and I can understand with systems like the dyna and pamco, when machining up the parts, they need to be a slightly looser fit to cater for the general public, because there may even be slight variations in the dimensions of other peoples advancer shafts, slot widths, etc. So necessarily introduce some slop so everything fits out of the box. An example of this is the pamco inner rotor diameter to hondas shaft has a clearance of 0.3mm. This is more excessive than the honda rotor which is closer to 0.05 or 0.1mm. This itself is not a problem or nothing to worry about, but just an example of my point.

  I do like the other systems on the market that do away with the advancer. The optical setup that cycle-x offers is nice due to its high precision, but optical sensors (unless someone can correct me) are only rated to 85 degrees from what i can see. Under continual use it will get hot under the points cover, so i question longevity. Under the points cover actually does get real hot, especially after a hot soak leaving the bike aside after a run, so component ratings need to be carefully looked at. Pamcopetes done his homework on this so i have absolutely no issues in using or recommending the pamco component wise for going the long haul. I'm really not worried at all about being stranded on the side of the road with it. Kind of like waiting for a meteor to hit you, oh it didn't happen, oh well, keep riding. Pete also has installed insulation behind the transistors, so he has given his design due thought, and i think to myself, very good.

So it was this whole timing jitter thing that got me thinking about doing away with the advancer in the first place, but if you maintain the points you won't have this problem (unless you do what i have done above & go into it a bit deeper).

cheers
Alex

[HondaMan]

The "85 degrees" spec is actually in Centigrade, works out close to 200 degrees F.