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Old 02-04-2012, 07:00 PM   #46
Pistol
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Pinging is the reason I'm fiddling with the timing in the first place.

I see by your list we have something else in common: the Moto Morini 350 Sport. Mine's a '79.

P
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Old 02-04-2012, 09:19 PM   #47
jm-2008
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Points gap an timing BTDC

[QUOTE=Pistol;17909697]For jm-2008: An update on resetting timing on the '65 M8:

Followed your suggested approach, including cleaning the points. Pulled the flywheel off, checked the location of the 3 screws holding the stator plate on. They're nowhere close to the midpoint--in fact, if I moved the plate to that position, the points wouldn't open anywhere close to the recommended level BTDC. So I shifted the plate back to its original position, then reset the points to just start to open at 3.25mm BTDC, using the two screws as outlined.


But here's where some confusion still exists for me--your notes suggest that
I should set the points gap to .015" at the point where the points start to open up (3.2mm BTD); my understanding, from rereading the workshop manual, is that the points gap (which represents the MAXIMUM distance the points open up) should be set LATER in the cycle, where the two small windows in the flywheel are at the 10 o'clock/8 o'clock position (essentially past TDC).

If the points need to open only very slightly to set off the spark, I could understand this. If that's not the case, I'm confused, because the way the flywheel cam is set up, the maximum points gap seems to occur long after the points start to open. My guess is that if I set the points gap at .015" at 3.25mm BTDC, then the gap would ultimately be far greater a bit later in the cycle (just past TDC).


Thoughts? Comments?


By the way, bike still won't start.


I should set the points gap to .015" at the point where the points start to open up (3.2mm BTD)

May not have explained the process correctly.
The points should start opening (ie: just break contact) at the prescibed setting BTDC.
If you set the points to .015" at 3.25mm BTDC you will in fact have advanced the timing significantly well before the 3.25mm you are aiming at as they will break contact well before the 3.25mm mark you are aiming at - definately not to be recommended (for the sake of the crank, big end etc).

Re JM method -
When the stator (backing plate) is set roughly in the middle of it's adjustment range (ie: screws around the middle of the slots) if you adjust the points to break contact at the prescribed 3.25mm BTDC the gap at fully upen will be in the vicinity of spec .015-018" ish gap.
The important issue here is to set when they break open and not stress about the gap!

FWIW -
Lots of issues can effect the gap, any small radial clearance (tolerance) where the backing plate (stator) fits in the crankcase, loose main bearings, damaged pivot pin (points), worn cam and or cam follower heel (points) can all effect the actual gap.

Note:
Points gap is more critical with a battery-points-coil ignition system (think they are referred to as Kettering systems), I don't believe it will make any tangible difference on these engines, certainly could not tell the difference with any Bulty's I have owned.

As for not starting, can you confirm the folowing -
1) Has it got any compression (primary and secondary)
2) Has it got healthy spark (must be in roughly the right place)
3) Is the fuel mix fresh
If these are OK it should run.
As mentioned previously to eliminate issues with the resistor/diode arrangement ground the green wire coming from the stator to the chassis and you should get a healthy spark all else being correct.
If not check for dust, grit (especially if you have run emery between the points to clean them) and if you have installed new points ALLWAYS run some fine emery between the contacts to ensure they do not have any varnish on the pads, Have definately been caught with all of these causes at some stage in the past.

Note re fuels -not certain what additives they put in your fuels (ethanol etc?) but old fuel mixed with non synthetic oils will develop an acrid smell (before it turns brown and varnish like) and will often not fire up in a two stroke, put it in the Briggs and Stratton mower and more often than not will fire and run! (don't ask me I don't know why!)
Fuels in OZ don't (or haven't in the past) gone off quickly but I understand it can be an issue in the USA, correct me if i'm wrong.

Give me an answer to these questions and we can progress from here.
PM if you wish
Regards,

JM-2008



More random notes on timing -
Timing varies according to the motor characteristics, compression ratio, exhaust pipe, engine stroke, max RPM expected and power curve required.
Sherpa's and Alpina's (the old ones were the same except for gear ratios, seat and tanks) delivery smooth tractable power around 2.8mm BTDC, they run OK at 3.0 - 3.25 but will idle lumpy and throttle response can lack the smoothness you get at 2.8mm
Pursangs, Matadors, Fronteras generally are required to deliver at higher revs hence setting them to slightly more advance BTDC
This is a general rule of thumb for the 250-380cc engines and may not allways apply to the tiddlers.
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Old 02-05-2012, 07:21 AM   #48
PSchrauber
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Mmmh:

Anyway how you do it, first set the gap between the points, it should be not less or spot on 0,4mm but not more then 0.45mm. This has to be done first, (talking from experience).

Now set timing, use a good TDC gauge, insert it where the plug should be and find out TDC, then turn backwards until you hear the beep, now you know when your points will close.

Now mark the rotor and the engine case, just a line that is corrospondending. You can also read now what the TDC gauge shows, mostly something completly different then you need. Go back- or forth until you reach the point where your BTDC shold be, mark this point on the sidecase again, using the red marked line on the rotor which has turned now as an indication where to set the line, here mark the engine case again with a green line.

Now you can take the cover off and loose the stator and rotate the stator from red line to the green line by turning. fasten the bolts, fasten the rotor and measure again. Normally I need two of these procedures until I got the timing correct.

There is sadly no better way to set the timing correct. Once set it will not change, only the point's have to be controlled regulary.
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Old 02-06-2012, 11:45 AM   #49
Pistol
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Thanks to all who have offered advice here. Will take another crack at timing it tonight.

jm-2008: The workshop manual lists 3.25-3.50mm BTDC as the setting for points opening for the Metralla 200. That's where I usually start--at the 3.25mm end of that range. Is 2.8mm really feasible for it, given the recommended specs?

Second--the bike has sufficient compression. It started and ran so-so all thru the fall, until I retarded the timing a month or so ago (because the pinging was troubling me. Kinda wish I hadn't! Oh well, I'll get it set here eventually, and maybe learn a lot in the process, which is more valuable anyway.

Third--fuel is fresh, 32:1 with Golden Spectro oil. So that's not an issue. Carb was pulled and cleaned thoroughly and reassembled...Amals are fine carbs--I have old Amal Concentrics on 3 Brit Bikes that run very well, so the carb is not a problem for me (yet).

Fourth--I did determine that the 3.25mm BTDC value is for the initial opening of the points, as I have always assumed. My issue is how to define exactly that the points in fact are open. The buzz box idea (see above posts) is one I wasn't familiar with, and makes a lot of sense. I just have to find one, or figure out better how to use the cheapo light box I own (which unfortunately hasn't clearly delineated for me when the points are open vs closed). I followed the workshop manual's directions for attaching the clips to the appropriate wire beneath the case, but I must be experiencing some interference, because the light never changes throughout, even when the points are clearly open.

Fifth--re: grounding the green wire coming from the stator to improve spark, haven't tried it, but it's a good idea worth trying.

Sixth--with regard to 'healthy spark', I can only say that I saw no spark when holding the plug against the fins while kicking it, with the points set to open at 3.25mm BTDC...hence the need to redetermine whether those points did indeed open at that exact juncture.

Seventh--the prior owner scratched some timing marks on the flywheel cover, but, sadly, they do not correspond exactly to the dial gauge values. His TDC mark is off slightly from actual TDC, and his marks for 3.5 and 3.0 mm BTDC are way off for both values. Could it be due to some stator plate adjustments?

to PSchrauber: Thanks, and the procedure you outlined for resetting is one I followed last Saturday. Except that it's hard with those two little windows to determine exactly where the points open and close. Pulling the flywheel doesn't necessarily solve the issue, because I need to turn the flywheel to move the cam. Where do you attach the leads on your buzzbox/lightbox to test?

Best,

P
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Old 02-06-2012, 12:05 PM   #50
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[QUOTE=Pistol;17922994]Thanks to all who have offered advice here. Will take another crack at timing it tonight.

jm-2008: The workshop manual lists 3.25-3.50mm BTDC as the setting for points opening for the Metralla 200. That's where I usually start--at the 3.25mm end of that range. Is 2.8mm really feasible for it, given the recommended specs?

Second--the bike has sufficient compression. It started and ran so-so all thru the fall, until I retarded the timing a month or so ago (because the pinging was troubling me. Kinda wish I hadn't! Oh well, I'll get it set here eventually, and maybe learn a lot in the process, which is more valuable anyway.

Third--fuel is fresh, 32:1 with Golden Spectro oil. So that's not an issue. Carb was pulled and cleaned thoroughly and reassembled...Amals are fine carbs--I have old Amal Concentrics on 3 Brit Bikes that run very well, so the carb is not a problem for me (yet).

Fourth--I did determine that the 3.25mm BTDC value is for the initial opening of the points, as I have always assumed. My issue is how to define exactly that the points in fact are open. The buzz box idea (see above posts) is one I wasn't familiar with, and makes a lot of sense. I just have to find one, or figure out better how to use the cheapo light box I own (which unfortunately hasn't clearly delineated for me when the points are open vs closed). I followed the workshop manual's directions for attaching the clips to the appropriate wire beneath the case, but I must be experiencing some interference, because the light never changes throughout, even when the points are clearly open.

Fifth--re: grounding the green wire coming from the stator to improve spark, haven't tried it, but it's a good idea worth trying.

Sixth--with regard to 'healthy spark', I can only say that I saw no spark when holding the plug against the fins while kicking it, with the points set to open at 3.25mm BTDC...hence the need to redetermine whether those points did indeed open at that exact juncture.

Seventh--the prior owner scratched some timing marks on the flywheel cover, but, sadly, they do not correspond exactly to the dial gauge values. His TDC mark is off slightly from actual TDC, and his marks for 3.5 and 3.0 mm BTDC are way off for both values. Could it be due to some stator plate adjustments?

to PSchrauber: Thanks, and the procedure you outlined for resetting is one I followed last Saturday. Except that it's hard with those two little windows to determine exactly where the points open and close. Pulling the flywheel doesn't necessarily solve the issue, because I need to turn the flywheel to move the cam. Where do you attach the leads on your buzzbox/lightbox to test?

Best,

P

FWIW - PSchrauber's procedure is the technically correct one however I have found my method will usually result in the points gap being very close to spec and it's a lot quicker.
What concerns me here is the fact that you saw no spark when you held the plug against the head?
It should be clearly visible (unless outside on a bright day) and should at least be clearly audible.
Not familiar with your light box scenario but the fact that it stays the same all the time leads me to think that maybe the points are not actually making contact when closed.
Either that or you are connecting to the wrong wire - tap in to where the coil primary wire connects to the terminal block.
Otherwise ask around and find someone with a digital multimeter with an audible continuity function and try that.
Again should work like the buzz box.

More random notes -
Amal concentrics are good when set up correctly however they do wear quicker that the Japanese items with anodised slides.
Spanish concentrics look the same but there are differences with the pilot circuit and other items (again from memory)
As for pinging, timing can be a factor however being lean under load may also cause similar symptons.
Keep me posted and we may be able to work through this.
Spark is a must, check first
Regards,
JM
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Old 02-06-2012, 12:47 PM   #51
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Where to attach the wires:
Before attaching the wires of the buzzer, lamp, multi- or ohmmeter disconnect the green wire from earth!
Disconnect all other wires from the ignition / generator that does not belong to the ignition too, the other electrical circuits may efffect the measuring.

Then place the wires of the lamp, buzzer, multimeter to the black wire and to a good earth like the cylinderhead.

Then you need a good tdc dail indicator that will fit to the air cooled cylinderhead, to measure TDC,
I don't want to bore you with German links so here a link from US: http://www.tresnainstrument.com/dial_indicators.html

The pin for the dail has to be extra long, so the dail is above the fins, my set up looks like this:



and assembled:


These dails are working very precicly and are easy to use.

BTW 01:
As the piston pin on Bultacos with ultra short stroke is not in the centre, just one to two mm off to avoid any nick of the piston any geometrical calculation with the crank/conrod will not work.

If you have a Multimeter or Ohmmeter this device normally also have a buzzer adjustment, look up your manual,
the old fashioned buzzer from Motoplat is shown to the right, the Multimeter to the left.




BTW 02:
it is also the possibility to use cigarette paper as an indicater when the points close, works but a fizzle and time consuming.

regards

P too
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Old 04-16-2012, 12:56 PM   #52
Pistol
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An update

Didn't get around to revisiting the Metralla's timing issue until I purchased a buzz box. Sure makes it a lot easier to do! Anyway, I hooked up the buzz box to the appropriate wire and ground, set the points gap to 0.40, and then checked the level of timing advance. It was 3.4 mm BTDC, way too far advanced...no wonder it wouldn't start.

Not only that, but I also noticed that I was getting no spark when kicking it through. I located the break in the copper coil wire and re-soldered it back together. Spark reappeared. Then I reset the timing advance to 3.1 mm BTDC. Bike still wouldn't start. Reset it once more, this time to 2.8 mm BTDC. Bike finally started up and idled well, first time in several months.

Took it out last weekend for a short ride. It accelerates rather poorly now...not sure whether that's timing related, or just poor carburetion. I checked the spark plug and noticed that the bike's running a bit rich now. So I adjusted the needle setting, dropping it one notch, to lean things out. We'll see what that does to acceleration and whether the pinging problem returns...

Stay tuned.

P
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Old 04-16-2012, 04:34 PM   #53
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Quote:
Originally Posted by Pistol View Post

Bike finally started up and idled well, first time in several months.



Stay tuned.

P
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Old 05-30-2012, 09:18 AM   #54
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Wasn't sure where to put this question, but since it's a[nother] Metralla issue and all the experts ( that would be PS and Stainless ) are here.....

Headlight went out - sealed early unit.

I have discovered to no surprise that the original is a rare alloy of unobtainium.
Is there an available option, maybe some Lucas unit ?

I am even considering replacing the bulb with a halogyn - if that could work.

Thanks for any help

John
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Old 05-30-2012, 09:57 AM   #55
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Quote:
Originally Posted by jcf View Post
Wasn't sure where to put this question, but since it's a[nother] Metralla issue and all the experts ( that would be PS and Stainless ) are here.....

Headlight went out - sealed early unit.

I have discovered to no surprise that the original is a rare alloy of unobtainium.
Is there an available option, maybe some Lucas unit ?

I am even considering replacing the bulb with a halogyn - if that could work.

Thanks for any help

John
So is the headlight broken? Most headlights for Bultaco came from the Spanish manufactor Rinder, (as I know).
I found even Rinder replacements / spares for the rectangle unit with the to the glas attached chrome ring and
sealed reflector for my 199b, so the chance to find one isn't too small, (I hope).

My knowledge to Metrallas are limited, can you send a pic, the measurements and maybe the parts number?

The halogen bulbs these will only last long if you connect a regulator in the wiring I believe the
old magneto generators produce some voltage peaks in my experience.
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Old 05-30-2012, 02:15 PM   #56
PSchrauber
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Here the complete lamp, 45.00€ without shipping.
http://motosclasicasmg.com/tienda/pr...oducts_id/3664
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Old 05-30-2012, 03:49 PM   #57
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The headlight it intact.

Will take some shots of it tomorrow.

I have a regulator already - I got tired of buying tail lights.

Thanks.
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Old 05-31-2012, 07:03 AM   #58
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Quote:
Originally Posted by Pistol View Post
For jm-2008: An update on resetting timing on the '65 M8:

Followed your suggested approach, including cleaning the points. Pulled the flywheel off, checked the location of the 3 screws holding the stator plate on. They're nowhere close to the midpoint--in fact, if I moved the plate to that position, the points wouldn't open anywhere close to the recommended level BTDC. So I shifted the plate back to its original position, then reset the points to just start to open at 3.25mm BTDC, using the two screws as outlined.

But here's where some confusion still exists for me--your notes suggest that I should set the points gap to .015" at the point where the points start to open up (3.2mm BTD); my understanding, from rereading the workshop manual, is that the points gap (which represents the MAXIMUM distance the points open up) should be set LATER in the cycle, where the two small windows in the flywheel are at the 10 o'clock/8 o'clock position (essentially past TDC).

If the points need to open only very slightly to set off the spark, I could understand this. If that's not the case, I'm confused, because the way the flywheel cam is set up, the maximum points gap seems to occur long after the points start to open. My guess is that if I set the points gap at .015" at 3.25mm BTDC, then the gap would ultimately be far greater a bit later in the cycle (just past TDC).

Thoughts? Comments?

By the way, bike still won't start.

P
Stop fiddling with the ignition. I am sure the lower end is loaded with fuel and the only way your going to get it to run is take the bike to a really big hill and bump start it. If the bike has spark its not the ignition that is keeping it from starting.

Dave
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Old 05-31-2012, 11:01 AM   #59
jcf
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Hope this light stuff isn't seen as a hijack of the thread - just thought it was the best place to put it as it is another problem someone with a Metralla besides me might need to resolve at some point.

I'll move it if it is in the way.

Anyhow :

Here are the pics - much cooler than a Rinder (didn't want to give it away till I had the pics): says BULTACO on it
and the # 16.21-032 and made in Spain below. HENSEV 67 at the top.



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