Norton Dominator 99 with K2F magneto

Update,

Its now revving little bit higher than before, but seems to be that only left cylinder is spitting flames.

Looking at the degree wheel with strobe i can see 5° difference between left and right cyl at idle..

Watching degree wheel with strobe while trying to rev i could see the wheel move/advancing about 20°, its hard to see because the numbers are sailing back and forth like its advancing and not advancing and advancing..
 
As I understand it, you have set the point gap, but have not reset the timing as yet.

The timing on the cylinders will vary by 2 degrees for each 0.001 inch difference in point gap. Converting to mm, this is about 8 degrees for each 0.1 mm. Your numbers are consistant with that. Note: trying to set one point gap on the small side to compensate for the larger gap, has no effect on timing difference between the cylinders.

You must lock the cam ring. I would agree you should ditch the manual cable, manual cam ring, and replace cam ring with new AAU type.

Slick

Update: your last post came in while I was composing this one. Have you reset the timing by removing and resetting the AAU?

The behavior of the advance you are seeing is most odd .... The AAU should go to full advance with rpm over 2500, and stay there. Perhaps the cam ring is dancing back and forth ..... lock it up!
 
Last edited:
texasSlick said:
As I understand it, you have set the point gap, but have not reset the timing as yet.

The timing on the cylinders will vary by 2 degrees for each 0.001 inch difference in point gap. Converting to mm, this is about 8 degrees for each 0.1 mm. Your numbers are consistant with that. Note: trying to set one point gap on the small side to compensate for the larger gap, has no effect on timing difference between the cylinders.

You must lock the cam ring. I would agree you should ditch the manual cable, manual cam ring, and replace cam ring with new AAU type.

Slick

Update: your last post came in while I was composing this one. Have you reset the timing by removing and resetting the AAU?

The behavior of the advance you are seeing is most odd .... The AAU should go to full advance with rpm over 2500, and stay there. Perhaps the cam ring is dancing back and forth ..... lock it up!
Click to expand...


Hello, i have not resetted the timing yet, i was running engine without magneto end cap but i could not see cam ring move, but i will lock it up and then reset timing.
 
I started to think back how it all started so maybe could figure it out.

I went to gas station and filled tank up with Shell V-power or thats what i meant to fill in. Soon after i went to the highway.

I told i was riding about 100kmh and i tried to accelerate it was coughing back to carb with high rate so i had to ease up the throttle, could still ride 100kmh.

Then i pulled over when i had a chance and changed plugs and continued. It did not help and i still could ride it somehow about 80kmh but not more and at this point it was really jerky to ride and was coughing and banging slightly to exhaust, slowly it ran weaker and weaker and once more changed plugs.

After last change it was running so bad that it was not coughing to carb anymore but was shooting flames out of exhaust with loud bangs. At this point i barely could ride it but with top speed of 30kmh and i got it home and it hasnt changed ever since.

If something like AAU slipped taper would had happened it would instantly go bad and not slowly, right? I could assume that the first coughs to carb was the beginning of the problem.

Could it be possible that the spark is too weak to lit the mixture properly at higher revs because of the condenser/capacitor?
 
Try draining your fuel tank, and refill with fresh fuel from a differentt station. A friend recently got diesel at a filling station (tank truck operator dropped diesel into wrong tank)... his car ran, but not well. His wife's car, which he fueled at the same time, managed to get 50 miles away before it quit for good. I would expect diesel to burn slow and give similar results to yours.

Never-the-less, you measured timing to be very late (18 BTDC @ full advance). The fuel quality has no effect on your measured value. Very late timing will cause flames and bangs (which is fuel burning in the silencers) .... The capacitor is not to blame for this.

Slick
 
I will check the timing again and change fuel to differend.

After adjusting point gab the last timing result i got was reasonable 35° BTDC full advance on other cyl. But i will check it tomorrow.
 
I heard an theory about the condenser.

When the points are arcing/sparking when they open like mine is doing right now, it will retard the ignition because the arc keeps the points "closed" even if they would really be open/not touching each other, and that way it takes longer time spark in plugs.

Edit: Does anyone have any experience with the Brightspark easy caps? Are they worth it, are they better than original or original replacements? Or is the best option to use original type condensers
 
Last edited:
KuusistoNorton said:
I heard an theory about the condenser.

When the points are arcing/sparking when they open like mine is doing right now, it will retard the ignition because the arc keeps the points "closed" even if they would really be open/not touching each other, and that way it takes longer time spark in plugs.

Edit: Does anyone have any experience with the Brightspark easy caps? Are they worth it, are they better than original or original replacements? Or is the best option to use original type condensers
Click to expand...
I like the condenser theory but it's just speculation until you resolve the timing issue by fixing the cam ring in place and resetting the timing to the correct advance. Can't solve anything without proceeding logically and correcting known problems and then ruling out other potential ones. There's probably a term for this approach but since I'm an amateur I don't know it!
 
Today i will remove the cable and see if i could fit a screw that would be pushing the original plunger down, if not then i need to machine new bolt with fixed plunger.
 
KuusistoNorton said:
Update,

Its now revving little bit higher than before, but seems to be that only left cylinder is spitting flames.

Looking at the degree wheel with strobe i can see 5° difference between left and right cyl at idle..
(QUOTE]

5 degrees is too big a difference between cylinders at idle, it will be the same on full advance-then you will almost certainly have the engine eating a piston!!!!
You need to have the magneto points opening at 0 and 180 degrees static this is achieved by cutting the mag bearing skims into quarters and fitting into a corner to correct it, the other method is to stone the cam down, which is much harder.
Click to expand...
 
Hello,

I was working later today so i did not have much time to work on the bike.

However i changed the fuel to fresh one and tried it out.

It was running better, could rev it little bit it was sounding like it would have electronic limiter at higher revs. Not spitting flames anymore from exhaust but it was spitting flames through carb.

Would the flame spitting through carb be to advanced ignition? One thing that also comes in mind is that the spark is jumping to wrong plug..

I dont know if im bothered trying to find the problem at this point anymore since the mag needs attention and service so i will have to take it out of the bike and try to fix it. After magneto is in good shape then we'll see if we have some problems with running the bike.

For the condenser/capasitor i was thinking of the brightspark easy cap solution. The cam ring has lot of wear so replacing it to a new auto avdance type cnc machined is necessary and that way i dont need to make to cam ring stop bolt either.
 
If you wish to have the magneto properly rebuilt, and I do not think anything but proper is worthwhile, send it to a competent technician/rebuilder. A proper rebuild is not a DIY project. It is a costly project, about $450 US, plus $100 more if you need a new cam ring.

While the job seems expensive, consider what is involved ..... new bearings, seals, capacitor, slip rings, brushes, high tension pickups, points block, rewound armature, magnetic boost, plus labor, and testing. A good technician will also, or should, properly center your cam ring to equalize the point gap, which will ensure your timing is equal on both cylinders. It is very important the armature spindle is perfectly centered, and that requires special tools and skill.

I take it you are in Europe, somewhere. Put out a post asking for referral to good K2F rebuilders where you live. Take it from there.

When your mag comes back, set up the timing according to my tutorial. If you do it right, you will not be disappointed, your bike will run better than ever.

Good luck with it.

Slick
 
Hello,

I cant get it how would it be so difficult to do by yourself.

With my working experience i would say that i could do everything else expect the windings, magnetizing and testing it out expect at vise.

But if thats so, then i'll throw magneto to trash can and fit electric ignition with just 1/4 of the price of reburnished magneto.
 
Yeah of course they do, but you need to only set the base advance and thats it. Rest is done with the computer and you can make the curve as you like it.

And im talking about the ignitech which i am familiar with already.

For example if original timing would be 32° BTDC and the AAU provides 24° advance which leaves 8° to you. Im considering that 8° advance as base advance since its fixed in place. Also you can set limiter at any rpm youd like.

Im talking about base advance since Moto Guzzi used to talk about base advance in their manuals.

And i think that its not so critical to get it spot on with the same way setting up magneto, since if you just get it close enough with the taper thing, you usually have lots of room to play with the pick-up plate to correct it up.

And its easy to try out differend advance curves and max advances, even to fiddle the base advance you dont need to do much. And if you want it even better you can use eiher TPS(throttle position sensor) or map sensor along with the ignition so instead of basic 2D advance curve you get 3D.
 
I were reading about boyer and pazon ignitions and they all seemed to have same type of timing procedure as mag.

I still could not quite get it why are you timing those when the crank is for example 32° BTDC position, and then hook the rotor in place and then stator plate.

One electric ignition from oldbrits i guess were set to TDC. I mean you had to find TDC and then you just turned the rotor until led light lit up and you tightened rotor into place.
 
KuusistoNorton said:
Hello,

I cant get it how would it be so difficult to do by yourself.

With my working experience i would say that i could do everything else expect the windings, magnetizing and testing it out expect at vise.

But if thats so, then i'll throw magneto to trash can and fit electric ignition with just 1/4 of the price of reburnished magneto.
Click to expand...

Here is a link that is very comprehensive and explains all that is involved in DIY magneto rebuild. Besides skill, special tools are necessary.

http://www.britbike.com/forums/ubbthreads.php?ubb=showflat&Number=446733#Post446733

If you have no special love of magnetos, go for one of the EI. Rather than trash the one you have, send it to me .... I will pay the shipping!

Slick
 
Last edited:
texasSlick said:
Here is a link that is very comprehensive and explains all that is involved in DIY magneto rebuild. Besides skill, special tools are necessary.

If you have no special love of magnetos, go for one of the EI. Rather than trash the one you have, send it to me .... I will pay the shipping!

Slick
Click to expand...
Slick, you beat me to it! I've been thinking about having that mag thrown out in my direction since I read the last post. On a more serious note, mags and EI both have their positive points (bad pun intended) but unless already upgraded, installing EI will probably require upgrading the charging system to reliably produce some more watts: possibly a new stator, rotor, regulator/rectifier and new coil(s). Can't get home with a dead battery on an EI system. By recollection the original system on a bike with a mag put out 80 watts on a good day when new. Norton weren't about to pay for a single watt more than the bare minimum, especially since the mag was supposed to take care of ignition. Can't remember if Model 99's originally came with coil ignition, but even so the system wasn't happy running brights for any period of time. By faded memory, in the UK in that era you could legally run in built up areas at night with just the parking light on.
 
KuusistoNorton said:
I were reading about boyer and pazon ignitions and they all seemed to have same type of timing procedure as mag.

I still could not quite get it why are you timing those when the crank is for example 32° BTDC position, and then hook the rotor in place and then stator plate.

One electric ignition from oldbrits i guess were set to TDC. I mean you had to find TDC and then you just turned the rotor until led light lit up and you tightened rotor into place.
Click to expand...

You’d be foolish not to check timing with a strobe, on any system.
 

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