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Recent comparison new power arc vs tri spark

Classic Norton Commando Motorcycles.

Re: Recent comparison new power arc vs tri spark

Postby Joe Schlaberdowski » Sun Mar 19, 2017 1:13 pm

o0norton0o, in your post you said you found a few modern magneto designs with an advance? I could not find any. If you can tell what they are, I'd like to look them up -- if they can be easily mounted on a '74 850. Also previous post says NO problems with starting at 28 degrees advance(after small trial and error adjustment for residual knock). Any one else have experience with this? By the way I originally wanted to find out about the brand new power arc, but this has morphed into a mag discussion. Actually I'm very happy about that, but if anyone has info about the new power arc I'd like to hear that too.

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Re: Recent comparison new power arc vs tri spark

Postby ashman » Sun Mar 19, 2017 3:52 pm

Sorry about taking over about new maggies but in 41 years of owning my Norton and gone through 3 electronic ingnitions with 2 failing so far from home, but my last Boyar lasted 30 years trouble free and as far as I know its still on another Norton that I gave it to a friend who since sold it, I have no knollage of the newer EIs but I run my Norton without a battery or at the moment setting it up to just run a very small battery just to have brighter lights when running at night.

As for my JH maggie my Norton is set up as a hot street bike with a hot cam, balanced crank for the Featherbed and lots of head work and Jims PWKs carbies which work really well with the JH, it idles evenly with a bit of a lump with the cam and will go from idle to flat out without any problems, as soon as I screw the throttle open it takes off instantly, usualy with the front wheel lifting, have so much fun on this bike, but I can also ride around town happly on 40 mph in top gear without any problems, my motor runs very freely and the JH has no problems keeping up with it, I can sit on the bike to kick start it and like I have said before many times it will start with only 1/2 swing on the kicker once its been started for the day all day long, but I do have the longer kicker on my bike which also helps.

When I am in the shed with a few mates having a few beers we play a little game, who can kick start my Norton, its so funny watching them try to start it, with the compression they all have troubles and give up after a 5 or 6 kicks, I jump on with just a short kick and it always fire up, it amases them every time, but to me its so funny watching them try.

In nearly 7 years with the JH I think its only kick back on me 3 times but that is usualy when the pistons are down the bottom of the stroke but it still fired up, the moden Maggies are so good, I think Morris maggies do have built in advance units, some don't like them sitting off the cam but I like it and when people ask what it is, some of the BS stories you can come up with its so funny, as well they run cooler on the side of the motor, its such a beautyfull thing why hide it behind the motor.

Ashley
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Re: Recent comparison new power arc vs tri spark

Postby lcrken » Sun Mar 19, 2017 7:07 pm

You are correct about the Morris magnetos, Ashley, at least the newest ones, but they don't make one for Commandos, just Harleys, Indians, Triumphs, and XS650 Yams. Their older ones are pretty much the same as the Joe Hunt, just reworked Fairbanks-Morse units. But Morris now builds their own design, which does have what they call a "start retard" feature, that retards the spark for kick starting, and then returns to full advance as soon as it has started. It's some sort of spring-loaded pawl mechanism, and seems to work quite well. Pretty clever, really. But the Joe Hunt units do not have that, and are fixed advance all the time. More info here

http://morrismagneto.com/

Ken
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Re: Recent comparison new power arc vs tri spark

Postby jseng1 » Mon Mar 20, 2017 8:37 am

See the Morris magneto retard advance lever at:

http://morrismagneto.com/?product=mra-g

Be sure they got it fixed now. I bought one a couple years ago. They didn't have it working right and I sent it back explaining what was wrong. The eccentric that made it retard was not aligned correctly. They said they would fix it but I never followed up on it. Morris doesn't make a mag with a mounting plate for the Commando (Joe Hunt does). But the MRA-G cover with the retard lever is supposed to fit the Joe Hunt as well as the Morris. I dropped the ball on magnetos because I've been busy concentrating on products of my own design.

*****************************************************
Here are the instructions I wrote up when I was adapting the Morris retard lever to the Joe Hunt Commando mag:

Magneto Retard lever mechanism

Replace original points with supplied set, install brass eccentric shaft. Turn cam so points are centered on lobe, turn shaft and stop when gap is smallest largest, set points to .020 inch (0.5 mm). Install new gasket and cap, with o-ring(s) fitted to shaft,. Start with largest o-ring. Push down on the cap by hand only to see if the cap closes against the gasket. Then grab the brass shaft with your other hand and push/pull on it to see if it moves up & down. Choose a combination of Orings so the shaft does not move up and down while the cap still closes against the gasket by hand. Tighten the cap screws gently while checking that the Oring(s) pressure is not too great and that the cover closes against the gasket without too much additional turning of the screws.

Next, install lever with set screw against flat, magnet facing down, and adjust height so
that tip of magnet contacts side of cap screw. The magnet keeps the lever in the advanced
position. Operate lever; if Oring(s) are too tight, they may squish out of place, and lever
will spring back rather than "stick" to the cap screw. Use low strength loctite on set screw. Remove lever when removing cap. For full retard, flip lever clockwise all the way to side of cap. This will retard your engine approx 20 degrees for starting.

Jim
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Re: Recent comparison new power arc vs tri spark

Postby ashman » Mon Mar 20, 2017 2:41 pm

Hi Jim

I really can't see why it needs to be retared for start up as I have always said my Norton fires up first kick every time with the JH advanced without retarding it, the same with my old Triumph with a JH was the same always started first kick every time, seems a lot of stuff you do that is not really needed, I have watched your video of you kicking your Atlas with the JH and my Norton will do the same over and over with the stock JH so I can't really see the fuss over retarding it for start up.

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Re: Recent comparison new power arc vs tri spark

Postby jseng1 » Tue Mar 21, 2017 9:42 am

Ashman
Its a new option for those who want it. Now you have a choice. Some are put off by the Commando side mount mag because there is no retard. This makes the magneto more attractive to those who are concerned about fixed advance and now a few more may go with the mag. No one is forcing anyone to do it.
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Re: Recent comparison new power arc vs tri spark

Postby Joe Schlaberdowski » Tue Mar 21, 2017 12:26 pm

There are two possibilities I see relating to the fixed advance magneto question(and, I'm sure, a whole lot more that I don't see). One, since Ashley fixes the issue of knock, or kickback on startup and pulling from very low rpm, by slightly retarding the advance till it does not occur, he may not be getting the benefit of full advance at high rpm when it could be used -- yet not noticing the loss of power because it is actually slight on less than a "full house" race setup. Or maybe none of us, unless we are competing with someone down at the local red light would notice it either. Or, maybe, since the reason for large advance is the time it takes the flame front to spread, especially in a high rpm situation with the intense swirl of gasses and rapid compression in the combustion chamber, the greatly increasing intensity of the magneto spark with increasing rpm partially offsets the need for such a large advance. Perhaps to the point that the top part of a magneto advance curve would, beyond a certain degree of advance, only bring a marginal increase in power. I know the reason for advance and the dynamics within the combustion chamber are far beyond my ability to analyze just sitting here typing away with no hard experimental evidence. Considering something absurd, obviously you would need NO advance if you could instantly distribute intense spark through out the entire volume of the combustion chamber. So, stating the obvious, degree of spark advance is not something once discovered and now set in stone. But if someone actually has information about this, experimental or otherwise, I'd be very interested. Just revealing my lack of knowledge is all.

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Re: Recent comparison new power arc vs tri spark

Postby Joe Schlaberdowski » Tue Mar 21, 2017 1:42 pm

Does the increased spark intensity that comes of increased magneto rpm increase the speed of propagation of the flame front in the combustion chamber? Thus reducing somewhat the need for such a high advance. So you could get away with retarding the spark a bit for easier starting without loosing too much on the top end.

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Re: Recent comparison new power arc vs tri spark

Postby Joe Schlaberdowski » Tue Mar 21, 2017 2:11 pm

Apologies. The second post above is a condensed version. Reason is I thought the first disappeared.

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Re: Recent comparison new power arc vs tri spark

Postby ashman » Tue Mar 21, 2017 3:10 pm

jseng1 wrote:Ashman
Its a new option for those who want it. Now you have a choice. Some are put off by the Commando side mount mag because there is no retard. This makes the magneto more attractive to those who are concerned about fixed advance and now a few more may go with the mag. No one is forcing anyone to do it.


Hi Jim

Thats all good as so many are so concerned about fix advance, to me it works great the way it is from start up, slow RPMs to flat out without missing a beat and of course carbies play a big part as well, both carbies and maggie must be tuned right, when I brought your PWKs you jetted them for the cam I was running and when I put them on it fired up first kick and with a few small adjustments they work so well together, the only problem with these carbies is sometimes float get caught up on the overflow cube being so close to each other, hopefully I have fixed that problem from your recommened advise, I have been doing a few other mods on my Norton at the moment and hopefully will be out riding it again soon.

Ashley
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Re: Recent comparison new power arc vs tri spark

Postby jseng1 » Thu Mar 23, 2017 10:12 am

ashman wrote:Hi Jim

...the only problem with these carbies is sometimes float get caught up on the overflow cube being so close to each other, hopefully I have fixed that problem from your recommened advise, ...

Ashley


The occasional hang up with the floats on the PWKs turned out to be the float needle ribs catching on the cross vent hole in the needle recess. There are 4 ribs on the sides of the float needle. The corners of the ribs are too sharp and need a little rounding off. I was hitting them with a jeweler file at a 45 deg angle until I got the manufacture to redesign the float needles.
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Re: Recent comparison new power arc vs tri spark

Postby ashman » Thu Mar 23, 2017 3:28 pm

jseng1 wrote:
ashman wrote:Hi Jim

...the only problem with these carbies is sometimes float get caught up on the overflow cube being so close to each other, hopefully I have fixed that problem from your recommened advise, ...

Ashley


The occasional hang up with the floats on the PWKs turned out to be the float needle ribs catching on the cross vent hole in the needle recess. There are 4 ribs on the sides of the float needle. The corners of the ribs are too sharp and need a little rounding off. I was hitting them with a jeweler file at a 45 deg angle until I got the manufacture to redesign the float needles.


Hi Jim

Do you stock these new float needles if so I might order some from you as last time it leaked I couldn't stop the flow of fuel out of the over flow, if you do I will PM you.

Ashley
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Re: Recent comparison new power arc vs tri spark

Postby ashman » Thu Mar 23, 2017 3:42 pm

Joe the orginal poster of this thread, sorry about the take over but you aren't having much luck with your orginal question about the new power arc vs tri spark with comparison, I throught you might get a few replies about that, I had a thread a while ago about the new JH maggies so maybe I should go back to that and add more to it as now there are more interest in the Maggie way, I am no longer interested in any ignition systems that rely on battery power, the extra weight of a big battery to a lighter bike and I know which way I want, my Norton is so much lighter than a orginal Commando and most of my weight is down low for better handling.

Ashley
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Re: Recent comparison new power arc vs tri spark

Postby Joe Schlaberdowski » Thu Mar 23, 2017 8:14 pm

Ashley, I like reading about all this concerning ignition systems. I thought through your success with a Joe Hunt mag and (see a long and boring post above) I've come to the conclusion that the intense spark from a mag at high rpm might require less advance to propagate the flame front in the cylinder. So setting it up the way you do, adjusting the timing until it's ok at low rpm or on start-up just might be fine. Surely some manufacturer has looked at this and can clear it up for me. Once that's cleared up, I'll know whether or not to get that power-arc.

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Re: Recent comparison new power arc vs tri spark

Postby ashman » Thu Mar 23, 2017 9:25 pm

Joe Schlaberdowski wrote:Ashley, I like reading about all this concerning ignition systems. I thought through your success with a Joe Hunt mag and (see a long and boring post above) I've come to the conclusion that the intense spark from a mag at high rpm might require less advance to propagate the flame front in the cylinder. So setting it up the way you do, adjusting the timing until it's ok at low rpm or on start-up just might be fine. Surely some manufacturer has looked at this and can clear it up for me. Once that's cleared up, I'll know whether or not to get that power-arc.


Hi Joe, I am not sure how it works as I am no tec person but I do like how the JHs work the more they spin the stronger the spark and understand what you say about the intense spark at high RPMs, like I have said before I set the timing at 28d static and if I get any kickback at all I just retard it ever so slitely, maybe if you like some more imput I am sure if you contact Joe Hunt themselfs I am sure they would answer your question, they are very helpfull.

Ashley
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