The Infamous 75' Trick Start 850 (2010)

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Google "Atlantic Green" to reach Dave Comeau.

Graeme, your starter system needs some work. It should not act as you are describing. If the starter simply won't turn over, I would strongly recommend replacing it with a Dave Comeau starter ($350 or so), 4 gauge cables, a new solenoid (my original one showed over 1 ohm of contact resistance), and a big (300 CCA) battery. You can do the whole thing for $500. If the sprag spins, you need to replace the sprag and likely the drive sprocket and crank gear, depending on how badly they've worn (Fred at Old Britts will measure the parts for you, and check the backfire assembly as well). The sprocket, crank gear, and sprag are costly, and replacement usually involves at least two of the three items.

I did all of the above last year. My Mk3 starts as sweetly as my modern bike, with a light touch of the green button. Les is telling us he has a similar experience with his Mk3. You shouldn't expect anything less.
 
I had my original starter rebuilt for $135.00 here in Illinois. A field coil was bad and they replaced the bushing with a bearing. The Sprag replacement cost me $182.00. :cry: I was informed today that a HD motor has been secured for me.I'll report back when the conversion takes place. I have upgraded the cables too. More later ,,,,,,

Tim
 
Thanks Rick, I agree the starter needs work but my pockets are empty at the moment and the kick starter is always available.
I tried to make it fail last week and test the battery to see if that was the problem. It wouldn't not start! I tested the batery after 3 starts ant it had just over 12 volts.
I ran heavy cables, positive and negative to the starter and engine and fitted a new solenoid. Gel Battery too, when the bike was rebuilt.
So I assume the starter is the weak link. It can wait for a while.

graeme
 
Don't you need the housing the field coils go in too? Is the entire HD starter the same size with the same gear teeth count? What about mounting hole locations? Any Different? Any other differences? No one I know around here in the flat lands of Illinois has a converted motor.
Click to expand...

You don't NEED the housing for the field coils, but that's what makes the swap easier. If you use the Norton housing, you have to remvove the screw that holds the coil and solder or spot weld the coil lead to the housing. That can be a pain. Use the Harley field coil (and housing) with the Norton armature and drive side end cap. The starters differ by the armature, drive side end cap and the number of coils installed.

I use new bushings, bearings, brushes, brush holder and springs.

What are you suggesting about Howard Rotavators Ron that they would be better off sold at tractor dealerships, I'm sure JOHN DEER wouldn't want to lower their handling quality
Click to expand...

Just saying...... :roll:
 
Ok sport's fans ,,,,,,, as I mentioned before with a new battery, new upgrade cables, new sprag, and a rebuilt starter I had a spinning gears but no spinning motor. Grrrrrr ..
I was able to find the needed parts for a four brush conversion from a HD P66A starter and had the shop do it.... Ta Da ! Still no better?? :cry: The gears just spin as before with no engagement of the sprag. Sprag is installed per the tech digest diagram. With the primary cover off now I can see the big gear spin but no engagement by the sprag. :? More later ........ :roll:


Tim_S
 
If the big gear is spinning then it can't be anything but the sprag. Why did you buy a new one in the first place? My 35 year old one is working fine with a proper starter motor and battery.
Jon
Indre et Loire, France
 
Tim_S said:
I was able to find the needed parts for a four brush conversion from a HD P66A starter and had the shop do it....

With the primary cover off now I can see the big gear spin but no engagement by the sprag.
Click to expand...

Is the large gear spinning in the direction of crank rotation? As it is possible for the starter motor rotation to be reversed when a 4-brush (4-field coil?) conversion is fitted, so the drive would then run backwards?
 
The reason I bought a new sprag is the cage holding the bearings? was split in three places. Some of the bearings fell out when I took it apart. As for the proper rotation of the starter. It rotates in the counter clockwise direction per the tech digest. Later today I'll take it apart and check the sprag again?? :?

My other MK3 has a 20 year old sprag in it and it works ok.? But I'm not taking that one apart and put the jinx on it.... :lol:


Tim_S
 
Is the large gear spinning in the direction of crank rotation? As it is possible for the starter motor rotation to be reversed when a 4-brush (4-field coil?) conversion is fitted, so the drive would then run backwards?
Click to expand...

The Harley starter normally turns the opposite direction to the Norton and must be reversed when used on a Norton. Just switch brush positions. Jim
 
After I got home from my free lunch with britbike220 I took another look at my sprag clutch situation. I disassembled the whole thing AGAIN and wiped everything down. Shook the sprag and said a few choice words then used a little emery cloth on the gear surface. Put it all together AGAIN but before I put the cover back on it I thought I should try it first. I'll be damed, :!: it spun the big motor :!: Go figure :? I did nothing different than before. And I can't say that in comparision to my other MK3 with a stock starter, the four brush conversion didn't sound like it was spinning any faster than on my other bike? So during the course of the afternoon in the shop I kept testing the system and it worked each time in 6 or 7 tries. Only time will tell .... :mrgreen:
Thank you all for your support.... Now back to the hockey game. 8)

Tim_S
 
Glad you got this sorted Tim. This is an issue I will be looking at in the future as my electric start never worked since I got the bike.With regards to the wiring involved with the starter circuit I read on this site http://www.motolectric.com/index.html the following...

"On the 1975 Norton MK3 they have a starting system which was notorious for not being able to start the bike.
The options were;
buy a new battery every 6 months,
rebuild the starter with a $200 (4) brush kit,
buy a new upgraded starter for $395.
The HICAP starter circuit for that bike costs $75 and after a 45 minute install the bike will start as well as with any of the other solutions. And will continue to start the bike for many many years."

They use this kit http://www.motolectric.com/makes/norton.html
They are using contaminant free copper which increases current flow.Cant argue with them really although maybe expensive for a few short pieces of wires and tiewraps
 
Sounds more like snake oil salesmen than electrical/electronic technicians...
New battery every 6mo?
My bone stock 75 ran the OEM sized YUASA for 4 seasons and only died 1/2 way through the 5th.
Never had to use the kicker. original single phase 180w lucas....ah but had (still have ) RITA ignition.

"For industrial applications, oxygen-free copper is valued more for its chemical purity than its electrical conductivity. OF/OFE grade copper is used in plasma deposition (sputtering) processes, including the manufacture of semiconductors and superconductor components, as well as in high vacuum devices such as particle accelerators. In any of these applications, the release of oxygen (and/or other impurities) can cause undesirable chemical reactions with other materials in the local environment."In practice, nominal conductivity differences between the three grades listed above are less than .1% of .1% at room temperature."...see wikopedia for full text

original norton cable is 1.588 ohms per foot, my 6 guage cable is .3951 ohms per foot. in theory thats 24.8% of original resistance.
I was able to verify 40% with test equipment.

what are their numbers...yup snake oil salesmen.
I would not doubt their cables work for $90 ($75internet) but not entirely for the reasons they tout.
:roll:
dave
atlanticgreen.com

speirmoor said:
Glad you got this sorted Tim. This is an issue I will be looking at in the future as my electric start never worked since I got the bike.With regards to the wiring involved with the starter circuit I read on this site http://www.motolectric.com/index.html the following...

"On the 1975 Norton MK3 they have a starting system which was notorious for not being able to start the bike.
The options were;
buy a new battery every 6 months,
rebuild the starter with a $200 (4) brush kit,
buy a new upgraded starter for $395.
The HICAP starter circuit for that bike costs $75 and after a 45 minute install the bike will start as well as with any of the other solutions. And will continue to start the bike for many many years."

They use this kit http://www.motolectric.com/makes/norton.html
They are using contaminant free copper which increases current flow.Cant argue with them really although maybe expensive for a few short pieces of wires and tiewraps
Click to expand...
 
As Dave Comeau has stated, on his website and in this forum, the three OEM starting cables are insufficient to deliver the initial starting current demanded by a decent starter (the instantaneous voltage drop across the cables is too high). Upgrading the cable size to 6 gauge solves this problem. Claims of improved performance using exotic metals is nonsense; ordinary copper does the job. If you want to make them yourself, any decent marine supply store carries 6 gauge, and even 4 gauge, cable and the appropriate terminals.

You should really look hard at Dave's starter upgrade. It's about the same price as a starter rebuild, and is shorter, lighter, and looks better than the original. It made an impressive difference on my rebuilt Mk3. Yuasa makes a 300 CCA sealed battery that just fits in the Mk3 battery tray.
 
I too had issues with starting. All the normal symptoms. But I fixed it, and I fixed it with prejudice.

I ordered a starter and cable upgrade from Dyno Dave, and added the biggest gel battery I could squeeze into the battery box. It now spins over faster than my R1. I've now got a second 850 that I picked up at Barber two weeks ago, it doesn't have a Dyno Dave starter, but it will soon.

$0.02,
Rod
 
The newly converted starter on my MK3 project cost me $100 total. The HD field coil I needed cost me $25 of that $100. I don't know what the spring/brush kit cost? I saw them listed for $50 in the J&P Cycle catalog for that. My local starter rebuilder shop did the work. The 6ga. cable can be purchased from NAPA. They will cut it to length as they sell it in bulk. They carry the connectors to. Can anyone give me a part number off of their high torque starter? What brand is it?
I heard one of Dyno Dave's starter's in action and it sounds like a mini jet engine. :)


Tim_S
 
rick in seattle said:
You should really look hard at Dave's starter upgrade. It's about the same price as a starter rebuild, and is shorter, lighter, and looks better than the original. It made an impressive difference on my rebuilt Mk3. Yuasa makes a 300 CCA sealed battery that just fits in the Mk3 battery tray.
Click to expand...

Rick -

do you have the model # for that Yuasa battery. I'm due for a replacement and want to pack as many CCAs as I can into my Mk3 battery box too.

Thanks

keith Kelly
 
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