Advice on new starter for Mark 3 ?

When I bought my Mark 3 nearly two years ago, the electric starter was (miraculously?) still working perfectly. Perhaps the prev owner had done the upgrade, or maybe this one was just "special"

Fast forward - the starter has been acting up and is now almost useless. 3 or 4 months ago, on one try out of 10, it would just make a grinding noise instead of turning over the engine. Then it was 1 time out of 5, 1 out of 3, etc.

Now it grinds more often than not.

As much as I admire all the Brit Bike purists who kick their engines to life, I've moved on and want my starter button to do the work for me.

So the question is which option to take, and here is where I am looking for some advice:

1) rebuild the current one
2) buy the Dyno Dave starter for $375 ( http://atlanticgreen.com/store.htm )
3) buy the CNW/Comstock model with its shiny chrome body $495.
4) buy a rebuilt one from OldBritts (4-brush, 4-winding) for $585.

Hmmm, now that I summarize the options so succinctly, it looks like the Dyno Dave option is a no-brainer. However, Dave has a big red "caution" note on his site - "if you use this starter, you should use mechanical points or a Rita electronic ignition. Don't recommend with an analog Boyer"

I have a boyer on the bike, and have absolutely no intention to switch to points.

Note: I have a good strong battery, the upgraded starter wire kit, and a Sparx alternator.

Thoughts, suggestions, opinions from others on their experiences with starters for the Mark 3?
Thanks

Keith

Tri-Spark and Sparx don't have the issues that the Boyer analog has.

pkeithkelly said:

the starter has been acting up and is now almost useless. 3 or 4 months ago, on one try out of 10, it would just make a grinding noise instead of turning over the engine. Then it was 1 time out of 5, 1 out of 3, etc.

Now it grinds more often than not.

Click to expand...

Why not strip the starter motor down, clean it and check it? Also there's a whole lot more to the starter mechanism than just the electric motor, as there's the sprag, the anti backfire device, gears, shafts and bearings within the starter drive that could be part of the problem?



However, if the armature is failing, then replacing the complete unit could be the easiest option?

pkeithkelly said:

However, Dave has a big red "caution" note on his site - "if you use this starter, you should use mechanical points or a Rita electronic ignition. Don't recommend with an analog Boyer"

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The key to the whole thing is battery power with heavier gauge starter cables. If there's enough power to run the starter without the voltage dropping to a point where the Boyer timing starts to wander then there shouldn't be any problems.
As you've said that you have a strong battery and upgraded cables then hopefully you shouldn't have any problems with a DD starter and Boyer ignition? Unfortunately some DD website info is getting a bit out of date (Lucas Rita recommendation for instance), as there are some even better modern alternatives, such as the Pazon and Tri-Spark ignition kits that work down to lower voltages than the Boyer kits, although the new MkIV Boyer is available now, or will be shortly, I think?


My own 850 MkIII has the Prestolite starter, I installed the 4-brush conversion, an AGM battery, heavy cables with a Boyer analog/analogue ignition and since fitting them I've never experienced any electric starting problems whatsoever, one touch on the button, and the engine bursts into life.

I bought my MK 3 on E-bay and the starter was missing. I purchased the one from CNN in Colorado, simply because I liked the looks of it. Blends in well with the rest of the engine. I received it very quickly and I am a happy MK3 owner since the starter works beautifully. I have a problem with my knee and therefore have a hard time kick starting the sucker. It might be a sissy button, but boy do I love it....
P.s. I Have a boyer ignition. As long as the battery is full and in good condition, it works flawlesly.

Josh in cold Canada

Here's an idea that I've had to mitigate the dreaded low voltage problem for the Boyer ignition (anyone with a lot more knowledge about electrics, please comment on its value or practicality). Could putting an appropriately sized capacitor in the ignition circuit insure a constant 12v to the Boyer, thus preventing the erratic timing?

Scooter

Here's an idea that I've had to mitigate the dreaded low voltage problem for the Boyer ignition (anyone with a lot more knowledge about electrics, please comment on its value or practicality). Could putting an appropriately sized capacitor in the ignition circuit insure a constant 12v to the Boyer, thus preventing the erratic timing?

Scooter

Keith, if your starter is making a grinding noise then it is at least turning and my first guess would be that a drop in battery volts when starting has let the Boyer do what it always likes to - fire at full advance, thereby damaging the sprag assembly.

I wish that I had read DD's advice twenty five years ago when my Boyer-equipped Mk111 pulled the hexagons off of the nut securing the anti-backfire device. :shock:

It seems to be a question of when rather than if with a Boyer and electric start and I certainly wouldn't think of re-fitting mine without changing ignition systems. I agree though that points is a step too far

I'm with LAB on this one . I did the 4 brush conversion, added heavy duty cables and a AGM battery. All it takes is a momentary push of the starter button and the bike is running. Also using the boyer ignition .

Ron Hulton said:

I'm with LAB on this one . I did the 4 brush conversion, added heavy duty cables and a AGM battery.

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Regarding the 4 brush conversion, where is this available and what size of AGM battery do you use?

I went the CNW route. Mostly for cosmetic appearance as said here above, it blends in with the motor.

My original starter worked just fine so I might have been one of the lucky ones. I traded it the original off for some Triumph parts that I needed to a fellow restoring his MKIII.

79 x 100 -

Your comment about "the Boyer firing at full advance and damaging the sprag assembly" might be what is going on with my bike.

When I pulled off the sprag a year ago when upgrading to a Sparx alternator, the sprag clutch/bearing fell apart in my hands.

I replaced it with the 18-tooth model from OldBritts.

Maybe the progressively worsening grinding noise when i push the starter button is not actually the starter, but the sprag clutch unit?

Getting eaten up because of Boyer misbehavior? (Though I have a new strong battery & upgraded starter cables).

Any surefire way to test this scenario? (The starter will turn the engine over about 1 time in 5 or so these days).

If I wanted to take the cautious but more pricey path, I guess I would do the following:
1) replace the Boyer with a Sparx or Pazon unit (the Boyer is probably 20 yrs old or more at this point) Cost = ~ $140
2) if problem still there, maybe the damage to the sprag clutch is already done, and I have to replace it. Cost = ~$170
3) If after that I find the starter is the real culprit, i will replace that too. Cost = ~ $400 to $500.

Sure would like to skip the $320 in steps 1 and 2 if I can.

By the way, according to Dave Comeau, in back and forth emails, any starter, when used with the analog Boyer, can trash the sprag unit. He doesn't seem to be a big fan of the traditional analog Boyer. Also added that Boyer is coming out with a new version that supposedly fixes the "low voltage scatter" though he didn't get one for testing yet. And supposedly the Pazon avoids the Boyer problem too. However, the test Pazon unit he had did not work at all.

Ideas for testing and diagnosing?

Thanks

Keith,
The first thing I would do is determine if the starter is turning, but the engine is not. You can pull the primary cover and try starting the engine several times while watching the gear train and crankshaft. If the gear train turns every time you hit the button, but the crank turns erratically, then you have a problem in the sprag clutch and/or anti-kickback device. If the starter motor stalls then you have a problem with the battery, solenoid, connections, or motor. You mention you have larger starter cables, so this is not likely the cause if the connections are good.

If you are at this stage, I would first replace the battery with the highest amperage unit that you can physically fit into the battery box. Since I have twin Mikuni's and tapered K&N air filters on my Mk3 I have replaced the battery box with one from a pre-Mk3 Commando. This will take a much larger battery. (However, I am using a RITA ignition). If this does not solve the problem, then attack the starter motor with a quality rebuild or either Dave's Hitachi starter or CNW's Prestolite clone. You'll need that good battery anyway.

If you find sprag is destroyed, you have treated the symptom. The cure is low voltage tolerant ignition or constant 10+ voltage supply during starting.

With regard to your starter and starter clutch assembly, you might find the following thread useful: http://accessnorton.com/norton_commando1863.html

Keith . Get that starter off and get it checked first . Any decent shop will load test it for you. You also need to confirm whether it is stock 2 brush 2 field coil or the converted 4 brush 4 coil .



rbt11548 .
4 brush plate can be purchased at most bike shops . $50 appr.

High Torque field coils from Accel P/N 40115 $ 50 appr.

My battery is a Deka ETX 14 200 amp.

There is a trick to wiring the starter so give a shout if you decide to do a conversion. Wire it the normal way and it will turn backwards.

Ron Hulton said:

rbt11548 .
4 brush plate can be purchased at most bike shops . $50 appr.

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I doubt rbt11548 would find the 4-brush plate sold at "most bike shops" in the UK, but RGM Motors sell them: http://www.rgmmotors.co.uk/

From my own experience, I can only say that that the field coil conversion may not be entirely necessary? As I can't see that my own MkIII's 4-brush converted starter could be made to work any better than it already does, it turns the engine over very easily and there's certainly no lack of compression.

I fitted the Tri-Spark Classic Twin ignition to my 850 - it's vastly superior to Boyer and works at very low voltages - ideal for lecky-start setups.

mwoo said:

I fitted the Tri-Spark Classic Twin ignition to my 850 - it's vastly superior to Boyer and works at very low voltages - ideal for lecky-start setups.

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Just bought one too, arrived yesterday hopefully it will be as good as reports.... since Her Majesty's Customs kindly decided to instruct me to pay for £28.08 for customs charges... rip off Britain yet again!

Thanks for all the info re -starter, have bought the welding cables to make up the leads and will look at the 4 brush conversion and higher cold crank battery.

L.A.B.
Does your starter have 2 or 4 field coils ? I tried the 4 brush plate and 2 field coils .. pretty useless. Installed the 4 high output coils and this unit is now flawless.

Cheers

Ron Hulton said:

L.A.B.
Does your starter have 2 or 4 field coils ? I tried the 4 brush plate and 2 field coils .. pretty useless. Installed the 4 high output coils and this unit is now flawless.

Click to expand...

= Just the two field coils and the 4-brush plate, and I find that it turns the engine over really quite easily with that setup.

Just the two field coils and the 4-brush plate

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I don't think I understand this. You are using 4 brushes but only two field coils? Do you have two brushes connected to the field coil and two grounded to the case? How does this improve the motor?