Author Topic: Electric leg?  (Read 999 times)

Online RDfella

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Re: Electric leg?
« Reply #15 on: 21.01. 2021 17:58 »
Thanks John. Greater redn that I anticipated. Maybe that's why fringedweller (every time I look at that I think I see 'fridgedweller') experiences a slowish turn-over? Am sure most m/cycle starters are under 20:1 redn. Would be interesting to see what amps it draws.
'49 B31, '49 M21, '53 DOT, '58 Flash, '00 Firestorm, Weslake sprint bike.

Online chaterlea25

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Re: Electric leg?
« Reply #16 on: 21.01. 2021 23:14 »
Hi RD,
One thing I miss from the days at work is the DC grip ammeter, It was a very handy diagnostic tool when blokes cars wouldn't start

John
1961 Super Rocket
1963 RGS (ongoing)

Online RDfella

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Re: Electric leg?
« Reply #17 on: 22.01. 2021 14:54 »
John - the ammeter with a clip at the rear? One in my tooltray - actually two, a plastic one that looks a trifle fragile and an all-steel one. Would hope the starter is pulling around 150A so a clamp (ring type) meter would be easiest. Apparently rule of thumb is an engine requires 1/20th of its horsepower to start - eg a 200hp engine requires c. 10bhp starter. Our bikes at around 40bhp would need a 2bhp starter. At 10v starting current that's 1500W divided by 10 = 150A. Roughly.
On a further note, was looking at an Alton starter kit fitted to a Velocette. From what I can judge, redn. ratio is around 30:1. Am now thoroughly confused regarding best ratio to choose.
'49 B31, '49 M21, '53 DOT, '58 Flash, '00 Firestorm, Weslake sprint bike.

Online chaterlea25

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Re: Electric leg?
« Reply #18 on: 22.01. 2021 17:26 »
Hi RD,
As the starter motors are universal DC type, the only thing that governs the speed is the load put on them and the internal friction,
I think I would start with a highish ratio? if the motor can spin the engine over then its revs will be governed by the effort to do so.
If the motor cannot spin fast enough to operate within its design limits  it will soon burn out

My 2 cents worth
John
1961 Super Rocket
1963 RGS (ongoing)

Offline KeithJ

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Re: Electric leg?
« Reply #19 on: 06.02. 2021 23:03 »
I fitted the starter in 2015/16 and have covered about 5500 miles.  I’ve spent a lot of time and effort on it and generally pleased with it.  However, I could not get it work as consistently as I thought it should even though it started easy on the kickstart.  The bike has a Mikuni carb and has been completely rebuilt, the dynamo has a belt drive and I’m running 12v with a DVR2 regulator.  I have tried two rebuilt mags and replaced the battery (it appears it was OK) but still could not get it to start as consistently as I’d like. 

The impression I had was the starter does not turn the magneto over in the same way as a kickstart which made me think it’s a mag issue.  Using the kickstart, the mag gets a sharp rate of turn but with the electric starter, it is a more consistent rotation.  Having excess oil in the sump certainly will not help.

I was looking at getting my mag rebuilt again but having read all I can about the reconditioning of mags, I did not feel confident I could guarantee getting the quality of rebuild I thought was needed.

Since I am still able to cope with the kickstart but wanting to make starting as easy as possible, I looked at electronic ignition.  I finally decided to go with Thorspark which I have just fitted with manual advance and retard.  It starts OK but due to lockdown, I have not been able to get out on it to see the level of improvement over the mag.

I’ve needed the sprag clutch rebuilt twice due to kickback, once when I forgot to tighten the mag pinion and the other I’m not sure how it happened.  Steve has been very helpful offering advice and prompt repair of the sprag clutch.

I recently had a gearbox problem which required removal of the starter and decided not to reinstall it but would otherwise have left it on.

If I had left the electric starter on with the Thorspark, I may have found that was all that was needed.  Who knows?

My feelings are:
If it is the difference between enjoying your BSA or not, it is a good addition and worth fitting.
Don’t expect it to start a bike which does not already start easily and consistently.
It is well made piece of kit which has been thought through
The instructions are very good and well detailed but do read them a few times to get to grips with what needs to be done, it really pays.

I orignally fitted it as I thought I had a hip problem but pleased to say that no longer is the case.

Just my experience.
'59 A10RR + Second engine

Online chaterlea25

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Re: Electric leg?
« Reply #20 on: 07.02. 2021 01:49 »
Hi Keith,
Thanks for the honest review of your experiences with the starter kit
Steve now insists that an auto advance is used in conjunction with the electric starter
The one thing I am going to add is a direct earth wire from the battery to the starter body
I have an original BTH magneto fitted to my SR, It throws out massive sparks. It will be getting serviced during the work of fitting the starter and gearbox work.
Like everything in life there are mag reconditioner's and there are Mag Reconditioner's

John
1961 Super Rocket
1963 RGS (ongoing)

Online Joolstacho

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Re: Electric leg?
« Reply #21 on: 07.02. 2021 02:05 »
Good to get various views.
I'm saving up!

Offline Colsbeeza

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Re: Electric leg?
« Reply #22 on: 07.02. 2021 02:07 »
Thanks Keith,
I have bitten the bullet and sent off my cush parts for Stephen's modifications. I was fortunate in sourcing a spare set of cush parts locally before I had the courage to risk them - the COVID post not so reliable yet. I posted it on 28th January, and today (7th Feb) after 10 days it has only just got to Sydney airport awaiting a departing flight to UK. Seems it may take a while.
From your comments and John's, it may pay me to go over the dynamo and magneto as they haven't been checked for several years, and add an extra earth.
Col
Colsbeeza
Australia

Offline KeithJ

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Re: Electric leg?
« Reply #23 on: 07.02. 2021 07:48 »
Yes, I had auto advance fitted with my electric starter.  My Rocket originally had manual A/R but when I fitted the electric starter I fitted another mag with auto A/R. Now gone back to manual A/R to use with the Thordpark ignition.  All the best
'59 A10RR + Second engine