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#537094 - 04/07/14 9:40 pm Am I setting the timing right? 69 A75R  
Joined: Dec 2012
Posts: 23
Mike Mattingly Offline
BritBike Forum member
Mike Mattingly  Offline
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Joined: Dec 2012
Posts: 23
Indiana
Just can't get this bike to start easy. Have the pretty electronic ignition. I've had the carbs cleaned twice, the tank cleaned once, and set the timing at least 5 times. Still have a heck of a time getting this bike to start. Wearing me out! The crazy thing is when I have it on my lift I can start it with little to no effort by hand.

I love riding this thing as it was my dad's but it's frustrating me to no end. Video shows the timing at both 3,000 rpm and at normal idle. After the engine is warmed up, I can't keep it in 4th gear unless the revs are up high. it starts to sputter and pre-ignite like the timing is too advanced.

Also, if anyone has any tips on how to properly start these bikes when cold and also when warm, I would appreciate your tips.


Last edited by Mike Mattingly; 04/07/14 9:44 pm.

1969 BSA A75R
2011 HD FLTRU
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#537104 - 04/07/14 10:27 pm Re: Am I setting the timing right? 69 A75R [Re: Mike Mattingly]  
Joined: Dec 2012
Posts: 23
Mike Mattingly Offline
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Mike Mattingly  Offline
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Joined: Dec 2012
Posts: 23
Indiana
Thanks much on the starting tips. I never have tried it at 1/2 throttle. Again thanks for the other tips. I'll double check the voltage on the battery and get it hooked up to a tender. I know the fuel in it is about 2 weeks old and it is not the higher octane variety. Thanks again.


1969 BSA A75R
2011 HD FLTRU
#537116 - 04/08/14 3:29 am Re: Am I setting the timing right? 69 A75R [Re: Mike Mattingly]  
Joined: Jun 2002
Posts: 9,282
Stuart Online content
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Stuart  Online Content
BritBike Forum member

Joined: Jun 2002
Posts: 9,282
Scotland
Hi Mike,

Several things occur:-

Originally Posted By: Mike Mattingly
the timing at both 3,000 rpm

What's the significance of this figure? That's the full-advance rpm for points, not Boyer-Bransden e.i., which are fully-advanced at around 5,000 rpm; however, when checking full-advance, you have to check that your individual ignition does stop advancing at that figure.

Are 5 KOhm resistor plugs or caps fitted? B-B red box has digital electronics and requires one or the other.

Which alternator rotor mark are you using to time? The rotor should have six lines, three marked "A" and three marked "B"; most triples use the "B" marks but early ones use the "A" - different crankshaft keyway position. So, especially as yours is a '69, you should check with the crankshaft timing mark (under large hex. head on the front of the timing-side crankcase) and plug.

Originally Posted By: Mike Mattingly
I've had the carbs cleaned twice,

Have you checked that the idle passages - all the way from the air filter and float bowl to the little holes in the main choke either side of the engine side of each slide - are clear? Fwiw, the tickover sounded a little high on your video, my triples tick over at around 750 rpm when warm.

Originally Posted By: Mike Mattingly
if anyone has any tips on how to properly start these bikes

Mike's are good, except I hold the throttle just a little open, not half.

Originally Posted By: 68triton
The stutter could be a plug, they foul easy on this model at the lower revs, If using B8ES try a no 7 hotter plug.

Mmmm ... I prefer to stick with the recommended heat - Champion N3, NGK B8 - but use a plug that works over a wider range. I started using B8EV (thin unobtanium/costalotium alloy electrode) back in the late 1970's, now use B8EVX, I get at least the 10,000 miles per set that the manuals say, I also consistently get 2-3 mpg more. bigt As your bike's e.i. requires resistor plugs, imho try NGK BR8EIX.

Originally Posted By: Mike Mattingly
I'll double check the voltage on the battery and get it hooked up to a tender.

. Would I be correct in thinking the bike has three 6V coils? My experience and humble opinion of 6V coils on a triple.

. If you must use 6V coils, bear in mind that the e.i. is nominally 12V so, because of the electronics, the battery should produce at least 13V, any less and the coils get less and produce an even-worse spark. frown

. You should check that the battery is maintaining Volts under load - just checking it without any load isn't any good.

. You should check that all battery Volts are arriving at the e.i. 'box' - i.e. there isn't any Voltage drop between battery and 'box'.

. While you're checking electrics, how is the return to battery positive (assuming standard electrics, not 'converted to negative ground') made? Because Boyer-Bransden fitting instructions don't specifically recommend otherwise, fitters are apt to connect the 'box' Red cable and last coil +ve to whatever. Ime and mho, this is A Bad Idea; those connections should be extended in dedicated cables to battery +ve specifically.

. I would exercise care with a battery tender, there are too many stories for too long that they eventually do the battery they're supposed to be 'tending'. I've only ever used a normal battery charger - albeit one capable of delivering the small Ah necessary to charge a motorcycle battery correctly - charging any unused battery about once a month and I feel cheated if I don't get at least a decade out of even a conventional lead/acid battery.

Hth.

Regards,

#537169 - 04/08/14 1:15 pm Re: Am I setting the timing right? 69 A75R [Re: Stuart]  
Joined: Mar 2006
Posts: 3,465
L.A.B. Online content
BritBike Forum member
L.A.B.  Online Content
BritBike Forum member

Joined: Mar 2006
Posts: 3,465
Norfolk, UK
Originally Posted By: Stuart
Which alternator rotor mark are you using to time? The rotor should have six lines, three marked "A" and three marked "B"; most triples use the "B" marks but early ones use the "A" - different crankshaft keyway position. So, especially as yours is a '69, you should check with the crankshaft timing mark (under large hex. head on the front of the timing-side crankcase) and plug.



As it is a '69 model, then, unless a later type rotor has been fitted, it won't have both the "A" and "B" lines, only three unmarked lines.

#537240 - 04/09/14 12:50 am Re: Am I setting the timing right? 69 A75R [Re: Mike Mattingly]  
Joined: Dec 2012
Posts: 23
Mike Mattingly Offline
BritBike Forum member
Mike Mattingly  Offline
BritBike Forum member

Joined: Dec 2012
Posts: 23
Indiana
Thanks Stuart and L.A.B. The rotor does not have A & B lines. I found the right tick mark by using a plug in the crank for when the #1 cylinder was in the compression stroke. Yes, I am using 6volt coils.

I will go through the list Stuart listed especially testing the voltage under load.

I appreciate everyone's comments. This forum has helped me tremendously.


1969 BSA A75R
2011 HD FLTRU
#537423 - 04/10/14 6:23 pm Re: Am I setting the timing right? 69 A75R [Re: Mike Mattingly]  
Joined: Dec 2012
Posts: 23
Mike Mattingly Offline
BritBike Forum member
Mike Mattingly  Offline
BritBike Forum member

Joined: Dec 2012
Posts: 23
Indiana
Stuart! Thanks for the tip on the resister plugs. I couldn't find anyone in town that had the BR8EIX so I got a set of BR8ES instead of the stock B8ES. World of difference! When I get on it now it lights up and comes to life instead of stumbling along. I hadn't road this particular bike since 1984 when my dad parked it. I was hoping I didn't have something catastrophically wrong with it.

manual says to set the gap at .020" that seems an incredibly narrow gap. Is that what everyone else is running on the triples?


1969 BSA A75R
2011 HD FLTRU
#537459 - 04/11/14 12:09 am Re: Am I setting the timing right? 69 A75R [Re: Mike Mattingly]  
Joined: Jun 2002
Posts: 9,282
Stuart Online content
BritBike Forum member
Stuart  Online Content
BritBike Forum member

Joined: Jun 2002
Posts: 9,282
Scotland
Hi Mike,

Originally Posted By: Mike Mattingly
BR8ES instead of the stock B8ES. World of difference!

bigt

Originally Posted By: Mike Mattingly
Manual says to set the gap at .020"

Might just be a misprint in that manual? I've always used .025".

Hth.

Regards,

#539922 - 04/26/14 5:10 am Re: Am I setting the timing right? 69 A75R [Re: Mike Mattingly]  
Joined: Aug 2001
Posts: 52
Robin Giesbrecht Offline
BritBike Forum member
Robin Giesbrecht  Offline
BritBike Forum member

Joined: Aug 2001
Posts: 52
Whitehorse, Yukon, Canada
Yes resistor plugs or resistor plug caps. Magic. Should also check with a degree wheel the mark on the rotor that is being used to check the timing. They have been known to be off from the factory. Sucks to hole a piston.



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