BritBike Forum logo
BritBike SponsorBritBike SponsorBritBike SponsorBritBike SponsorBritBike Sponsor SteadfastCyclesBritBike SponsorBritBike SponsorBritBike SponsorBritBike SponsorHepolite PistonsBritBike Sponsor
Upgrade to: Gold Membership | Premium Membership | Vendor Membership | Site Sponsor Membership
Member Spotlight
Gary E
Gary E
Medford, Oregon
Posts: 2,704
Joined: January 2006
ShoutChat Box
Comment Guidelines: Do post respectful and insightful comments. Don't flame, hate, spam.
Search eBay for motorcycle parts in following countries
Australia, Canada, France, Holland, Italy, United Kingdom, USA
Random Gallery photo
a word from..
Manuals on DVD (Shipping included)
Previous Thread
Next Thread
Print Thread
Rate Thread
Page 1 of 2 1 2
'68 Spitfire starts but won't stay running
#809291 05/18/20 2:06 pm
Joined: Dec 2002
Posts: 639
Likes: 2
MarcB Offline OP
Britbike forum member
OP Offline
Britbike forum member
Joined: Dec 2002
Posts: 639
Likes: 2
Background: this happened once on the first ride of the year a couple of months back. In approximately the same spot (1 mile from my house) the bike shut off. I pulled over, restarted it, and it had been fine since (about 300 miles since that incident).

Yesterday, I took my bike out and it started sputtering about half a mile away and completely shut off. I fiddled with fuel to ensure I had good flow and wiggled the wiring into the headlight and into the timing case just to see if that helped, but it didn't. I ended up pushing the bike home.

The behavior is this: bike will start and idle for a short time, sometimes long enough to pop into gear and start rolling, but sometimes just enough to think it has started and then it dies. Once it's dead, it doesn't restart on its own even when rolling downhill in gear. Once I come to a complete stop, one kick and it starts right up.

I am attaching a youtube video I took when it happened (issues start around the 1:20 mark). You can see that I'm almost always able to get the bike to restart, though it doesn't stay running for long. It feels to me like an ignition issue but thought I'd solicit input from the community as to how to test the individual components, considering that the bike seems to start up fine in my driveway but fails while on the road.

Here are details on the bike:
'68 Spitfire (9:1 020+ pistons, 932 Concentric premiere carbs), recent motor rebuild (500 or so miles).
Boyer MkIII ignition with 6v coils (about 25 years old)
Sparx 3-phase alternator with solid state reg
New Motobatt MB9U battery

One final note: the headlight remains on while coasting to a stop, indicating that the ignition switch is good, but I'm not certain if that is definitive.



Support Your #1 BritBike Forum!

Check out British motorcycles for sale: British Motorcycles on e-Bay UK, British motorcycles on e-Bay North America
Re: '68 Spitfire starts but won't stay running
MarcB #809296 05/18/20 2:32 pm
Joined: Aug 2001
Posts: 5,130
Likes: 12
Britbike forum member
Offline
Britbike forum member
Joined: Aug 2001
Posts: 5,130
Likes: 12
First thoughts, its running out of fuel.
Or the ignition switch is intermittent.
Or both.

Do some stuff and report back.
Drain float bowls into a white cup, look for stuff in fuel, time fuel flow from both taps.
With a meter set on ohms and the bike fuse pulled , check resistance across ingnition switch terminals when on and off, waggle evrything in the on position and look for flickering resistance readings, should be damn near zero no matter what when On. Ant deviation is a fail. Your headlight wont know the difference but the Boyer will.
How much fuel is in the tank, is the cap breather clear, are all filters clean.


71 Devimead, John Hill, John Holmes A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: '68 Spitfire starts but won't stay running
MarcB #809299 05/18/20 2:56 pm
Joined: May 2013
Posts: 6,665
Likes: 18
Britbike forum member
Offline
Britbike forum member
Joined: May 2013
Posts: 6,665
Likes: 18
I’d guess a wiring issue. Hot wire the ignition to the battery, replace the wires going between the coils and earth, then try again. To kill the engine stop the bike and put it in a high gear then hold the brake on and drop the clutch, the ignition will switch off if it senses no crank movement. So the trigger wires or wires going to the stator plate are also worth checking as is the megnetism of the Boyer rotor.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: '68 Spitfire starts but won't stay running
MarcB #809303 05/18/20 3:07 pm
Joined: Aug 2001
Posts: 5,101
Likes: 9
Britbike forum member
Offline
Britbike forum member
Joined: Aug 2001
Posts: 5,101
Likes: 9
I had this symptom once, caused by corroded spark plug wires. Conduct when cold, not when hot - and it takes but a minute for them to heat up. The same phenomenon can apply to a partially broken wire in the ignition circuit - conducts when cold, not when hot. In this case though, it typically takes longer to fail (and longer to cool).

On the subject of "stuff in the fuel", when you drain the float bowls, look for water too. Water is heavier than gasoline, so if water is present, you'll see bubbles on the bottom of the bowl. As long as the water stays on the bottom of the float bowl, it doesn't cause a running problem, but when the fuel in the float bowl is agitated, the water mixes with the fuel and causes the engine to stall. Once allowed to settle, all is ok again.


Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
Re: '68 Spitfire starts but won't stay running
MarcB #809306 05/18/20 3:25 pm
Joined: Aug 2001
Posts: 6,486
Likes: 14
Britbike forum member
Offline
Britbike forum member
Joined: Aug 2001
Posts: 6,486
Likes: 14
This same thing was happening to my 1971 Triumph TR6R.The TR6R is running points and I also suspected the ignition switch, checked for loose connections, weak battery, coils and carburetor and blocked fuel cap. However, I hadn't thought about the spark plug wires.

Thanks for adding that in Mark Z...that might just be the problem. Simple but overlooked...sheesh facepalm


Jon W.


1957 6T Thunderbird 650
1968 T100R Daytona 500
1971 TR6R Tiger 650
1970 BSA A65F 650
1955 Tiger 100 - Project
1971 BSA A65 650 - Project
1972 Norton Commando 750 "Combat"


"Every time I listen to AC/DC, so do my neighbors"

Re: '68 Spitfire starts but won't stay running
MarcB #809307 05/18/20 3:26 pm
Joined: Dec 2002
Posts: 639
Likes: 2
MarcB Offline OP
Britbike forum member
OP Offline
Britbike forum member
Joined: Dec 2002
Posts: 639
Likes: 2
Fuel looks good. I dropped the plug and also checked the main jet, figuring if it was scummy then the needle and pilot may be as well. Everything was clean. Needle also functional (didn't drop off the clip). Fuel flow looks adequate and fills the bowls with the ticklers in the normal amount of time.

Some questions about bad coil, ht lead, or plug: wouldn't only one side be affected by this? I suppose with EI one coil with a bad primary winding will cut off power to both. Would checking coil resistance show this?

One more point I missed in the original post: intermittently, I would have similar hesitation at high RPMs (above 4000) but the bike would putt around at 3500 without hesitation. This would go show up incrementally, meaning it would start as a minor annoyance and increase as I went along. Next time I took the bike out there were no issues (until this situation).

Re: '68 Spitfire starts but won't stay running
MarcB #809308 05/18/20 3:30 pm
Joined: Apr 2005
Posts: 1,883
Likes: 3
Britbike forum member
Offline
Britbike forum member
Joined: Apr 2005
Posts: 1,883
Likes: 3
Other than fuel problems described above I'd check:
- HT leads, should be solid in their coil seats and spark plug' caps
- Boyer trigger wires, they could loose contact in every connection and in my case it took to disconnect them and connect again to get them working properly, but had to check 2 connections to make them work again.

Re: '68 Spitfire starts but won't stay running
MarcB #809309 05/18/20 3:30 pm
Joined: Mar 2005
Posts: 10,414
Likes: 16
Britbike forum member
Offline
Britbike forum member
Joined: Mar 2005
Posts: 10,414
Likes: 16
Is the Motobat new to the bike?

Does the spark plug wires have resistor caps (required for Sparx 3 Phase Regulators).

If the battery is new to the system, we have heard of Pazon's having problems with Lithium Ion with regulators that are "noisy" (example our 120 watt regulator) . It hasn't been a problem with conventional lead acid batteries. I haven't heard it being a problem with Boyer's.

Is the regulator providing high enough voltage to charge the Motobat, and keep it charged? See Motobat charging requirements.

Re: '68 Spitfire starts but won't stay running
MarcB #809317 05/18/20 4:46 pm
Joined: May 2013
Posts: 6,665
Likes: 18
Britbike forum member
Offline
Britbike forum member
Joined: May 2013
Posts: 6,665
Likes: 18
Originally Posted by John Healy
we have heard of Pazon's having problems with Lithium Ion with regulators that are "noisy" (example our 120 watt regulator) . It hasn't been a problem with conventional lead acid batteries. I haven't heard it being a problem with Boyer's.


Funny you mention this, I once had an issue where I had a Boyer fitted and the bike vibrated violently, for the duration of the ride I hardly kept my feet on the pegs, it never happened with the Pazon or the points I had fitted before the Boyer. The bikes got a 3 phase Podtronics. The same Boyer is now fitted to a friends bike with a Boyer reg rec and works faultlessly.


Originally Posted by MarcB
One more point I missed in the original post: intermittently, I would have similar hesitation at high RPMs (above 4000) but the bike would putt around at 3500 without hesitation. This would go show up incrementally, meaning it would start as a minor annoyance and increase as I went along. Next time I took the bike out there were no issues (until this situation).

Had a similar issue with a dual output coil, a new dual coil fixed the issue. With points I have had 1 coil go bad, the other cylinder kept running but the other died under load (going up a hill) was fine not under load, impedance checks at the coil were all fine but a change of coil fixed the issue.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: '68 Spitfire starts but won't stay running
MarcB #809332 05/18/20 6:20 pm
Joined: Aug 2001
Posts: 5,130
Likes: 12
Britbike forum member
Offline
Britbike forum member
Joined: Aug 2001
Posts: 5,130
Likes: 12
"One more point I missed in the original post: intermittently, I would have similar hesitation at high RPMs (above 4000) but the bike would putt around at 3500 without hesitation. This would go show up incrementally, meaning it would start as a minor annoyance and increase as I went along. Next time I took the bike out there were no issues (until this situation)."

This strongly suggests a bad electrical connection, some places to look.
The fuse, look for corrosion, if its the wee cylinder type clean all connections, fuse and contacts.
Any crimp / bullet in the wiring chain.
The ignition switch itself.
battery earth connection,
motor earth connection, Fresh paint can really spoil your day here.


71 Devimead, John Hill, John Holmes A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: '68 Spitfire starts but won't stay running
MarcB #809453 05/19/20 12:23 pm
Joined: Dec 2002
Posts: 639
Likes: 2
MarcB Offline OP
Britbike forum member
OP Offline
Britbike forum member
Joined: Dec 2002
Posts: 639
Likes: 2
Thanks for the input. I'll have some time to dig into this later this week and will work forward from the battery.

Re: '68 Spitfire starts but won't stay running
MarcB #809620 05/20/20 3:27 pm
Joined: Aug 2001
Posts: 342
Britbike forum member
Offline
Britbike forum member
Joined: Aug 2001
Posts: 342
You may also want to check that you have a good ground connection from the engine to the battery. My 1970 Thunderbolt with a Boyer behaved in a similar manner and a ground wire from the engine to the positive terminal on the battery solved the problem.

Re: '68 Spitfire starts but won't stay running
MarcB #809795 05/21/20 12:11 pm
Joined: Dec 2002
Posts: 639
Likes: 2
MarcB Offline OP
Britbike forum member
OP Offline
Britbike forum member
Joined: Dec 2002
Posts: 639
Likes: 2
Good news: I can reproduce the issue in my driveway so I won't have to rely on as many guesses or side-of-the-road troubleshooting. The bike started well from cold but died while I was putting on my gear. Then, it wasn't as easy to start as in the video above. Once restarted it would die before I could get it into gear.

First test was a battery draw test on my new battery. I planned to use the headlight to see how well the battery recovered but right away I encountered an issue with the headlight not turning on. I opened it up and found a melted connector. The wire to the low beam was bent at a pretty sharp turn coming out of the connector and I'm guessing that's what did it:
[Linked Image from i.imgur.com]

With this issue resolved, I found the battery to be healthy and able to sustain the load and recover to 12.5 V.

I proceeded to check the trigger plate connections and, through the timing cover, things looks good and tight.
I then made my way to the coils and HT leads.
  • Plug cables with 5k ohm caps measure 5k ohms. Ends are tights and fiddling with it didn't change the reading.
  • Coils in series measure about 4.4 ohms on the primary windings (I'm guessing this translates to 2.2 per coil, but I haven't disconnected them from each other yet). Seems a bit high but I'm not sold on this being the issue yet.
  • Coils measure 7k ohms on the output side



I did find that the red wire from coil to battery + was a bit frayed but replacing it with a test lead didn't change anything.

By the time I reconnected everything, I could not get it to restart. I actually see this as good progress because it will be easier to track down the issue if it's not so intermittent. I had to stop there but next steps will be to see if the plugs are firing (assuming it still won't start) and then whether I can get the plugs to fire by bypassing the trigger plate.

Re: '68 Spitfire starts but won't stay running
MarcB #809849 05/21/20 5:34 pm
Joined: Aug 2001
Posts: 5,130
Likes: 12
Britbike forum member
Offline
Britbike forum member
Joined: Aug 2001
Posts: 5,130
Likes: 12
Leaving the bike idling while you put on your gear is part of your problem.
I have a voltage indicator on my bike with a 3 phase high output alternator, at idle the battery does not charge, the budget for voltage starts to balance around 2,000 rpm. Next time you try this check battery volts before and after , expect the after to be a couple of volts lower than the before.
Indeed leaving the bike to warm up with no load is a very bad idea, particularly if it needs enrichment during this period, you are washing oil off the bores and with no load the system does not truly warm up, yes the pipes get hot and will blue with no airflow, but everything else will stay stone ish cold.. People that do this are copying fools. It has no merit, .
I never leave my bike idling for long periods. The motor warms up far quicker under light load, start your bike and ride off.
After about 200 yards knock off the choke, keep the revs below 4K for about 6 miles till the oil has some heat in it.


71 Devimead, John Hill, John Holmes A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
1 member likes this: Allan G
Re: '68 Spitfire starts but won't stay running
MarcB #809859 05/21/20 7:38 pm
Joined: Apr 2005
Posts: 1,883
Likes: 3
Britbike forum member
Offline
Britbike forum member
Joined: Apr 2005
Posts: 1,883
Likes: 3
Hi Marc, just looking at the EI connections doesn't work - they always look good and tight, but oxidize internally.
You have to separate them and connect again. Certainly after checking you lost your spark.

Re: '68 Spitfire starts but won't stay running
MarcB #810199 05/25/20 2:25 am
Joined: Dec 2002
Posts: 639
Likes: 2
MarcB Offline OP
Britbike forum member
OP Offline
Britbike forum member
Joined: Dec 2002
Posts: 639
Likes: 2
One more update:

(Most of the steps below stem from John Healy's excellent article on Boyer troubleshooting: http://vintagebikemagazine.com/technical-articles/Boyer-trouble-shooting/)

I checked the trigger plate connections and everything looked good there. I then pulled a spark plug and touched the trigger leads together to check for spark and got a good strong spark... for a while. After cleaning the connections and before buttoning everything back up I decided to check again and found no spark. I wiggled everything I could think of and still nothing.

I got the multimeter out and checked that I had power at the key switch, ammeter, and all the way back out to the Boyer. Then, out of the blue, it all was working again. Because the Boyer power (white) is located very close to the coil ground (to battery +), and because my coil-to-ground wire looked suspect, I assumed that this bad wire was losing connection intermittently and that wiggling around with it caused everything to work again.

I replaced this ground wire and started testing for spark again... nothing! Got the multimeter out again and continued down the line. Since the Boyer was getting power, next in line was the black wire to coil neg. Nothing there at all.

So, seems to me like there's something amiss with the Boyer box but I would likely blame any failure on the intermittent ground resulting in voltage spikes. I left everything hooked up to see if tomorrow everything chooses to work again but it appears that I'll be looking to replace it.

Re: '68 Spitfire starts but won't stay running
MarcB #810210 05/25/20 6:24 am
Joined: Sep 2013
Posts: 2,464
Likes: 15
Britbike forum member
Offline
Britbike forum member
Joined: Sep 2013
Posts: 2,464
Likes: 15
Quote
... continued down the line. Since the Boyer was getting power, next in line was the black wire to coil neg. Nothing there at all.

So, seems to me like there's something amiss with the Boyer box ...
the black wire ... from Boyer box to coil ... is normally off .

its only on for , milliseconds at a time , when the output transistor gate is opened ,
... the coils are flashed ... and then collapse and Fire when the gate closes .

you have to "work" the 2 trigger wire inputs to get a ... black-wire-output .
one way is to touch the stator wire inputs ... each contact cycles one output ,.( the normal test )
this mimics the AC cycle input of spinning magnets .
where the input circuit senses an ac wave decrease .

Last edited by quinten; 05/25/20 6:32 am.
Re: '68 Spitfire starts but won't stay running
MarcB #810231 05/25/20 2:06 pm
Joined: Aug 2001
Posts: 5,130
Likes: 12
Britbike forum member
Offline
Britbike forum member
Joined: Aug 2001
Posts: 5,130
Likes: 12
Before you condemn the Boyer make sure the ignition coils are not failing, 6 or 12 volt coils? do they get hot when testing?
What is the resistance across coil LT terminals.?
Check each coil seperately across the LT terminals before and after testing. Does anything change?


71 Devimead, John Hill, John Holmes A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: '68 Spitfire starts but won't stay running
MarcB #810253 05/25/20 5:58 pm
Joined: Mar 2005
Posts: 10,414
Likes: 16
Britbike forum member
Offline
Britbike forum member
Joined: Mar 2005
Posts: 10,414
Likes: 16
Marc If you want to we can test the Boyer.
John

Re: '68 Spitfire starts but won't stay running
John Healy #810257 05/25/20 6:17 pm
Joined: Dec 2002
Posts: 639
Likes: 2
MarcB Offline OP
Britbike forum member
OP Offline
Britbike forum member
Joined: Dec 2002
Posts: 639
Likes: 2
Originally Posted by John Healy
Marc If you want to we can test the Boyer.
John
Thanks for the offer. Haven't checked the date code on the box yet but I'd bet it's early-90's.

Let me ask this: if the Boyer has a bad connection on the red wire, would it still output anything on the black? Boyer negative to coil/battery ground is the last thing I haven't checked. Everything else checks out (other than the missing spark).

Re: '68 Spitfire starts but won't stay running
MarcB #810298 05/26/20 12:24 am
Joined: Aug 2001
Posts: 5,101
Likes: 9
Britbike forum member
Offline
Britbike forum member
Joined: Aug 2001
Posts: 5,101
Likes: 9
Originally Posted by MarcB
Let me ask this: if the Boyer has a bad connection on the red wire, would it still output anything on the black?
No.
Originally Posted by MarcB
Boyer negative to coil/battery ground is the last thing I haven't checked. Everything else checks out (other than the missing spark).
Don't you mean Boyer POSItive to coil/batterey ground? Black Boyer wire goes to one coil (-). Jumper wire goes from coil one (+) to coil two (-). Coil two (+) goes to ground (battery positive), and Boyer red wire goes to ground (or to coil two (+), which then goes to ground.

As (Quinten, I think) said, the thing about it breaking up over a particular rpm screams of a connection problem. I've seen this many times.

Check the three wires mentioned above as follows: 1. Push and pull on the wire in its terminal. Remove the terminal insulator if necessary to see what's going on. If there's any wiggle play between the wire and the terminal, that's bad. 2. Feel all the wires for flexibility. If you feel a "limp spot" anywhere, the wire could be partially broken inside the insulation where you can't see it. This happened to me on my A65, in the jumper wire between the two coils. The bike would run about five miles, then die (I have Boyer EI as well), then run again after cooling off 5 to 10 minutes. Took me a couple of weeks to find the problem.


Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
Re: '68 Spitfire starts but won't stay running
MarcB #810301 05/26/20 12:33 am
Joined: Dec 2002
Posts: 639
Likes: 2
MarcB Offline OP
Britbike forum member
OP Offline
Britbike forum member
Joined: Dec 2002
Posts: 639
Likes: 2
I took advantage of a "hey it's working" moment to see if I could get it to fail. Luckily, the street right outside my door is a fairly long hill so, if the motor dies and won't restart, I can turn around and coast back down. After a couple of laps around the neighborhood the motor stalled once but restarted and was fine after. I could get it to stall, though, by making small changes to the black wire at the coils.

It seems that, with the bike in the garage, I could not get it to fire the coils even after messing with the connections there so I'm unsure that's the bulk of the issues. I've come to the conclusion that either the connector on the black wire to coil negative is bad or the Boyer box is bad.

I went ahead and replace the original connector on the black wire and will keep close to home to see if that's all it was.

Re: '68 Spitfire starts but won't stay running
MarcB #810394 05/26/20 8:53 pm
Joined: Dec 2002
Posts: 639
Likes: 2
MarcB Offline OP
Britbike forum member
OP Offline
Britbike forum member
Joined: Dec 2002
Posts: 639
Likes: 2
No improvement with the new connector at the black wire.

I did two laps around the neighborhood: first one it died but restarted one kick, second lap it died and took a bunch of turning-it-on-and-off tries before it restarted.

Re: '68 Spitfire starts but won't stay running
MarcB #810402 05/26/20 10:02 pm
Joined: Aug 2001
Posts: 5,130
Likes: 12
Britbike forum member
Offline
Britbike forum member
Joined: Aug 2001
Posts: 5,130
Likes: 12
Next time it dies have a voltmeter handy, leave ign sw on, put red meter lead lead to batt positive, then follow batt neg, note reading , then black lead to ignition switch blue brown , note reading, then ign sw white , note reading. If these are all close to initial battery voltage with no significant drop then good, ignition switches are more unreliable than coils which are more unreliable than boyers in my experience. Ive never had to replace a Boyer, ive changed several coils and ignition switches.
A bad coil will often fail as it heats up, if you have some freeze spray , next time it fails spray the coils and see if it restarts.


71 Devimead, John Hill, John Holmes A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: '68 Spitfire starts but won't stay running
MarcB #810452 05/27/20 6:10 am
Joined: May 2013
Posts: 6,665
Likes: 18
Britbike forum member
Offline
Britbike forum member
Joined: May 2013
Posts: 6,665
Likes: 18
Good tip on the freeze spray Gavin


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Page 1 of 2 1 2

Moderated by  Allan G, Jon W. Whitley 

Link Copied to Clipboard
Home | Sponsors | Newsletter | Regalia | Calendar | Bike Project | BritBike Museum | Spiders Cartoons | DVD- Manuals & Parts books
Upgrade to: Gold Membership | Premium Membership | Vendor Membership | Site Sponsor Membership
Powered by UBB.threads™ PHP Forum Software 7.7.4