B50 with Wassel ignition misfiring

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B50 with Wassel ignition misfiring

Post by bbenxe » Mon Feb 19, 2018 5:59 pm

Hi folks,

got my B50 back together with a rebuilt 6-plate clutch this weekend (thanks for the help Ian Hingley!) to find that although it started beautifully, that was about as far as we got. At any higher revs than idle it starts to misfire, and riding down the lane is tremendously jerky, with the occasional enormous BANG as unburnt fuel in the exhaust ignites. Fresh fuel, battery charged, and was riding lovely when last out about 4 months ago.

I replaced the coil with a new one (whose primary and secondary resistance checks out fine) as I've had issues with a crushed one before that gave similar symptoms when hot, but no joy.

Then I noticed that my battery sits happily at 14V, but leaps up to and over 16V with any revs, which is when the misfiring starts. This would seem to imply my voltage regulator/rectifier that comes with the Wassel ignition kit is no longer doing its job, so I've ordered a new A-Reg One version from Paul Goff that he claims to be more reliable than the Wassel versions.

Now the Wassel ignition claims to work over a range of 10-16V, but the coincidence seems a large one.

Do you think my poorly regulated battery voltage is the likely cause of the misfire? Or am destined to spend next weekend not riding too?

Ben
'66 Matchless G2 CSR scrambler, '71 BSA B50 street scrambler, '75 Bultaco 250 flat tracker, '81 Montesa 200

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Re: B50 with Wassel ignition misfiring

Post by minetymenace » Mon Feb 19, 2018 7:03 pm

It is very easy to take a digital meter and measure volts and assume that it reading is accurate. The +ve rail on the bike's electrics is full of noise that can make a cheap meter read wrong and and expensive meter give unexpected results.

If you are reading over 16v when revving the engine, I would expect to see your battery over charging, may be get warm, and if it is a traditional with wet cells and a vent (rather than a sealed one) I would expect to see the level drop quite rapidly (excessive gassing).

Without seeing the circuit for the Wassel ignition, this next bit is only a guess. It is very common to protect circuits from overvoltage, easily done with a zener or some other device or circuit that clamps the supply to prevent damage to the expensive circuitry inside the ignition unit. It may be that it is the electronic ignition that is regulating your alternator output!

One thing to try is to disconnect the charging circuit (alternator rectifier and zener) and run the ignition (total loss) just on the battery. If you don't get the missfire, it is probably your charging circuit that is the cause of the problem. If you still get the missfire, you may have two problems......sort one at a time.
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Re: B50 with Wassel ignition misfiring

Post by bbenxe » Mon Feb 19, 2018 7:13 pm

I like your thinking Minety. Will try disconnecting the current regulator/rectifier and seeing the effect.

Ben
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Re: B50 with Wassel ignition misfiring

Post by hhh » Mon Feb 19, 2018 7:19 pm

Running the headlight should burn enough juice to bring the voltage down below 15.

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Re: B50 with Wassel ignition misfiring

Post by Jeff K » Mon Feb 19, 2018 8:14 pm

I know a lot of EI will go to full advance(or no retard) if they see low voltage. I am not sure what they would do with too much voltage. Have you tried using a timing light? I known the high voltage is the problem, but I am curious as to what it is doing and if it is damaging the EI.
Jeff

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Re: B50 with Wassel ignition misfiring

Post by bbenxe » Tue Feb 20, 2018 7:15 pm

Thanks for suggestions so far.

Disconnecting the charging circuit seemed initially to have worked, but the misfire returned dramatically after about 3 minutes warming up and then five minutes of riding. Pulled nicely in those five minutes though! Roared to the MOT station (picked up an advisory for the unbaffled exhaust...), but only limped home. Ran out of light to try to properly explore the issue.

Runs OKish just above idle and with only a little throttle, but extremely poor after that.

I'm leaning towards the issue being electrical as nothing has changed in the engine, carb, or exhaust setup since October when it was running very nicely. As a first port of call I will spend next weekend chasing poor connections in the ignition circuit. Will also try to check in a darkened garage whether the spark is leaking out the HT cable onto anywhere else.

I know of no way to test the Wassel EI unit itself. I'll recheck the static timing setup and will attempt to borrow a strobe but suspect this won't show anything much up since there are periods (e.g. before the bike has fully warmed up) when it seems to run very well. Having just bought a new reg/rec that may or may not actually be necessary given the unreliable readings of multimeters I'm not inclined to immediately splash on another EI unit!

Frustrating that the symptoms are so similar to another issue I've had with the same bike that I traced to the coil shorting on it's casing as it had been over-clamped into distortion, and so shorted onto the casing when warmed up! But coil here seems fine. Hmm.
'66 Matchless G2 CSR scrambler, '71 BSA B50 street scrambler, '75 Bultaco 250 flat tracker, '81 Montesa 200

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Re: B50 with Wassel ignition misfiring

Post by Andy Chaos » Tue Feb 20, 2018 7:54 pm

Ben i have been sorting the charging system on my A65 fitted with Wassel ignition and could not get a steady reading on my meter.
It kept going to 18v then zero at the Battery and i very nearly bought a new reg/rectifier.
I discovered the Wassel cdi box interferes with the meter up to approx 8" away but with enough distance it reads a steady 13.5V.
That might have been your problem with the charging as for the misfire does your coil get hot ?
Andy

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Re: B50 with Wassel ignition misfiring

Post by bbenxe » Tue Feb 20, 2018 8:00 pm

I'll check that Andy, it was certainly warm when I touched it but that was after some cooldown time, to the point the exhaust was touchable too.
What would it imply if the coil was hot as opposed to just warm (which I gather is normal)?

EDIT: some googling tells me it would imply resistance has dropped too low in the coil from a short, drawing more power and generating more heat, but I've tested primary resistance at a healthy 5ohms. Will check anyway whether it really is getting hot.

Ben
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Re: B50 with Wassel ignition misfiring

Post by stew79 » Tue Feb 20, 2018 8:45 pm

hi ben, if the coil is getting hot its probably a fault in side the ignition box. (far too much electrical on time) if so it cant be fixed, but take the plug cap of and see how far the spark will jump to the head, from the ht wire. if its less than 6mm that could cause the miss fire. (with a resistor cap and probably a resistor plug you will get less spark energy when its running, better check them with a meter as well) if the spark looks good connect up a strobe light. not to see where its sparking, (thats for later) but to see if it still flashes when the engine misses. if it flashes constantly when missing, it could be a bad plug, or its not in the right place (out with the degree wheel etc etc) if thats right then its the carb or mechanical issues, (only 3 things that make an engine run)
stew

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Re: B50 with Wassel ignition misfiring

Post by Andy Chaos » Tue Feb 20, 2018 9:40 pm

Are you using the correct voltage coil ?
The A65 uses 2 x 6V coils on a12v system.

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Re: B50 with Wassel ignition misfiring

Post by minetymenace » Tue Feb 20, 2018 9:59 pm

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Re: B50 with Wassel ignition misfiring

Post by BSA_WM20 » Tue Feb 20, 2018 11:46 pm

Being a Clubbie for 30 years, thus being exposed to everyone's problems I give any Wassel item a broad berth.
Back in the day they were adequate now days I feel they are all made in China and shipped without any quality control.
Thus there seems to be way too many of their items that a dud from new.
Quadruple check all of the wiring and connections.
High revs = vibrations and a bad joint that just wiggles a little at idle can make & break contact at speeds .
Start by hot wiring the ignition unit directly from the battery, alternator disconnected.
A good battery will run the ignition for around 2 hours.
Problem goes away then the bikes wiring is at fault, not the unit.

Ignition switches are a big cause of problems ( which is why we rewire with relays )
Bike Beesa
Trevor

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Re: B50 with Wassel ignition misfiring

Post by stew79 » Wed Feb 21, 2018 4:28 pm

thats some good advice with the fresh hot wire to eliminate the loom, why didnt i think about that ? but if the coil gets very hot its still got issues.
stew

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Re: B50 with Wassel ignition misfiring

Post by BSA_WM20 » Thu Feb 22, 2018 9:25 am

An electrical load is Watts
Wattes failed physics but passed maths
SO they do not care how they get them
24 Watts is 4V x 6A ; 6v x 4A ; 10V x 2.4A ; 12 V x 2 A or 24V x 1 A
All are 24 Wats but the 6 Amp circuit will get a lot hotter.
Thus is you are getting a voltage drop before the coil it will get hot really quick.
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Trevor

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Re: B50 with Wassel ignition misfiring

Post by stew79 » Thu Feb 22, 2018 10:29 am

all very good but not related to the problem ? (voltage drop BEFORE the coil ?) any way, 5 ohm coil with 12 volts is 2.4 amps if it was on all the time. (thats 28.8 watts, but only in theory not allowing for other losses etc) ) but it should not be on all the time, only pulsed from the electronics (5 ohm coil with transistor ignition wont give that good a spark, usually those coils are a lower res, 2 or 3 ohm)
stew

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Re: B50 with Wassel ignition misfiring

Post by Canberra » Thu Feb 22, 2018 12:49 pm

I spent and inordinate amount of time trying to fix similar problem and found a faulty main switch. Try hot wiring the ignition around the switch and see if that cures it. At least you can eliminate the switch if you still have the problem.
John

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Re: B50 with Wassel ignition misfiring

Post by minetymenace » Thu Feb 22, 2018 1:25 pm

Seems to me there is some very dodgy science going on here. "KISS" as they say, all that is required is some tests to isolate the problem. A thesis on the dissipation of energy within a motorcycle ignition systems should be left until after the problem has been resolved and a celebratory beer or two has been quaffed rendering the contributors a tad squiffy but excusably fluent is BS (bad science I think that stands for). It will be something obvious like faulty switch or dodgy connection, if not, then the tronic nishers or possibly the coil.
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Re: B50 with Wassel ignition misfiring

Post by ghislain » Thu Feb 22, 2018 2:50 pm

Had such a problem few years ago, and it was the kill-switch connectors that had become loose under the tank ... :werd
Perfect starting and idle but after vibrations made contacts uncertains... :idea:
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Re: B50 with Wassel ignition misfiring

Post by kommando » Thu Feb 22, 2018 6:12 pm

Being a Clubbie for 30 years, thus being exposed to everyone's problems I give any Wassel item a broad berth.
Correct, most Wassels stuff is bad and best avoided but this EI is an exception as its made by Vape from the Czech republic who have a good reputation and is not made in China unlike their Lucas Green Box stuff.

All EI's will make you bike more susceptible to original wiring issues as they require a better supply than points can get away with, and of course 90% of electrical issues are to do with the carb.

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Re: B50 with Wassel ignition misfiring

Post by ghislain » Thu Feb 22, 2018 6:23 pm

Very different in France ....Here, 90% of carb problems are electrical .... :laugh
May be a problem of hygrometry??? <214
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Re: B50 with Wassel ignition misfiring

Post by Ian Hingley » Thu Feb 22, 2018 7:52 pm

Hey Ben!

I remember posting on here some years ago asking about fluctuating voltage readings at the battery. The suggestions were that an old-school analogue meter would give more consistent and understandable readings than a digital multimeter. Yes, I've got one if you want to pop round...

I do think the loose connection/bad earth/bad switch suggestions are the way to go first though.

Cheers

Ian
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Re: B50 with Wassel ignition misfiring

Post by minetymenace » Thu Feb 22, 2018 8:14 pm

Mr Hingley wrote:old-school analogue meter would give more consistent and understandable readings than a digital multimeter
.

100% agree. AVO's for ever!
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Re: B50 with Wassel ignition misfiring

Post by BSA_WM20 » Fri Feb 23, 2018 6:38 am

stew79 wrote:all very good but not related to the problem ? (voltage drop BEFORE the coil ?) any way, 5 ohm coil with 12 volts is 2.4 amps if it was on all the time. (thats 28.8 watts, but only in theory not allowing for other losses etc) ) but it should not be on all the time, only pulsed from the electronics (5 ohm coil with transistor ignition wont give that good a spark, usually those coils are a lower res, 2 or 3 ohm)
stew
We wire EI's thus on all BSA's we rewire
Battery fused relay coil battery.
More than once I have measured the voltage at the coil to find it was less than 10 V with a good battery reading 13.5 V
If it plays up as the engine revs up then
1) it is getting spikes from the alternator
2) there is a bad connection making & breaking contact
3) the unit is faulty.
Now you can hot wire various parts, bypassing bits & pieces to determine the culprit .
You can take the EI unit and or coil off the bike to eliminate loose wires or shorts within them.

Be methodical and write down the results of each test.
Bike Beesa
Trevor

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Re: B50 with Wassel ignition misfiring

Post by stew79 » Fri Feb 23, 2018 8:32 pm

has any one heard from hwan recently ? thought he might have been on here recently with some of his ideas. i miss his input, even if i dont agree with him.
stew

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Re: B50 with Wassel ignition misfiring

Post by bbenxe » Sun Mar 04, 2018 9:40 pm

Many thanks all for your suggestions!

Been out riding today and misfire seems totally absent now! Since the misfire was sporadic it was hard to scientifically pin down which fixed the issue as I only had a small lane to test on while it had no MOT, but three things I changed in ascending order of how likely they were to have fixed the issue were:

1) waggled some wires but couldn't identify any actively loose connections
2) leaned out the pilot circuit which I now realise was quite rich
3) relocated the EI box which was strapped directly to the coil and I suspect was being interfered with...

Apart from being caught in this afternoon's torrential rainstorm it felt great to be out riding again! With new 17T gearbox sprocket it's a lot happier at road speeds (was on 14T before!)

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Re: B50 with Wassel ignition misfiring

Post by beat » Sun Mar 04, 2018 10:19 pm

on a snow ride !
:thumb :thumb

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Re: B50 with Wassel ignition misfiring

Post by FGF » Sat Nov 30, 2019 3:39 pm

Hello BBenxe ,

i work on a B50 SS 71 which ignition is a wassel one.

i have no paper about it , if you still have the fitting manual , could you send me a copy ?

many thanks

regards
francois

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Re: B50 with Wassel ignition misfiring

Post by Ubert767 » Sat Nov 30, 2019 4:12 pm

Hello Francois,

See this-------

http://www.grintriumph.com/images/Elect ... W61495.pdf

Rob

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Re: B50 with Wassel ignition misfiring

Post by FGF » Sat Nov 30, 2019 7:35 pm

Thanks UBERT ,

i 'd have a question to dismantle the inner and outer timing cover.

i see the stator plate and i can note it's angular position in the case but what about the rotor ?

can i strip the outer case without loosen the center bolt ?
i 've read the wassel manual and i don't see how is fitted the rotor ..

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Re: B50 with Wassel ignition misfiring

Post by FGF » Sun Dec 01, 2019 3:23 pm

The WASSEL manual tell :

'' 9 Fit the magnetic rotor ...Do not tighten the bolt as adjustment will be required.
10 Hold the stator plate in the contact breaker housing. Centralise the adjustment slots and turn
the magnetic rotor on its taper to align it with the appropriate timing mark (anti-clock A clock
C depending on model).
The stator plate should be central on the adjuster slots with the rotor timing mark central
in the timing position hole. ''

when the rotor and stator are fitted , how can be seen any mark on the rotor ?
wassel.jpg
my fair starting B50
because i've started it twice fairly , i didn't want to change it' s fitting...

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Re: B50 with Wassel ignition misfiring

Post by Ubert767 » Sun Dec 01, 2019 5:05 pm

Hello Francois,

Best practice is to fine-tune the fully advanced timing position using a strobe timing light, once these marks have been used to get the engine running.
Rob
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Last edited by Ubert767 on Sun Dec 01, 2019 9:46 pm, edited 1 time in total.

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Re: B50 with Wassel ignition misfiring

Post by FGF » Sun Dec 01, 2019 7:11 pm

Super Rob ,
i can see exactly the marks when both stator and rotor are fitted.

in this state, it's difficult to rotate the rotor which is behind with a ''large finger'' ...

to reassembly , i put the crankshaft at full advance with the alternator mark .
( the standard mark has to be for 30-31° for a 1971 B50 like mine , 34 ° will be better if i can use a timing disc ...)

then , fitting the inner and outer timing cases , i 've to align the two marks you show on the photo .

it 'won't be very easy but it's the only solution.
may be , i could put a mark on the inner case with the rotor position to begin the reassembly.

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Re: B50 with Wassel ignition misfiring

Post by FGF » Tue Dec 03, 2019 10:11 am

a new discovery : i put the Wassel rotor on it's A mark , full advance timing.
the fitting is close to the good one , just to have a quick sight.
wassel.jpg
the new LUCAS 's mark ( made by my seller or earlier ) seem to be about 30 degres further than the initial mark...
and the bike has start two times easily.
lucas_calage.jpg
i can't run with it because i 've return oil problem but , someone use such fitting with the Wassel ?

second discovery : the lower thread ( outer timing case ) put to 1/4 '' UNF is worn out .. does an heli coil can be put here ? too short ...

thanks for your advices

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