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1972 Commando running issues - pls help a new owner.

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1972 Commando running issues - pls help a new owner.

Posted by richard_chan at April 07. 2017

Hi everyone,

I've acquired a 1972 Commando, and since then, i thought i could get it on the road asap, but seems not.

I have had mega short rides and found in any gear, the bike will cough and not rev pass 2-3000rpm. Twisting the throttle does nothing after 2500, it just doesn't want to accelerate.

Since then, i have cleaned out the carbs with a Andover Carb rebuild kit, the carbs didn'tseem so dirty to me for a bike which was sitting for about 10 years.

New filter and new rubber, gaskets connecting the carb, new fuel line and take outlets.

Today I started her up again, hoping it was just a blocked jet, but it has still not solved the issues. The bike basically is doing the same thing. On the stand, full throttle, it will only go up to 3500rpm or so before shutting down completely.

I have not yet checked the timing as yet, and it looks like it is a Boyer ignition system? I'll have to double check.

What else should i be checking in my case? Is it a timing issue?

Usually I'll put it down as a carb issue, but i spent a good hour on each carb making sure it was all ok. Unless I'm missing something?

Any help would be appreciated.

I'll keep updating this thread when i have had a chance to look at the timing more.

Thanks.

Rich

Re: 1972 Commando running issues - pls help a new owner.

Posted by john_holmes at April 07. 2017

You need to check the timing, both the fully advanced position and that it is advancing. Check tappet clearances etc. Have you replaced the rubber tube that runs between the 2 inlet manifolds, if its leaking from being split then that will stop you accelerating.

Re: 1972 Commando running issues - pls help a new owner.

Posted by robert_tuck at April 07. 2017

The fact that it shuts down completely says its an ignition failure , bad timing or tune will normally keep running  somehow.  Boyer stator plate wiring failure is common.

Re: 1972 Commando running issues - pls help a new owner.

Posted by richard_chan at April 07. 2017

Hi John, thanks for the reply.

Timing is the next thing to do, tappet clearance will be done together.

 

And yes, i changed out the hose between the carbs. It's snug now, only had the bike running in the garage, so will check for leaks again when possible.

Thanks for the tips.

 

Previously john_holmes wrote:

You need to check the timing, both the fully advanced position and that it is advancing. Check tappet clearances etc. Have you replaced the rubber tube that runs between the 2 inlet manifolds, if its leaking from being split then that will stop you accelerating.

Re: 1972 Commando running issues - pls help a new owner.

Posted by richard_chan at April 07. 2017

Thanks for the reply Robert.

I have no experience with Boyer. If stator plate wiring fails, a replacement is required I'm assuming? Would a Pain Surefire replacement be worth swapping out?

The Boyer unit it self looks a bit tired tbh. I am looking for a plan B if the unit could be the problem. But in saying this, the bike only shut down when i was really full throttling it on the stand. It could have been over fueled hence shut down? But the strange thing is still that it never got up pass maybe 4k rpm...

Previously robert_tuck wrote:

The fact that it shuts down completely says its an ignition failure , bad timing or tune will normally keep running  somehow.  Boyer stator plate wiring failure is common.

Re: 1972 Commando running issues - pls help a new owner.

Posted by john_holmes at April 07. 2017

The boyer stator wire issue can be repaired, it affects Commandos more than any other bike due to the engine being isolated from the frame so the wire is subject to bending forces more.

 

One repair (there are others)

http://www.decentcycles.com/how-to/96-boyer-wire-repair-kit

 

After you have fixed the broken wires make sure you leave a loop in the boyer feed wire just before it enters the timing cover, also fit a wad of foam under the points cover so it presses on the stator plate and the wire connectors. Both these actions will stop it happening again.

Re: 1972 Commando running issues - pls help a new owner.

Posted by richard_chan at April 07. 2017

So i just went to the garage to take a quick look.

Boyer ignition, but i cant see model. Can anyone take a look and let me know so i can find a manual for it?

From memory and looking (should have taken a pen and wrote this down, so i might be wrong.) The timing stator plate is where points should have been, wires then run up to the coils. Coils have four connectors, two of the connectors were made redundant (bottom two), then top two connectors looks like a split from stator plate to a box, which i couldn't see any writing as it was hung up weirdly.

 

Photos as below post.

Re: 1972 Commando running issues - pls help a new owner.

Posted by richard_chan at April 07. 2017
Sorry had to upload images elsewhere, limited size here and photos only takes big photos... http://i.imgur.com/Fj2cFiv.jpg http://i.imgur.com/kDKm2a4.jpg http://i.imgur.com/8MY42Pv.jpg http://i.imgur.com/h3xoWUc.jpg

Re: 1972 Commando running issues - pls help a new owner.

Posted by richard_chan at April 07. 2017

Hi John,

Would you know of one manufacturer based in the UK? Or EU?

Seems like this link is in the US? hard to find where they are from tbh. Site doesn't say, unless i missed it.

Thx

Previously john_holmes wrote:

The boyer stator wire issue can be repaired, it affects Commandos more than any other bike due to the engine being isolated from the frame so the wire is subject to bending forces more.

 

One repair (there are others)

http://www.decentcycles.com/how-to/96-boyer-wire-repair-kit

 

After you have fixed the broken wires make sure you leave a loop in the boyer feed wire just before it enters the timing cover, also fit a wad of foam under the points cover so it presses on the stator plate and the wire connectors. Both these actions will stop it happening again.

Re: 1972 Commando running issues - pls help a new owner.

Posted by david_evans at April 07. 2017

The photos of the boyer look like it is in pretty good condition to me. I would be looking at the ignition timing first then moving onto the fuel system. When you say it shuts down after revving up, does it cut completely or does it gradually drop out, misfire and stop? Is the petrol tap allowing plenty of fuel though into the carbs, try opening both taps. Is the fuel fresh? If the cut out is sudden check for a short circuit or try running a wire from the Negative side of the battery to the white wire into the boyer ( fit a switch in this wire)

Re: 1972 Commando running issues - pls help a new owner.

Posted by richard_chan at April 07. 2017

Hi David,

I slowly twisted the throttle, going all the way up to full, the rev just slowly going up to around 4k, then gradually drops out. There is definitely misfiring. At full throttle, the rev does no go up pass 4k, and cough and engines dies.

Fuel is fresh, bought today.

I emptied the previous fuel, opened both sides. Fuel flows looked ok.

I checked the bottom of the carbs by unscrewing the bowl bottom, plenty of fuel in there. The tickles before starting up actually let's too much fuel in, as the carbs do leak from the gaskets (which are new).

May i ask why run a wire from negative of battery to the white wire into the Boyer? And fit switch?

 

Thanks for your feed back.

 

Previously david_evans wrote:

The photos of the boyer look like it is in pretty good condition to me. I would be looking at the ignition timing first then moving onto the fuel system. When you say it shuts down after revving up, does it cut completely or does it gradually drop out, misfire and stop? Is the petrol tap allowing plenty of fuel though into the carbs, try opening both taps. Is the fuel fresh? If the cut out is sudden check for a short circuit or try running a wire from the Negative side of the battery to the white wire into the boyer ( fit a switch in this wire)

Re: 1972 Commando running issues - pls help a new owner.

Posted by richard_chan at April 07. 2017

And and do you happen to know what model Boyer this is? I'd like to look for a manual and timing procedure.

Thx

Re: 1972 Commando running issues - pls help a new owner.

Posted by richard_payne at April 07. 2017

A really silly question, but you wouldn't be the first if you're not used to Amals. Are you operating the choke correctly, i.e. tight wire for normal running ?

If the float bowl gaskets are leaking then the bowls are probably distorted which means some work performing figures-of-eight with a surface plate and fine wet & dry paper.

Re: 1972 Commando running issues - pls help a new owner.

Posted by richard_chan at April 07. 2017
Hi Richard, Yes, this is my first Amals. First Norton. I didn't have to use the choke lever to start, it just kicked over. But the choke was off. (I'm pretty sure). Lever is located on the left side of handle bar, tilted all the way up (towards 10 o'clock). As in this photo http://i.imgur.com/9JHVJRy.jpg Is that my first newbie mistake then? Noted on the leak I'll check the balance of them. Thx. Previously richard_payne wrote:

A really silly question, but you wouldn't be the first if you're not used to Amals. Are you operating the choke correctly, i.e. tight wire for normal running ?

If the float bowl gaskets are leaking then the bowls are probably distorted which means some work performing figures-of-eight with a surface plate and fine wet & dry paper.

Re: 1972 Commando running issues - pls help a new owner.

Posted by richard_chan at April 07. 2017

In regards to timing, do i actually need a timing scale or degree plate to do the timing? I've never had a bike which requires actual degree in timing, rather than using a depth gauge in cylinder head.

Thx

Re: 1972 Commando running issues - pls help a new owner.

Posted by ian_goodhall at April 07. 2017

If your choke lever is in the same position as that picture you posted then your choke is ON. This would explain why it won't rev. The lever needs to be turned all the way so that it's pulling the cable taught and lifting the slides for the choke to be off.

It is somewhat counter intuitive.

Re: 1972 Commando running issues - pls help a new owner.

Posted by richard_chan at April 07. 2017

Oh dear.

I read the user manual and i was sure that in this position is off.

So cable taught, choke is OFF, and loose is ON.

I will make a point to try it out tomorrow as soon as i find time and see if this has fixed my issues. I'm betting you're right and me being the newbie... This is rather embarrassing tbh, but that's why we ask questions, to learn.

Thanks.

 

Previously ian_goodhall wrote:

If your choke lever is in the same position as that picture you posted then your choke is ON. This would explain why it won't rev. The lever needs to be turned all the way so that it's pulling the cable taught and lifting the slides for the choke to be off.

It is somewhat counter intuitive.

Re: 1972 Commando running issues - pls help a new owner.

Posted by richard_payne at April 07. 2017

Don't be embarrased, Richard. Most of us have done it. In my case I was about sixteen with a crowd of my 'mates' standing around. Oh how they laughed.

The symptoms that you described fit an engine running with choke exactly. If the lever is not tightened enough, it can happen in use as well. That's confusing.

You should have a timing degree plate on the inside of the inspection window that you use for strobing. They are on slotted fixings so can be out a little but will be near enough to run. Checking the timing plate with the use of a degree disc can wait until you're a little more familiar with the thing !

Re: 1972 Commando running issues - pls help a new owner.

Posted by james_fanning at April 08. 2017

... and finally , if the correct choke lever position for normal running doesn't solve the problem , just check the small breather hole in petrol cap is completely clear. A blocked breather orifice (totally or even just partially) will produce your running symptoms. Blockage quite likely also if bike has been standing for 10 years. I've had exactly this on a Commando - and fixed in seconds.

Re: 1972 Commando running issues - pls help a new owner.

Posted by richard_chan at April 08. 2017

Thanks for the tips Richard , I'll make a dash to the garage as soon So I'm free to test start the bike. No working on it until Monday, but a quick test start will be need for my own sanity. Will check the tank cap too quickly for a quick fix.

Have a great weekend all. Update coming soon.

 

Previously james_fanning wrote:

... and finally , if the correct choke lever position for normal running doesn't solve the problem , just check the small breather hole in petrol cap is completely clear. A blocked breather orifice (totally or even just partially) will produce your running symptoms. Blockage quite likely also if bike has been standing for 10 years. I've had exactly this on a Commando - and fixed in seconds.

Re: 1972 Commando running issues - pls help a new owner.

Posted by John Hawden at April 08. 2017

Its the choke mate, don`t ask me how I know

Re: 1972 Commando running issues - pls help a new owner.

Posted by richard_chan at April 08. 2017

So back from a quick test as i onky had half and hour.

Played with the choke, turned it anticlockwise down and the revs went straight up. The engine ran, but it popped a lot and started throwing flames out the exhaust. Doing this on a Saturday during lunch time in suburbia Germany inside a low ceiling garage was probably not a great idea.

I'm guessing I better sort out the timing first before a second attempt?

Any other suggestions or items on the list to check , pls feel free to add.

Timing, tappet, new spark plugs (again), look inside fuel cap airhole for blockage, try choke lever again ... If all fails, then check over the Boyer unit.

Re: 1972 Commando running issues - pls help a new owner.

Posted by john_holmes at April 08. 2017

You were starting it from cold, and took the choke off straight away ?

 

If so your mixture would have been weak until the engine warmed up, so nothing to suggest anything is wrong other than never owning a Commando before and needing to learn its foibles. Next time get it started with the choke and then go out for a ride using low revs then within a 1/4 mile take the choke off and then get the engine up to temp before opening it up.

Re: 1972 Commando running issues - pls help a new owner.

Posted by richard_chan at April 08. 2017

I tried turning the choke down at first, but it didn't want to stay idle, so i turned it back up and let it warm up for a bit.

The engine got warm and i tried it again. Still the same.

The rev sent up and went back down and it didn't have enough rev to keep idling. I tried turning the throttle adjuster on the handle bar and balance the choke to keep it idling, but that didn't really work either, it just kept back firing and popping.

On the tuning note - what is the standard turn outs for the two Air  pilot Screw and the throttle screw?

I asked Simon at Andoerver, his suggestion was 1.1/2 turn out on pilot screw, and throttle screw - when throttle slide is at the lowest point, turn the screw so it makes contact with the slide, then further 2 more turns.

I'm a little confused by this, how do i know when the slide is at its lowest and made contact? Am i suppose to make this adjustment with the carbs off?

 

Previously john_holmes wrote:

You were starting it from cold, and took the choke off straight away ?

 

If so your mixture would have been weak until the engine warmed up, so nothing to suggest anything is wrong other than never owning a Commando before and needing to learn its foibles. Next time get it started with the choke and then go out for a ride using low revs then within a 1/4 mile take the choke off and then get the engine up to temp before opening it up.

Re: 1972 Commando running issues - pls help a new owner.

Posted by christopher_winsby at April 08. 2017

Look at Bushmans Amal its a good guide

Re: 1972 Commando running issues - pls help a new owner.

Posted by john_holmes at April 08. 2017

You probably  need to clean out your pilot jets, only 100% reliable method is to glue a 16 thou drill into a wd40 red tube and using your fingers drill them clean, the pilot jet is in the brass bush at the bottom of the hole the pilot jet mixture screw is screwed into.

Re: 1972 Commando running issues - pls help a new owner.

Posted by richard_chan at April 08. 2017
Nice tip. Reading through it now. Thanks. Previously christopher_winsby wrote:

Look at Bushmans Amal its a good guide

Re: 1972 Commando running issues - pls help a new owner.

Posted by richard_chan at April 08. 2017

I had to read the guide suggested above to know what you were taking about. Now I know. Thanks.

 

Previously john_holmes wrote:

You probably  need to clean out your pilot jets, only 100% reliable method is to glue a 16 thou drill into a wd40 red tube and using your fingers drill them clean, the pilot jet is in the brass bush at the bottom of the hole the pilot jet mixture screw is screwed into.

Re: 1972 Commando running issues - pls help a new owner.

Posted by richard_chan at April 10. 2017

Hi everyone,

My cry for help once again...

I tried to do the timing before testing the choke. It worked semi ok, i was able to run the bike with the choke off for a little.

But for the timing, because i have the Boyer unit, i needed to be at 31 degrees BTDC , which was done prior to resetting the stator plate.

The previous owner had the magnet tiled a bit further than the Boyer instruction stated. It was tiled left side higher than right side magnet. I fixed this and aligned the magnet to the Norton sign as stated in the instruction. Installed the stator plate as required.

Started the bike hoping it'll be ok. But no. Couldn't in my life get the timing to 31 degrees , it remained at over 40 degrees no matter which way i turned the stator plate. It popped and banged as well. The kick started will walk me back a few times when i had turned the stator plate anticlockwise.

I'm at a lost here on how to make it to get even get below 40 degrees.

Help anyone? Please? Any feed back, suggestions would be appreciated.

Fyi - not cleaned the carb again as yet, i am hoping to do this when i have more time this week..........

Re: 1972 Commando running issues - pls help a new owner.

Posted by john_holmes at April 10. 2017

The instruction settings are only a starting point, due to the components used when you use the strobe you will normally find it needs adjusting so it was best left where it was. If its stuck fully advanced then you could have the 2 trigger wires transposed, they use black/white and black/yellow and once the white ages it starts to look yellow DOH. So check the trigger wires are connected the right way round both at the stator and up at the box. One last check is to just transpose them anyway as its possible the internal wiring is wrong from the factory, Pazon have definately made this mistake, not heard of it with a Boyer but there is always a first time and the symptoms are exactly as you describe.

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