timing a 68 Commando

commando6868 · Jul 28, 2012

I have done everything according to the Boyer instructions, but I cannot get the timing to the right degree. It doesn't seem to want to retard no matter what I do to the plate. It seems to be stuck around 36 degrees or higher. I know that things are reversed with everything behind the cylinders, so if anyone has done an original 68 with the black box Boyer Mark 4, I could use some advise. Any tricks to doing this.
Thanks, Mike

comnoz · Jul 28, 2012

commando6868 said:
I have done everything according to the Boyer instructions, but I cannot get the timing to the right degree. It doesn't seem to want to retard no matter what I do to the plate. It seems to be stuck around 36 degrees or higher. I know that things are reversed with everything behind the cylinders, so if anyone has done an original 68 with the black box Boyer Mark 4, I could use some advise. Any tricks to doing this.
Thanks, Mike

Reverse the two wires to the pickup. Then your advance will work again -and you will need to reset the timing. Jim

L.A.B. · Jul 28, 2012

commando6868 said:
I have done everything according to the Boyer instructions, but I cannot get the timing to the right degree. It doesn't seem to want to retard no matter what I do to the plate. It seems to be stuck around 36 degrees or higher. I know that things are reversed with everything behind the cylinders, so if anyone has done an original 68 with the black box Boyer Mark 4, I could use some advise. Any tricks to doing this.

Hopefully, you do understand that you must set it up using the "Atlas" clockwise rotation timing hole?

commando6868 · Jul 28, 2012

Yes, I have it set up for the Atlas.Tomorrow I will try Jim's suggestion about reversing the wires. I guess because it is spinning in a different direction than the later Commandos? i never had this problem with my '75

Mike

L.A.B. · Jul 28, 2012

commando6868 said:
Yes, I have it set up for the Atlas.Tomorrow I will try Jim's suggestion about reversing the wires. I guess because it is spinning in a different direction than the later Commandos? i never had this problem with my '75

As far as I'm aware, the box and pickup black/yellow and black/white wires should still be connected as normal regardless of rotation.

If it's wrong now then they are probably crossed over somewhere?

http://www.boyerbransden.com/pdf/KIT000 ... 00017_.pdf

commando6868 · Jul 29, 2012

Re: timing a 68 Command"

L.A.B. said:
commando6868 said:

Yes, I have it set up for the Atlas.Tomorrow I will try Jim's suggestion about reversing the wires. I guess because it is spinning in a different direction than the later Commandos? i never had this problem with my '75

Click to expand...

As far as I'm aware, the box and pickup black/yellow and black/white wires should still be connected as normal regardless of rotation.

If it's wrong now then they are probably crossed over somewhere?

http://www.boyerbransden.com/pdf/KIT000 ... 00017_.pdf

I have the box and plate wired correctly. The coils are the non Lucas brand, ( Ceba? ), with the numbers 1 and 15 next to the tabs instead of + and -
Has anyone actually installed one of these on the early Commando? Points behind the cylinder and tack drive off the end of the cam?
Has anyone done this:
" Reverse the two wires to the pickup. Then your advance will work again -and you will need to reset the timing. Jim "

Not many of these out there I guess.

Mike

L.A.B. · Jul 29, 2012

Try swapping the wires over as Jim said, because it won't do any harm.

usefulidiot · Jul 29, 2012

my 68 came with a boyer installed...worked fine when i got it so havent adjusted...however,if u need me to look at wire colors just let me know

commando6868 · Jul 29, 2012

usefulidiot said:
my 68 came with a boyer installed...worked fine when i got it so havent adjusted...however,if u need me to look at wire colors just let me know

Yes, I would appreciate that.

Thanks, Mike

willy mac · Jul 29, 2012

I see you mentioned that you couldn't get the timing right by moving the plate, is that because you haven't got the range of movement to adjust or that it's just not doing anything when you do?
I have a "Behind the Barrel" set up too and found that when I positioned the magnet in the timing window as per instructions @31 BTDC I could'nt get the timing right either, to get round that I centered the plate, loosened off the rotor and moved it clockwise (looking in from the primary side)to make the edge of the magnet line up with the edge of the pick up, that seemed to do the trick and I followed that up with checking the timing with a strobe which has an advance facility on it, all seems fine.

comnoz · Jul 29, 2012

commando6868 said:
usefulidiot said:

my 68 came with a boyer installed...worked fine when i got it so havent adjusted...however,if u need me to look at wire colors just let me know

Click to expand...

Yes, I would appreciate that.

Thanks, Mike

I am not sure of what your exact problem is. If the advance is not working. ie- the timing does not advance as the rpm rises and retard as it comes back to idle- then you would want to reverse the wires. There were some units built some time back that had the wires incorrectly coded. If the wires are reversed then the timing will not change with the engine speed.

If the problem is that you can not rotate the plate far enough to get the timing where it should be then you need to remove the center bolt from the rotor and break it loose from it's taper and rotate it to where the slots in the pickup plate are centered on the hold down bolts when the timing is close to correct. Then the small amount of adjustment available from the slotted holes will let you get it right where it needs to be. Jim

commando6868 · Jul 29, 2012

comnoz said:
commando6868 said:

usefulidiot said:

my 68 came with a boyer installed...worked fine when i got it so havent adjusted...however,if u need me to look at wire colors just let me know

Click to expand...

Yes, I would appreciate that.

Thanks, Mike

Click to expand...

I am not sure of what your exact problem is. If the advance is not working. ie- the timing does not advance as the rpm rises and retard as it comes back to idle- then you would want to reverse the wires. There were some units built some time back that had the wires incorrectly coded. If the wires are reversed then the timing will not change with the engine speed.

If the problem is that you can not rotate the plate far enough to get the timing where it should be then you need to remove the center bolt from the rotor and break it loose from it's taper and rotate it to where the slots in the pickup plate are centered on the hold down bolts when the timing is close to correct. Then the small amount of adjustment available from the slotted holes will let you get it right where it needs to be. Jim

I think the rotor needs to be moved, I will have to put this off for a few days for now.
The Boyer box is a new Mark 4, the advance is moving when it goes up and down. One suggestion on timing is to do it at 28 degrees at 2000 rpm instead of 31 degrees at 5000 rpm and the results would be the same.
Anyone else tried this? 5000 rpm's, per the Boyer instruction is really cranking. I have done it this way on my '75 with the MicroDigital Boyer.

Mike

Hobot · Jul 29, 2012

Anyone else tried this? 5000 rpm's, per the Boyer instruction is really cranking. I have done it this way on my '75 with the MicroDigital Boyer.

Its a tradition to Dance with Commando's on center stand to rev up enough to see full Boyer advance as more accurate than trying to hold a set rpm to match the graphed degree's at that rpm. Put thick-ish carpet or padding under center stand to stop the legs leaving witness marks across your flooring. If you are afraid to rev your engine between 5-6000 rpm unloaded then you ain't got the guts it takes to fully fetter and time a Commando. 5900 is factory listed safe sustained 850 rpm. Very young children get scared to be close to a Commando blipped into full adv rpm. If engine blows up at home under red line rpm then a blessing to happen at home - so what's the worry, get on with it like a real Nortoneer.

L.A.B. · Jul 29, 2012

commando6868 said:
One suggestion on timing is to do it at 28 degrees at 2000 rpm instead of 31 degrees at 5000 rpm and the results would be the same.
Anyone else tried this?

Advance curves between individual boxes are not always identical, so the advance figure at 2000 RPM for one box may not be exactly the same as yours at 2000 RPM and could mean it will be a few degrees out, in any case, can you be sure your tacho reading is absolutely accurate? The reading could easily be off by + or - 10%

commando6868 said:
5000 rpm's, per the Boyer instruction is really cranking.

Wear earplugs!

Revving up to 5000 RPM doesn't seem anywhere near as dramatic if you are wearing earplugs, and it only takes a few seconds to check each time!

Hobot · Jul 29, 2012

Wear earplugs!

Revving up to 5000 RPM doesn't seem anywhere near as dramatic if you are wearing earplugs, and it only takes a few seconds to check each time!

LOL! I time mine inside a tin shed so consider this remark applicable to protect ears of young children. Thanks for evidence hobot's down-dirty advice to just grin and bare it blipped up over full advance rpm w/o looking at tacho, just watch the time marks to stop increasing, only takes a second or a few times to see where full advance [generally] lands and diddle from that for loudest joys.

commando6868 · Jul 29, 2012

hobot said:
Anyone else tried this? 5000 rpm's, per the Boyer instruction is really cranking. I have done it this way on my '75 with the MicroDigital Boyer.

Click to expand...

Its a tradition to Dance with Commando's on center stand to rev up enough to see full Boyer advance as more accurate than trying to hold a set rpm to match the graphed degree's at that rpm. Put thick-ish carpet or padding under center stand to stop the legs leaving witness marks across your flooring. If you are afraid to rev your engine between 5-6000 rpm unloaded then you ain't got the guts it takes to fully fetter and time a Commando. 5900 is factory listed safe sustained 850 rpm. Very young children get scared to be close to a Commando blipped into full adv rpm. If engine blows up at home under red line rpm then a blessing to happen at home - so what's the worry, get on with it like a real Nortoneer.

Yeah, I have cranked my '75 up to 5000 more than a few times to get it right, even had a neighbor call and complain once, I guess it must be those Dunstall "silencers" !
The 2000 timing rpm is a suggestion from a very knowledgeable Norton tech guy.
So far I haven't blow up my engine in the garage, but it is still early in the day!

Mike

pete.v · Jul 29, 2012

commando6868 said:
hobot said:

Anyone else tried this? 5000 rpm's, per the Boyer instruction is really cranking. I have done it this way on my '75 with the MicroDigital Boyer.

Click to expand...

Its a tradition to Dance with Commando's on center stand to rev up enough to see full Boyer advance as more accurate than trying to hold a set rpm to match the graphed degree's at that rpm. Put thick-ish carpet or padding under center stand to stop the legs leaving witness marks across your flooring. If you are afraid to rev your engine between 5-6000 rpm unloaded then you ain't got the guts it takes to fully fetter and time a Commando. 5900 is factory listed safe sustained 850 rpm. Very young children get scared to be close to a Commando blipped into full adv rpm. If engine blows up at home under red line rpm then a blessing to happen at home - so what's the worry, get on with it like a real Nortoneer.

Click to expand...

Yeah, I have cranked my '75 up to 5000 more than a few times to get it right, even had a neighbor call and complain once, I guess it must be those Dunstall "silencers" !
The 2000 timing rpm is a suggestion from a very knowledgeable Norton tech guy.
So far I haven't blow up my engine in the garage, but it is still early in the day!

Mike

I think this is one of the unsung luxuries of the Pazon Unit, only having to go to 4000rpm to set full advance

Hobot · Jul 29, 2012

timing a 68 Commando

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