Norton Commando 1969 timing issues

concours said:

It should still start & run

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Hopefully the new electronic ignition will be released from customs next week along with the rest of the parts I ordered. Any suggestions for me to check meanwhile Concours?
Thanks

I'd have to see the patient.

Measured the pressure with a bit of oil in the barrels and went up a bit: left side from 110 to 140 psi and right side from 100 to 115 psi.
Piston rings will need replacement right? regardless of the rest
Cheers

Migsan said:

Measured the pressure with a bit of oil in the barrels and went up a bit: left side from 110 to 140 psi and right side from 100 to 115 psi.
Piston rings will need replacement right? regardless of the rest
Cheers

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Not really, You might have some carbon on the valve seats , that lets air escape, You need to run the bike and drive it some and then do a compression test when the motor is warm/ hot and open the throttle and kick it firmly about 8 compression stroke, Look at the gauge after the 1st- 3rd kicks and write down those numbers. The biggest increases are in the first few kicks.

Carl H said:

Not really, You might have some carbon on the valve seats , that lets air escape, You need to run the bike and drive it some and then do a compression test when the motor is warm/ hot and open the throttle and kick it firmly about 8 compression stroke, Look at the gauge after the 1st- 3rd kicks and write down those numbers. The biggest increases are in the first few kicks.

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Thanks Carl
So should I remove the motor head to see how it is and perhaps reseat the valves?

I mean the bike never started so I won't be able to test the engine warm

Those compression figures pre and post oiling will start an engine, so sort your engine starting issues first. Then a few runs may sort out the low compression without further work or at least identify a culprit, knowing your culprit before opening the engine makes it a lot easier.

My Vincent Rapide had that issue recently. It was caused by worn out needle jets.
The carbon spots on the Valve seats lowered to compression to the point where it could barely be felt on the kickstart. Normally one can stand on the kickstart on compression and it wont move for a long time.
Even with the very low compression, the bike ran fine.
I think it was down 2mph on dyno hill, dropped from 72 to 70 mph at top.
It makes me think those CR to horsepower calculators such as the Wallace Racing item are accurate. They show very small gains with increased Cr, perhaps .5 HP going from 9 to 1 to 10 to 1 on a 50 HP engine.

Glen

ok so I will wait for the new ignition system and try again to fire it up. Although before when I replaced the MK3 boyer with the MK4 from my t140 I was also unable to start it. Not even pushing it over a ramp.

Thanks
Miguel

sorry just one more thing I nottest just now while trying to confirm the piston measures (+20 and super clean). I had both sparks out and was kicking the kick start by hand and slowly to have a better view inside. Started hearing a tsssss like build up pressure. Is that from the lower part of the engine? and if so is it normal?

Many thanks

Both pistons rise and fall together, so when they fall they compress the air inside the crankcase and the timed breather lets it out when its open. When the timed breather is not open the compressed air will move around creating hissing sounds.

I read through the whole thread again, have you checked the cam chain yet for camshaft timing ?

I'm not sure of how much of the T140 ignition components you transferred to the Norton, but the Triumph cam (exhaust) that turns the Boyer rotor rotates CW while the Norton cam rotates the rotor CCW. IIRC there is a difference as to where you align the stator plate.

Best.

kommando said:

Both pistons rise and fall together, so when they fall they compress the air inside the crankcase and the timed breather lets it out when its open. When the timed breather is not open the compressed air will move around creating hissing sounds.

I read through the whole thread again, have you checked the cam chain yet for camshaft timing ?

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yes I checked the chain and all seemed in order. checked the marks and the number of links in between according the instructions given here!
Thanks Kommando!

RoadScholar said:

I'm not sure of how much of the T140 ignition components you transferred to the Norton, but the Triumph cam (exhaust) that turns the Boyer rotor rotates CW while the Norton cam rotates the rotor CCW. IIRC there is a difference as to where you align the stator plate.

Best.

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Yes I am aware. All I changed was the black box boyer ignition MK4. The stator plate although I also experimented with it was aligned on the CCW.

Thanks

Migsan said:

Yes I am aware. All I changed was the black box boyer ignition MK4. The stator plate although I also experimented with it was aligned on the CCW.

Thanks

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The biggest weakness with the Boyer is the stator plate (the bit you’ve left on there), or rather the soldering of the wires onto it. Did you check that area carefully?

I would think the Boyer could be checked for spark at the plug, to see if those 'suspect' stator plate wires are OK, no? I think you actually checked for a good blue spark? A weak spark (white or yellow) and marginal compression, plus any carb issues will cause a lot of grief. But I'm still thinking the compression is good enough.

But then push starting did nothing also, or did you get even a poot? I've forgotten. Good fresh battery or jump with a car battery also helps.

Sorry for being late for the party.
Hope you are not fighting a rotor which has had the hub spin/move slightly. A common issue with earlier bikes. If it is subtle, it will not affect anything, but when trying to time the bike the marks are off. Notice the rotor in the pic attached. The keyway does not line up with the marks (It should). This one is about 5 - 10 degrees out. The rotor nut & washer will hide this issue from sight. A real prick to diagnose for sure. Things like this are why I'm bilingual.



Cheers

When you do get the old girl running, just set the timing to 25deg @ 2500rpm using a strobe for a Boyer Mk3. Long story but it works out in the wash & saves screaming the motor at 5K.
Cheers

TheCounty said:

When you do get the old girl running, just set the timing to 25deg @ 2500rpm using a strobe for a Boyer Mk3. Long story but it works out in the wash & saves screaming the motor at 5K.
Cheers

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I think it's 20 degrees @ 2,500 rpm although I tend to use 23 degrees @ 3,000 rpm.

The rotor was already fitted but I will take it out during the week to check. I achieved nice blue spark with the t140 boyer ignition black box with both the original stator plate and with the t140 as well. Recharged the battery as well. When I tried to push started I got a pop or two but no follow up. The timing was done at 31 degrees. also checked the degrees plate and it was nice and tight.
I will wait for the new electronic ignition and check the rotor in between to let you guys know.

Thank you all for the help!
Miguel

Hi everyone
So received the ignition last week along with the oil switch and other parts.
Was installing the banjo bolt for the new switch and it wouldn't go in. It turns out there was one of those helicoil inside which came out with the bolt. So yesterday took the timing cover to a welder and at home was able to drill it and tap it with the titanium bolt.
Assembled the new ignition and timed it 31 degrees. Place a bit of gas inside both barrels like you guys taught me.
tickled both carbs and kicked and guess what she fired up second kick
It turns out it was the bad ignition all along plus the T140 boyer didn't work either previously on the bike even though it gave good spark
Also checked the alternator rotor previously and the marks were correct.
The downside of this all is that I had the center stand on top of a wooden board to free the rear wheel and with the kicking it moved and the bike drooped on the floor like in slow motion. Luckily didn't had the gas tank on and the left foot peg took all the damage and gain a bit of a bend. Also got a small mark on the speedometer bezel but the pipes and everything else were unarmed.

Have two questions regarding the S type pipes, is it normal to be so close to the side cover? and also the fuel line is really close or even touching the barrel, can't it melt the?

Anyway just wanna to thank everyone for the help and patience! wouldn't of done without all the support. In the end we pushed through

Cheers