One of first 500 of contract C14498 with leg shields
I did the same exercise lately.
The matching points were also gone but fortunately I marled the drive pinion so there was not a 3rd wheel to be aligned.
A pity that the I5 and E5 marks were not used as matching marks.
After some trail and error it finally looks when on TDC like this:
Heiko
Gents,
I am of the opinion that the picture of Heiko does not show the engine at TDC and therefore might be a little confusing.
When keeping the settings as specified in the original maintenance manual the cams should more or less be in the same positions.
That is how I have done it until now.
I am however game to try the setting John gave.
Modern petrol might require or allow for some change of settings.
The "military" setting always works and the settings on these old bikes are not as critical as on modern cars or motorcycles. There may however be another optimum after 70 odd years.
Cheers,
Rob
Hello,
I have not done any further work on the engine since I took the pictures.
The manual says:
"Inlet open 27° to 30° before top center"
- so is this: Inlet is 100% open (I think so ) or starts to open?
"Exhaust closes 27° to 30° after top center"
- so this is: Exhaust just starts to close ( I think so ) or is it 100% closed?
This might have mislead me, what is now correct?
Thanks,
Heiko
Hello Rob,
Thank you for your reply, please do you think my setting is ok ?
My TDC 1 is like fig. 14 p18 in the manual: In and Ex cams are parallels at 4 o'clock
My TDC 2 (after 360°) photo show exhaust cam begin to close and Inlet cam begin to open.
Any help is much appreciated
This is what happens when you do not follow the instructions in the manual. It all gets very confusing and you end up making mistakes. To time the engine properly read page 18 to 20 of the instruction manual available for download on this site. It even gives instructions for when the marks are missing. (if marks are present do not trust them, people may have altered them over the years).
When you feel confident in knowing what you are doing then by all means experiment with whatever different timing figures you want but it will still be an "experiment".
The figures are Inlet starts to open 27-30 degs (5/16") BTDC
Exhaust fully closed 27-30 degs (5/16") ATDC
Obviously this refers to TDC on the exhaust stroke not the compression stroke.
The figures from Mike Pemberton only puts the exhaust 2 degs out of spec ie 25 instead of 27-30 so could be worth a try.
try not to over complicate things ,start by downloading a timing wheel off google print it cut it out and paste it to some card ,make a hole and put it behind the large crank nut ,put engine at TDC doesnt matter what stroke your on because at this stage there's no cams fitted ,firstly fit exhaust cam and pinion in a position that the valve as just fully closed @ 25 degrees ATDC ,using the timing wheel and independent marker for reference ,the pinion only drives the exhaust cam ,by doing that you have told the engine its on exhaust stroke ,next mesh inlet cam @30 degrees BTDC again using your timing wheel as reference ,if you can not quite get it to your required settings move the pinion to a different slot and try again ,as you know theres 3 slots each moves the time by 1/3 of a tooth
how do i post pictures please
The cams setting :
TDC: compression
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Hébergé par Imagesia, le meilleur hébergeur d'images du net !
RFE: 30° after PMH exhaust just closed no play
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Hébergé par Imagesia, le meilleur hébergeur d'images du net !
AOA: 30° before PMH inlet just start to open
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Hébergé par Imagesia, le meilleur hébergeur d'images du net !
Hope it helps
The cams setting :
TDC: compression
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Hébergé par Imagesia, le meilleur hébergeur d'images du net !
RFE: 30° after PMH exhaust just closed no play
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Hébergé par Imagesia, le meilleur hébergeur d'images du net !
AOA: 30° before PMH inlet just start to open
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Hébergé par Imagesia, le meilleur hébergeur d'images du net !
Hello John
I am building a 16h engine, from my reading Norton did not put marks on the gears and if I am correct, these gears are driven from exhaust cam. I am trying to get my head around the timing, I feel once you get it it is quite straight forward. Do you have any pictures of you setting the timing if so they would help a lot?
Thanks
Steve