New member hello and AAARRRGH!!!

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rpatton said:
kromatid750 said:
Tighten up the exhaust nut while the engine is still hot, preferably running.

Could you share what you found regarding the alternator markings?


Yes, I started the tightening procedure as soon as the bike was turned off.

With the alternator rotor, the cast-in markings are just in the wrong place. I didn't check accurately, but maybe 10-15 degrees out. I can only assume that it is a unit intended for a different bike (it is a Sparx) - I can't see how it can be manufacturing error, but you never know!

Bob
 
Hi Bob
really pleased you finally found and rectified the problem, always suspected it was timing, main thing is you have it running :D
I suspect it was substantially more than your estimate of 10-15deg as it would have started being only that far out.
Once you have re torqued the head and re set the valve clearance, may I suggest you strobe the timing to get it spot on.
You will then no doubt itching to take it up the road (hope you have the seat) enjoy and don't forget to keep re torqueing the head another coupl of times at least.
Cheers
JohnT
 
Outstanding kromatid750!
Now I am interested in your carb setup. Can you offer some detail on what you have?
I have, and might again, run a 40TM pumper and had clearance issues with general fitment and the bell crank and the frame webbing.
 
kromatid750 said:
With the alternator rotor, the cast-in markings are just in the wrong place. I didn't check accurately, but maybe 10-15 degrees out. I can only assume that it is a unit intended for a different bike (it is a Sparx) - I can't see how it can be manufacturing error, but you never know!


The Lucas/Sparx rotor timing marks (both "right" and "wrong") are usually in alignment with the keyway.

New member hello and AAARRRGH!!!
 
I'll try and address posts/questions tomorrow, but am about to slap a steak on the griddle and have already started on the first bottle of red (there are two of us!). I don't have access to the important bits of the bike at the moment, but did just wonder if the key slot in my Maney crank is in a different position to standard. I don't imagine it is, but will check with Steve in the morning.

Cheers, Bob
 
OK. I took the rotor nut off this morning, and nothing amiss with the rotor - timing marks line-up with the keyway slot. This meant it was the position of the keyway in the crank. It is a Maney crank, so I gave Steve a call and all was explained. Apparently, Norton changed the position of the keyway over the years. Obviously, with such small production runs, Steve had no choice but to simply pick one of the iterations to follow - I just wish he had told me when I bought the crank!!!

As far as my carb set-up is concerned, it is just a Sudco off the shelf version of the twin Keihin FCR 35mm flatslides sold by CNW, that I bought off eBay. I won't know how well they are jetted until I start riding, but they are supposed to be jetted for an 850. I already had the manifolds and connectors that CNW use and the kit contained everything else. They are a tight fit; and presently are just a little too close to the frame downtubes, but clear the webbing ok. I am going to have to find a way of bringing them nearer to the head. On a Roadster, the carbs obstruct the RH petcock, on my Interstate, the bottom of the tank fouls the twin cable carrier. I have resolved this problem by drilling out the rivets and lowering the cable carrier to the lower set of location holes and converting to a single pull system.

Cheers, Bob
 
kromatid750 said:
OK. I took the rotor nut off this morning, and nothing amiss with the rotor - timing marks line-up with the keyway slot. This meant it was the position of the keyway in the crank. It is a Maney crank, so I gave Steve a call and all was explained. Apparently, Norton changed the position of the keyway over the years. Obviously, with such small production runs, Steve had no choice but to simply pick one of the iterations to follow - I just wish he had told me when I bought the crank!!!

As far as my carb set-up is concerned, it is just a Sudco off the shelf version of the twin Keihin FCR 35mm flatslides sold by CNW, that I bought off eBay. I won't know how well they are jetted until I start riding, but they are supposed to be jetted for an 850. I already had the manifolds and connectors that CNW use and the kit contained everything else. They are a tight fit; and presently are just a little too close to the frame downtubes, but clear the webbing ok. I am going to have to find a way of bringing them nearer to the head. On a Roadster, the carbs obstruct the RH petcock, on my Interstate, the bottom of the tank fouls the twin cable carrier. I have resolved this problem by drilling out the rivets and lowering the cable carrier to the lower set of location holes and converting to a single pull system.

Cheers, Bob

Can anyone else add to that remark about keyways being cut at various angles on different years? Inquiring minds want to know... :idea: :?:
 
If the different keyway cuts are so, and I've no reason to doubt, my question would be: Why?
 
Hi Bob
having had a look at the picture on Steve Maney's site it would appear the the keyway slot is 90deg off normal. No wonder it was spitting/kicking back. I do not have a Maney crank on mine, so no experience of this.
The suggested earlier checks suggested would have found this had they been carried out!
Main thing is that it's running and we have all learned something.
Cheers
JohnT
 
JohnTy said:
Hi Bob
having had a look at the picture on Steve Maney's site it would appear the the keyway slot is 90deg off normal. No wonder it was spitting/kicking back. I do not have a Maney crank on mine, so no experience of this.
The suggested earlier checks suggested would have found this had they been carried out!
Main thing is that it's running and we have all learned something.
Cheers
JohnT
Anyone know WHY this would be designed 90 degrees from standard?
 
[/quote]
TDC mark and piston TDC as indicated.[/quote]

There is no TDC mark to check against, just a BTDC scale. Looking for the timing being out because of crankshaft keyway position or faulty markings on the rotor was not really a likely scenario, I don't think one that anyone suggested and therefore the last check I made. The situation could have been resolved earlier by the use of a degree disc, but ones use would only be absolutely necessary if the problem that emerged actually existed - as it did!

Also, the rotor was covered by the chaincase, so difficult to get a real feeling of how far the timing marks are moving, when they are only visible as they move into the 'window'. I was suspicious that I was moving the motor more than expected to reach 31 BTDC, but it has been a few years since I built the motor and around 20 years since I last owned and serviced one, so maybe I was not as alert to the clues that were presented as I otherwise would be.

It turned out to be a really easy problem to diagnose, particularly after I had worked out what it was!!!

Bob
 
JimC said:
If the different keyway cuts are so, and I've no reason to doubt, my question would be: Why?

Matt at CNW says that there is in fact no variation in keyway position, from as far back as the Atlas. Steve Maney has no reason to be economical..... and his cranks are mainly used for racing, so keyway position irrelevant. If he chose a position for the keyway to suit his own needs, surely he would have said so? I am visiting the UK for a couple of weeks from tomorrow, so may call in and ask him some more about it.

So, if we accept Matt is correct, maybe Steve was misremembering or perhaps he was looking at racing cranks - I have no idea!?!?

Bob
 
JohnTy said:
kromatid750 said:
Just a bit of straw clutching while I think about it:

There is a possibility that the primary cover on my bike is not original. Any chance the degree marker can be different on newer/older models?

Bob
Hi Bob
well, how about getting the right cylinder on the compression stroke (put your finger over the plug hole! then with a small screw driver in the plug hole (very carefully) gently nudge the engine over until approx. TDC and then have a look where the hole in the rotor is. Should be on or close to the pickup (between the led and the connection block)
If it isn't then you got the problem.
Cheers
JohnT
Hi Bob
this was what I was referring too, it would have shown the rotor position off 45deg (half crank speed)
But lets celebrate the positive, it is running and we all know a little more. :D
You can now look forward to riding the rocket, even more so with the lightweight crankshaft. :shock:
Enjoy.
JohnT
 
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