| Author |
Message |
    
Ian
Member
Username: the_bigfella
Post Number: 18
Registered: 10-2008
| | Posted on Thursday, May 14, 2009 - 08:19 am: | 
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G'day guys
I've set the points on my Pup to about 11 thou, but they open three times on a single revolution. Which time should I be using to set the timing of the engine?
I was of the impression that the fence on top of the piston went towards the side that the exhaust and carby attach to - but the parts diagram shows it on the other side. Can anyone advise the correct side please?
Thanks
Ian |
Eric Schulz
Senior Member
Username: eric_schulz
Post Number: 54
Registered: 01-2007
| | Posted on Thursday, May 14, 2009 - 10:03 pm: |
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After reading your post, I had to wonder where you found a magneto with a three lobe cam. A single cylinder magneto would open the points only once per revolution. What make and model of magneto do you have?
As far as I am aware, the deflector on the piston of a 2 stroke engine is facing the inlet port. This is to send the incoming mixture up to the combustion chamber.
Eric |
David Myers
Senior Member
Username: dave_myers
Post Number: 68
Registered: 11-2006
| | Posted on Friday, May 15, 2009 - 12:15 am: |
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Ian, 11 thou is too fine.. Set the points at 14 - 15 thou as the shaft may have a slight bend in it and gives a false opening. Like Eric, I do not know of any Magneto with a 3 pole cam..
The deflector on the piston is the opposite side to the Carby / Manifold. The manual, as shown is correct. On a normal 3 port 2 stroke the Deflector is toward the Transfer / Carby port, but the Blaxland uses a window porting in the piston and the inlet is directed through the piston to the other side of the cylinder.If it is the wrong way it will not start. My 3.1/2SXT is on the left looking from the Front, opposite the Carby etc.
Dave |
Eric Schulz
Senior Member
Username: eric_schulz
Post Number: 55
Registered: 01-2007
| | Posted on Friday, May 15, 2009 - 12:24 am: |
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Dave, thanks for clearing up the piston deflector position. I was thinking normal 3 port because I don't have a Pup to play with.
Eric |
Ian
Member
Username: the_bigfella
Post Number: 19
Registered: 10-2008
| | Posted on Friday, May 15, 2009 - 02:27 am: |
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Thanks guys. I've got the piston in the right way (phew) and with the points set right it looks much better. I'll check things over with the multimeter in the morning... time it, pinch my fuel tank back from my son and give her a burl. |
neil r jones
Member
Username: senojn
Post Number: 23
Registered: 08-2006
| | Posted on Friday, May 15, 2009 - 03:21 am: |
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To term 'burl' for for non Aussies refers to spinning or turning . From the Scottish ,similar to whirl or twirl .
Always nice for international participants to be able to understand colloquialisms, that is 'local language '. |
Ian
Member
Username: the_bigfella
Post Number: 20
Registered: 10-2008
| | Posted on Monday, May 18, 2009 - 07:19 pm: |
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I hooked her all up on the setup bench yesterday and gave her that burl. Success. I christened her with a bit of Coopers Stout too. A bit smokey at first, but she's running fine.
Here's the video.
http://www.youtube.com/watch?v=4lJTHn2EMEQ&feature=channel_page
I'd like to give her a test under load. She spins at 650-750 at idle on the bench, which as I understand it is normal full speed when spinning an 11" x 11" prop. Does anyone have any suggestions for what can be done to put a load on her - short of digging a swimming pool and getting a 12' shaft? |
Greg Y
Advanced Member
Username: gregoryan
Post Number: 38
Registered: 09-2004
| | Posted on Monday, May 18, 2009 - 08:28 pm: |
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I think a good easy artificial load would be an alternator, where you can add car headlights for more loading. Perhaps that electric-starter that you appear to have there in the vid clip can be used as a generator in the same way?
Another good variable load would be a centrifugal waterpump with a closed-water-circuit via a variable gate valve. When the valve is shut off, this creates the least load, as the water spins in one spot. When the valve is opened this water is thrown around the circuit creating drag. I imagine at least a 1- 1/4" bore, pump, would be needed to load that size engine. |
Todd Vidgen
Senior Member
Username: todd_vidgen
Post Number: 120
Registered: 03-2008
| | Posted on Monday, May 18, 2009 - 08:38 pm: |
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They will be smokey at first until the initial
charge of oil in the sump"finds" its level.
Keep that coopers away from the maggy otherwise
your engine may develop problems from alcohol
poisoning.
Is that a dyna start you used to start it with?
If so you could use it to simulate a load
Just be careful not to put too much tension
on the belt,as this can really bugger up the
front(in your case rear)Babbitt bearing.
Bronze cylinders are few and far between so
treasure yours and guard it with your life
Nice work,
Todd |
