Triumph Rat Motorcycle Forums banner
  • Hey everyone! Enter your ride HERE to be a part of September's Bike of the Month Challenge!
1 - 7 of 7 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter · #1 ·
Hi!
I have been having troubles with my baby for years.
It is an 1969 Bonneville with Amal MKII:s and a Joe Hunt.
She is hard to start, blurry in low revs and quite often on only one cylinder.
If I put in brand new plugs everything is better for a short time. Very short. More or less the first miles and then we are back to "normal"
I have cleaned the carbs and put in fresh gasoline.
Could it be the magneto and if so what in the magneto could go wrong? I have never worked on it and have no friends that is friendly with a Joe Hunt here in Sweden.
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #3 ·
Hmmm. Might have missed that actually.
Very fine paper for cleaning and point gap 0.012-0.015, right?
 

·
Registered
Joined
·
2,965 Posts
I don't know what the gap should be.

If the points faces are crusty or corroded, yes, polish them with a file or abrasive. Or fit new ones.

Clean them with petrol or some sort of solvent, on a rag. I draw a clean strip of paper through them then, to remove fibres or grit.
 

·
Registered
Joined
·
66 Posts
Could it be carburation problem. A 69 Bonnie wouldn't normally be wearing mark 2 Amals, so they would need a bit of setting up to get things running right.
Make sure the cold start jets are closing fully and the seals on the bottom are in good order, otherwise it will run rich and foul the plugs.
 

·
Registered
Joined
·
186 Posts
The mag timing is more important than the gap - .015 gap works. Make sure the points just break at full advance notch on the crank shaft (38 degrees btdc). Use very thin paper of continuity light to indicate point break. The Mag's magnet can loose magnetism although that is not common - it can be replaced or re-magnetized. I also run a mag with MK2s on a much modified 750 short rod motor. On well worn Mk2s there is a common cold start plunger problem. The brass plunger body wears inside the aluminum plunger bore in the carb body which causes the plunger body to Not block off the air passage. This is more of a running issue than a starting issue. Check mag points and timing; check all air passages in the carbs - one or both of those are likely culprits. By the way, the two Mag bikes I have have never had the mag points or magnets replace and are 40-45 years old.
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #7 ·
Thanks all for the suggestions.
Will try them out and come back with a report.
Friendly place this. I like it.

Carbs has been cleaned in some professional cleaner at work and then blown with compressed air.
I don´t think it is them but you never know....
 
1 - 7 of 7 Posts
Top