Fast Eddie
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- Joined
- Oct 4, 2013
- Messages
- 21,570
Gents, I’m struggling with the mk11 carbs on this T140 I have just bought.
The carbs are brand new and fitted with 20 pilot jets, 106 needle jets, number 3 slides, 200 mains. These are the ‘standard’ settings for this bike according to Amal.
I have ensured the enriching circuit plunger is sitting properly with slack on the cables.
It is very rich. Currently, I’m only talking about low revs / small throttle openings cos it’s a newly rebuilt motor, when opened up briefly it it seems to clear, but the low end is very rich.
So I started reading up and learned that carb settings for the late model T140s (mines late 1980 so probably a 1981 model year, but kinda unsure) are a bit of a nightmare with EPA spec bikes vs none EPA spec bikes etc.
The carbs will be coming off today to see if I can find anything amiss. Float height is my first port of call.
I have a brand new pair of mark 1.5 concentrics in stock and am sorely tempted to fit these at the moment (I had a Harris Bonnie with these and it was fantastic).
But I’ve also had Bonnies in the past with MK11s that ran perfectly, so something is obviously amiss, and I’d like to know what.
I’ve read the John Healey notes posted elsewhere about the difference between EPA and none EPA settings but am confused as to which is best regarding overall performance with today’s fuel. I’m also confused because I had thought that EPA settings would be weaker, but some jets are richer?
As you can tell, I’m somewhat discombobulated over this. Does anyone have any sound advice as to the best way to get these MK11 carbs running as Amal / Triumph intended?
The carbs are brand new and fitted with 20 pilot jets, 106 needle jets, number 3 slides, 200 mains. These are the ‘standard’ settings for this bike according to Amal.
I have ensured the enriching circuit plunger is sitting properly with slack on the cables.
It is very rich. Currently, I’m only talking about low revs / small throttle openings cos it’s a newly rebuilt motor, when opened up briefly it it seems to clear, but the low end is very rich.
So I started reading up and learned that carb settings for the late model T140s (mines late 1980 so probably a 1981 model year, but kinda unsure) are a bit of a nightmare with EPA spec bikes vs none EPA spec bikes etc.
The carbs will be coming off today to see if I can find anything amiss. Float height is my first port of call.
I have a brand new pair of mark 1.5 concentrics in stock and am sorely tempted to fit these at the moment (I had a Harris Bonnie with these and it was fantastic).
But I’ve also had Bonnies in the past with MK11s that ran perfectly, so something is obviously amiss, and I’d like to know what.
I’ve read the John Healey notes posted elsewhere about the difference between EPA and none EPA settings but am confused as to which is best regarding overall performance with today’s fuel. I’m also confused because I had thought that EPA settings would be weaker, but some jets are richer?
As you can tell, I’m somewhat discombobulated over this. Does anyone have any sound advice as to the best way to get these MK11 carbs running as Amal / Triumph intended?