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Triumph TR6 - Rebuilt carbs running very lean

I recently rebuilt the Stromberg carbs on my 76, new jets, seals, gaskets, pressure relief valves, etc. I then followed the tuning instructions that were available on the Buckeye website. I adjusted the carbs as far to rich (clockwise) as possible. Even at this extreme setting, the engine is running very lean. The plugs are all very white. Do I need new metering needles? Is there something else that could be causing this? Any suggestions will be appreciated.
Mark Hauck

Hi Mark,
Have you checked your timing ??... I've found over the years that most problems are timing related.
Do you have points or electronic ignition ?
Charlie
Charlie Ballard

You may need to adjust the float so the fuel level is higher in the chamber. That will rich things up.

Brent
Brent B

Mark--In addition to Brent & Charlie's suggestions, is it possible that you put the temp compensators and/or bypass valves out of adjustment or forgot to return all the seals (especially that small round one that goes on the nose of the compensator valve? A recheck of float heights (18 mm?) would be a good idea, although you have to remove the carbs to that.

I assume it was running OK before the rebuild; if not, it may be worth checking your needle designation by pulling on the needle and looking for the small lettering on the needle shaft that is normally hidden by its brass nut. I believe the correct needle profile is B1AF.

Good luck and keep us posted.

Rick O.
72 TR6
Rick Orthen

Rick, where exactly is the compensator valve and how do the seals fit on them? I recall the super small rubber washers in the rebuild kit but I don't remember removing the old ones. Maybe they had disentegrated. That could be my problem.


Charlie and Brent, I will also double check the timing and the float heights.

Thanks Guys.

Mark
Mark Hauck

I posted an earlier response, but it must have gone lost...

Remember that the "book" setting for float height is based on a particular needle valve available at the time. With the aftermarket as it is, the valve you're using now is probably different. If it needs to be open more to get the fuel flow that's needed, the float level will drop. When all's equilibrated, the carbs will be too lean. By setting the float to a higher level (lower gap measurement) the valve will be more open at a higher fuel level. The end result is a richer mixture.

After a while you'll be like me - you can get a carb off, adjusted, and back on in about 20 minutes. Not that I'm bragging about how often it's been done....

Brent
Brent B

Mark--The temperature compensator (TC) is on the right side of each carb and is covered with a white (prolly yellow by now) plastic cover held by 2 slotted screws. Remove the TC by unscrewing the 2 screws on the TC body wings and pulling it from the carb body. There should be 2 rubber washers: one on the base of the snout and another smaller one on its face. Most likely the smaller one will be stuck in the carb body and you'll have to pick it out. This is also a good time to check the TC valve movement; there should be no binding.

Rick O.
Rick Orthen

Thanks Rick. I am going to check the needles to see what I have and then I may adjust the float levels.
Mark Hauck

This thread was discussed between 12/10/2004 and 14/10/2004

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