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Triumph TR6 - Carbs

My '69 doesn't have adjustable jets, so when one of our club members offered me a pair of CD175's from his GT6 I jumped at the chance. I'm thinking that I might just swap out the pistons to get the much sought after adjustability, my carbs being recently rebuilt. So here is my question: are the jet tapers the same for the GT and the TR?

Tony
A. J. Koschinsky

The GT6 models came fitted with CD150s, not CD175s. If this particular GT6 had CD175s on it, then someone at some time changed it over. Given the displacement difference between the GT6 engine and the TR-6 engine, I don't see the same jet needle profile being suitable even if this particular GT6 was indeed fitted with CD175s.

I would also wonder if the jet bore is different between the CD150 and CD175. I know that if you look at an SU HS4 (same throttle bore as a CD150) and an HS6(same throttle bore as a CD175) the jet diameters are different. A difference in jet bores would definitely preclude interchangability of the jet needles.
SteveP1

My thinking too, but I preferred to let the expert answer
DNK

I don't have the history of the carbs, but he was certain they are 175's. The car was far from stock when he got it so who knows what the history is. If they are 175's from a TR6 (or heaven knows what) it could explain the tuning issues he had which caused him to go to a completely different set up.

When I get the carbs next weekend I'll have to dismantle them and see what lies within. I hope there are some identification markings on the needles. I've had my carbs apart many times but never looked for markings.

I had the TR out for its first run of the year this weekend. Minus 19C but the roads were dry. I didn't put the top down - the whining from the passenger seat area would have increased too much in both pitch and intensity. It ran a bit lumpy on the way to town to the club breakfast which gave rise to the carb discussion. On the way home, though, it ran perfectly.

Tony
A. J. Koschinsky

Tony

I admire your courage on the -19 drive in March.

On the carbs - I have a 69 with original carbs and non adjustable needles and I have toyed with the idea of modifying the stem shank to allow some adjustment using the set screw to hold it in place. I haven't tried it yet though. The problem is it is cumbersome as the carb tops have to be removed to do the adjustment and fine tuning.
Michael Petryschuk

Just to close the loop on this, I got the carbs yesterday at our weekly club meeting (drove the TR6 again, only -16 this time so things are looking up) and they are, indeed, 150's. There may be bits on them that might be usable (matching end table lamps, anyone?) but my hopes of an easy conversion to adjustablity have been crushed for the moment. On the other hand, the car is working just fine so perhaps this is the cosmos telling me to leave well enough alone.

Tony
A. J. Koschinsky

This thread was discussed between 23/03/2014 and 31/03/2014

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