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Tips & Tricks


Roger
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Hi! I know that several members here on the forum have decades of experience of Triumph ownership and I guess we all have learnt one or two useful things over the years (usually the hard way…). It would be a shame not to share some of that wisdom to others and it will also give potential members a reason to join the club and the forum. JohnD recently posted an excellent instruction how to prevent sump leaks (thanks John!). http://forum.tssc.org.uk/index.php?/topic/108-correcting-the-sump-flange-to-prevent-leaks/ It is that kind of tips & trix that I hope to see in this topic.

 

I have started this thread in order to share some of the things I think have made Triumph ownership easier for me, and it would be great if some of you out there also have something to add. Feel free to add any tips & tricks you find useful in this thread!

To be continued...

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Stromberg jet position, fuzzy or operational definition?

 

I will start with a method of setting the jet position in the Stromberg carb (CD 150 in my case) using a caliper, instead of “counting turns” as described in the work shop manual (WSM). To my knowledge this method has not yet been described in the Courier (?) or here on the forum. According to WSM one should first “turn the adjusting screw until it just contacts the underside of the air valve…   …then unscrew the adjusting screw three turns

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The problem with the WSM procedure is that the jet position “just contacts the underside of the air valve” is a fuzzy definition, and this position will be slightly different from “operator to operator” and also from “time to time” if we try to repeat the procedure. Another problem (at least for me) is that I frequently forget how many turns I have done, and then I have to start from the beginning over and over again (early stage of senile dementia I guess).

 

But first, let us look at the jet:
Threads are defined by

  1. The outer diameter, in our case measured in inches.
  2. The number of threads you can count per inch (TPI, Threads Per Inch) or the distance between two threads (=Pitch). TPI can easily be measured using a thread gauge.

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The threads on the jet are 3/8” UNF, 32 TPI. Hence, one 360 degree turn will move the jet downwards one pitch (25,4/32) i.e. 0,80 mm / turn. See turns converted to mm below.

gallery_94_38_11836.png

There are several advantages using a caliper (or depth micrometer) instead of counting turns. One is that we get a very accurate and fixed starting point. Another advantage is that if you for some reason have to dismantle for instance a leaky carb that otherwise have been performing very good then you can measure the exact position of the jet before taking it apart, and then make sure you position the jet in exactly the same position when you reassemble it again. It is also easy to get lost when you adjust two carbs in a 6 cylinder engine, and after a while you do not remember how many turns you have done and in which direction on each carb. You can find out by removing the piston and measure the jet position with a caliper.

 

If you have access to a depth micrometer then it will give you a better accuracy, but a proper caliper will be good enough.

 

I hope this information can be useful! Note that this position of the jet will only give you a starting point, and you will have to continue to fine tune the carb(s) according to the manual to obtain best results.

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Hi roger , i also started a tools and tips on october 20th but it didnt take off

 

having run the last  ( Lost) forum we had a load of idea's in tips and odds and sods   but I cant be doing all that again.

 

its a good place but with  no chapters  or headings to browse things like this just get lost unless you wade through the  whole thing

 

Pete

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Hi Mike & Pete,

Thanks for the feed-back! English is not my first language (as you probably already have noticed) so I’m a bit reluctant to publish anything in the Courier, unless someone can do a proper spell check and remove the weird parts written in Swenglish… But if you think this is useful and interesting enough (and technically correct?) then of course it could be published in the courier. I could take better pictures and polish the text a bit. Who should I send it to?

Pete, I was not sure if I should put this under “Fuel System” or “General” but I have a few more tips and trix in pipeline about very different subjects, so I thought it was worth giving it a try under “General”. But I agree that it is difficult to find a good heading.

Cheers,

Roger.

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  • 2 months later...

Hi. Thanks Pete ( I was disapointed your original post was not fed back) and Roger. I feel tips and tricks are invaluable to save time and money and very interesting in themselves. I am fairly new to old car ownership so still learning a lot but will post anything useful.

Cheers

Dave

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