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Needles
- Thread starter davjac889
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martx-5
Yoda
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Why?? Is your engine running too rich?? That's what the jet adjustment is for. If you can't get the mixture right with the jet adjustment, then either the jets and/or the needles could be worn. The profile on the SM needle is what Triumph decided is right for the car as stock. If the engine is modified, then needles might have to be changed, but I always seen that go the other way...toward richer needles.
Here's a needle comparison program...Click on 0.100", then on the next page you can compare up to four needles.
https://www.mintylamb.co.uk/suneedle/
Here's a needle comparison program...Click on 0.100", then on the next page you can compare up to four needles.
https://www.mintylamb.co.uk/suneedle/
TR3driver
Great Pumpkin - R.I.P
Offline
If it's running too rich with the nuts all the way up, then "leaner" needles won't help (except to the extent that your old needles are worn out). The idle portion of the needles are all the same, the "lean" part is at mid to full throttle.
Most likely, you need to replace the jets (possibly needles too) and be more careful about getting the jets perfectly centered. When the centering is a bit off, the needle rubs on the side of the jet and eventually wears a groove that passes extra fuel.
Could be other things too, of course, like the jets not returning after you use the choke; fuel pressure too high; sunken floats, etc. But after you've checked all that, try changing the jets.
Most likely, you need to replace the jets (possibly needles too) and be more careful about getting the jets perfectly centered. When the centering is a bit off, the needle rubs on the side of the jet and eventually wears a groove that passes extra fuel.
Could be other things too, of course, like the jets not returning after you use the choke; fuel pressure too high; sunken floats, etc. But after you've checked all that, try changing the jets.