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MG MGB Technical - SU needles
71 roadster, 18v engine, 60thou, oversize, K&N filters. The rest is standard. Should this still have the standard needles in the SUs. Also where should the needles be positioned in the piston, as there is room for them to be moved up and down a little on the spring. I have them with the needle shoulder level with the bottom of the piston at the moment and wondered if this was correct. Trev |
Trevor Harvey |
That's the right place to position the needle. Best starting point for a needle with K&N's on a basically standard engine is AAA. |
Paul Walbran |
My +60thou stage ll, big bore, K & N is on ABD. I messed around a long time, but on the rolling road these proved very good and still 30mpg!! |
Allan Reeling |
Most standard engines with K&Ns run best on AAM - a few on AAA or for a richer top end, AAB |
Chris at Octarine Services |
The needles that were in the engine before the rebore a couple of years ago were ABD. After the rebore and the K&Ns AAA were fitted but it was a struggle to get the engine to run well on them. So recently I switched back to ABDs but the engine ran worse. So it was back to the AAAs. A bit more work was done on the carbs, internal cleaning and more care with the setting up, and today its had a good run and runs much better, pulls and revs well into high revs. Thanks all for your input. Trev |
Trevor Harvey |
This thread was discussed between 06/07/2013 and 07/07/2013
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