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Joined: Apr 2013
Posts: 142
L - Learner Plates On
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OP
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Attempting to get my carbs tuned on a TR3 engined +4. The piston liners have been replaced from 83 to 86mm (1991 to 2138cc). Still running freshly rebuilt stock H6s, currently they have the "SM" needles in them but I'm running very lean through the rev range after the displacement bump (no other leaks). I would like to switch to a richer needle, and from the limited information I have found the "RH" seems to be the way to go. Does anyone have any further input or other needle suggestions?
Thanks and happy motoring,
Read
1960 Morgan +4 4 seater
1997 Nissan 240sx S14
2011 Nissan 370Z
2009 Triumph Street Triple
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JohnV6
2022 CX Plus Four
2025 Renault Scenic Alpine etech "Yvette"
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Aye, and a great site it is! Lots of info about DCOEs, and SU's are really simple - just can't find a great answer. I did see a chart somewhere comparing the needle diameter along the shaft.
My best bet might just be to try new ones out.
1960 Morgan +4 4 seater
1997 Nissan 240sx S14
2011 Nissan 370Z
2009 Triumph Street Triple
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Joined: May 2011
Posts: 1,245 Likes: 2
Has a lot to Say!
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Has a lot to Say!
Joined: May 2011
Posts: 1,245 Likes: 2 |
RH vs SM dimensions along the shaft (from Haynes Techbook Weber Carb Manual)
0.100 vs 0.099
0.095 vs 0.095
0.0915 vs 0.0915
0.0878 vs 0.0885
0.0846 vs 0.0855
0.0813 vs 0.0825
0.078 vs 0.0795
0.075 vs 0.0765
0.072 vs 0.0735
0.069 vs 0.071
0.066 vs 0.069
0.063 vs 0.067
0.060 vs 0.065
0.057 vs 0.063
Hope that this is of some use.
Don.
Last edited by Max5; 22/03/15 08:45 PM.
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Has a lot to Say!
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Burlen Fuel systems have an online needle calculator http://www.mintylamb.co.uk/suneedle/Simon @ Mulfab
Simon @ Sifab.co.uk
Sifabtemporary@gmail.com
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Joined: Apr 2013
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Thanks for the information guys! It was leaning even at idle, it appears that the RH wouldn't significantly change that would it - perhaps I'd need a larger jet? I'll give her a try!
Last edited by Read T; 22/03/15 10:38 PM.
1960 Morgan +4 4 seater
1997 Nissan 240sx S14
2011 Nissan 370Z
2009 Triumph Street Triple
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Joined: Sep 2008
Posts: 516 Likes: 1
Talk Morgan Regular
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Talk Morgan Regular
Joined: Sep 2008
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Why not visit the TR Register forum and search carb needles. If you can't enrich the mixture by adjusting the carbs, it sounds to me like a different problem.
Couldn't swear to this but I didn't think that increasing capacity on those engine requires a needle swop.
Malcolm T
1966 +4
1957 TR3
1963 TR4
1983 LR 110
1985 Robin Hood 2.0l
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Couldn't swear to this but I didn't think that increasing capacity on those engine requires a needle swop. I thought about this too, it seems like the engine would just pull more air through the carbs which would "pick up" more fuel at the same time.
1960 Morgan +4 4 seater
1997 Nissan 240sx S14
2011 Nissan 370Z
2009 Triumph Street Triple
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