Identify My carbs, i think HS6 SUs not Hitachi. Good, Bad, Indifferent?
Posted 28 December 2014 - 11:42 AM
Can someone tell me what the main differences are and are these worth keeping or going to Z therapy 240z carbies with SM needles etc.
Current;y, ca pulls hard, however i have lowered the jet down another one turn as it was lean, now seams ok still a bit flat above 5600rpm and will not rev to anything over 7K not even at idle,that could be more the dizzy.
Posted 28 December 2014 - 01:28 PM
Seem to be working fine, a bit of a adjust here and there has helped!
As per your other thread, better to be looking at your dizzy for your issues.
Posted 28 December 2014 - 03:46 PM
Posted 28 December 2014 - 04:57 PM
And I really don't think you'd be wanting, or needing, to rev past 7.....why? Asking for trouble. Better to sort the car's gearing out to suit your needs.
Posted 28 December 2014 - 05:39 PM
Posted 28 December 2014 - 05:55 PM
Very similar performance between these and Hitachi's, nowadays how well they run depends on the condition of the carbs rather than what type they are.
Real SU's are easier / cheaper to get parts for, both standard bits and "tuning" bits. I rebuilt a pair a year or two back for a cost of under $200, including having the carb bodies re-bushed, new jets / needles / gaskets / special non-sink adjustable floats and high-flow ball valves for the float chamber. All the bits (except the fancy floats and needle / seat) were available from Carburettor Service Co in Sydney, who also did the rebushing. Fancy bits came from Burlen in Pomgolia.
Only thing I don't like is the method of adjusting float level on the British SU's - most of the 1 3/4" ones I have need to be adjusted by adding / removing shims / washers from underneath the valve (which is a little fiddly to get spot on). Hitachi's can be adjusted by bending the float lever. You can get (as I did) special adjustable floats for the SU's.
Posted 28 December 2014 - 06:11 PM
Perhaps you may need to look at re-jetting them if they are still jetted for the smaller Dolomite engine.
Posted 28 December 2014 - 06:29 PM
"SM" needles are listed as British SU needles, I assume Z-therapy use these in their Hitachi carbs. You should be able to get a pair of these needles and bolt them into your carbs quite easily and cheaply.
Posted 28 December 2014 - 06:58 PM
Posted 28 December 2014 - 07:22 PM
Posted 28 December 2014 - 07:38 PM
Just a quick question, whats the difference between HS6 and what I have which are HU6 ? Does the middle letter, mean year of manufacturer ? The Hu6 I purchased new around 7-8 yrs ago..
Dunno, only types I know of are H, HD, HS and HIF. H & HD are quite old, HS is the most common type from the 60's / 70's, and the later HIF which are completely different with the float chamber built into the carb rather than bolted on the side.
Could be something newer I guess, I've only fiddled with older carbs.
The "6", incidentally, is the size - 1 3/4"
Posted 28 December 2014 - 08:52 PM
The HS6 needle is much longer and fatter then the hitachi one. The hitachi one will not fit into the HS6 carb as this has a spring loaded needle seat. SO i think SM needels are in order.
Posted 28 December 2014 - 09:26 PM
Posted 28 December 2014 - 09:54 PM
Posted 29 December 2014 - 07:37 AM
Also be aware that if the "SM" is recommended for an L24 (I'm not sure exactly what it is recomnmended for), it may still not be ideal for an L28 due to the larger capacity of the L28. Probably a good starting point though I guess.
I've already mentioned CSC in Burwood, Sydney, but SUMidel in Sydney also stock a large range of needles for $12 - $15 each - http://www.sumidel.c...gory/su-needles Don't be put off if they answer the phone as "Fabre" - once you start talking SU carbs, they put you onto someone else who seems to specialise in them, not sure what the business relationship is between SUMidel and Fabre ??
And just for completenes, if you get really carried away with a rebuild, here are the newer style floats that are adjustable, unsinkable and ethanol resistant - http://sucarb.co.uk/...ayup-float.html. Not needed, but make float level setting a little easier.
Posted 29 December 2014 - 01:02 PM
fun and games
Posted 29 December 2014 - 03:02 PM
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