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Richer Needle for HS2

Posted: Tue Jun 12, 2012 5:17 pm
by Tom and Maria
Please could someone tell me what needle would be richer than standard (and indeed what is standard) for an HS2.

Since I tapped the carb spacer and ran the rocker pipe to it (to sort a crankcase pressure problem) the mixture has been slightly weak. Obviously I have adjusted this as best I can by enriching it the usual way, but thought a new needle might be a better solution.

Thanks,

Tom

Re: Richer Needle for HS2

Posted: Tue Jun 12, 2012 7:11 pm
by bmcecosse
How big a hole did you make in the spacer? Doing this should only really affect the idling mixture. What colour are the spark plugs after a good run (no idling) - and did this mod sort out the pressure problem ??

Re: Richer Needle for HS2

Posted: Tue Jun 12, 2012 10:43 pm
by Tom and Maria
I made a 2.5mm hole which solved the problem perfectly. I increased it from 1/8'' which hadn't quite done the job at first try.

The plugs are white edging on cream after a long run, not the cafe latte colour I'd hope for but not white white.

It doesn't idle quite as steadily (as expected) but it isn't a problem.

The alternative is that I fit an hs4 with a wrong sided float which I have handy. I'd need a new needle for that too as it currently has a very lean one in it, maybe aaa, can't remember right now.

I'd rather keep the hs2 for originality, but currently the adjuster has been wound down 10 flats, and to go any further seems excessive.

Ideas?

Re: Richer Needle for HS2

Posted: Tue Jun 12, 2012 10:52 pm
by bmcecosse
1/8" is ~ 3mm.......... But that's the size hole I used when doing this job - and yes it works well! Just live with the slightly poor idle - the creamy white plugs are all right. The HS4 will give you a bit more power although 'wrong side' float bowl may cause a problem when accelerating. The AAA needle would be fine in that carb.

Re: Richer Needle for HS2

Posted: Wed Jun 13, 2012 4:48 pm
by Tom and Maria
Whoops, I meant the measurements the other way around.

Thanks for the answer, I think I just needed reassuring.

Tom

Re: Richer Needle for HS2

Posted: Thu Jun 14, 2012 9:09 am
by Alec
Hello Tom,

Minor 948 1960 - 62 the rich needle is a AH2, for the 1098 it is a H6. Have a look at this link, a useful S.U. needle comparison.http://www.mintylamb.co.uk/suneedle/ You need to click on the carburettor in the jet size selector. Standard needle for the 948 is M , weak is EB, for the 1098 standard is AN and weak EB again.

Alec

Re: Richer Needle for HS2

Posted: Mon Jun 18, 2012 5:47 pm
by dp
This might be of use to you and others:

http://www.winsu.co.uk/