Hi all. Hope you can help. I'm embarking on making my 1098 go a little faster. I've got disc brakes. I got a 12g940 head from a local chap and it's in original condition. I'm going to have the exhaust valve seats recessed. I also obtained a HS 4 carb along with inlet manifold and a nice airfilter.
I stripped the carb today and it has a wax stat in the jet tube and the it's marked AUD 4795. It has a needle numbered ADH . Can anyone help me? I need to know what needle I should obtain and also. If I get a new jet tube will it fit in the same holder the old one came out of and do I bin that was stat and putt 2 pennies in? Hope you can help and sorry if this is obvious. I'm an old hand with moggies but never ever tinkered with making them a bit faster. Many thanks
Hs4 on a 1098
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BaritoneUke
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- Posts: 56
- Joined: Thu Dec 07, 2023 9:24 am
- Location: North West UK
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Re: Hs4 on a 1098
Interesting...I've been looking into making my recently purchased 57 2 door saloon a bit more powerful so I can think about a 5 speed box 
First change I'm making is a 1098 engine with a better camshaft because it's best to do the oil pump too and that's an engine out job, and a better head is going on too, with a single HS4 like you. Not too thirsty. I've changed the waxstat to normal jet. Going to try a number 6 needle but there are similar options if you search the web. I dumped the waxstat jet and put in a standard jet with choke link adaptor 40 quid.
David Vizard's book on tuning the A series engine is an eye opener. Basically he identified improvements along the lines of (I think) inlet & exhaust manifold improvements (so better head unless you improve the 202 head yourself), then exhaust system, then carb, then perhaps camshaft (but others might correct me on this) then perhaps supercharger
So if you're putting on new head might be worth thinking about the exhaust (the company 'maniflow' comes to mind...but you could be looking at 600/700 for a system with a nice open manifold). In a nutshell the tuning process is getting the engine to breath better and when you've got that, adding petrol.
First change I'm making is a 1098 engine with a better camshaft because it's best to do the oil pump too and that's an engine out job, and a better head is going on too, with a single HS4 like you. Not too thirsty. I've changed the waxstat to normal jet. Going to try a number 6 needle but there are similar options if you search the web. I dumped the waxstat jet and put in a standard jet with choke link adaptor 40 quid.David Vizard's book on tuning the A series engine is an eye opener. Basically he identified improvements along the lines of (I think) inlet & exhaust manifold improvements (so better head unless you improve the 202 head yourself), then exhaust system, then carb, then perhaps camshaft (but others might correct me on this) then perhaps supercharger
So if you're putting on new head might be worth thinking about the exhaust (the company 'maniflow' comes to mind...but you could be looking at 600/700 for a system with a nice open manifold). In a nutshell the tuning process is getting the engine to breath better and when you've got that, adding petrol.
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BaritoneUke
- Minor Friendly
- Posts: 56
- Joined: Thu Dec 07, 2023 9:24 am
- Location: North West UK
- MMOC Member: Yes
Re: Hs4 on a 1098
While I remember...mintylamb.co.uk is the place for su needle data...confusing as hell but starts to make sense the more you hear from people 
