HS6 original Set Up

[ham204]

Hi All, the previous owner has fiddled around with the carbs to 'improve' them once he put some ITG filters on. He told me that he changed the needles and I have an old set of jets in the boot. Can someone let me know what is the original number for the needles and jets please? I wouldn't mind if there is an improved needle/jet that I may use.

[SprintMWU773V]

The needles and jets do depend on the age. Later cars had waxstat type jets and slightly leaner needles, like a BDQ. If he's been running a freeer flowing air filter then I'd imagine something like a BBT will have been fitted. If it has (or should have) waxstats then throw them away or remove the wax pellet and replace with 2 1p coins. You might or might not also have throttle butterflys with 'poppet' valves in them. Again these were introduced to lower emissions by leaning out the mixture on the over-run. Personally I prefer non-waxstat and non poppet butterflys.

Depends how original you want to go an perhaps most importantly does the car currently run OK? If it does leave it alone else you're opening a huge can of worms.

[Jon Tilson]

Sorry but I have to disagree on waxstats...they usually work well, but they start to not work when they get dirty and cant loose heat.
So keep them clean...

Later Sprints with waxstats do have a leaner needle and this knocks at least 10 mph off the top end. As the jet size is the same I see no reason
not to go for the earlier needle especially with a free flowing air filter.

Jonners

[ham204]

Actually the engine doesn't sound too well - up to now I've detected a rotor arm that has smashed into the dizzy cap, air leaks galore, what seems to be a sticking valve and a fuel pump belting out 4.5psi. I'm back to the original airfilter, mech pump, magnetronic ignition (still to be sorted out), new cap and leads, TDC alloy spacer blocks on the IM. Before I removed the carbs and changed the ignition, there was a definite improvement, although I cannot do much for the sticking valve right now. The carbs themselves look ok but definitely not original needles and one of them seeps oil on the bridge so I'll need to open them up and check them out.