HS6 Fixed needle centering tips

[houleyh]

Does anyone have a tip on how to center a fixed needle of an HS6 (Obviously I do not have a tool).. Everytime I tighten the nut, the bearing moove and de-center the jet...

Thanks

 

[NickMorgan]

Assuming that everything is lovely and clean, so that the piston will not bind and also assuming that the needle is fitted correctly and is not bent, this is what I have always done. Can't be sure that it is the correct procedure, but it has always worked for me.
I loosen the jet locking nut and then tighten the jet mixture nut up as far as it will go. Then I remove the oil damper piston and push the piston/needle assembly down using a pencil, while tightening up the jet locking nut. I then lift the piston a couple of times to see if it drops back down OK. It usually takes a couple of attempts. Then it is a case of adjusting the jet as per the manual and then a bit of fine tuning.
I have heard people saying that the jet mixture tensioning spring should be removed while doing this, but that involves removing the jet to replace it after centering, which I would have thought could knock it out of adjustment again.
Something that I have also done when having difficulty is to loosen the three dash pot screws while pressing the needle assembly down with the pencil and give the dash pot a wobble and then re-tighten the screws. If the dash pot isn't perfectly seated then centering the jet would be impossible.
I also imagine that if the old cork seal is being re-used this could push the jet off centre.
I hope this non-technical summary helps!