Ariel Owners Motorcycle Club

The rocker feed stud thread has stripped where it screws into the timing case, the stud size is 1/4", can i drill the damaged thread out and fit a later larger 5/16" stud ? The bottom chain cover fixing bolt hole looks very close to oil feed hole if I fit a larger stud will I brake through into that fixing hole ?
Cheers
Michael

I have seen a 5/16th stud used a few times. Why not go metric with the thread in the Aluminium and step the stud down to the original 1/4?. keep all the other bits as they are. Nev

Helicoil ... ? .. if you're careful

Hello Michael,
There is enough room for a Helicoil and that way you can keep the original stud and banjo. If I had to do that job again I would remove the case from the bike to make it easier to work on. Whether you tap the hole for a new stud or a helicoil make sure your tap is perpendicular to the surface of the case or you will have a hard time preventing an oil leak. Guess how I know.
Good luck, Chris

Not sure if this is a good application for a helicoil, The face where the banjo fits against is affected by the helicoil and there is not much depth ( from memory) of metal available in the casting.. If you remove the entire piece it wouldn't be difficult to weld it up and re do the thread. The face must be normal to the stud or it will always leak. (Onto the exhaust pipe). Nev

From 1950 until the rocker feed was taken from the return line, all timing covers used a 5/16 stud for the rocker oil feed so there is no problem tapping out to 5/16 and using the later stud and oil banjo which are readily available from drags.
David

I have stripped the Threads on my 1945 NH 350 oil feed stud (see pics). What would you recommend as the best way to repair? I believe the stud is 1/4". Drill it out? Weld in a replacement 5/16"? Suggestions?

Satchison
the stud screws out. Use a good pair of vice grips and unscrew the stud from the timing cover. New studs are available from drags. Fit 2 nuts to the outer end of the new stud and lock together then and use the locknuts to screw the new stud in.
David

Thanks David. I was hoping that was the case. I have found the parts on Drags and will order them up. Cheers!

I assume that the orientation of the oil feed stud orifice makes no difference?