Hi
My spark plug thread has stripped, can someone tell me the correct thread so I can get a thread repair kit. or can someone recomend a repaiir kit.
PS
The spark plug I fitted is a champion N4C
Cheers
Mark
M14 x 1.25 pitch
repair kits widely available as long as saveable. if not, then it will have to be machined out and a new bush fitted and re machined.
needs to be air tight.
That makes, according my understanding, six different threadforms on one bike.
Have I mssed any?
Little surprise that the British bike industry disappeared.
Adrian.
Hi
Thank you for your reply
I was aware that the plug was not 100% tight in the right cylinder and I started it in the garage and the plug shot out.
It look clean just stripped the thread.
I have been watching on youtube how to do the job without taking the cylinder head off, using grease on the tap and blowing out any filings with compressed air.
any thoughts
Mark
always easier to watch than do, keep the piston at TDC , another option is to remove the exhaust pipe and use a hoover to suck anything out.
regarding the threads, its always been that pitch until the Japanese came in and started using smaller threads/plugs.
problem with the British made machines is that small threads mainly had to be BA, when bikes started being sent to America as main market the odd number UNC or UNEF came in. Likewise BSF and BSW were changed for UNF and UNC.
generally on aluminium components the coarser UNC and BSW were used to prevent stripping out, the UNF and BSF were used on normal steel components which could stand the torque used to tighten.
BSC was the norm fine pitch thread originally used for cycle parts thin sections where threads are needed, to be replaced by UNEF.
BSA/Triumph merged and used their stocks BUT certain components were still being used by other manufacturers and car makers so had to be kept as universal SO explains why so many were used. hopefully!!
In machining we were told things would be simpler when we went metric, yeah right. Metric standard, metric fine, metric coarse, panzerghewinde, and others..PZGW are used on some military items we made, and made a brief appearance on railway brakes.
Thanks again for advice
I think I will have a go with the head on, I can always remove head if needed.
I will put the piston at top dead centre on exhaust stoke and blow out and vac through the exhaust port.
I have one of them devices that I can view in the cylinder to make sure all files have gone.
Chaz,
And BSP 🙂
Try to forget BSP as also BSPT for taper, and in our company we work to our own tolerance, closer than BS for an air tight fit, vacuum brakes, this bu99ers up suppliers as we often get new ones that work to BS instead of reading our drawings. Their components are a baggy fit. Of course some American brands use NPT to also confuse.