rocker box leak.

[MICKREEVES]

When I assembled my C15SS engine, I used the old rockerbox gasket, expecting I would need to dismantle again later.
I found the engine was fine. no further work needed, except -- leaking rocker box!!
To replace the gasket, the engine has to be removed. A long job, and I needed help to lift the engine.
Next time, I intend to replace the rockerbox studs with hex headed bolts. Then it can be removed with the engine undisturbed.
It should work??
Mick

[MALCOLM.JOHNSON]

I do not know the engine in detail, but if the rocker box can be removed when the studs are removed, then remove them now. You can do this if there is enough thread exposed by fitting two nuts on and tighten one to the other and remove the stud using the lower nut.... or.... remove the nuts, clean the threads and apply a small dab of "threadlock", which can be separated with heat later once removed, if required. Personally I do not like replacing studs going into alloy casings with bolts as it is much easier to damage the coarse thread in the casing, than it is to tighten down a fine thread nut on a stud. If it was something I wanted to do to make a part easier to remove, I would either put a screwdriver slot in the top of the stud or make studs with a longer fine thread that will accept two nuts, hence making removal easier (or a pair of half nuts). Studs do not need and should not be over-tightened in alloy casings, as at best the thread is raised and distorted, or at worst stripped. Also on this point, if you do have a leaky joint face, held by studs, remove the studs and dress the face around the stud holes gently with a flat file, to remove any of the previous mentioned raised threads. A gasket will seal much better if you do that! When replacing casing screws in timing covers particularly, clean all old gasket glue that may be down the holes by using a finger held metal drill to twist all the debris out followed by an appropriate tap to clean the thread if you have one. I have lost count of the thread repairs I have had to do because old gasket glue has hydraulically burst the casing or blown the thread, especially when the old casing screws had been replaced by allen set screws, hence greater leverage. BSA twins were particularly prone.   

[MICKREEVES]

The studs were too tight to remove with two nuts locked.
Perhaps they would be easier with the engine hot, but alas
I cannot start the engine anymore!!
Mick

[gusmagicbus]

If you can't get the rocker box off (incidently I can on my C15SS80, its very tight but perhaps my studs are little shorter / screwed in more), you can take the cyclinder head off with the engine in and then remove the rocker box. Perhaps this is easier that removing the engine. The other option is just to support then engine, remove mounting bolts and drop it down just a few mm out the bottom of the frame, your rocker box must almost come out if mine can!?

[MICKREEVES]

I did look at that, but decided there would still not be enough clearance.
In fact, withe engine mounting bolts removed, there was still not enough clearance. I had to remove the rear wheel,
and the chain guard, the n lift the engine  out.
Mick