1973 R75/5 Rocker Box Cover questions

[bigvic54]

I just acquired a 1973 R/75 Airhead and I'm having issues with the Rocker Box Cover.

The right side cylinder was missing the stud securing the rocker box cover. The parts catalog says it should be a M8 - 1.25 stud, however, the hole is M10 - 1.25. The manual doesn't show any kind of fitting to reduce the threads and it doesn't look like this was drilled afterwards.

Has anyone ever seen this? Any suggestions?

 

[kbasa]

I just acquired a 1973 R/75 Airhead and I'm having issues with the Rocker Box Cover.

The right side cylinder was missing the stud securing the rocker box cover. The parts catalog says it should be a M8 - 1.25 stud, however, the hole is M10 - 1.25. The manual doesn't show any kind of fitting to reduce the threads and it doesn't look like this was drilled afterwards.

Has anyone ever seen this? Any suggestions?

It probably wound up stripped because it's easy to do.

 

[20774]

If stripped, then something like a helicoil could be used so that the stock bolt can be used again. Be careful of extra swarf so that it doesn't get into the spark plug hole. You could also consider dropping the appropriate sized hex nut in the hole in the head...it might have to be ground down to fit. Then with that in place, you can feed in the stud with some red Loctite to hold it in place. Note the acorn nut used on this stud doesn't have to be torqued all that much...be sure and use a waverly washer. The two outside studs are probably doing most of the work to seal the rocker cover in place anyway.

 

[melville]

There are step studs available, M10 on one end and M8 on the other. They got used a lot for VW exhaust studs BITD. Might be a bit of a challenge getting one long enough for the application. Definitely worth a trip to the hardware or auto parts store.

Edit--if the threads are M10 X 1.25, there was probably a Helicoil in that hole. The step studs are usually M10 X 1.5 on the thick end. So you might get a Helicoil and thread it in, maybe with some red Loctite on the outside.

 

[kbasa]

There are step studs available, M10 on one end and M8 on the other. They got used a lot for VW exhaust studs BITD. Might be a bit of a challenge getting one long enough for the application. Definitely worth a trip to the hardware or auto parts store.

Edit--if the threads are M10 X 1.25, there was probably a Helicoil in that hole. The step studs are usually M10 X 1.5 on the thick end. So you might get a Helicoil and thread it in, maybe with some red Loctite on the outside.

100%, man. Kinda my thought, too.