Re-torquing 850 Commando head.

Hello all,

This is my first time posting on this forum. I have a 75 Commando that I inherited from my father, which sat for some time after he passed away. However, the bike is still in phenomenal condition and runs exceptionally well considering. When I brought the bike back to Tennessee and got it running, I noticed the Commando had a blown head gasket. I took it to a British motorcycle mechanic in Nashville to have it replaced (he recommended and installed a copper replacement), but told me he noticed the head was warped a little bit. The mechanic said it was not that bad and a re-torque after several hundred miles should seat the gasket. However, he has since gone out of business and I do not feel comfortable attempting to torque the head myself.

I have read horror stories of people pulling the head bolts when attempting to torque them, and this makes me very standoffish toward the whole process. I guess I am a little gun shy when it comes to working on this bike because I do not want to screw it up. My father rebuilt it from the ground up, but since he passed when I was young, all I know about what was done to the bike is an article Classic Bike Magazine did on it in the 90's. Apparently, Brian Slark helped build the bottom end, isolastics, and transmission of my Commando which is another reason I do not want to screw it up. Is there anyone near Nashville that would be willing to re-torque the head for me (or know a good shop)? I will pay for your time, just would rather it be done correctly then me attempting it and something go wrong.

Thanks.

I could have helped but just packed up my garage and am moving to DC monday. I'm assuming it was Bill who replaced the gasket?

You could email Mike Harrod. He's the TNOA president and a very nice and helpful guy. He can help get you squared away.

mikes_n15cs@yahoo.com

Nashville...if Memphis is not too far away for you: take it to Memphis Motor Werks where Leo Goff can advise and help you out.

Hi nortncom!

torquing the head fasteners is very easy and takes little time, also do not fear the job, almost impossible to do harm

Perhaps if you tell us where you live a forum member may be available to help you out.

If not, then you can do it yourself if you have a torque wrench and a drive socket with some extensions.

There is really only one fastener that is awkward to get to and it is in the middle back of the head.

You won't be able to get a torque wrench on it but that's ok, you just snug it "hard" by hand.

If memory serves I use a 13mm box end wrench on it, a very thin box end, and I had to take it to my bench grinder to mill some metal off it so it would fit around that nut

Although a set of wittworth sockets is preferable, I don't have any and so just use whatever sockets seem to fit the tightest on each nut that I have in the garage.

Hopefully others will reply with link to the torque numbers and tightening sequence.

You will need to just take off the tank to better get to the front three recessed nuts with your extension.

There are also two upward facing bolts in the front of the head you can easily get a box end on and again just good hard snug on those should do as I don't think you can get a torque socket on them.

Windy is in Shady Valley...don't have a clue how far it might be from you but he would be a good resource.

memberlist.php?mode=viewprofile&u=19

thanks for the reference but Leo Goff would be closer to Nashville as I am at the far east end. but I would be more than willing to help if he wants to make the run and I might even show him some good mountain roads :mrgreen: plus I do have a campground so he would have a place to stay a few days.

Thanks everyone for the prompt replies. My internet has been on the fritz, so it has taken my a little longer to reply than I had hoped.

Jsouthard-- yes it was Bill who performed the work on my Norton. Judging by the 850 Commando in your profile pic I believe yours was up there the same time as mine. Ours look strikingly similar-- your bike really made me want to run some clubman bars on my bike as well. Do you have any idea why Bill closed up shop? He always seemed to have a lot of bikes in his shop.

Here are a few pics of my bike. This was earlier this year before I had ridden it, so the front brake has some surface rust on it.

nortncom said:

Thanks everyone for the prompt replies. My internet has been on the fritz, so it has taken my a little longer to reply than I had hoped.

Jsouthard-- yes it was Bill who performed the work on my Norton. Judging by the 850 Commando in your profile pic I believe yours was up there the same time as mine. Ours look strikingly similar-- your bike really made me want to run some clubman bars on my bike as well. Do you have any idea why Bill closed up shop? He always seemed to have a lot of bikes in his shop.

Click to expand...

Not sure what happened. He was going to open another near Brentwood but i heard he moved out to the east coast. Kind of fell off the grid. Bike looks great. I'm going to miss those Tennessee roads.

I am in the process of trying to acquire some whitworth tools for the head bolts, but I am not completely sure what size I need for this job. Consequently, I do not have the money for a complete set at this time. What size sockets/wrenches would I need to complete this? Thanks for the help.