Head bolt tightening

garncarz · Post by **garncarz** » Tue Apr 08, 2014 6:08 am

Can the head bolts on a CA78 be tightened while the engine is still in the bike?

Tinman · Post by **Tinman** » Tue Apr 08, 2014 6:36 am

Unfortunately no. When you do torque them, start in the middle and work way outboard, crossing your torque pattern. Torque value is 16lbs. I think loudmouse torques his to 20+ lbs.

garncarz · Post by **garncarz** » Tue Apr 08, 2014 8:23 am

Tinman wrote:Unfortunately no. When you do torque them, start in the middle and work way outboard, crossing your torque pattern. Torque value is 16lbs. I think loudmouse torques his to 20+ lbs.

I also read that they should be re-torqued after the engine has been up to operating temperature. So the procedure is: Drop the engine, torque the bolts, reinstall the engine, ride, drop the engine, re-torque the bolts, re-reinstall the engine?

Well that just sucks now doesn't it. Thanks, Soichiro.

Tinman · Post by **Tinman** » Tue Apr 08, 2014 10:05 am

garncarz wrote:
Tinman wrote:Unfortunately no. When you do torque them, start in the middle and work way outboard, crossing your torque pattern. Torque value is 16lbs. I think loudmouse torques his to 20+ lbs.
I also read that they should be re-torqued after the engine has been up to operating temperature. So the procedure is: Drop the engine, torque the bolts, reinstall the engine, ride, drop the engine, re-torque the bolts, re-reinstall the engine?

Well that just sucks now doesn't it. Thanks, Soichiro.

Yes it does! Some re-torque after the 1st or 2nd heat cycle, some have waited till 500 miles to re-torque.

You should have it down after dropping the engine the 2nd time, piece of cake. Good luck.

garncarz · Post by **garncarz** » Tue Apr 08, 2014 12:22 pm

The shop manual calls out yellow and white cap nuts. My 47 year-old set is all the same color - rust. What's the difference? Any need to replace the old cylinder nuts?

Thanks again for all the help!

garncarz · Post by **garncarz** » Mon Apr 14, 2014 11:34 am

garncarz wrote:The shop manual calls out yellow and white cap nuts. My 47 year-old set is all the same color - rust. What's the difference? Any need to replace the old cylinder nuts?

Thanks again for all the help!

The "yellow" nuts have copper washers and the "white" nuts have aluminum washers. Who'd have thunk?

garncarz · Post by **garncarz** » Mon Apr 14, 2014 11:46 am

Well, I got up my nerve and dropped the engine yesterday. Everthing looks pretty good inside. I didn't measure them but the cylinder walls are bright and shiney with no scratches. Lots of carbon on the heads and piston tops (soft toothbrush and aircraft paint stripper).

While I am at this point, is there anything I should do before it goes back together? Anything in the pictures look amiss?

Oh, you really want to make sure that you have a firm grip on the cam chain masterlink clip so it doens't fall down into the crank case. Ask me how I know.