Collective thoughts please...

Larzfromarz · Post by **Larzfromarz** » Wed Oct 10, 2012 12:53 pm

Hey guys,
I need your help regarding the top overhaul (what we call it in the airplane biz), I'm really bummed and finally up against the wall.
Here is the story;
1966 Ca160, initial problem broken rings and blowby on the right cylinder. Replaced the piston and rings (all std size) clean painted and serviced all parts.
Reassembled, timed, valves adjusted, no obvious problems, gassed up and ready to start. Hit the button and she chuggs right away great. Hit the button again a few turns and "pink". Stop everything! Inspected externally to find nothing unusual. Removed a tappet cover and hit the button again. The engine turns freely and is making compression (pistons moving and valves closed) at the tailpipe. The valves however aren't moving, hmmmmm. Remove the breaker cover and hit the button- cam isn't turning. Seems like cam chain. Remove engine for disassembly of top end. Upon disassembly sure enough the cam chain masterlink retainer is broken. Fortunately ALL pieces are recovered with a magnet from the sump- don't have split the case. Reassemble, re-time, re-adjust valves, reinstall. Battery, gas, hit the button for three or four turns of the starter and "PINK" again. Left the tappet cover off this time (breaker cover too). Valves were moving (at first) until the pink.

Larzfromarz · Post by **Larzfromarz** » Wed Oct 10, 2012 1:12 pm

Sure enough the cam chain separated again. Removed and disassembled again. Fished broken parts from the sump again.
Note at this point: The master link is the same for the starter chain and is the same as the links in the 150 motor. How do I know cause I've had to "rob" them all from my spares! I hate making the same mistake twice much less three times-
OK this reassembly (3rd): With the head removed and the cylinder and tensioner in place, i "motored" the lower end with a drill on the alternator bolt. Lower end spins freely with no noises or obvious trouble. Now I fished the cam chain into place and fastened with robbed clip from the 150 motor.Loosened the valves in case I had over adjusted. Rotated motor by hand enough times to see the chain go around twice. Next I motored the engine again with the drill. Seems ok. Go eat lunch.Come back and rotate the engine by hand again and sure enough pink again- on the bench! This time at least I think I could tell the link was near the crank when the retainer broke again. Ok three times I'm doing or have done something incorrectly. The link breaks the same each time. I am lost as to what can cause this. I did not split the bottom cases (yet) to look for contact. It seems like there must be something catching the clip and breaking it. While I've looked as best I can expect I need to split the case to find the culprit.

Spokes · Post by **Spokes** » Wed Oct 10, 2012 1:15 pm

Check the oil spinner cover. It may be rubbing against the oil spinner cap. I had to teardown my 160 (as you know) because the oil spinner cover was tight against the oil spinner cap, thus causing the oil spinner cap to break. I then lost oil pressure to the top end and cooked the cam.

Larzfromarz · Post by **Larzfromarz** » Wed Oct 10, 2012 1:20 pm

I do have closed end of the clip facing the direction of rotation, and there isn't contact between the valves and pistons.
I'd appreciate some schooling. While I am (or was) a competent mechanic I am new to the Honda twins and there is something I have missed- its true that you don't know what you don't know and I don't know.
Looking forward to the input from the group and Thanks!

Larzfromarz · Post by **Larzfromarz** » Wed Oct 10, 2012 1:24 pm

@Spokes- I did accomplish good oil pressure ( had about 1 qt in the sump)while motoring the bottom end and had oil flowing from the channel up to the head.

Larzfromarz · Post by **Larzfromarz** » Wed Oct 10, 2012 2:45 pm

Well in the time it took to write the previous posts I was able to remove the lower end. While I dislike working incorrectly I absolutely love finding out what I did wrong. Each time I fished the cam chain the results we like in the following picture. I could have solved this with Spokes magic camera but....
You can see the metal protrusion on the crank that caught the retainer clip and the chain, while not engaged properly, engaged enough to "motor" the engine and operate the valves properly (it even ran for a second or two). It even seems to have correct tension in the faulty condition.
Fortunately all this cost me was some time and a little pride, but is all worth the learning for me and maybe somebody else too.
Sorry I beat you guys to the punch but I couldn't let this one go. I must be cursed cause I bet Spokes had a cam chain problem.
I'll report tomorrow after the reassembly and install. Thanks to all for the help you would have offered.
Now if I can only find another retainer....

Larzfromarz · Post by **Larzfromarz** » Fri Oct 12, 2012 4:51 pm

Successfully reassembled. Ready for install.
One new habit I'll use on each of the next engines I build. Since I don't have 'run -in' fixture I simply motored the engine with a drill on the alt bolt. You should know pretty quickly if there any problems with rotating assembly or valve and timing gear. Also allowed me to be sure of my valve clearances. Sure beats having to install and find something wrong afterwards. Should be a time saver and confidence builder for those who need it. Also allowed me verify oil pressure and flow to the top end fairly critical, right Spokes?

Spokes · Post by **Spokes** » Fri Oct 12, 2012 5:56 pm

Yes, without oil pressure your work cam turns into a grooved mess. I too will verify oil pressure upon reassembly. This was the first time that I ever had a problem with oil circulation...

Larzfromarz · Post by **Larzfromarz** » Sat Oct 13, 2012 1:14 pm

It's a common practice to prime most engines before first start. It's just not always practical to do so ( thus good assembly lube).

Are you about ready to re-fire yours Spokes?

Spokes · Post by **Spokes** » Sat Oct 13, 2012 4:32 pm

No not yet. I'm arguing with myself about installing rings or not. I have another CA95 coming next week and two sets of Buco saddlebags to finish.

And... a friend at work bought a used go-cart for his kids for xmas. I am going to make it a cool cart...lot's of things to do. (not to mention a 50 hr work week....phew)

Larzfromarz · Post by **Larzfromarz** » Mon Oct 15, 2012 8:24 am

Yea!The 160 runs again. Real quiet too, no funny noises. Need to twiddle the carb and timing a bit. No smoke so looks like problem solved. Pumps good oil.
I'll take this one to the VJMC meet here in central FL in early Nov.

Spokes · Post by **Spokes** » Mon Oct 15, 2012 8:08 pm

Congrates on getting the bike running. I should have mine going soon. The VJMC sounds like a good time. Sometime next year I have to get involved. I would love to show my work at a VJMC event. Mid Fla should only be about 4-5 hrs away.

Larzfromarz · Post by **Larzfromarz** » Tue Oct 16, 2012 6:39 am

Amazing how much better it runs when both carb bolts are tight. A little valve adjustment (I set loose to get it running and lubed) should stop a light popping in the right side exhaust note.
Your precious petcock parts are installed and waiting a leak test tomorrow. I still have to recover the seat for this bike before the show. I hope to take this and the 66 Superhawk.
Today I'm going to look at box of 69CB350 (parts). Supposed to be all there. we'll see if the bucks are right.

Larzfromarz · Post by **Larzfromarz** » Sun Oct 21, 2012 3:18 pm

The bike is running fantastically and we are very happy. One small leak at the drain bolt is the only trouble thus far. Sounds pretty good.

grubsie · Post by **grubsie** » Thu Sep 12, 2013 5:59 pm

Hey Larzfromarz,

Just happened to run into the same problem you described. I remembered reading this thread and just found it again to see what the problem was. My chain link clip bent while rotating by hand. There was a funny sounding noise while rotating and sure enough the clip was bent when it came back up on top of the cam. Wish I had some spares, will probably have to find on ebay?

Question is, how do you keep the chain on the crank sproket and be sure its there, while installing the cylinders and head? I really do not want to split the cases to be sure.