Thursday, Apr 24 2014 [25,724 miles]
The guestimate as to what the ultimate cause of the proplem that lead to this teardown was weak valve springs. It is a fact that the springs were old and tests show that they were weaker than new springs. But still… am I 100% sure that there wasn’t a cam issue? Time to find out.
test valve/piston clearance
![Test time](./t-141141303-3798.jpg)
Test time
![Clay on piston](./t-141141307-3799.jpg)
Clay on piston
![Cylinder head, no gasket](./t-141141318-3800.jpg)
Cylinder head, no gasket
I put some clay on the piston and then mounted the heads. For a worse case check I did not use a head gasket and I set the valve lash to zero. The heads were fastened “snug”, not torqued to the specified amount. I didn’t want to over do it without a head gasket. I turned the moter over several revolutions then stopped with the left side at TDC between compression and power stroke.
left side test
![Must do it again](./t-141141322-3801.jpg)
Must do it again
![Plenty of space](./t-141141324-3802.jpg)
Plenty of space
I forgot to wipe down the valves with an oily finger so it wouldn’t stick the clay. I’ll need to do the test a second time.
I cut away some of the clay to measre the thickness. It shows I’ve over 3.5 mm of clearance. Whan I add a head gasket I’ll get even more space.
left side 2nd try
![Intake has less clearance](./t-141141341-3803.jpg)
Intake has less clearance
![About 1 mm](./t-141141343-3804.jpg)
About 1 mm
![Still 1 mm](./t-141141344-3805.jpg)
Still 1 mm
The second time the clay didn’t stick to the valve. The intake doesn’t have as much clearance as the the exhaust. I measured about 1 mm at closest contact (without a head gasket). I think that is enough.
right side test
![Right side check](./t-141141405-3806.jpg)
Right side check
![Results](./t-141141408-3807.jpg)
Results
![Looking good](./t-141141412-3808.jpg)
Looking good
I remembered to oil the face of the valves so the clay didn’t stick when testing the right side. What did stick was a pushrod. More on that later. The results of the test show plenty of clearance on the right side, too.
install left head
![head gasket](./t-141141429-3809.jpg)
head gasket
![clean head](./t-141141430-3810.jpg)
clean head
![valve lash set](./t-141141455-3811.jpg)
valve lash set
![Fresh wavy washers](./t-141141457-3812.jpg)
Fresh wavy washers
![Buttoned up](./t-141141502-3813.jpg)
Buttoned up
I installed the left head with a fresh head gasket and set the valve lash. I used my oil can to make sure the rocker arm was well lubricated as well as the rocker-to-valve surfaces. With the valve cover on the bike is beginning to look as it should.
install right head
![Check pushrod tube seal](./t-141141508-3814.jpg)
Check pushrod tube seal
![New gasket](./t-141141529-3815.jpg)
New gasket
I mentioned above that the pushrod was stuck. It felt as if I was pulling against a spring when I tried to remove the rod after taking off the rocker arm assembly. A closer look showed that the pushrod tube seal was flexing as I pulled on the rod. I loosened the cylinder base nuts and pulled the cylinder back enough to remove and check the seal.
I think it got folded in a way that the end of the rod was catching on the lip of the seal. I re-installed the seal and cylinder. The pushrod is no longer catching.
Once that was done I installed the right head with a new gasket, set the valve lash, oiled the moving components, and installed the valve cover.
needs exhaust and carburators
![Looks like a boxer](./t-141141603-3816.jpg)
Looks like a boxer
![Needs exhaust and carbs](./t-141141607-3817.jpg)
Needs exhaust and carbs
That’s all I had time for this afternoon. Tomorrow I’ll clean up the exhaust and install along with the carbs. It’s supposed to rain — a test start and ride might have to wait until Saturday.