CL 72 Kickstarter woes

OldScrambler · Post by **OldScrambler** » Mon May 11, 2015 3:46 pm

I looked closely at 7 different knuckles..................6 are cracked. The one that is still good has no chrome and I need it for my CL72 project(s).............sorry. I have a few others to look at but they are still on assembled bikes / motors.

G-Man · Post by **G-Man** » Mon May 11, 2015 4:55 pm

It's a classic fatigue situation. A sharp corner in an area that suffers cyclic loading is considered a stress raiser. A way of stopping the crack growing is to drill a hole at the end of it.

http://en.m.wikipedia.org/wiki/Stress_concentration

G

OldScrambler wrote:I looked closely at 7 different knuckles..................6 are cracked. The one that is still good has no chrome and I need it for my CL72 project(s).............sorry. I have a few others to look at but they are still on assembled bikes / motors.

mike in idaho · Post by **mike in idaho** » Mon May 11, 2015 5:11 pm

One way to salvage a cracked knuckle would be to machine the od of the knuckle down to the bottom of the snap ring groove and turn out a collar to put on the end(it would look like a thick washer). It could be a light press fit onto the machined area and would keep the splines from spreading. Keep it in place with a pair of small setscrews or a drop of Bearing Mount Loctite.

connor1 · Post by **connor1** » Mon May 11, 2015 7:48 pm

G-Man wrote:That's a pretty tidy-looking bike. I can see that the rear fender is an aluminum one. What's the front? What year?

G

Thanks. Get up close and you see all her imperfections. Just tested the rear fender with a mgnet and you are correct aluminum. How could you tell from that pic? To bad its bobbed or it would be worth $200. The front is bobbed as well and is steel... I have two steel rear fenders that aren't cut that I am planning on blasting and painting to see if I can get a more stock look. Also need those stock handlebars.

Hoping to take this bike to the US Eastern Moto Giro next year....we'll see.

connor1 · Post by **connor1** » Mon May 11, 2015 7:53 pm

OldScrambler wrote:I looked closely at 7 different knuckles..................6 are cracked. The one that is still good has no chrome and I need it for my CL72 project(s).............sorry. I have a few others to look at but they are still on assembled bikes / motors.

Thanks for trying. I have one with a hairline crack on its way from the Uk. It will have to do until I can dig up a better one and make that my spare.

Hoosier Tom · Post by **Hoosier Tom** » Mon May 11, 2015 8:37 pm

connor1 wrote:Just tested the rear fender with a mgnet and you are correct aluminum. How could you tell from that pic?.

The rivets, the mounting bracket and shape indicate it's aluminum. When you spend time with these bikes you'll learn.

HT

G-Man · Post by **G-Man** » Tue May 12, 2015 12:38 am

Mike

That sounds like a possibility. There still needs to be a slot for the kickstarter spring to locate. though. If Honda had made that slot with a round end then these things might have survived.

I suppose that they've exceeded their design life already...... :-)

This is one I have started repairing. It was pretty worn as well as cracked. First put a hole in the end to kill the stress raiser at the end of the crack.

Grind through the cracked portion.

Weld up.

Just need to re-machine and throw in the box for chrome plating....

G

mike in idaho wrote:One way to salvage a cracked knuckle would be to machine the od of the knuckle down to the bottom of the snap ring groove and turn out a collar to put on the end(it would look like a thick washer). It could be a light press fit onto the machined area and would keep the splines from spreading. Keep it in place with a pair of small setscrews or a drop of Bearing Mount Loctite.

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CL 72 Kickstarter woes