Oh the horror!

[Garnet]

It is fun to speculate about the repair methods, but for about $80 deliverd to your door for a brand new one or half of that for used, I know what I would do.

[dougie]

It is fun to speculate about the repair methods, but for about $80 deliverd to your door for a brand new one or half of that for used, I know what I would do.

+1

[George Ryals]

I just went down stairs to my shop and did a few easy tests on a 5 speed output flange. A file easily cut the flange material. I was able to, with a moderate hammer tap, make a centerpunch mark. My conclusion is that the flange is NOT heat treated for hardness. It seems to me that you would not want it hardened as it would be prone to crack when the tapered shaft is pulled into the flange. I don't have a messed up one to try it on, but I believe it could easily be drilled, tapped and helicoiled to repair the threads.

[Ken in Oklahoma]

. . . By watching the spot change color the gunsmith knows when the spot will be annealed after cooling. After the machining process he again heats the spot to a shade of red (I think) and after quenching the spot is again hardened.

I'm not likely to be adding anything to this thread, but I'm not going to let that stop me. I've been interested in hardening and tempering high carbon steel for quite a while--more or less in the vein of what a blacksmith would do.

Generally speaking, a blacksmith will heat up high carbon steel to a glowing cherry red in subdued light. At this point the carbon in the steel is in solution with the iron. He will then quench the steel in water or oil which cools the steel so quickly that the carbon doesn't have time to precipitate out of the steel and form carbon nodules within the steel. At this point the steel acts much like glass. A sudden shock can cause it to shatter. Steel this hard isn't useful for many applications. It muse be tempered to a softer condition with a remaining hardness as needed for the application.

Tempering steel is done at a much lower heat than the original hardening process. Sometimes tempering the steel is called "drawing" it. What the blacksmith will do is reheat the steel to a certain temperature. Going all the way to a glowing condition will effectively take all the hardness out of it. That is the steel is annealed, very bendable, and not very breakable.

Heating the steel to a lower temperature will remove some of the hardness from the steel, essentially splitting the difference between dead hard and dead soft. What temperature the steel is tempered at will vary the steel somewhere between the two end conditions.

The blacksmith will judge the hardness he's looking for and will set it by watching the color of the steel change. That is done by grinding or otherwise cleaning the steel so that the silver of bare steel is seen. The colors come from oxidation of the steel and the final hardness is a function of the color achieved. We've all ground a drill bit on a grinding wheel too long and watched it turn blue on the tip. We know that the tip of the bit has been tempered too much and won't cut steel now. We know that we have to carefully grind away the too-tempered end of the drill bit to get to the harder untempered steel. Now we do it right, cooling the bit frequently, and are rewarded with a sharp drill bit that will cut steel.

Going from cold to hot (hard to soft) we heat up the steel and can see a rainbow of colored oxide form on the once silver steel. Initially you will see a pale yellow form. At this point the steel is still very hard. Then it will turn brown as the heat is increased. The steel becomes softer yet. As we heat the steel more and more more colors appear running toward blue and violet. The steel becomes increasingly softer, but less brittle.

Depending on the application the blacksmith will stop the process where he needs it to be.

You've noticed that clock springs are usually a deep blue. The springs have been tempered to the ideal tradeoff between brittleness and elasticity to act and last as a spring. Some springs are silver, which means that the outer oxide has been removed for some reason--perhaps cosmetic.

You can have some fun playing with this stuff. If you have an old hacksaw blade that would be a fun one to try. (Don't use a bi-metal blade though because only the cutting edge is high carbon steel.). With your handy dandy oxy acetylene torch, or perhaps mapp gas torch heat the blade till the end is glowing red. Then quench it in water. Then put it in a vice and hit it with a hammer (guarding your eyes). The blade will snap like a piece of glass. Take one of the hard pieces and try to file it. It won't file. The hardened blade is hard as or harder than the file.

Then you can draw the temper with a propane torch. Clean the hardened piece of blade on a grinder or sander, or perhaps even a wire wheel. Get it all silver. Now play the propane torch on one end and you will see the oxide colors form that I was talking about. Further testing with a file or a scratch awl will reveal that the bluer the color runs the softer the blade has become.

. I think knowing the correct shade of the correct color, requires knowing the charicteristics of the particular metal being worked on and a drive flange would be a cheap thing to experment on.

Yeah, since we don't know exactly what steel the flange is made of we're really not quite sure what we're doing hardening and tempering wise. High speed tool steels are particularly hard to figure out. I could never harden and temper that kind of steel even if I had a good idea what I'm doing. And if the tool steel is air hardening, I could never get it soft without lowering the temperature veeeeeeeeeery slowly.

One I broke off a tap in a part I really needed. There was no way the broken part of the tap was going to come out. No problem, thought I, since I knew something about blacksmithing. I decided I would anneal the tap and heated it with my oxyacetylene torch. I never did get that tap to soften. Ultimately I heated the part itself up to red hot and then drove the broken end of the tap through with a punch. I then redrilled the hole with a larger size and tapped it for a larger bolt.




Ken

[vanzen]

...The stock bolts are metric fine thread. I'm sure helicoils and inserts can be obtained but you are unlikely to find them in stock kits. That means they are likely to be more expensive.

Inserts are fairly cheap. Insert kits (drill, tap, install tool, and inserts) are relatively expensive ...
Buying a complete M8 x1.0 (as a flange screw) insert kit with 5 inserts is $71.29
This will be Time-Sert brand (as I use) from toolskwik
These are available in many metric sizes and thread pitches.

[bbelk]

Thanks for int input. This was fun to come home to after 10 days off. I learned something about some things.

Rob - thanks for the offer, and I may come back to that yet.

I have found a semi-local guy with the tool and he thinks he can come up with a used flange.

I will reassemble the whole bike and test out the new clutch to see if the jerkyness that I was trying to fix is actually fixed. I didn't find anything wrong in there except the diaphram spring needed replacing. I replaced it and the friction disk and just cleaned everything up real well. If as Duane suggested, I need somework on the input shaft as well, it would be nice not to have to do this a third time.

Then I will take it all back apart and bring the whole transmission to the guy with the tool and the part and start over.

Brad

[Garnet]

http://www.youtube.com/watch?v=iAJ2AoEw ... re=related

[bbelk]

I went for a short ride yesterday (no airfilter and only one muffler) and the clutch was smooth as silk. So it pained me to have to pull it apart again.

The gearbox is sitting on the bench. The stripped threads are visually obvious. I think I will find out today what will happen with it.

[Duane Ausherman]

Don't mess around with the next size bolt. Swap out the flange and be done with it.

For a temp fix, I would not be afraid of using glue to hold in the one bolt. It is easy to test it for coming loose by a finger in a few seconds. Are you willing to test it often and as soon as you find it loose again, just stop riding. I would not trust it on a long trip.

First get a good flange, then get ready to remove the transmission and have someone do it for you. It is a rather simple job if one has the tool.

[Ken in Oklahoma]

Don't mess around with the next size bolt. Swap out the flange and be done with it.

For a temp fix, I would not be afraid of using glue to hold in the one bolt. It is easy to test it for coming loose by a finger in a few seconds. Are you willing to test it often and as soon as you find it loose again, just stop riding. I would not trust it on a long trip.

First get a good flange, then get ready to remove the transmission and have someone do it for you. It is a rather simple job if one has the tool.

But, but, but, Duane, that would surely put the kiss of death on this topic. And it's going so good . . . . . .

Not to get personal, but is that "practicality" gene acting up again?

There's some medicine you can take for that. It's alcohol based . . . . . . Well, OK, it is alcohol. But it works. There will be some verbosity, but it'll be on a refreshingly new subject.




Ken