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Reading Standard Crank Shaft

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Post Tue May 02, 2017 7:40 pm

Posts: 116
I have been encouraged to share the process of replacing the broken crank shaft on my Reading Standard twin.

First a little background; Last August I bought a RS motorcycle basket case at an auction. The engine had been apart since it broke a flywheel in the late 1950s. Luckily the baskets of engine parts were stored in an attic. The chassis did not fare so well - it spent years in a barn that leaked & eventually fell down on top of the RS.
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Post Tue May 02, 2017 7:46 pm

Posts: 116
After spending the last 6 months assembling what was there & making most of the missing pieces it looks like the following picture. I did buy rims from Al McRoberts & had Buchanan make the spokes. Tires are from Coker. The seat was done by Jethro Smith.
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Post Tue May 02, 2017 8:10 pm

Posts: 116
The engine was assembled without internals to allow me to make the various pieces that attach to it. Now it is back on the bench all apart.

It turned out that this is an experimental racing engine built at the factory. Apparently it was common for RS to ship experimental bikes to export dealers. This bike was sold new by McBride Cycle in Toronto, Ontario. The engine no. 21-5 would indicate a special run.

The stroke is shorter than normal & the bore is smaller. It was almost a "square" B&S situation. The engine also has ball bearing mains which had been abandoned earlier in favour of bronze bushings. I think misalignment of the mains caused the flywheel to break. Fortunately very little damage was caused to the cases by the break.
Parts are just plain not available so a Frankencrank is being created.

I have found Harley Davidson model U pistons have the correct compression height & at .040 oversize they will fit the cleaned up cylinders. The skirt needed to be trimmed about .250" to clear the baffles at the bottom properly. 1936 Indian Chief rods are about .250 shorter than the RS racing rods. The wrist pin end needed to be narrowed considerably & honed out to fit the HD pistons but they will now work & lengthen the stroke to just under the standard RS 4" stroke.

The flywheels & pins will be made from scratch. I hope to assemble the crank with press fit joints rather than tapers & nuts. This is done on many modern engines.

More to follow when I figure out what has gone wrong with my picture system ------

Jack

Post Tue May 02, 2017 8:19 pm

Posts: 116
To confirm the piston travel & the exact stroke I made an adjustable crank pin as shown. this made it easy to dial in the exact piston top location to match the original spec. By locking the bushing I could then easily measure the location of the new crank pin.
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Post Tue May 02, 2017 9:54 pm

Posts: 116
The problem of alignment of the mains should be looked after with the self aligning, double row bearings I am using.

I was able to find these with the same OD & width as the originals. The bore is larger but the new shafts will be made to suit.
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Post Wed May 03, 2017 8:35 am
Pa Site Admin

Posts: 6055
Location: Ohio USA

Super nice work and engineering Bro !!

Post Wed May 03, 2017 3:21 pm
GuS

Posts: 408
Location: Bergen, Norway
Thanks for sharing.

Interesting design of those flywheel halves. Some weight reducion of rotating mass make the engine respond quicker. But the halves and the tiny shafts must make the setup quite flexible.
Is the second set on your bench a new made set of flywheel halves?
GuS

Post Wed May 03, 2017 5:54 pm

Posts: 116
Thank you Pa.

Gus, the extra pair of wheels came with the parts. I think they were cast at a local foundry in the 60s & partially machined. The fellow who was working on the engine died in 1970 so all information is lost. I do not know what material the wheels are made from & fear they may be too hard. The foundry specialised in man hole covers & pipes - the quality of the iron was not terribly consistent. I plan on similar wheels without the cut out holes but weight reduction to be about the same as the old ones. The shafts will be somewhat larger in the bearing areas. Hopefully this will make a stiffer assembly. The Indian crank pin is larger dia. & the pressed in ends can be much larger than the current tapers.

The picture below is of a HD 120 cid crankshaft assembly. I am thinking cut outs similar in design might be OK. A little more relief around the main shaft would help with lubrication. The welds are a safety I think - many pressed shafts are not welded. Research has told me that the shaft is .007" larger than the hole. Assembly would involve dry ice & heat .
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Post Thu May 04, 2017 1:23 pm
GuS

Posts: 408
Location: Bergen, Norway
Very interesting.
0.007 is a very tight interference fit. My table of deep freezer cold and kitchen stove heated is far away fom that, confiming your need of dry ice. Are you sure you need to go to those numbers to achieve a strong enough connection?
Interference fit is a common design. K models had that, but believe the later Ks went back to taper and nut.
But modern HD got that. I woud guess it has to do with production cost rather than a better technical design....but thats guessing from my side.
Truing a pair of interference wheels must be a pain in the butt. The in/out i guess is eliminated with the straight bore, but the alignment must be a pain. Guess you have to make some kind of jig to get it spot on on the first try..
Another issue you might consider in combination with the level of interference fit is the material in shaft and wheel. Some material "grab" better than other. T&O wheels are claimed to have better grip or friction factor due to their metal structure. And anyone working with stainless shafts etc. knows that some of the alliys are notorious for shearing if too tight fit and not using copper paste or similar upon assembling.... just some thoughts from my side. Good luck and keep on sharing your story.
GuS

Post Thu May 04, 2017 2:52 pm

Posts: 116
Gus,

I agree on .007 being very tight & will discuss it with the custom crank shop that I hope to have make the shafts & wheels. I know they use a hex on the ends of the shafts & EDM the holes to suit so there is no chance of rotation.

Early discussions revealed that they use 4140 for their wheels & A1 (I think) for the shafts. 4140 is pretty stable & machines well. It will work harden in the press fit area & should really grip well.

I had the same question on truing the shaft assembly. After some digging I found the simple solution - you leave the main shafts oversize, harden them, assemble them then grind the main shafts true like a regular crank shaft. The end result is a shaft true in all planes.

Another question that I have not found information on is how you end up with the correct rod bearing side play. Once the pin is pressed in & the temperatures level out it would be almost impossible to move anything. A horse shoe shaped spacer might do the job??

To use the Indian big end I need to go the press fit route since there is hardly enough width in the wheels to use tapers & nuts.

I wonder if HD went back to tapers & nuts on the K because at the time very few dealer's shops would have the equipment to service them.




Jack

Post Thu May 04, 2017 3:16 pm
GuS

Posts: 408
Location: Bergen, Norway
The end play can sometimes be a lot of fiddling even with tapers until you get the hang of it. Remember the first crank i trued, thought i never would complete. Once you got it trued and thightend, the end play was wrong, and you had to start all over again :D
Have you thought of having a stepped crank pin? Once pressed til it bottoms, you have the right end play?
Another idea can be a trust washer in a recess. 3 or more threaded pins from the outside allow you to set the end play after innstallation. But you neet to come up with an idea to prevent it from rotating and rattling.
GuS

Post Thu May 04, 2017 3:46 pm

Posts: 116
Gus,

Thank you, another case of looking past the simple solution. A stepped pin could definitely set the rod end play. If the hex method is used there will be a natural step on the flats of the hex.

Jack

Post Fri May 12, 2017 10:08 pm

Posts: 1200
Location: Ojo Caliente,NM,USA
Jack,
I'm hearing some ugly rumors about the reasonably priced Chief rods. Some of them have stamped roller retainers that fail in a few thousand miles. Remove one of the plastic covers and be sure yours have the thick machined retainers. If they have the thin stamped sheet metal retainers you need to get a set of the good ones. I've probably got at spare set.
Dusty

Post Thu May 18, 2017 6:35 am

Posts: 116
Dusty,

Thank you! I just found your post, I will go out & check the retainers shortly. I do think they are the stamped type. I know the machined type you described & can see that they would be much better. I used the same machined type on my HD 45.

The shop I hoped to use for the flywheels seems to have faded away. I guess I am lucky my parts weren't there when they went underground!!

I may have to make the assembly myself. Any suggestions on materials for the wheels & pins as well as press fit interference would be welcome.

Jack

Post Thu May 18, 2017 9:31 am

Posts: 116
Dusty,

The roller retainers I have are indeed stamped & I can see the potential for failure. I would be very interested in a set of "real" retainers & rollers if possible. My rollers are .2497 +/- .0001 diameter & of unknown manufacture. They measure .302 long - the machined retainers may take a different length?? The total width of the 4 bearing stack is 1.583". A standard .250 roller diameter would be good since I will be making a new crank pin.

Jack
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Last edited by Jack Innes on Thu May 18, 2017 12:47 pm, edited 1 time in total.

Post Thu May 18, 2017 9:40 am

Posts: 116
Would the stock Chief rod bearing use 2 lengths of rollers like the HD 45 bearing pictured?
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Post Thu May 18, 2017 1:33 pm

Posts: 3321
Location: Central Illinois, USA
Jack!

Indians uses rollers all of the same .250" length, even in wheel hubs.

I have some of those stamped cage assemblies on the wall, and assuming all else was in order, I can't guess why they fail.

.....Cotten

Post Thu May 18, 2017 6:33 pm

Posts: 1200
Location: Ojo Caliente,NM,USA
Cotten wrote:
Jack!

Indians uses rollers all of the same .250" length, even in wheel hubs.

I have some of those stamped cage assemblies on the wall, and assuming all else was in order, I can't guess why they fail.

.....Cotten

I don't know for sure but I have seen it mentioned several places that they have a unusually high rate of failure. On a intricate stamping like that there are so many places to do it wrong. Wrong or inconsistent steel. Too much bend in one stamp, wrong bend order and any number of other shortcuts to increase profits.

Jack check your messages.
Dusty

Post Fri May 26, 2017 5:51 pm

Posts: 116
Not hearing from the shop that I had counted on to make the crankshaft, I decided to go forward myself.

The material arrived yesterday & I have started turning the wheels. The first one is now turned to thickness & diameter. The wheel material is 4140 steel & the shaft & pin material is 8620.

As luck would have it I received an email last night from the illusive shop. I have not discussed it with them but perhaps they can make & fit the shafts. They use a hex on the pressed in ends which really eliminates the chance of movement.

I still cannot find actual information on the interference fit on pressed shafts. Many new engines, some HD K models & even the very early 1 cylinder HD bikes have pressed shafts. Somewhere there must be factory specs given.

I also have read a lot on Balance Factor, to me it seems on older engines 50 to 55% is what is used. Any thoughts on that???

Jack

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Post Fri May 26, 2017 9:08 pm

Posts: 1200
Location: Ojo Caliente,NM,USA
I use Indian's method assemble the crank with both rods. Install the front piston with rings and locks. Place it loosely between centers and drill the heavy side through both wheels until it will rest in any position. Lots of old mechanics swore by tape 3 dimes on the front piston in addition to the Indian factory stuff. I have tried it and it might be a little smother but very little.
Dusty

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