• Husqvarna Motorcycles Made In Sweden - About 1988 and older

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1973 450WR not shifting right

Grunbay

Grunbay

Husqvarna
AA Class
My 1973 450WR shifter is not returning to center. If you manually move the shifter, it shifts into the gears. The problem is that it doesn't return to center by itself.

Does anyone have any ideas on what may be causing this?
 
That's really bad news... Two possibilities; Simple one first, remove the primary case, use a small wrench to move the shift shaft. If the shaft sticks the problem is in the center case. You will have to split the cases to find the exact problem. Could be crud built up around the shift shaft or selector paw, could be a bad spring. One other simple item, if the shift shaft comes out with a stub on the sproket side. Remove the front sproket cover and see if the shaft end is packed with debris.
 
Sounds to me like the return spring on the shifting shaft either broke (which is unlikely) or the case was assembled without the dowel pin straddling the return spring upon assembly. Either way split the cases and correct problem and while you have it apart, replace the bearings and seals and inspect the dogs on the gears. There is peace of mind knowing that your motor/transmission is like new.
 
Good advice puckerbush - I already followed your advice!

I took the engine apart this past weekend. The new bearings are on order. The pin was there, and the spring is not broken. After I get the new bearings, I'm gonna reassemble the engine without the crank and make sure it shifts. the good news is that my piston and big end bearings both look great! I completely agree on the comfort one gets when you do it yourself!
 
Grunbay,

Very Important! Your '73 450 WR is a five speed. Make sure the transmission is in 3rd gear when you assemble. The dimples on the shifting barrel are as follows: 1st Neutral, 2nd, 3rd, 4th and 5th. The spring loaded detent ratchet should be in the 3 gear dimple. The stepfeeder gear (see photo) should have two teeth exposed on the left side of the shifting barrel and one tooth on the right. Also the stepfeeder gear is installed flat side up. If you don't get this right, you will be splitting the case again.
DSCN0140.JPG
 
All of the parts have been gathered! The WR goes back together this weekend. Thanks for the great tip.

I will report back on how it shifts (the rest of the story, etc).
 
That service bulletin was right on the money! When sliding the plunger on the spring, it was definitely hanging up on the lip. I turned a bevel on the inside with my lathe and burnished the inside go the bore with a 1/4" stone on my die grinder. I assembled the tranny inside the cases an it seems fine now!

One question. As I am preparing the put the crank into the cases, I noted, as I pried out the old crank shaft seal on the left side (the one that is installed from the inside of the crankcase) that the old seal was installed with the seal spring toward the bearing. Every other 2 stroke engine I have assembled requires that the seal spring point toward the crank, thus sealing in the crankcase pressure.

Was my engine assembled wrong by a previous mechanic, or does the Husky seal go the other way?
 
Grunbay said:
That service bulletin was right on the money! When sliding the plunger on the spring, it was definitely hanging up on the lip. I turned a bevel on the inside with my lathe and burnished the inside go the bore with a 1/4" stone on my die grinder. I assembled the tranny inside the cases an it seems fine now!

One question. As I am preparing the put the crank into the cases, I noted, as I pried out the old crank shaft seal on the left side (the one that is installed from the inside of the crankcase) that the old seal was installed with the seal spring toward the bearing. Every other 2 stroke engine I have assembled requires that the seal spring point toward the crank, thus sealing in the crankcase pressure.

Was my engine assembled wrong by a previous mechanic, or does the Husky seal go the other way?
Click to expand...
 
Grundbay, I too hope your shifting problem is taken care but we really won't know for sure until you get your bike back together and take it for a test ride.

Regarding the left side crank seal, I don't have any documentation showing the correct way that seal should be installed but I can say that all the vintage Husky motors I've taken apart over the years had the seal installed as you found yours, and as dumbdotdog describes above.

Let us know how the shifting works out once you’ve had a test ride.
 
Grunbay said:
That service bulletin was right on the money! When sliding the plunger on the spring, it was definitely hanging up on the lip. I turned a bevel on the inside with my lathe and burnished the inside go the bore with a 1/4" stone on my die grinder. I assembled the tranny inside the cases an it seems fine now!

One question. As I am preparing the put the crank into the cases, I noted, as I pried out the old crank shaft seal on the left side (the one that is installed from the inside of the crankcase) that the old seal was installed with the seal spring toward the bearing. Every other 2 stroke engine I have assembled requires that the seal spring point toward the crank, thus sealing in the crankcase pressure.

Was my engine assembled wrong by a previous mechanic, or does the Husky seal go the other way?
Click to expand...

Heres documentation for installing the left crank seal the proper direction, from page 120 of the MK Workshop manual. The picture is fuzzy but its obvious the seal spring faces outward.
 

Attachments

Thanks Crash.

I have reassembled the engine. It goes into the frame this weekend. My fingers are crossed !
 
Well, even though it seemed to shift when I re-assembled the tranny without the crank, upon completion it is doing the exact same thing. It is not returning to center.

I guess I'll ride it a bit after the snow melts and see if it auto-resolves within a few miles. If it doesn't break-in, I guess I'll pull it apart again, but I don't know what else to do!
 
If I understand you correctly the trans shifted okay before you cinched up the center cases. If that’s right then with the cases cinched up tight, does the shifter move as freely as it should or does it feel like it may be binding when attempting to move it up or down? If it doesn’t move freely the shifter shaft may be binding and the only thing I can think of that would cause that condition is an extra washer on one end or the other of the shifter shaft. Do you have an exploded view of the trans to make sure everything went together as it should?
 
It's even a bit more mysterious. I assembled the case halves with the tranny in place and torqued down the cases, using the old center gasket. I had left out the crank for this test. it seemed to shift OK when I did this, although it is tough to tell without an engine stand, which I don't have.

Then figuring I was good-to-go, i disassembled the cases, pulled in the crank, and reassembled.

Your guess about a possible extra washer is a potential explanation. I did have the problem before as well as after. I thought that I had looked over the parts diagrams pretty well, but I may have missed something. I have just now closely scrutinized the parts diagram and service manual (for what it's worth) and I don't recall any extra washers.

I did install the seal onto the shifter shaft after the engine was finally assembled. I'm thinking that perhaps that seal is binding a bit. If that's the case it would presumably loosten up pretty quickly. I'm grasping at straws on this explanation, I think!
 
I thought that I'd update in case anyone was curious on this.

I disassembled again and measured the cases and the assembled shaft. I had about 1/2 mm more shaft than case space. therefore, I replaced the washer on the shaft with one that is 1/2mm thinner than the original. It returns to center now! Finally!

My guess is that some prior mechanic lost the original shim and put in something that looked like it fits, but it was thicker than the original lost shim.

The bike shifts perfectly, and runs like a bull!! Gosh, it's loud, though.
 
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