420 Auto first gear clutch question

[stormer254]

A parts engine arrived last week and on opening up it has the 500 and 430 steel shoes, did they fit them to the 420 as well or is it a previous owner updating things?

 

[Michel Dufayard]

I 've bought a 420 motor 4 years ago, and it had the same 430 clutch and shoes.
Updated I think.

 

[fran...k.]

Is the drum the normal 420 drum, welded to the gear?

If what I see in the picture is just the newer shoes on the older drum update is not the way I see it.

The 420 and 500 auto crank stubs appear the same to me so perhaps the 500 auto stuff will swap into the 420. The 430 stuff is narrower/shorter stub of crank

 

[WayneL]

I believe the 430 / 500 components are interchangeable.
The 430 / 500 drum has the cut outs for the kick start pawls. I believe the 420 uses the sprag clutch.

Apparently the first 500's had the welded clutch drum, refer to service bulletin 8-163, which is superseded by the bolt together assembly, date is 13/7/84.

You might need to look a little closer to see what else is updated. Maybe the crank stubs are the same for the 420 / 500 / 430.

 

[fran...k.]

I believe the 430 / 500 components are interchangeable.
A] The 430 / 500 drum has the cut outs for the kick start pawls. I believe the 420 uses the sprag clutch.

B] Apparently the first 500's had the welded clutch drum, refer to service bulletin 8-163, which is superseded by the bolt together assembly, date is 13/7/84.

C] You might need to look a little closer to see what else is updated. Maybe the crank stubs are the same for the 420 / 500 / 430.

A] I agree
B] Thanks for posting
C] What I see in the parts I have, not in the manual as they mix in earlier pictures at times and certainly in the 430 is as follows. the 420 has the sprag or one way clutch with a bronze bushing on either side, the 500 has two needle bearings and the 430 has one needle bearing, the whole side cover is narrower for the 430 auto vs the 500 auto. The oil catch basin in the cover that feeds oil to the hole in the crank stub for the air cooled ones goes away and a slot to turn the water pump appears.

 

[WayneL]

Only one needle bearing on the WC 430 - so the gear on the 430 is narrower (ie. sits closer to the crank) and hence the thin WC side cover...nice pick up.
So dos this mean that the 420 and 500 1st gear clutch hub / gear arrangement is interchangable?

I guy over here (not on Café Husky) is looking to reproduce the 1st gear clutch drums and steel shoes, it would be nice to know if they can fit the 420 (with different gear/carrier) as well as the 430/500.
I will post in a separate thread when he is looking to commit to numbers for production.

 

[Michel Dufayard]

"I guy over here (not on Café Husky) is looking to reproduce the 1st gear clutch drums and steel shoes, it would be nice to know if they can fit the 420 (with different gear/carrier) as well as the 430/500.
I will post in a separate thread when he is looking to commit to numbers for production."

Nice idea ! I think a lot of auto riders would be interested by new clutch drums and new steel shoes !
Is he an Aussie guy or American ?

 

[Michel Dufayard]

My 420 with 430 drum and shoes, compared to 430.
I've bought the 420 like this.
The 430 drum is welded to the 420 gear.

 

[WayneL]

Great post Michel.
The 500 gear/ drum is a combination of the two - bolt on drum, same drive gear as the 430 and the longer carrier (to take the two needle bearings). Will post a picture of mine later in the week.

The guy looking to make the auto parts is a local Aussie guy. Will keep you posted.
I had previously sent an email to Andy from HVA about producing these bits, but he said there is a long list of components in front of them, before he would consider it.

Sorry for the hijack Stormer254

 

[stormer254]

No apologies needed, I started the thread to learn about and improve my Autos and that is exactly what is happening.

I find it hard to believe that the steel shoes are an improvement on the brass ones, surley they wear quicker and put yet more steel filings through all the bearings and sprags?

 

[PEZBerq]

Husky knew what they were doing. Steel shoes were an upgrade. They do not wear quicker than brass. If you change the oil after every ride day the wear particles don't do any damage. Steel particles are also attracted to the magnetic drain plug unlike brass particles. The non sprag clutch ( freewheel) first gear design was a major improvement

 

[stormer254]

I always change the oil after a ride, so got that part covered. Presumabbly the clutch drum will wear quicker with the the steel shoes? Am I right in assuming the bearing between the brass bushes in the clutch drum is a sprag?

 

[fran...k.]

No apologies needed, I started the thread to learn about and improve my Autos and that is exactly what is happening.

I find it hard to believe that the steel shoes are an improvement on the brass ones, surley they wear quicker and put yet more steel filings through all the bearings and sprags?

It is more than that, the prior 360,390, and420 (most likely 250 but I don't think they were imported here) have dis similar metals, bronze? and steel. I have been lead to believe dis similar metals like that will wear less. I have seen worm gear assemblies different metals. 360 and 390 have the blade and fork attachment the other way around but the bronze ones have slots/grooves in the shoes on a slight angle where the later has smooth shoes and a spiral machined into the drum ( in addition to the starting notches). I never tested the later shoe metal, it is magnetic but there are four magnetic elements aren't there Fe, Ni, ?,?.

Chainsaws use centrifugal clutches, There are aftermarket drums for low cost in many instances. Some band sawmills use centrifugal clutches. I think balance of that assembly is important as the taper can kind of weld itself on in some cases, what else could make that happen when it is re torqued upon assembly and running like called for.

"Am I right in assuming the bearing between the brass bushes in the clutch drum is a sprag? " Yes one way bearing, sprag, perhaps other name as well.

 

[fran...k.]

Husky knew what they were doing. Steel shoes were an upgrade. They do not wear quicker than brass. If you change the oil after every ride day the wear particles don't do any damage. Steel particles are also attracted to the magnetic drain plug unlike brass particles. The non sprag clutch ( freewheel) first gear design was a major improvement

Got to wonder if the origional pull rope start should be investigated. Think snowmobile, and that is where these things excel the most.

 

[PEZBerq]

I always change the oil after a ride, so got that part covered. Presumabbly the clutch drum will wear quicker with the the steel shoes? Am I right in assuming the bearing between the brass bushes in the clutch drum is a sprag?

There is no brass bush or sprag on the steel shoes models that use the spring loaded pawl for kickstart drive - certainly not on the 500 anyway . You can tell these models because they sound like they have a bucket of bolts inside the cases when they run down to rest after killing the motor. The pawls clatter over the engagement holes once the spring overcomes the centrifugal force on the pawl.

 

[stormer254]

There is no brass bush or sprag on the steel shoes models that use the spring loaded pawl for kickstart drive - certainly not on the 500 anyway . You can tell these models because they sound like they have a bucket of bolts inside the cases when they run down to rest after killing the motor. The pawls clatter over the engagement holes once the spring overcomes the centrifugal force on the pawl.

Got that on my 430 scared, the life out of me the first couple of times!

 

[Michel Dufayard]

Nisse Nilsson made some improvement on shoes ans springs !

After lot's of driving and racing with automatic bikes I really liked the concept.
However one problem with these bikes was that the gearboxes wasn't very durable.
But problems can be solved! I had many ideas on how to improve and develop the gearboxes to be more durable.
The picture below shows a prototype of mine from the early 1980's. It's a new construction of the freewheel for the kickstarter.
This idea came up when i had to cancel the race Novemberkåsan in Gävle 1980,
because the original Husqvarna freewheel for the kickstarter broke down


The picture below shows different centrifugal weights.
The ones to the left is original Husqvarna parts made in brass with the fragile tension springs.
The ones to the right are my own construction in steel with more durable compression springs.
On my weights I glued brakebands as friction joints.
This construction makes the gearbox more durable because the gearoil wont get filled with brass shavings.
This is a major problem with the Husqvarna automatic gearboxes.

See link and pics:
http://www.lindstrom-mx.se/nisse_nilsson2.htm

 

[Michel Dufayard]

The evolution of 1st clutch freewheel for starting 420 ae.

 

[stormer254]

Nisse Nilsson made some improvement on shoes ans springs !

After lot's of driving and racing with automatic bikes I really liked the concept.
However one problem with these bikes was that the gearboxes wasn't very durable.
But problems can be solved! I had many ideas on how to improve and develop the gearboxes to be more durable.
The picture below shows a prototype of mine from the early 1980's. It's a new construction of the freewheel for the kickstarter.
This idea came up when i had to cancel the race Novemberkåsan in Gävle 1980,
because the original Husqvarna freewheel for the kickstarter broke down


The picture below shows different centrifugal weights.
The ones to the left is original Husqvarna parts made in brass with the fragile tension springs.
The ones to the right are my own construction in steel with more durable compression springs.
On my weights I glued brakebands as friction joints.
This construction makes the gearbox more durable because the gearoil wont get filled with brass shavings.
This is a major problem with the Husqvarna automatic gearboxes.

See link and pics:
http://www.lindstrom-mx.se/nisse_nilsson2.htm

He is a hell of an engineer!

 

[fran...k.]

I have inspected what I have in parts.

It seems (Likely) that the entire transmission insides can be switched 420 four speed vs 500 three speed. The primary reduction is different, the starter gear appears the same at 11 teeth. As can be seen in above posts a lot is possible if you want it enough.