How to repair Auto clutch spring on the trail?

Checking in with others who have Autos. Just putting my tool kit together and thought I'd ask.
Assuming the problem is usually a broken 1st clutch spring.

What to do you carry to repair a broken Auto spring on the trail? Besides a spare spring...
What are the steps?
Any tricks you have learned?

Any advice is appreciated.
Thanks.
Dave

I have thought about this ...... and then thought ... It'll be fine !! So far (touches wood) I have not had a broken spring. My way of thinking is that if your 1st gear shoes are seriously worn, that would make the springs have to travel further, and then more prone to breaking. Mine seem good so far. But I did make sure the holes that the springs locate in were nicely rounded and free from any sharp edges or burrs. I even polished them slightly with the dremel tool.
The most important thing is to fit a spring guard plate, so that if a spring does break, it cannot damage the casing or the clutch. Michel has a fine sketch on here detailing this. Make one and fit it before you go any further.

And epoxy glue a magnet to retain broken spring part !

It has been quite a while since I actually did trail rides and entered events on an auto. The 420 never broke a spring, I never had a registration so it probably didn't go as far. The 430 with it's pig tail springs as I call them did break a few two at least. Hopefully the ones Michael had made up are better than the ones that came in the shoe and drum kit. (oh, I never needed a shoe and drum kit with the bronze shoe set up just one hack saw cleaning) I was unable to figure out how to change the springs without taking the pivot pins for the bob weights. Those pivot pins would not just come out on the side of the trail, at least not any of the ones I dealt with on the 430. Sure there was talk of laying the bike on the side and changing a spring but it just didn't seem, with the force I had to do it. I carried a whole clutch assembly, a bar with two pins for a holder and my puller to get the thing off. I know it did break once on the trail but I was close to a railroad track and it just made more sense to push the bike to a point the truck could get to instead of dealing with the dirt all over the place. At least I was prepared in the event it gave out in the bottom of a valley. I do not think the springs broke at the contact point with the inner attachment. In the event you do have a device to keep the main part from jamming against the cover (water cooled worse as it has 3 lumps) it is not going to really go into neutral at idle.

Upon further recollection one guy talking about trail side repairs finally changed his story to he just removed the broken pieces and limped home from initially stating installing a new spring trail side.

Fran

In the last 16 years of riding Autos ( I ride 360, 390 and 420 autos mostly trail riding) I have broken two 1st gear clutch springs, both on 420 autos two separate times. Both springs were the ones heat treated blue which I think were a bad batch. Both times I layed the bike on its side and removed clutch side cover and removed the broken spring from the hub and the tail that was stuck to the magnet and then continued riding with two springs. With one shoe dragging on the clutch drum it made it more difficult to keep the engine idling but didn't effect it to much while at speed. Both times I was more than 8 miles from where parked my truck and unloaded. Like Fran said there is not a good way out on the trail to remove the pins the brass weights pivot on in order to change springs as they have a light press fit. I wish there was a better/easier answer to the spring R&R problem.

Marty

Thanks for all the the great advice, grouty, Michel, Fran, Marty . Much appreciated.

Making my list:
1. check shoes / hub gap. A gap of no more than 3mm sound right?
2. round, smooth out spring holes.
3. make and install a spring plate guard. Michel posted his spring plate sketch for me a few weeks ago. Thank you Michel. I'll make one.
4. epoxy magnets inside case to catch broken spring pig tails.
5. check springs, no blue ones.
Oh, remember to touch wood.

If a spring does break, stop, lay bike over, remove cover, remove broken spring pieces, and replace cover. Keep it out of 1st as much as possible.

Some other thoughts...
- to balance to load on each spring, should all the 1st gear clutch springs be measured for length and matched?
- the enduro guys who raced Autos at the IDSE, talk of swapping out the clutches on the trail in less than 10 minutes.
Probably takes some practice. Fran, I have a spare 1st gear clutch assembly, a bar, and a puller.
- I was wondering if you can limp home on two springs, now I know its possible. Thanks Marty. I've never broken spring to find out. My rides can be over 10 miles out. A long way to push a bike!

Now I have some setup work to do!
Dave

It must be faster to change the drum clutch, shoes,springs all at one time
than trying to change only one spring on the shoe

Staying in or not in first gear I do not think really matters the power flows through that first gear clutch to get to the rear wheel no matter what is going on in the larger drum to the rear.

Without a spring on the first gear clutch so long as you keep up speed I would not call it limping. It is going to be abusive getting from neutral to drive. Perhaps a bit more dangerous at a real slow pace and perhaps possible to stall the engine. As I understand it the 420 and later have parts that engage different than earlier that have lumps on the shaft that probably are more of an issue to repair.

Forgot to mention a tow rope... I always carry one. Yes, good insurance.

with power flow always through 1st gear clutch, when in 2nd or 3rd will it slip if one spring is broke / gone?

No, with one spring removed from the 1st gear clutch, then one shoe will always be making contact with the drum even at low rpms such as at idle. That is why Fran was saying it would be easier to stall the motor. Once the motor is in gear and you bring up the rpms and speed it will still shift into 2nd and 3rd and 4th (if you have 4 gears).

Marty

Got it. Makes sense.
When in drive, with good springs, the 1st gear shoes are always engaged even when 2nd or 3rd clutches engaged? Is this correct? Is that how power flows from crank to counter sprocket?

Yes. As soon as you move, 1st gear is engaged. It will not drop out until you come to a stop. Likewise in 2nd, 1st is turning. When in 3rd, 2nd and 1st are turning. When in top 3rd, 2nd and 1st are turning.

Have had a few break while in the middle of Baja.
1st time no spare just took cover off and removed broken pieces I could get out.
Being 200 miles from East Overshoe nowhere was in hurry to get moving I didn't think about how the engaging 1st gear was going to be. Well it turned out to be ugly, rounded and burred the splines on both gear and shaft.
Pulled the counter shaft/cover off and beat the gear onto the shaft SnapOn ratchet for hammer and socket extension for punch, once back together dug hole for the rear wheel to drop into with frame resting on the ground, had to dig out under the footpeg for boot clearance. Got it moving again made it back to town.
Replaced the spring rode 700 more miles next 2 days. Never took it out of gear.
The above way to start in gear is one of several ways to start the auto in gear.
Kick while rolling down hill.
Lean over on side stand.
Bike on rock or log w/ rear wheel off ground.
Started taking spare springs and tool, to change them out.
Some time later had all the bolts shear on the main drum, 300+ miles in 1st gear only.
As far as the Auto's go think I've just about seen it all.
Getting ready to make some 1st gear clutch shoes will post when done.
Later George

I had a spring break, got the engine started in neutral then pushed bike and clicked in to gear while rolling, she did stall if you went too slow, luckily wasn't more than a mile from the car and trailer

Go

George, are you going to making the 1st gear shoes for the 390/420? How about the 41KP and 48KP 1st gear clutch springs for the 390/420?

Marty

Yes shoes first, the first shoes are the ones that go over the hub, will do the other style after.
Then the springs.
Later George

Will they be the "forked" type 1st gear shoes or the earlier solid type (i.e. the 78 style) ?

They will be the Forked type, then the single slab style 2nd.