Auto Clutch no.1 Springs

Been away a for a couple of days so going to try again, I will try the 390 shoes with the 390 springs, I can't use the 390 centre so some careful measuring to see if the centres are different will have to be carried out. The 390 shoes are burred over their grooves, I guess they will need fine tuning with a hacksaw first. I will use the 420 clutch drum. Any body got any advice?
Is there a spec any where on the springs if I try to get some made?

The 390 and 420 hub seem to have the same part number. The drums have different numbers though. But as Fran mentioned there was a modification kit that Husky had which replaced a bunch of parts. All I have for spec on the first gear springs was the 41kp spring tension. Give the spring maker one of your good springs as a sample to work off of. If I had a spare set I'd send them your way but I don't. Getting the clutch shoes grooved and cleaned up will be good to do. Stick with it, the autos are good bikes! Mine has been solid so far and I'm looking forward to flogging it hard this year!

I think you are mis undestanding what I stated. The 420 and earlier ones the drum is welded together with the primary drive gear. The 420 gear is straight cut, the earlier gear is cut a little on an angle. The 420 and later the big bob weights attach to the center as a fork. The earlier one in the picture I posted the bob weights attach as a blade. The kit is for when they went to the little bob weights on the big bob weights for starting and the bob weights became magnetic, and the slotting moved to the drum. Those (500 and 430) the drum bolts to the drive gear with the fastners I mentioned. I never got any 390 stuff from an in person to person deal but happened to end up with the workshop manual for that model. Hopefully I am not making any mis statements.

Done some measuring, and the weight of the brass shoes is the same as are the dimensions, the springs also appear to be identical, the diameter of the firstgear clutch is the same, the only difference is the helical gear. On further investigation, I have taken out the gearbox main shaft, I think either a bit of old spring was causing the problem or the 1st gear or its enagaging dogs had become dislodged during my earlier reassembly. I only have the manual for the 390 and the first gear and gear selection lever are quite different. There is no circlip holding on the gear and the engaging dogs which is making it hard to reassemble! Also the manual says the gear lever has to be turned anti clockwise which does not quite seem right. Is there a manual or supplement that covers this?

Just had a look at the 1986 3 speed manual and it shows the same selection method on the 1st gear and pawl and a different method of reassembly. The 1982 manual on these threads still shows the helical primary gears and different 1st gear! The only other difference seems to be that the lever is at the bottom of the gear not the top so I think I will put her on her side when I try to reassemble her later! Any comments please.

Are you talking about this manual 1982 420 AE Owners manual Section 4 Transmission ?
http://www.yourhusky.com/files/4._Husqvarna_Transmission.pdf

Thre are a lot of differences between that and the 420 in reality. I guess I do see how the way the stuff in the pictures does actually engage the shaft not a hardened piece on the far end splined to the shaft like the ones I have taken apart. other differences are the brake for the front drum, the needle bearing on the picture of the brake piece where a ball bearing is in actuality. I also think I see the blade type attachment of the first gear bob weights instead of the fork type. I also don't recall seeing bolts attaching my 420 drum but that stuff isn't where this keyboard is. From my experience the 420 and 430 and 500 auto engage in the same manner sliding what I believe is the first gear lengthwise along the shaft in one position it engages the four dogs in the other it spins freely on the shaft the gear on the freewheel cluster is long so it stays engaged to that. It is kind of tricky putting it together but not real bad.

It seems like at the beginning of this thread the first gear springs you have are too long.

Fran

I think you are correct Frank, I reassembled the gearbox and clutches and exactly the same result, I did manage to get her into gear by rolling her down the drive and clicking her into gear, she then rode okay changing gear okay but every time I tried to slow down she would stall as the first gear clutch will not disengage
So unless I can locate some correct springs I am to put it bluntly buggered! I have asked before but is there anyone who knows the full spec for the springs so if I can not locate some I can try and get some made.Obviously any leads or offer of springs will be very gratefully received. Thanks for every bodies help and advice

Got some new springs, grooved the shoes , exactly the same result, I have pushed her into the back of the shed while I have a good sulk

Some mechanical things can be quite frustrating.

When you have that hub and bob weight thing in your hand with the springs in place are the springs firmly pulling the bob weights tight against each other? If they are then perhaps the issue is drag created by the starting one way clutch (sprag thing) or the bushings that drum assembly rides on the crank assembly.

That is the best I can think of at this point. Either shortening the spring or welding up the hole in the bob weight and re locating it farther in if the assembly doesn't pull in tight. I am not in a position to know if some either hubs or bob weights were produced with the spring holes in the wrong place.

Fran

The frustrating thing is that it all worked perfectly before the springs broke, I don't believe it is the sprag clutch you can put the bike in gear (dead engine) and push it easily, no drag at all. Nothing else has been changed.

Hi Stormer, I know this is a very old thread but I was wondering if you ever fixed the problem? There are differences in the first gear clutch springs. Sounds like the spring length was to long. Measure with calipers on the inside to inside of the spring hooks and you should have about 2.00 inches to 2.15 inches max. in length. Many of the NOS springs I have found measure 2.20-2.30 inches and will cause the shoes to drag a idle and difficulty engaging drive. Hope this helps out other 390-420 auto riders!
There are some light modifications you can do to make the springs last a very, very long time. If anyone is interested let me know.

Marty

Hi Marty, I certainly would be interested, as I want to ride my bikes anything to help keep the going is extremely useful.

Hi Stormer,
I have been riding and restoring the 360, 390, and 420 autos for about 13 years. I ride my autos regularly and hard so I have a pretty good idea what works.
This is what I do to help the first gear clutch springs live longer. I use a 45 degree counter sink and just slightly chamfer the spring mounting holes in the clutch hub and then use a very small sanding roll in a air powered die grinder and polish the edges of the spring mounting hole. This is only needed to be done on the outboard facing side of the holes as that is the surface that makes the hard contact with the spring loop. Do not enlarge the holes, you just want to remove that sharp edge. As you most likely know the edge of the hole wears a notch into the spring loop and that is where the springs break. By polishing and smoothing the hole edge it will not allow the notch to form into the spring. And proof of this is that I have never seen a clutch spring break at the end that hooks into the brass shoe because the brass cannot wear a notch into the spring.
As for the 420 clutch hub working loose on the stub shaft, I use valve grinding compound and lap the hub to the shaft and then I torque the nut to the same specs as the 430 auto, 85 ft/lbs due to the 420 uses the same nut # 161271201 as the 430 auto uses. The recommended 65 ft/lbs is a "carried over" spec that was used on the 360/390 autos, they have smaller diameter threads compared to the 420/430 autos. Also after installing the clutch hub re-torque it after 10-15 minutes ride time and the motor has cooled down. Simple enough to do, just lay the bike over and remove the clutch cover. No need to drain the oil. I have rode mine with out re-torquing the nut but I do re-torque it as soon as possible.
For trans oil I use Pentosin ATF1. It is a full synthetic automotive trans fluid. I have tried many fluids/oils over the years and found that this stuff works the best and I feel it works better than the original Husky/Ohlins oil. I use it for 3 tank fulls of gas and then dump it. I have never had it boil or burn. Trans shifts positive. Since using the Pentosin I have noticed very few particles on the drain plug magnet. Very easy to find, I buy it at Napa auto parts here in the states at $16.00/Qt. A handy size as I just drain the old oil and pour in a full Qt, no need to check the oil level hole.
Oh yea, for the oil drain plug gasket I use an automotive O ringed drain plug washer as it does not leak and can be used over and over and over again.
If you have some of the long clutch springs you can still use them with older worn shoes. Funny thing, I have never thrown a clutch shoe away, I just re-groove them and when they get pretty worn down I use the longer springs with them.
Just a side note that is a clue to your auto having a broken first gear clutch spring, If your auto was idling clean and good while in gear and then you notice it won't stay idling in gear but idles in neutral then that is a good sign just ONE of the first gear clutch springs have broke. Lay the bike over and pull the cover and check it out. Well I have rattle on quite a bit, as I sure like my autos, they always put a big grin on my face when I ride them. I have plenty of the manual shift Huskys but when I go riding 8 out of 10 times I pick one of my autos to ride. Now if I could get my VDO speedometers to survive! I have had three go bad so far this season.

I never posted that I solved my original problem which is very remiss of me, basically when I was torquing up the main shaft nut I was locking the clutch to the bearing centre so it would not free wheel. Since then I ALWAYS CHECK FOR A BIT OF AXIAL FREE PLAY!!

Thanks for the information Motomwo, after 40 years of Villiers, Starmakers, Stormers and Greeves I have a lot to learn

I have several 1st clutch springs in a bag with # 161515501.
This number 161515501 appears to have changed to 161279301.
http://www.teuber-motorsport.com/catalog/product_info.php?cPath=451&products_id=123206

For what models are these springs ? 360-390-420-500 ?

The 16 15 155 01 springs I have.
They seems to have a coil more than others springs.

Do they have a stronger pull than the springs with less coils, might be to give more revs in 1st before engaging, perhaps for scrambling?

The 16 15 155 01 springs are the one on the right #4 ( 500 DUF).
Less coil is stiffer as said motosportz, so 1 more coil is softer.
The wire is also thinner than the Gatos spring #3
When reproducing the 500 ae springs last year, the springmaker
tested the springs, and found the #3 was two times stiffer than the #4.

The only reason I can see for softer springs is to engage the clutch at earlier revs, the 500 was never noted for suffering from not enoughpower lower down the rev range, perhaps it is to tame the power a bit and reduce heat production by having the clutch slip less?