Need rear axle for my Hawg-Ty mini

#1
Took my mini for a ride in the mountains today and the drive side chain tensioner failed allowing the rear axle to slide forward in such a manner the threads are FUBAR and cannot be repaired
The rear axle is 15 mm in diameter and 343 mm long ( 13.50") Both ends are threaded for what appears to be 9/16"x20 NF. About two inches on each end is threaded,
I cannot find any bar stock this size unless it is stainless steel. I'm not sure my 9/16x20 die will thread stainless steel?
Anyone here know where I may be able to get a replacement rear axle? The length is a problem as most are much too short for sale.

Here is the rear axle. 15mm in diameter and 343mm long with damaged chain tensioner.
axle1.jpg

This is what the chain tensioner should look like.
axle2.jpg
Here is the mangled one. It does not look very strong. I had to wire the axle in place to make it back to the trailer.
axle3.jpg
 

mustangfrank

Well-Known Member
#5
Took my mini for a ride in the mountains today and the drive side chain tensioner failed allowing the rear axle to slide forward in such a manner the threads are FUBAR and cannot be repaired
The rear axle is 15 mm in diameter and 343 mm long ( 13.50") Both ends are threaded for what appears to be 9/16"x20 NF. About two inches on each end is threaded,
I cannot find any bar stock this size unless it is stainless steel. I'm not sure my 9/16x20 die will thread stainless steel?
Anyone here know where I may be able to get a replacement rear axle? The length is a problem as most are much too short for sale.

Here is the rear axle. 15mm in diameter and 343mm long with damaged chain tensioner.
View attachment 283207

This is what the chain tensioner should look like.
View attachment 283208
Here is the mangled one. It does not look very strong. I had to wire the axle in place to make it back to the trailer.
View attachment 283209
They sell mild steel in 1ft, 3ft and 6ft lengths if you are staying with 15mm.

https://www.mcmaster.com/metals/steel/tight-tolerance-low-carbon-steel-rods/

If your bearings could use replacing maybe switch to an appropriate inch size axle and bearings?
 
#6
For what ever the reason the CHICOMS put the chain tensioners on the wrong side of the rear axle. All that I have ever seen have always PULLED the rear axle backwards to keep a set tension.
The Hawg-TY has it being pushed by the rear axle. Not a great idea that has failed.
I'm going to make my own tensioner and PULL the rear axle to the rear to keep and hold the tension on the drive chain.
 

toomanytoys

Well-Known Member
#8
I've never seen one push like that. I snapped 2 tensioner arms on my coleman. It pulls but for some reason they made them so cheap that the nut stripped off. I bought heavier duty ones off amazon
 

mustangfrank

Well-Known Member
#9
Yeah, I think I'd get stronger/larger diameter tensioners but leave the rear pushing design just because it's tidy on that frame. Can't tell from the pictures but it looks like if you leave the axle a little longer and space the new "eye" out a bit it will be straighter and less apt to bend. I'm thinking of a more traditional eye bolt like Bonanzas use.
 
#10
I ordered two heavy duty machined chain tensioners. If the drive side starts to bend again I'll try a 5/16" type rather than the original 1/4 bolt type.
The OEM tensioners are dead soft. Very easy to bend.
I will shim out the new ones so there is a straight push on the tensioners.
 
#15
The Flange nuts and chain tensioners showed up today.
The opening in the chain tensioners were 22 mm and the flange nuts were 23 mm. I turned the flange down to 22 mm.
The nuts were a tight fit on the axle at 1/2x20 NFT.
I Loc-tight'ed the threads and was able to tighten to 70 foot pounds. I did use grade 8 fender washers to hold the axle in place. The drive chain is dead-bolts in line with the torque converter drive sprocket and rear wheel drive sprocket..
The new chain tensioners were well made but are shipped finger tight on the support shaft. Those too were Loc-Tight'ed to stay in place.
I did not ride the bike as I want the Loc-tight to set up and harden. I'll give the mini a ride on Monday and if it holds up will take it for a ride in the mountains.
The drive side is double-nutted.
axl1.jpg

The brake side was too short to double-nut but is held in place by the brake drum support arm.
axl2 right.jpg
I had to turn down the flange by 1mm to allow it to fit inside of the new chain tensioners.
flange nut.jpg
 
#18
Took the Hawg-Ty for a one mile ride on my mountain and all seems to be normal again. Axle stayed adjusted and chain stayed tight with just enough play.
Depending on the storm coming in from the West,I may go for a ride in the mountains for 15-25 miles or so. I'll try to video the ride.

New sprung seat offers a much nicer ride over the rocks and boulders.
Front and rear racks hold all the stuff I need for a fun and safe ride in the boonies.

Lithium batters have held their charge over the months and the charging circuit I built is still working. Lithium batteries do not like to be over/under charged. I set the control for 12 VDC.


repaired axle1.jpg

repaired axle2.jpg

battery voltage.jpg
Just a test of the repaired axle for about a mile up my mountain.
[plains7.JPG
 
#19
Well crap,
I took the Hawk-Ty up/down my road to get ready for a long ride on Wednesday. On the way back to the garage I let off the gas and the chain was bouncing off of the chain guard.
Upon investigation I found the two new chain tensions were pulled out of the aluminum bolsters with one being bent.
I assumed the devices had just failed due to poor CHI COM materials.
bent tesioner1.jpg

Bent tensione2.jpg


I retreaded the 6mm adjustment bolt holes to 5/16" to increase strength. I reassembled the parts and tightened the rear axle securing nuts only to have the right hand axle end snap off in its nut! I noticed that the threaded shaft had cracked under strain as there was dried mud in the crack.
At least the axle shaft did not fail in the middle of no-where NM.

Bent tesioner broken axle3.jpg
Now I'm back to square one again. This time it has to be a new axle which no one has for sale due to the odd-ball length of 13 1/2".
The Go To supplies do not carry 15 m/m bar stock. Stainless steel is out there but I'm concerned it will be too soft to use under the torque of the rear axle nuts?
It all stems from going to a torque converter and upping the engine to a 6.5 HP from a 196 c/c engine.
At this point I'm going to add a pulling chain tensioned rather than the pushing type as there is a lot of strain on this device under full load.
 
Top