QS motor shaft wear

Overclocker

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qshaft2.jpg

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so my shaft wear is getting worse over time so i gotta do something about it asap. been mulling over a few options:

1) weld the sprocket :lol:

2) build up the splines w/ MIG. high heat settings and 0.6mm wire should deposit some tiny little drops of weld. shouldn't be too hard to shape them w/ a dremel. but i don't have hardfacing wire so it'll probably wear out fast.

3) stack 2 sprockets (welded together) to interface w/ as much splines as possible. then plug weld a washer over the shaft to hold the sprocket in.


any other bright ideas?
 
Can you tap the shaft and get the sprocket clamped on properly?

New sprocket and a ton of loctite?
 
To be able to run really wide wheels on a honda monkey, they sell the kit in the picture. It has an extension shaft (supported by a bearing plate) that grips the splined axle a lot more than the 6mm of a sprocket. Not plug and play for a qs, but a variation of it might preserve the motor shaft and put the wear on a replacable part.offset-front-sprocket-14-23mm-kepspeed.jpg
 
There are some Loctite products that are meant for loose splines.
Loctite 660 might work for you.
 
Try this loctite and report back. I'll be amazed if it works, but people seem to be using it for pretty heavy duty stuff... If it does work I've got lots of slightly knackered parts it could save :lol:
 
j bjork said:
A better sprocket that grip on the whole splines?

What size is the shaft and what sprockets do you use?

IMG_20210430_114230.jpg

so here's the plan. the top sprocket is 20mm/16mm. the bottom one is 20mm/17mm and drops freely into the QS shaft, the top one doesn't. so the plan is to shave around 0.5mm so the sprocket will have to be heated and then pressed onto the shaft for a tight fit. i really should've done this from day 1 :lol:
 
Are you sure you have to modify it?
On my qs 138 70h v2 a JTF 1263 fits with a few gentle knocks with a plastic hammer.
The first time was harder because my shaft was a little damaged from using loose fitting chinese "one size fits all" sprockets.
I think my shaft was less damaged than yours.
But I dont know if the shaft is the same on your motor.
 
j bjork said:
Are you sure you have to modify it?
On my qs 138 70h v2 a JTF 1263 fits with a few gentle knocks with a plastic hammer.
The first time was harder because my shaft was a little damaged from using loose fitting chinese "one size fits all" sprockets.
I think my shaft was less damaged than yours.
But I dont know if the shaft is the same on your motor.


yeah the 20mm/16mm sprockets definitely won't fit. need to grind off a bit to make them 20mm/~16.5mm

anyway here's what i eventually did. basically two stacked sprockets to grab as much spline as possible. the 2nd one is now just a toothless "ring". both are tight-fitting on the shaft. then i set my MIG to 200 amps and deposited some tack welds. yes i welded to the shaft :lol: but i cooled it off between welds so it shouldn't affect the hardness at the splines. to remove sprocket just grind off the tack welds then use a gear puller

IMG_20210620_111831.jpg
 
That looks like it should stay stuck for a while. The only thing I would worry about is if there is any play at all on the shaft, it will allow bending around the welds and they might fatigue over time.
 
fechter said:
That looks like it should stay stuck for a while. The only thing I would worry about is if there is any play at all on the shaft, it will allow bending around the welds and they might fatigue over time.


this fix wouldn't have been possible without the 20/16mm sprockets. the QS shaft is 20/17mm so by shaving off a bit on the inside of the sprocket and expanding it w/ heat i've been able to force fit w/o play at all.
 
xenodius said:
So you're gonna get a new shaft when you have to replace your sprocket? :shock:

well i only placed 6 little tack welds directly to the shaft, and only on the end, no welds on the side of the shaft. so to remove i'd simply have to carefully grind off the 6 tacks w/o grinding too much into the shaft itself. the sprocket should come off w/ a 3-jaw puller

i reckon i could probably replace the sprocket about 10 times w/o screwing up the shaft too much :lol:
 
Overclocker said:
j bjork said:
A better sprocket that grip on the whole splines?

What size is the shaft and what sprockets do you use?

IMG_20210430_114230.jpg

so here's the plan. the top sprocket is 20mm/16mm. the bottom one is 20mm/17mm and drops freely into the QS shaft, the top one doesn't. so the plan is to shave around 0.5mm so the sprocket will have to be heated and then pressed onto the shaft for a tight fit. i really should've done this from day 1 :lol:

Where can I find the 20/17mm spline sprocket? (6) 4mm splines? I have a qs 138 90h
 
Ampsprockets has some sprockets specifically designed for various electric motors including qs 138 70h and 90h
 
Legna199111 said:
Ampsprockets has some sprockets specifically designed for various electric motors including qs 138 70h and 90h

Yea them and electro braap charging 40$ plus tax and shipping per sprocket. Yak about price gouging for a 3$ Chinese sprocket
 
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