Maintenance: Rear axle bearings rear sprocket and engine tensioner bolt


(Ji Simmons) #1

In looking over everything, I came to find I have a bent axle. New one on the way, and I’m not even going to open up the can 'o worms about stiff vs. soft… It has a medium in it, and that’s what’s going back in.

I did notice that the chain tension is variable depending on where the axle is rotated. I suspect this is due to the bend, but after fooling with the two piece rear sprocket a bit to try to dial that out, I got to thinking- how critical is it to get the two halves exactly the same distance from each other on both sides? Using a digital caliper, I was able to get them within 0.02mm of each other.

I also noticed the outer races of the two engine side axle bearings could move around a small bit in their carriers. I presume this allows the axle to float a bit in relation to chassis flex, but want to address it if it’s not ok. *edit- I did notice that the middle bearing doesn’t have any grub screws holding it to the axle. Is this what’s meant by running it loose?

Finally, I read on some UK karting board that Tony Kart frames have a tendency to crack under the engine mounts if the tensioner bolt is left tight against the mount. Thoughts? How tight is enough if it’s supposed to be touching the mount?

And as an after thought- are there any books or websites that cover general maintenance stuff like what I’m asking here? I don’t mind asking, but I feel like this is pretty basic kart wrenching stuff that should be covered somewhere.

Thanks! :slightly_smiling_face:


(Mike Clark) #2

If it’s working, then keep with medium. You can get axles straightened.

I use the chain to get them to mesh & Don’t care what the gaps are. Some just have spots that are tight. Check for stiff links.

[quote=“Mandrake, post:1, topic:3885”]
I also noticed the outer races of the two engine side axle bearings could move around a small bit in their carriers. I presume this allows the axle to float a bit in relation to chassis flex, but want to address it if it’s not ok.[/quote]
they should able to move angularly, but no real free play

[quote=“Mandrake, post:1, topic:3885”]
Finally, I read on some UK karting board that Tony Kart frames have a tendency to crack under the engine mounts if the tensioner bolt is left tight against the mount. Thoughts? How tight is enough if it’s supposed to be touching the mount?[/quote]
Don’t know about Tony Karts or cracking. I thought the tensioner was for ease of adjustment AND it helps prevent the engine from sliding back if the engine mount bolts loosen.

Besides here:


You are welcome and I expect others will help you.

You also can learn a lot from others in the pits/paddock. Sometimes opinions differ.


(Ji Simmons) #3

I’m not sure what you mean by the bearings moving angularly, but if you mean the outer races could rotate ccw and cw when viewed from the rear, then yes, they do move in that manner ever so slightly, but no radial or axial play. I’ve been told that it might be a good idea to clean the bearings and lube them with triflow while the axle is out. Yes or no?

What you said about tensioner makes sense. I’ll keep it snug against the mount.

I appreciate those links. The only track in the state is closed, and the only kart shop in the state has a phone number that goes directly to a voicemail box that isn’t set up. As I’m using the kart to autocross until a track opens up, there is nobody locally to bounce info and ideas off of. I am quite literally on my own here. I haven’t had a chance to sit down with them much, but I did see in the first one an article about axle replacement, so I read it and have a better understanding of the finer details. Thank you!


(Mike Clark) #4

Normally and axle would be 90 to the carrier. I think it is OK to have it so the bearing go to say 93 & 87 to allow the chassis to twist.
This is what I consider angular movement:

It is common to flush bearing while still in the kart. I put a half circle cutout in the top and bottom of the shields on mine to be able to flush them better. I figure since dirt is going to get in any way I’d make it easy to get out.
When bearing is out of kart I like to really clean them out, with a soak.

One thing to do on the front is tighten the axle nut until you can’t spin the spacers and then back off til they can be turned but have no real slack.


(Ji Simmons) #5

Thanks for the video. Yep, we’re on the same page on angular movement. Since the axle is going to be out, it doesn’t look like it’ll be much trouble to remove the bearings from the carriers to give them a good cleaning and relube.

On the front axle- that’s almost what I do. It does baffle me that there isn’t a spacer between the inner races, but I suppose there’s a reason for that. I did notice after the last time I drove it that there is some play between the outer races and the hubs on the inboard front wheel bearings. I managed to stuff a 0.002" feeler gauge between the bearings and the hubs, so I removed them, used a center punch to stake the bore of the hubs where the bearings ride, and applied some primer and Loctite 648 bearing retainer with new bearings in hopes that can save it. If not, I’m going to be looking at a complete spindle/hub/brake setup from Italian Motors as these Tony Kart parts are no longer available. The front rotors are about 1mm thinner than new, and as they’re NLA as well with no suitable subs to be found, the spindle/hub/brake swap was inevitable anyway. The bearing issue may just speed things along.

I’m beginning to find that buying an older kart is like buying a $500 horse- the cheapest part is the purchase. :slight_smile:


(Mike Clark) #6

Used kart help you learn and it you have a major problem it is softened by the price.
They can hold you back too.


(Ji Simmons) #7

Very true, and my skill level and reasons for purchase and intended use dictated used vs. new. No regrets. :grin: