KTM Forums banner
  • Hey everyone! Enter your ride HERE to be a part of this month's Bike of the Month Challenge!

1 - 8 of 8 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter · #1 ·
So I recently purchased a 2017 150 with kick start issues. I took it apart and found the idle gear with no bushing. Also found some damage to the back of the clutch basket and I noticed that there's nothing holding this idler gear on! After I did some research I found that ktm actually updated the case half so there's more support as well as a hole to place a bolt that holds the gear on. Im curious if anyone has just drilled into the case to make a retainer for the gear. Or if I'm just sol and I have to buy the new cases.
101506
101507
 

·
Super Moderator
Joined
·
2,090 Posts
We purchased a 2016 125sx for my son. This was the bike that was to take him to a championship or two... but he ended up riding his 2012 most of the time as the 2016 was a temperamental thing. We fixed one thing and something else would go wrong. He is sure that the 2016 is possessed... One things that went wrong was the gearbox. KTM had in their wisdom changed gearbox supplier, but the new supplier did a crappy job on hardening of the gears. I took motor apart and asked KTM to replace the gears. But they told me that they would not do that as they had not had any issues with them... (A big lie as many had same issues). So I bought the new gears and fitted them. Next the crank started giving issues so we parked the bike. It sits in the corner of my workshop awaiting for that day when I can be bothered fixing the bike... might never happen. We now happily ride a 2013 150sx that I have done some upgrades on and it is now a handful for many/most of the 250f riders... And the 2016 wheels are good as spares.

Regarding your issue, I never took notice of what you describe even if I had the motor apart. Probably too many other issues with the motor on my mind. But I am sure ours has same fitting for the idler gear in the case w/o any bushing (remember wondering about that... thou I can not remember our gear eating in to the clutch basket). But will now have a look and see if ours has the same issues (most probably has). Once I get that far I will tell you what I did about it. But might take a while before I get to it...

Regarding new cases... they only sell as a pair.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #3 ·
I'm super bummed about it. Even if the brass bushing that it comes with it is tapered I still don't see how the gear even stays on. I'm curious if I can replace it with a steal bushing so it doesn't fail but then I have to worry about that case breaking so I'm at a bit of a loss. I'd really like to see what yours is looking like if you get the time to tear it apart a little.
 

·
Super Moderator
Joined
·
2,090 Posts
Wish I knew. Different metals expand differently with heat. When/if that steel bush gets warm and the heat is transferred in to the alloy, will it get tighter or looser? This is the bushing: 3 BUSHING IDLER GEAR 50433024050 . You are telling me it is a brass one, but that there was none on your 2017 engine and you are contemplating fitting a steel one (as you show in the picture). As there is more than enough oil in there I am sure that a steel one (as in the picture) will do the trick. Now you have made me curious regarding what I have in there. As our engine is a 2016 I do not expect there to be a bolt holding the gear in place. (where does that bolt fit? Is it in middle of the bushing "shaft" and has some sort of washer that is "dimpled" in the middle, where the hole for the bolt also is in the "washer" so it goes in to the middle of the shaft?) I see if there is a minute or two this w/e where I have time to put our 2016 on the bench and find out. And yes, I can se the reason KTM has fitted a bolt that keeps that bush in place... nothing much else they could do.

So you had a steel gear spinning on a shaft with no bushing (making the "shaft" far to small) and the gear loose and rubbing on the clutch basket. Wonder where that initial bushing disappeared? Or perhaps KTM never fitted one...

If we have a brass bushing there (and I ever want to see our 2016 125 engine back up and running) I will still have to fit something that stops that gear rubbing on the clutch hub... As our crank has issues (was rebuilt but balancing is crap) I will have to split the engine anyhow. So I can at the same time see what would happen if I fitted a bolt to keep the idle gear from rubbing on the clutch basket.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #6 ·
Wish I knew. Different metals expand differently with heat. When/if that steel bush gets warm and the heat is transferred in to the alloy, will it get tighter or looser? This is the bushing: 3 BUSHING IDLER GEAR 50433024050 . You are telling me it is a brass one, but that there was none on your 2017 engine and you are contemplating fitting a steel one (as you show in the picture). As there is more than enough oil in there I am sure that a steel one (as in the picture) will do the trick. Now you have made me curious regarding what I have in there. As our engine is a 2016 I do not expect there to be a bolt holding the gear in place. (where does that bolt fit? Is it in middle of the bushing "shaft" and has some sort of washer that is "dimpled" in the middle, where the hole for the bolt also is in the "washer" so it goes in to the middle of the shaft?) I see if there is a minute or two this w/e where I have time to put our 2016 on the bench and find out. And yes, I can se the reason KTM has fitted a bolt that keeps that bush in place... nothing much else they could do.

So you had a steel gear spinning on a shaft with no bushing (making the "shaft" far to small) and the gear loose and rubbing on the clutch basket. Wonder where that initial bushing disappeared? Or perhaps KTM never fitted one...

If we have a brass bushing there (and I ever want to see our 2016 125 engine back up and running) I will still have to fit something that stops that gear rubbing on the clutch hub... As our crank has issues (was rebuilt but balancing is crap) I will have to split the engine anyhow. So I can at the same time see what would happen if I fitted a bolt to keep the idle gear from rubbing on the clutch basket.
I'm really curious to say the least. I'm sure the steel would be fine in there. I just don't want it to be too strong, then break the cases instead of the bushing. I know for a fact that the they replaced it and rode it till it came apart(the oil looked scary). I found another guy that had the same issue with his 2016 150 and he told me he ended up putting loc tite on bushing. He said he rode it for 20 hours then sold it with no issue. But even then I still don't see how that idler gear would stay true on the cases axle without some kind or retainer. I bet it happened in the past and seriously damaged the oem basket (makes sense because of the hinston they replaced it with). just making assumptions but I would imagine that the oem is much softer than the billet. Im really considering drilling in a helicoil and just using a flush washer like they do on the new ones. If I went that route I'm just more likely to break the cases so I'm torn... 🤷
Need to figure something out, not ready to fork out the money for cases and a rebuild...
101537
 

·
Super Moderator
Joined
·
2,090 Posts
I'm really curious to say the least. I'm sure the steel would be fine in there. I just don't want it to be too strong, then break the cases instead of the bushing. I know for a fact that the they replaced it and rode it till it came apart(the oil looked scary). I found another guy that had the same issue with his 2016 150 and he told me he ended up putting loc tite on bushing. He said he rode it for 20 hours then sold it with no issue. But even then I still don't see how that idler gear would stay true on the cases axle without some kind or retainer. I bet it happened in the past and seriously damaged the oem basket (makes sense because of the hinston they replaced it with). just making assumptions but I would imagine that the oem is much softer than the billet. Im really considering drilling in a helicoil and just using a flush washer like they do on the new ones. If I went that route I'm just more likely to break the cases so I'm torn... 🤷
Need to figure something out, not ready to fork out the money for cases and a rebuild... View attachment 101537
That looks like leftovers from a brass bushing?? Or perhaps the oil/light plays a trick. But in any case to find that amount of filings in the motor would keep me awake night time!!
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #8 ·
Oh
That looks like leftovers from a brass bushing?? Or perhaps the oil/light plays a trick. But in any case to find that amount of filings in the motor would keep me awake night time!!
Yeah its definitely the bushing and what came off the basket
 
1 - 8 of 8 Posts
Top