KTM 125 Engine Bolts Loose

Related:
Create New Tag

2/26/2018 6:17 PM

Hey guys, anyone else have problems with the 2 lower engine bolts coming loose on their KTMs? I’ve used blue loctite and even changed out the nuts for fresh ones. But for some reason they come just a bit loose and bike vibrates a lot.

Any thoughts?

|

2/26/2018 6:41 PM

Not on mine yet, but it’s only done a few hours of riding time. Could you drill and lockwire them?

|

2/26/2018 7:08 PM

Bruneval wrote:

Not on mine yet, but it’s only done a few hours of riding time. Could you drill and lockwire them?

Yeah I have safety wire on them so they don’t back all the way out. There’s not much room to get the wire super tight though.

|

2/27/2018 4:20 AM

Have you tried lock nuts? Are you tightening them enough? Cant imagine blue loctite not holding them

|

2/27/2018 5:40 AM

I would be looking for other loose bolts or frame issues as those bolts will not just come loose if the engine is not moving around. I would be looking at head stay bolts, swing arm bolts or anything else that the engine bolts to.

Paw Paw

|

2/27/2018 7:34 AM

Paw Paw 271 wrote:

I would be looking for other loose bolts or frame issues as those bolts will not just come loose if the engine is not moving around. I would be looking at head stay bolts, swing arm bolts or anything else that the engine bolts to.

Paw Paw

Everything is torqued, swingarm, headstays. When I feel the vibration come back the bottom 2 bolts are an 1/8 turn loose. It’s so weird.

I’m going to try different nuts again with red loctite.

When everything is tight, the bike feels good. But do you think it could be a sign something in the bottom end is out of balance?

|

2/27/2018 7:44 AM

What year bike and how many hours?

Paw Paw

|

2/27/2018 8:35 AM

My 2017 250sx doesn't but my 2013 I had to keep an eye on. I actually had a lower engine bolt come completely out on the Pala main track and it scared the shit out of me. My bike felt all loose and I pulled over to find the lower/front bolt had come out.

|

2/27/2018 9:36 AM

Paw Paw 271 wrote:

What year bike and how many hours?

Paw Paw

2016 KTM 125. 75 hours. Top end done every 20 hours. I’m going to do a compression test tonight and maybe I’ll pull the top and to see if there’s any vertical rod play?

|

2/27/2018 9:37 AM

seth505 wrote:

My 2017 250sx doesn't but my 2013 I had to keep an eye on. I actually had a lower engine bolt come completely out on the Pala main track and it scared the shit out of me. My bike felt all loose and I pulled over to find the lower/front bolt had come out.

Yeah I had the whole bolt come out this summer during the 125 dream race. Now I safety wire them so at they can’t back out.

|

2/27/2018 1:58 PM

Would you guys call the 2 lower bolts, “Engine Bracket Screw @ 60nm” torque or “Screw, engine brace @25nm”

just looking at the manuals torque specs...

|

2/27/2018 2:33 PM

CarlinoJoeVideo wrote:

Would you guys call the 2 lower bolts, “Engine Bracket Screw @ 60nm” torque or “Screw, engine brace @25nm”

just looking at the manuals torque specs...

"Engine bracket screw" says its an M10 bolt while "Screw, engine brace" is an M8.

Bracket screw is probably the through case bolts while engine brace is probably the head stays.

|

2/27/2018 3:22 PM

CarlinoJoeVideo wrote:

Would you guys call the 2 lower bolts, “Engine Bracket Screw @ 60nm” torque or “Screw, engine brace @25nm”

just looking at the manuals torque specs...

MX915 wrote:

"Engine bracket screw" says its an M10 bolt while "Screw, engine brace" is an M8.

Bracket screw is probably the through case bolts while engine brace is probably the head stays.

^corrrect

|

2/27/2018 3:43 PM

CarlinoJoeVideo wrote:

Would you guys call the 2 lower bolts, “Engine Bracket Screw @ 60nm” torque or “Screw, engine brace @25nm”

just looking at the manuals torque specs...

MX915 wrote:

"Engine bracket screw" says its an M10 bolt while "Screw, engine brace" is an M8.

Bracket screw is probably the through case bolts while engine brace is probably the head stays.

seth505 wrote:

^corrrect

Ahhh Ok I think this is where I went wrong. Now I’m at the right torque spec and I’ll see how it does.

|

2/28/2018 6:07 AM

CarlinoJoeVideo wrote:

Hey guys, anyone else have problems with the 2 lower engine bolts coming loose on their KTMs? I’ve used blue loctite and even changed out the nuts for fresh ones. But for some reason they come just a bit loose and bike vibrates a lot.

Any thoughts?

Thanks for the advice
Today i Check the Bolts on my 150SX and they where completely loose.
I fix it with 60Nm and secure with Blue Loctite,
will check again After a few rides.

|

3/1/2018 12:12 AM
Edited Date/Time: 3/1/2018 12:32 AM

You should check the swingarm bolt. When swing arm bearings seize the center bushing f the bearing starts to rotate with the bearing and eating away engine cases. This makes engine come loose even when swingarm bolt is torqued properly and cause vibration which makes all the other engine bolts to get loose. In worst case this can lead to cracked frame or engine cases. Why KTM doesn't use steel inserts in the engine cases to prevent this from happening still amazes me. You can fix the problem by using shim plates in swing arm area to get correct clearance. You should check also all other engine mounting points and use shim plates if there is any gaps between mounting lugs and engine cases.

Photo

I also learned from KTMTalk that there is a steel bushing available from KTM that you can use protect engine case in swing arm area but that requires machining the engine cases to fit. https://www.motosport.com/oem-parts/part-number/75030010000

I have had several KTM's and have to deal with this problem many times. Nowadays I usually check every engine mounting bolt and swing arm bolt before I go riding

|

3/1/2018 2:38 AM

|

3/1/2018 8:41 AM

Thanks I forgot about that shimming thread. I just torqued my swingarm. I’m going to order these shims and see how it works.
Photo

|

3/1/2018 4:32 PM

So I stopped by McMaster Carr at lunch and picked up the shims.

I took off my rear wheel and shock to get a good view at what was going on. Once I backed off the swingarm bolt, it had massive play! The case is doing exactly what is shown the the photo above. The shims fit perfect in the wear area.

I was able to fit a .2mm on both sides between the swingarm and the frame, also a .5mm on both sides between the swingarm and engine case! I got everything back together and the torque came muchhhhh easier, with less compressing of the frame.

Everything is to spec now, I'll see how it holds up this weekend!

|