Engine mounts and crash bars

[dobbi]

Well, after quite a few fairly heavy offs on the RHS over the past few years I noticed that the oem carsh bars were sat 8-9mm from the frame and the upper front engine mount that holds the crash bars was missing.

 

I bought a new bolt but it was clear that the alloy threads of the engine has stripped. There is very little holding the bolt in and a tap on the crashbar will make the bolt pop out.

 

I am going to do a thread repair but I can't see any other way than removing the engine to do it as there is the engine mounting adjuster hollow bolt in the way.

 

Has anyone done anything like this before without having to remove the engine? not keep on epoxy resins and tapping as it is just not strong enough.

 

As a matter of interest, the oem crashbars get you to use the original engine bolt, so it is not screwed in perhaps 5 to 6mm into the engine. That is probalby why it stripped in the first place!.

 

Dave

Edited August 9, 2023 by dobbi

[katana]

How much thread is left in total?  On my GS, I could get a longer bolt and use quite a few extra threads.

[Dougie]

As @katana says there could be more thread left as you said the bolt didn’t use many threads. Get a “depth gauge” rod to test the available depth to the base of the hole from the head then find a new longer bolt. You can tell how much thread is holding by comparing the two bolts then to be safe. 

[dobbi]

Its a bit hard to tell what has been stripped and what is good but there must be some good threads in there.

 

I'm waiting for a 12mm bolt to come which is a bit longer. original is a M12, 50mm long polt with a 1.25 pitch. I've got a 60mm and will space it out with washers if there is any extra depth left.

 

Im away for a bit trip in 3 weeks so haven't time to drop the engine to do a proper repair, but my only worry is that another big drop on the LHS (why is always on the LHS!) might strip the whole lot!

 

Thansk for the suggestions.

[dobbi]

Well,

 

A good enough repair for the moment!

 

a 60mm m12 bolt with the oem indented washer behind and one m12 washer in front (hard to get a flanged m12 bolt over 50mm).

 

There was a good 4 to 6mm of decent thread left so on it goes and lets hope for no big smash downs on the RHS (I wrongly said LHS in the last post.

[DT675]

Yup, it’s a bad design. Mine did the same. I cleaned the threads, got a longer bolt and installed with some loctite.  Hasn’t been an issue since but I haven’t crashed on it either. 

[OK185]

This is making me scared with my Puig crashbars. Mine are also bent to pieces and mount in these holes.

The last thing I want is to strip threads in the engine on the next drop.

I wonder if this is just bad luck or if we will see much more of this in the future. A lot of brands mount their crashbars at these points. 

I can understand if this happens with aftermarket parts that use the wrong screw length, but it really shoulnd't happen with the OEM bars. 

 

Edited September 12, 2023 by OK185

[DT675]

It is not bad luck.  The RHS bolt is too short.  The LHS bolt is fine.  And, all the reports on here of whom have had problems, has been with the RHS.  EVERYONE that has the OEM crashbars should replace the RHS bolt before it becomes a problem.  Then just check all the crash bar bolts from time to time to make sure they stay tight.  Loose bolts will rip out in a fall.  Then you shouldn't have a problem.  If your worried about your aftermarket bars, just check the RHS bolts thread length, measure the threads in the engine and see if you need a longer bolt.  Easy enough.  

 

The reason this happens is the RHS of the engine has an engine adjustment spacer on that side and the LHS of the engine bolts tight to the frame without one.

[RiderEh]

25 minutes ago, DT675 said:

It is not bad luck.  The RHS bolt is too short.  The LHS bolt is fine.  And, all the reports on here of whom have had problems, has been with the RHS.  EVERYONE that has the OEM crashbars should replace the RHS bolt before it becomes a problem.  Then just check all the crash bar bolts from time to time to make sure they stay tight.  Loose bolts will rip out in a fall.  Then you shouldn't have a problem.  If your worried about your aftermarket bars, just check the RHS bolts thread length, measure the threads in the engine and see if you need a longer bolt.  Easy enough.  

 

The reason this happens is the RHS of the engine has an engine adjustment spacer on that side and the LHS of the engine bolts tight to the frame without one.

Thanks, I did not know about this. Can you confirm what bolt should we should use? M12 x 60mm socket cap screw?

[DT675]

8 hours ago, RiderEh said:

Thanks, I did not know about this. Can you confirm what bolt should we should use? M12 x 60mm socket cap screw?

This has a little more info on it-

 

https://www.tenere700.net/topic/5575-stripped-engine-threads-repair/#comment-63333