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I purposely chose the SW Motech top rack (below) because I prefer its more robust design. Givi's own top rack typically uses a cantilever arm with a bolt right in the middle of it. Lots of reports of it breaking at that bolt. Shad's design allows you to retain the grab rail, so you can mount the OEM panniers. I don't ever plan on having OEM panniers so that benefit doesn't apply to me. One downside to retaining the grab rail is that Shad only uses one bolt at the grab rail, vs. SW Motech using two (see below). This sucker is stout! In fact, I lost one of the bolts under the top case (see below pic, left side) from it vibrating loose (yeah, $#%&@! Inline4 buzz) and rode with just 3 remaining bolts holding that top case rack, for I dunno how long. I probably could've ridden it like that for the next 3yrs. Thing was still solids as ever. But, it looks bad, and I have spares.

Regardless, I just don't see the addition of the top case causing the whole subframe to fail. My Givi V47 weights a whopping 9.72 lbs. I rarely haul heavy items in it. At most, it's my laptop, which I'd be surprised if it's more than 10 lbs. I'm no welterweight but probably don't qualify as a lard *** in most people's books. And I only ride solo. If some rider breaks his N1k subframe and wants to blame his top case, that's his prerogative. I don't see that happening.

My guess is the N1k's vibration that's at fault. I've already lost a few fasteners on mine. Thankfully none that were critically structural. Windscreen screw was one. The SW Motech rack bolt (mentioned above), and one other small one I don't remember where. It's a hassle for sure to have to check the whole bike regularly. I've had other bikes that likes to shake screws loose. Some worse than others. This N1k is not winning any favors from me because of this. Threadlocker helps, but still annoying.

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It doesnt cause the subframe to fail. Sorry for not making that clear. It also wouldn't be related to how strong the cases mounts are, either. In fact, "robust" case mounts will make this worse as they would weigh more. Those arms can be as strong as a bridge and it wont change anything.
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This is related to how the subframe attaches to the main frame. It uses 4 bolts. This picture shows what the issue is. Its like Kenors described. I can see using nuts to lock the bolts. That makes sense.

Check them? Dont check them? Its all good.
 

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A Black 2019 N1K
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There is a "right" way and a "wrong" way for fit the longer bolts.

I would suggest that the "right" way is to :--

1) Screw the longer bolt into the aluminium sub-frame, using some non-permanent Locktite on the thred, and to torque the bolts to the factory spec of 25 N-m (18 ft-lb).

2) Then holding the bolts so that they don't turn, add a washer & nut and torque the nut down to 25 N-m (18 ft-lb).

It is suggested that you use a 8mm high-tensile bolt, rather than a mild steel bolt as it will have a higher sheer strength.
 

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Properly fastened,, even a low carbon 4.6 steel M8 bolt has a shear strength of some 2000 lbf. Medium grade 8.8 is 5000 lbf, I think. There isn't a pillion @$$ on this earth big enough to shear 1 of them, let alone 4. Much less a 25 lb top case and rack.

The problem is the bolts coming loose. That could be the guy that did the top rack install either under torqued or over torqued the replacement bolt. Or used wrong size/length bolt.

Or like I said above about engine vibration buzzing them loose. Any combination would conspire to cause an early demise of those bolts.
 

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Volfy, yea....that's it. Thats a great idea! That's why I brought it up. Only took 4-5 posts for you to get the point. Not bad.

The facebook guy "fixed" his with titanium bolts, missing the point as well.
 

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<< snip >>
The problem is the bolts coming loose. That could be the guy that did the top rack install either under torqued or over torqued the replacement bolt. Or used wrong size/length bolt.
<< snip >>
The bolts that failed in the photo that RC posted are not the bolts that hold the top rack on. They have no relationship to the sub-frame bolts shearing.

But you are correct is suggesting that the problem is likely to occur when the sub-frame bolts come loose. Repeated vibration and the resultant repeated application of a sheering force will eventuall break each bolt.

Typically the failure will be in the area where the body of the bolt ends and the thread starts due to micro-cracks in the metal as a result of the thread cutting process.

If you are going to buy 4 new longer bolts, why not buy some typical high tensile bolts at your friendly hardware store (class 8.8), which as you mention have double the shear strength of a run-of mill mild steel bolt.
 

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Murph, I found it interesting that the facebook guy actually blamed the bolt, itself. As if titanium would solve the problem. The guy never mentioned switching out those bolts. I'm sure his damaged bolts were stock.

I liked the Idea both you and Kenors suggested. Use longer bolts, and add a locknut on the back side. At that point, you can see the locknuts when you remove the seat.
 

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Can someone comment on the replacement bolts size needed to put a lock nut on? So M8 x ?thread x ? long..... Since I have the side cases and added the Shad top case bracket, I'd like to be proactive and do this modification. Thanks
 

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Kinda indicates just how rare this failure actually is doesn't it. All reading about this failure caused me to do was check the torque on the bolts when the plastic was off for other reasons.

Really, nobody knows the size bolts?
 
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Hi,
I've read through this thread as I'm desperately looking for a solution to the wind blast noise I get on my 2020 Ninja. I have the kawasaki touring screen on the bike and this does nothing to prevent the noise. I always wear good quality earplugs. Unfortunately I wear an XL helmet and changing brands with my head shape is very difficult to find one that's comfortable. Having just toured for 1500 miles around Scotland I'm either going to trade the bike for a more upright adventure style that allows me to sit behind a screen or buy one of these Vstream screens. I'm 5"10. Could anyone give me a current update on how they're getting on with their Vstream screens please. Thank you
 

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I know this depends on the riders height, and their helmet, but I would not choose a v stream for noise issues. I find mine to be very noisy.

My Puig is the most quiet shield I've used, but it doesnt have amazing wind protection.
 
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