Changing internal bolts

[DKGS850]

Dear all,

I am doing an end to end renovation of my trusty old GS850 GN, and I have encountered some problems with the screws / bolts found under the clutch cover. Even though I have invested in the proper JIS screwdrivers, I am shredding bolts left and right. Instead of buying new JIS bolts, I have found some hex bolts in the local hardware store. Ill need to cut them to size, but they are stainless steel, and the thread fits.

Have any of you done a similar bolt replacement? Is there a better alternative than hex bolts?

I have read a lot about steel quality and the advantages of having a bolt in a lower quality than the subject you are mounting them in, and I am pretty sure that these bolts will tear through the cranck case if over tightened. I cant find any torque settings or instructions on thread locker use on assembly (please share if you know) Below please find a picture of the possible replacement hex bolt and one of the destroyed JIS bolts.

 

[Tom R]

Go on ebay - you can find an entire stainless bolt kit for your bike.

 

[Brendan W]

It is almost normal to replace the old external JIS screws with socket head capscrews - hex or Allen key type and stainless is often the choice. You may have trouble getting a tool on all the screws if you use a hex head.
Be careful with the length. They are different, some by only 5mm but it can result in a screw bottoming out and letting the oil leak out.
Inside, I avoid galvanised fasteners. They are more shiny than stainless. I just don't trust them. Long story and don't even mention cadmium in hot places. I would use black before either.
The fastener in the picture looks cheaply made by the roughness of the threads and look galvanised. Look for something better.

 

[DKGS850]

Go on ebay - you can find an entire stainless bolt kit for your bike.

Hi Tom
I have bought an allen bolt replacement kit, for a lot of the external cover bolts, but I haven't found any kits for "internal use" . Maybe I am using the wrong search terms. Can you recommend a kit?

BR M

 

[DKGS850]

It is almost normal to replace the old external JIS screws with socket head capscrews - hex or Allen key type and stainless is often the choice. You may have trouble getting a tool on all the screws if you use a hex head.
Be careful with the length. They are different, some by only 5mm but it can result in a screw bottoming out and letting the oil leak out.
Inside, I avoid galvanised fasteners. They are more shiny than stainless. I just don't trust them. Long story and don't even mention cadmium in hot places. I would use black before either.
The fastener in the picture looks cheaply made by the roughness of the threads and look galvanised. Look for something better.

I hear rumours of a kit. If I am unable to procure that, I will look for individual bolt i better quality.... and without galvanization.

Thanks

BR M

 

[eil]

The stock Suzuki fasteners are basically made out of parmesan cheese. If you keep stripping out the heads of them, you need one of these:

http://www.homedepot.com/catalog/productImages/1000/67/6763a5b6-88b0-48c4-a7e9-47fb3aaf1913_1000.jpg

It's called an impact driver. You use it like this:

https://images-na.ssl-images-amazon...us/tekton/tekton-impactscrewdriver-use-sm.jpg

They're cheap and will save you a lot of time down the road. No, it won't fit the JIS screws perfectly, but as soft as they are, it doesn't have to.

 

[bwringer]

I've replaced lightly stressed internal fasteners like that one with stainless steel -- those appear to be for the retainer plate around the shift drum. Add some blue Loctite and torque to spec (these have 6mm thread) and you'll be peachy keen. Measure and buy the correct length fasteners -- lopping off the excess is a rather inexact process.

Do NOT replace internal fasteners that are under larger amounts of stress, or anything larger than M6. For example, the cam cap bolts are a special length and hardness and should not be substituted. On some engines, there are internal case bolts, so if you replace these with socket head, make triple-sure the slightly taller heads aren't going to interfere with anything.

If you replace a fastener with a flanged head, make sure you use a washer to spread the load in a similar way.

Also, do a little research and make sure you understand exactly how to measure and spec fasteners and threads.

 

[DKGS850]

Thanks for your help, Gentlemen.

@eil: Thanks for the tip about the impact driver. I ordered some Vessel JIS "IMPACTA" screwdrivers, that were supposed to do something similar. Didnt work though. The bolts either stripped or remained stuck. An engineer contact of mine were more successfull though, so now all the old bolts are out. Now I just need to decide what to replace them with

@bwringer: Please explain the issue with upgrading the bolt to a better quality steel. The new ones, that I have found, is grade A4, which should be in the better end. I understand that aluminium is softer than steel, especially my new steel bolts, and that you want the bolt to cave in, instead of the threads in e.g. the cranck case... but.. is that still an issue if you torque to specifications, or does it only go wrong when you go off in a torque tension frenzy?

Blue loctite is hard to source in Denmark, but I found Blue Permatex Medium Strenght. Will that suit my purpose?

 

[hannibal]

Blue Loctite does not require heat to remove. Red Loctite does. I think Permatex Blue would work fine.