Disc Bolts

That's excellent info @Sev, both myself and a friend (that builds Ducati and Lamborghini engines for a living, so has experience with tightening stuff at the least) have had this problem when fitting stuff to my F9 track build with Ti bolts, it's cost me a couple of throttle housings in the past few weeks alone and I've finally gone back to using OEM fasteners on fragile components as a result as neither of us understood what was happening. The bolts felt nowhere near 'tight' yet the torque load applied was obviously enough to snap light alloy castings.

Thanks for the info

 

Nelson at Almeria recently:

 

You were clearly at the wrong track day...

 

I bet you were a bit thore thitting on that

 

If you replace an 8.8 steel bolt with A4 stainless, it's pretty damn close. But if you use an A2 stainless bolt, you are pushing your luck.

 

http://www.namrick.co.uk/acatalog/Home_Metric_Stainless_Steel__Grade_A2_and_A4__54.html

 

Thanks for that @Sev very interesting and informative, I gotta 'fes up and state I'd never heard of a JIS screwdriver before you mentioned and will order a set this evening for when I come across them.

FWIW I also use (and prefer) socket head bolts and use them wherever possible (ie wherever they'll fit) if appropriate, I don't like the button heads jobbies @Nelson mentioned.

The bolts I was replacing in the throttle housing example were flanged hex head (back in there now too) but they the bolts just didn't feel tight yet must have been as the housing cracked right through - twice (FFS!).

Thanks again for the info @Sev, every day's a school day

 

Just checking here - says it's a Philips?

 

Ah OK cheers for that.

I was looking at the Vessel 930 Megadora range, looks ideal for me:

https://www.vesseltools.com/handtools/screwdrivers/megadora/930jf-series-detail

Sorry for the temporary, but hopefully useful, thread jack!

 

JIS is news to me. I only knew about Philips and Pozidrive.
Could explain why some screw heads don’t seem to work well with either...

 

Could this be why it’s so hard to get the float bowl screws out of Mikuni carbs intact @Arquebus ?

 

Apart from corrosion, IMO it is the main reason - I have several screwdrivers and bits that I reshaped by grinding to get those stuck screws out.....You will find the same thing can occur with the coffin type clutch and brake master cylinder cover screws.

 

IIRC all the engine cases on earlier Jap bikes had those damn crosshead screws that never came undone easily......we used to see loads of bikes with mashed up screwheads.

 

Use the new-found knowledge man... JIS screws!

 

Nah......I learned a long time ago to use socket head screws (once the buggered JIS ones were out).

 

Yeah I did the same, still, I'm getting a set of those JIS drivers as mashing sh*t up really pisses me off!

 

How much Japanese stuff is there on a Ducati?
No Mikuni carbs since the 90s...

 

I can't think of any mate other than the aforementioned carbs and I still have a few Supersports left, I think the bolts that hold the rear wiring on the 999 are those JIS screws as well, either way for about 30 quid I'll have 3 screwdrivers that appear far superior to the Philips and PoziDriv drivers I have, oh and I'm a tool whore!

 

As long as you can get the correct clamping force without overstressing the fasteners you will be fine.

 

This is the correct answer