1971 SF a couple of questions please - Updated

Kickback

Kickback

Junior member
Location
Somerset UK
Having recently acquired Shaun's lovely 71 SF during lock-down I used the time off the road to strip, clean and fettle the bike. It's my first bike for over 30 years. Having previously had Hondas the mechanicals seem very familiar although the robust materials and quality of engineering are a step up, it's a lovely thing to work on.

A couple of questions please; There was some blow-by from the balance cross pipe, I've followed advice and used some 0.127 0.005? 5 Thou stainless shimstock to sleeve the socket which worked really well producing a perfect interference fit. Firstly which way should the exhaust flange half circles face? Mine are chamfered one side, does the chamfer face towards or away from the head please?

Also I have searched high and low including in the Green book, ILOC and the web and cannot find a full list of torque values for the bike, I'm after the torque for the brass exhaust flange nuts, I'm guessing it will be low, about 10 ft pounds  / 13.5 nm but wanted to check please?

Finally the tank filler surround paint has been chipping off (and dropping in the tank). I have searched the web but cannot establish what the original finish was, I'm assuming it's a steel filler surround, were they painted tank colour or stainless/polished metal please?

Thank you
Greg
 

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Hi Greg,

I honestly can"t remember the flange orientation ,doesn:t seem to be the the Green Book, but others here will know.The copper nuts are BMW self tightening nuts,a tip from here and on all my Laverdas,I"ve never needed torque values,as manual says a steady even progressive tightening is ample,don"t over tighten or a snapped stud will result.
As for the paint, yes my painter didn"t mask this off (and comes due to the ethanol), my other bikes have bare steel,I" d protect the main tank finish and blocking the filler hole and gently fine emery off the paint.One of those jobs one my list I never got around to.!!

Hope this helps,again others may know more.

Shaun
 
My tank, when new, had paint in there. Fuel, even in the pre-ethanol days, made it wrinkle and lift. I peeled the softened stuff off and have run like that ever since.
 
Thank you Shaun, Sock & Haggis, that all makes sense. I'll post up some pictures of the jobs and result when it's all done.

Is there a comprehensive torque value guide? I have found a short list posted and some generic values for fastener sizes, but not a full list.
 
That's a good question for this particular fixing. The flange-roses can bend if done up too tight. I err towards lowish [by hand/feel] torque for these and for the first few rides make sure I have a spanner with me make sure they are still nipped up when I stop. These nuts always loosen as things bed in and find their natural position after a few thermal cycles, so just keep chasing them down until they don't come undone anymore.
 
... oh, and be sure to keep some M7 nuts in your tool roll - not available on every street corner.
 
These BMW  exhaust flange nuts self tighten Paul, don"t seem to loosen in my experience but good advice to nip up after a ride or two,when refitted.
 
Here" a source for new ones if required.

https://www.ebay.co.uk/itm/BMW-E36-E46-3-SERIES-EXHAUST-MANIFOLD-NUTS-HEAD-STUD-LOCK-NUT-M7-HEX-COPPER/400783640583
 
Surely theres some sort of after sales service Shaun?, like a van that turns up with a hot babe to fettle those little things that need sorting, ::)
 
They are good nuts for sure, but they don't self tighten, they just don't self loosen.  :)  It's the settling down of things that causes the initial looseness, esp any compression to the gaskets.

Manifold fixings are a science in themselves, even the BWM style (deformed prevailing torque) nuts are old hat now.  To 'fit-for-life' on a 150,000 mile design life is a huge challenge.  I'll see if I can grab a Bentley one and post a pic... It's nuts! ;)
 
time for a nice opportunistic sales pitch:-
  I NOW SUPPLY A STEEL/FIBRE/STEEL LAMINATE  ITEM - WILL TAKE UP TO 650?c - REDUCES POSSIBILITY OF EXHAUST FLANGE NUTS WORKING LOOSE AS THEY COMPRESSES LESS  THAN THE CU ONES AND END UP ABOUT THE SAME THICKNESS

  ?1.60p  each or ?10 for six inc Uk postage. - Regards - Phil

 

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BOOM! Get in there

Missed extra opportunity though Phil, you could have spelt out 'PT' with them, or at least drawn a cock-n-balls  :D

Your chair is suspiciously devoid of stains from dunked & dropped biscuits in the between-the-legs zone.
 
Kickback said:
Thank you Paul
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Shouldn't be necessary. Once back to bare metal I'd be surprised if you get any rust there. Mine never had paint there by the time I bought it in 1974 and still haven't rusted after 47 years of use and non use.
 
LJ-2 said:
Never had those copper nuts work loose though,on all my Laverdas
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Still have the original factory M8s from my SF1 - they're actually brass. Never used a torque wrench on them either, and never had one come loose.

On the small valve head for the SFQ I've upgraded to M8 studs and converted the header insert area to take the later type headers, ie no double-stepped header.
 
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