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welding a nut onto a Mild Steel Ex for EGT
Posted: Tue Aug 04, 2009 10:34 am
by druist
i am ditching the scootrs stainless, as i have a mild steel NK expansion. I have a mig welder (135amp) and want to put my EGT meter on it and need to put a receiving nut on the downpipe. BUT what sort of nut eg metal do i get, as all look either alloy or stainless?
And i take it all welded metals need to be the same?
thanks
drew
Re: welding a nut onto a Mild Steel Ex for EGT
Posted: Tue Aug 04, 2009 10:50 am
by red ghost
Your best bet is to use a mild steel fitting.
I made a stainless fitting as my lead-in pipe is stainless

Re: welding a nut onto a Mild Steel Ex for EGT
Posted: Tue Aug 04, 2009 12:42 pm
by tavspeed
not sure,but i think the probes have a 1/4" bsp thread on them you could get either a mild steel or stainless 1/4" b.s.p socket(plumbcentre or plumbers merchants should have mild steel ones) and cut it to the required length,best way to weld it would be to t.i.g it using stainless rod,you might get away with miging it using 0.6mm wire,but protect the threads in the boss to stop any spatter getting on them,cheers all.
Re: welding a nut onto a Mild Steel Ex for EGT
Posted: Tue Aug 04, 2009 10:13 pm
by cryogenic
Does this have to be a welded item a very simple way and cost efective is the stainless jubille clip from camlam with the cone and threads already fixed to it and you can carry a spare camlam sell them seperatley now. :baddevil:
Re: welding a nut onto a Mild Steel Ex for EGT
Posted: Thu Aug 06, 2009 3:36 pm
by druist
Tav you are right about the 1/4 bsp thread, though it tapers. I picked up a brass one from a plumbing shop.
Though i am now wondering, DO I NEED ANYTHING? Could i just drill a hole in the pipe say just of 8mm, try and start a tiny thread with tap n die, then just twist the sender housing in as far as it goes, surround the join with some exhaust gasket red - seal??
Or wouldnt this work??
I know other ppls egt meter sender ends will differ.
Re: welding a nut onto a Mild Steel Ex for EGT
Posted: Thu Aug 06, 2009 4:18 pm
by Lazarus
druist wrote:i am ditching the scootrs stainless, as i have a mild steel NK expansion. I have a mig welder (135amp) and want to put my EGT meter on it and need to put a receiving nut on the downpipe. BUT what sort of nut eg metal do i get, as all look either alloy or stainless?
And i take it all welded metals need to be the same?
thanks
drew
Hi Druist sorry I cant help with your question, but I have one of my own regarding your change of pipe.
Have you compared both pipes on your scooter and if yes what were your findings regarding power/speed/etc
cheers
Re: welding a nut onto a Mild Steel Ex for EGT
Posted: Thu Aug 06, 2009 8:16 pm
by druist
not yet Lazarus, a few reasons for getting the NK pipe a) i kept getting problems with the ss one, leaks. b) for the past couple of years from what i have read mild steel seems to favour 2 stroke c) i can upgrade this particular pipe should i ever go the RB20 route. That said, i wont part with the scootrs one just yet as i want to compare them and i will try to remember to let you know any difference found as due to lack of garage i havent had a chance to change it yet.
Re: welding a nut onto a Mild Steel Ex for EGT
Posted: Thu Aug 06, 2009 8:29 pm
by druist
BTW dont suppose anyone can remember the length from the piston skirt to the probe?
Re: welding a nut onto a Mild Steel Ex for EGT
Posted: Thu Aug 06, 2009 9:17 pm
by cezeta
druist wrote:i am ditching the scootrs stainless, as i have a mild steel NK expansion. I have a mig welder (135amp) and want to put my EGT meter on it and need to put a receiving nut on the downpipe. BUT what sort of nut eg metal do i get, as all look either alloy or stainless?
And i take it all welded metals need to be the same?
thanks
drew
simon at b race used a vespa head nut on mine. its 7mm but just needs a 8 mm tap running through it. i assume he used that as its a tall flanged nut .
Re: welding a nut onto a Mild Steel Ex for EGT
Posted: Thu Aug 06, 2009 9:28 pm
by TS1-200
druist wrote:BTW dont suppose anyone can remember the length from the piston skirt to the probe?
100mm I believe, by the way I am about to fit an EGT guage to mine, this may be a stupid thing to say but wouldn`t the probe cause some restriction to gas flow, or alter the flow in any way, to affect performance ?