Measuring SPRINGS

[stirlinggaz]

hi,
i need 2 exhaust springs. its for a 30yr old 2t micron system, original new springs are n/a. (the flange is hand made anyway)
it fits like this : the flange slips onto engine,exhaust slips into flange,
the 2 springs connect the 2 lugs on the exhaust to the flange.

the distance from lug to manifold is 100mm.

according to some sort of caclulator i found on-line, this is what i need
type : extension spring (with open hook at either end)
wire guage : 2.5mm
outer diameter 13.5mm (compared an old, smaller exhaust spring)

number of active coils? f*ck knows, but looking at another exhaust spring, which has a free length of 36mm,
the distance needed is 100 divided by 36 is 2.7.
wee spring has 12 "active coils" so for a bigger spring i need to calculate
2.7 x 12 = 33.

so i need a spring that can cover 100mm, with outer diameter of 13.55mm with approx 33 coils.

problem is the hooks at either end. they seem to vary a bit in length. looking at 2 odd springs i have here, one has a hook of 10mm other is 15mm.

how to know what size of spring to order?
do i just take a gamble & order 100mm minus, say 20mm for the springs?
so order 80mm springs?
is there any easier way to work out what size springs i need?
this could turn into a game of chance. the springs needs to be tight enough to hold it onto the flange, too loose & it wouldnt be air tight.

anyone any ideas?

cheers,
GAZ

[Minty]

Ring a couple of garages, I'm guessing they amass springs over time and may have exactly what you need if they said it was ok to pop down with the pipe.

Possibly for the price of a pint.
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[Rogerborg]

I'd err on the short side, on the basis that it can effectively be extended by looping <insert ghetto bodge solution> through the lugs.
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Biking is 1/20th as dangerous as horse riding.
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[Old Git Racing]

I got some random exhaust springs from Padgetts in Batley. They carry different springs for old 2 stroke racers, maybe send them an e-mail with some dimensions on and se what you get.

OGR
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2022 Tiger Sport 660 2019 Street Twin 2003 K3 gixxer 1000 1998 Srad 600 track hack

[stirlinggaz]

hi,
my thinking was, work out what length of spring i need, for it to be stretched tight to 100mm & be real tight.
then go buy a couple of random springs from a guy that sells this sort of stuff, at the car boot sale/market this sunday.
that way i might be be ready for plug chops etc sun afternoon. & get the rest of the bike finished easter w/end.

dont really fancy waiting on postage etc when i know this guy has loads of random springs, for like a quid each.

i'll just gamble on 2 or 3 pairs of springs slightly shorter than 100mm.

cheers,
GAZ

[temeluchus]

[Pete.]

[Vincent]

You want them pretty tight....and the ones with the swivel ends make fitting them a bit easier. they also need to be clear of the pipe....and not rattle too much.
I've found it a bit of a chore finding the right ones sometimes.

Should have a few odd ones here somewhere.........
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Space Is Deep

[Vincent]

These are what you probably need. I think they're Lomas? Not sure if he's still going If not, you can have these....for a fiver

https://i77.photobucket.com/albums/j71/Drewskovitch/Jap%2070s%20bike%20toys/Bike%20toys/P3283034_zpsndf1ia9c.jpg
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Space Is Deep