Copper base gasket?

[stinkwheel]

I can't remember if I asked this before or not.

Any engineering reason* why I shouldn't fit a base gasket cut out of a single piece of copper sheet to an air cooled 2-stroke? (In this case, a Jawa 350 twin)

To avoid argument, let's assume it is the same thickness as the proper fibre one and that I'm going to clag it with blue hylomar anyway.

*Other than the obvious "because it would take ages to cut out", it's halfway done anyway, just needs the holes putting in and annealing.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[MarJay]

[Pete.]

No reason that I can think of. Might do well to anneal it before use, but since it's not holding combustion pressures that might not even be necessary.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[tatters]

Would,nt the compression of the copper gasket be different to that of a fiber gasket when the cylinder is bolted down. increasing/decreasing the squish.
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Past:NRG50,AF1125(x2),NSR125RR,ZZR250,CX500,VFR400,KR1S,ZZR600(x2),CB400N,YZF1000(x2),KH125,Z200,FX400R,CBR954RR(x2)GPZ500S,GT550,VFR750F(x2),RD350N,XR650R,CBR600F,CB250,KDX250,YZF750R,CRM250,400EXC,KLR650,TTR600RE,DR350S,R100GSPD,RGV250,VMAX1200,DL650,KZ750 Present:G650XC,C12,CRF450X,1190ADV

[MarJay]

[stinkwheel]

[tatters]

thats a big difference, currently trying to work out endfloat of 0.05mm on a R100 gearbox bloody nightmare.
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Past:NRG50,AF1125(x2),NSR125RR,ZZR250,CX500,VFR400,KR1S,ZZR600(x2),CB400N,YZF1000(x2),KH125,Z200,FX400R,CBR954RR(x2)GPZ500S,GT550,VFR750F(x2),RD350N,XR650R,CBR600F,CB250,KDX250,YZF750R,CRM250,400EXC,KLR650,TTR600RE,DR350S,R100GSPD,RGV250,VMAX1200,DL650,KZ750 Present:G650XC,C12,CRF450X,1190ADV

[Pete.]

You have 2 thou endfloat and it's a problem? - or you are trying to achieve 2 thou endfloat?
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[lonner]

[stinkwheel]

Woot. Reduced the squish difference by a factor of 4 from standard by lapping the LHS head.

LHS: 2.12mm
RHS: 1.90mm

NB: For anyone reading this who doesn't know much about engines. A difference of 0.22mm in squish between either side of a 2-stroke twin is still absolutely appalling.

A squish band of over 2mm is fecking enormous.

You should not need to use red hermatite to join your crankcases, nor should you have to use it on your cylinder head. You should most definately never use green permabond on any part of your engine at all.

Blue hylomar on the base gasket is acceptable however.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[MarJay]

Am I sensing the beard twitching urge to put on a pair of socks and sandals and geek off over two stroke motorcycles?

What bike is this? I assume its the Jawa?
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British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F; Cheap project: CBR900RR FireBlade
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[stinkwheel]

[stevo as b4]

People find it hard to believe, but as i've said before the H100 is a lightweight tool of choice in the sub 125cc catagory for 1st&2nd gear wheelies without the clutch!