Why copper washers

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paulincayman

Hero member
Location
Cayman Islands
Was wondering what the mechanical benefits are of using copper washers vs flange nuts , nuts and lock washers etc on crank case studs , never seen that in any other engine..
 
there are only two copper washers on the crankcase halves of a triple crankcase, these have closed end nuts as well, only one of those two (on the left side main bearing clamp) carries oil, the other has a copper washer so that (IMHO) the clamping forces between the two nuts are the same, copper washers are used elswhere on these engines, cam cover, and cam chain tensioner locknut (I have seen carnage here because a steel washer was used and the bolt fell out) to name two the former would be for both oil retention and anti rattle loose, in the case of the tensioner its for anti rattle loose only, the primary chain adjuster, again for oil tightness and also anti rattle loose, so to recap, they usually provide oil tightness but can also give security. Sump plug anyone? (dont want that coming out!, mine is always wired)
CLEM
 
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CLEMTOG said:
there are only two copper washers on the crankcase halves of a triple crancase, these have closed end nuts as well, only one of those two (on the left side main bearing clamp) carries oil, the other has a copper washer so that (IMHO) the clamping forces between the two nuts are the same, copper washers are used elswhere on these engines, cam cover, and cam chain tensioner locknut (I have seen carnage here because a steel washer was used and the bolt fell out) to name two the former would be for both oil retention and anti rattle loose, in the case of the tensioner its for anti rattle loose only, the primary chain adjuster, again for oil tightness and also anti rattle loose, so to recap, they usually provide oil tightness but can also give security. Sump plug anyone? (dont want that coming out!, mine is always wired)
CLEM
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Do you lockwire hand tight spin on oil filters too?😉😁
 
nick7 said:
There is no need to lockwire a sump plug, ordinarily...have you ever done that?Guess racers must...
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Ordinarily not, but after 45 years of oil changes the case thread might not be good as new, suggesting a moderate torque combined with teflon tape and lockwire.
 
Once you have used lock wire (on the race bikes) it is a hard habit to break. I have done it on my cars, confident that the necessary nick up is enough. A van I bought had the sump plug in so tight it needed a huge nut welded on to it and even when hot a metre long lever to crack it un-done, I was sure the sump would split. For oil filters on race bikes it is standard practice to screw on a hose clamp to attach the safety wire, for peace of mind as well as scrutineering. They made me safety wire the bloody primary chain adjuster on my Laverda, and I had to argue out of safety wiring the neutral switch cover. They could forget about it all now though because you have to have the under engine tray with capacity for the entire oil contents. Despite that, most major oil spills on the track have come from busted/fallen off oil hoses and the occasional con-rod out of the cases.
Copper washers get squashed and bite on the studs, end up thin and need replacing, and the thick ones like Laverda use are not easy to find. You should be able to use sealant instead but copper washers are specified. Maybe they feared too much sealant would be used and end up in the oil-way. Other brands use those washers with sealing rubber.
 
"There is no need to lockwire a sump plug, ordinarily...have you ever done that?Guess racers must..."
you demonstrate that you dont mind your sump plug coming out Nick. Even if you only tightened it by hand and you then wired it, it wont cme out, and would take a fortnight for the oil to run dry.

I once followed a Jap bike that pissed its oil in about a mile, he stopped because he thought he had a flat back tyre, the sump plug was lodged onto the four into one exhaust system, lucky bastard times three, one he didnt crash, two he didnt lose the sump plug, and three the remaining and draining oil didnt catch fire! the trailing smoke had to be seen to be believed and the police/ local council werent too pleased either.

forget the law of the land, you ordinarilly dont have to wear a crash helmet or use a seat belt but I bet that you do! how much grief, cost and aggro is it to wire the plug? about 2p per shot and 3 minutes time, minimal aggro, and when people see it they assume it is an ex racer, whoopee doo dah! (in my case that is correct and I have trophies to prove it)

CLEM
 
CLEMTOG said:
"There is no need to lockwire a sump plug, ordinarily...have you ever done that?Guess racers must..."
you demonstrate that you dont mind your sump plug coming out Nick. Even if you only tightened it by hand and you then wired it, it wont cme out, and would take a fortnight for the oil to run dry.

I once followed a Jap bike that pissed its oil in about a mile, he stopped because he thought he had a flat back tyre, the sump plug was lodged onto the four into one exhaust system, lucky bastard times three, one he didnt crash, two he didnt lose the sump plug, and three the remaining and draining oil didnt catch fire! the trailing smoke had to be seen to be believed and the police/ local council werent too pleased either.

forget the law of the land, you ordinarilly dont have to wear a crash helmet or use a seat belt but I bet that you do! how much grief, cost and aggro is it to wire the plug? about 2p per shot and 3 minutes time, minimal aggro, and when people see it they assume it is an ex racer, whoopee doo dah! (in my case that is correct and I have trophies to prove it)

CLEM
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Yeah yeah...Ive got 5 bikes and had bikes since 1979, the most oil I've had on a back tyre is from the breather tube on a Jota..a far greater menace than an escaping sump plug😉
 
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