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Hope everyone had a Merry Christmas and or Happy Holidays( that's me being politically correct) I have a 2000 KDX200 and I was wondering if there is supposed to be copper washers under the nuts holding the cylinder head on? I looked up the OEM fische for it and it shows none, but I think they should be on there IMO. What do you guys think?
Little Jeff

Just trying to beat CC to the punch with this post.

Why do you think there should be copper washers there?

Almost every 2 stroke I have ever seen has had copper washers there. My KTM does, I know, that's a KTM though.
Little Jeff

Yeah, my buddies KTM and YZ both have copper washers under the head bolts. My KDX has not.

J.

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skythrasher wrote:Just trying to beat CC to the punch with this post.

Whul....wusTHAT s'posed to mean?

I'm sure there's something about that meant to be pointy and prickly and barby..I mean...like whatever that has to do with anything the likes of which I've ever said, I don't know.

Please, may I direct your attention to your service manual..or, the lack thereof being painfully self-evident to especially yourself, refer to the following:



Notice the lack of any washing material, copper or otherwise, in the location subject to (meaning 'beneath' or 'under' in this instance) the indicated flanged head nut.

That the official above diagram shows only ONE such nut being used MAY mean the other six DO indeed have such washerment material.

..but I doubt it.

Cheers!

I saw that fische also, but was just curious as to why Kawasaki doesn't put them there to where as most 2 strokes have them.
Little Jeff

my guess would be they are NOT needed

My guess: The superior performance of the KDX is due, in part, to the considerable weight savings had from not using head fastener washers.

That's pretty obvious, ain't it?

Right?


Or...........

Maybe KDXs don't need to have their heads off every three rides...so lack of such a washer ain't no big deal.

That works!

Thanks for all the replies. No washers it is
Little Jeff

My guess: The superior performance of the KDX is due, in part, to the considerable weight savings had from not using head fastener washers.

That's pretty obvious, ain't it?

Right?

LMAO!

I've seen em both ways. Depends on the type of nut used. None of my kart motors capable of 18,000 RPM use them....Use flanged nuts

..wasn't s'posed to be funny. I mean...facts is facts..........



Don't get me wrong. You can put washers on there if'n you wanna. Don't know that it would hurt anything. It's not like the copper washettes are going to compress with heat/cool and fail.



Well...maybe not.

If it was a 80ft/lb fastener, I'd use a washer. But..they're 18ft/lb or somesuch. Probably not enough to gall the aluminium.

Malleable metal washers (usually copper) are used to compensate for machining imperfections. KDX's have no machining imperfections

Washers such as these are sometimes called "crush washers" and are found on most hydraulic fittings.

Here's my take on it. All the bikes I have seen that have copper washers on the head have the dual rubber ring style head gasket. The head bolts fit in between the inner and outer rings, and there are water pathways there. Without the washers you could get water pushing up and out around the head bolts. Since the KDX uses a copper or aluminum crush style gasket, and there are no water pathways directly around the head bolts, the copper washers would not be necessary.

Crush washers generally have something to crush...like some sparkplugs have...or the copper gaskets used on the cylinder/pipe joint in the KDX. Are these storied head washers designed that way? I thought they were simply flat washers.


Curious...how is a copper washer going to provide an effective seal to the stud? If they were designed to crush in such a way..you would have a dickens of a time getting the head off.


...I don't have no money...and where the hell is my driver's license!!??

The crush washers that I have used do a really good job of sealing. They actually mold around the mating parts and make a gasket of sorts. They are a one time deal. Once the nut of mating part is tightened on them and then removed they are not useable again.

canyncarvr wrote:Crush washers generally have something to crush...like some sparkplugs have...or the copper gaskets used on the cylinder/pipe joint in the KDX. Are these storied head washers designed that way? I thought they were simply flat washers.


Curious...how is a copper washer going to provide an effective seal to the stud? If they were designed to crush in such a way..you would have a dickens of a time getting the head off.


...I don't have no money...and where the hell is my driver's license!!??

I would imagine they would seal the same way copper washer on banjo bolts seal.

But....washers (copper or not) on banjos are on the OUTside of everything to be sealed..providing 360º of seal on one axis and likewise a total seal on the other axis.

That's not so on a cylinder stud. There is an unsealed path THRU the washer (and NOT sealed) 'cuz of the stud.

Note that brake cylinders have bolts in 'em...not studs.


There's a bolt on the LH side of a Yamaha Warrior that has a copper washer on it..because the threaded hole the bolt threads into is OPEN to the crankcase. IF screwing something into/onto threads was a suitable sealer..they wouldn't bother with a copper washer on that bolt.

Never mind. It matters not a whit anyway. How many angels CAN dance on the head of a pin, anyway?

Who cares?

Ya'll shut up now....

indeed CC but I wasn't disagreeing with you in the firts place.

Whenever these copper washers are provided for me, I measure them, and turn identical ones off on the lathe that are made out of bronze instead.