does anyone know where I can get these two gaskets?

or has dimensions and recommended materials so I can fabricate if I am unable to procure for a ridiculous price? :-)

I saw an aftermarket part on eBay that was cup shaped. I have not disassembled mine to inspect closer but mine would appear to be flat...is this so? I don't want to take apart without replacements or wife will really get upset about gas fumes in garage, also don't want to blow house up since water heater is in garage too.

I really appreciate any help or guidance on this, thanks!
Martin

KDI Reproductions

Thank you so much MarkT, I just ordered, both parts $20!!!!

$20 is a deal, since they can't be had anywhere else, and they fit like a dream, speaking from experience. I've done two of the 3-piece caps (72/3) and two of the 2-piece caps (74), and everything fits and seals very well. Take pictures as it comes apart, and take it apart slowly and carefully. Don't let it fly apart on you like the first one I did. Make sure you see how the spring fits into the "key" mechanism. I just did a 74 DT175A cap, and whoever was in it before got that spring in wrong.
If you lose or strip out any of the screws or clips, Yamaha still sells them:
www.partzilla.com/catalog/yamaha/motorcy...974/dt360a/fuel-tank
There is a trick to putting the one you're doing back together. Dress the bigger rubber piece around its male part first; then align the three screw holes correctly with the fiber replacement disc. You'll see they are not all equidistant; two sides of the triangle are slightly longer.

I've used the same KDI gasket on my 74 DT250, I had to modify mine, It wasn't vent properly. In my case fuel would stop flowing to the carb, when you opened the cap the vacuum would release and fuel would flow. Markt was following me on a dirt road, I'd pull in the clutch, remove the ignition key, unlock the gas cap, put the key back in the ignition and bump start. I'd leave the cap loose but gas would splatter.
It took awhile to figure out.
Yours may not do that.

I got the three piece one for my RD350B from Yambits here in the UK. However, there is a fault, whereby you have to put that hole in yourself.

I have attached some fitting instructions that I found somewhere on the internet.

Wow - thanks a ton guys, really appreciated!