Hi all, I’ve wrecked the head on one of the screws holding down the plates which hold in the RH crank shaft oils seal (I’ve ordered the correct JIS screwdrivers, but I just couldn’t wait for them to arrive). The part number of the screw is 98580-08012-00.
A quick google search shows these are not available.
Does anyone know where I can get a replacement? Obviously I know the dimensions etc, but I don’t know what grade of metal it’s made from, so not too sure what to buy.
Any help would be appreciated. Details of a UK supplier would be good. Thanks….

CMSNL are showing two in stock for less than a couple of quid each.

Given that there has been a part supersession, then this means that Yamaha themselves have probably changed the finish on it. 

If they were to have other parts that you need, then this would make the postage less painful.

As the part will be hidden and shouldn't be under stress, then I'd be tempted to fit any old M8 12mm screw/bolt. 

Being 8mm with a big phillips head i think you'll be safe to start it moving wit a chizel across the top to get it turning. I've done worse lol. alternatively give the head of the screw a beating with a punch to bring the shape back in then smack a 'good' No3 phillips into it & use an impact driver & it'll fall out. Those ones are always tight to get moving initially.

On my '78 125, I had one of the case screws under the magneto with a striped cross hatch. I measured one of the other ones shaft (7/32"), then I center drilled it with a 5/32" only as deep as the screw head. (digital caliper very handy). After I measured the depth of the drilled hole, I drilled with a 1/4" and as soon as the area that the drill bit was trying to cut was greater than 1/32 of an inch, the screw head popped off. I un screwed the headless screw by hand. I hope this helps in your case.