My new project is a 74 TY 250. I thought the skid plate on it was one of the fiberglass/plastic stock ones but when I took it off it turned out to be a cast aluminum one. I have saw stamped alloy ones but never cast. It has some embossed lettering that says J & M PLATES with Yamaha under that. Have any of you TY gurus seen these?

Never.Maybe aftermarked plate.

Chrs:Mike

The 75-76 TY 250 skid plates were aluminum, same bolt pattern as the 74-75

Fred

take a look at

http://blackcatvintagetrials.com/2009/10/30/freds-fancy.aspx

lots of mods

Yes and I used one! The bash plate you describe is the one fitted on my Majesty. I found it on one of the many "scrap TY250A's" that have been through the shop over the years. I tried to find the manufacturers but can only assume they went out of business as they could not be traced. It was a superb shield in all respects.

You can see it as fitted on my 320 Majesty in two articles written in Nov/Dec 2007 on my "Blog" entitled;

"Yes your Majesty"

and

"Mastering the Majesty"

Tony

A guy from Londonderry New Hampshire designed and sold them. He commissioned a local foundry to make a bunch. The TY250A came stock with a composite plate and most riders worried it wasn't enough protection so the guy sold quite a few. Unfortunately, they were pretty heavy and cracked in two after a few good hits. I went through two. I'm surprised you found one in one piece.

The TY250C(we didn't see the "B" model in the States) came stock with a much improved aluminum plate.

Thanks for the info guys. I was pretty sure this was an after market plate. It is heavy, I weighed the thing and it is 4#. When I took it off the bike you could see that the oil pump cover had been cracked and welded back up. I would guess that was when this unit was installed.

Tony I hope you don't mind if our Yamahas come out looking a lot like yours as your blog has become my instruction manual for building them I sure wish I had got into Yamys when you were building and selling them. It would have been a lot easier and probably cheaper.

Here's a couple pics of the skidder,

Dennis

Yes, thats the same one I used. I polished mine with some ACE sanders and autosol and it came up like chrome. I liked the way it protected the flywheel cover. I have had some similar aftermarket ones on other Yams that were fiberglass but they were nowhere near as good.

Tony

and cracked in two after a few good hits. I went through two. I'm surprised you found one in one piece.

A cast bashplate isn't a good idea. Casting is very brittle and will crack as you described.