It is a .91 Four stroke, that is all I know about it. Looks like an OS, Magnum, or TT to me. Might be a saito as well, but I don't think that is a style Saito has used recently.

Any ideas?

Looks to me to be an old style (surpass I) OS .91 FS. Where did you find that picture?

From an auction I won last night.

looks like Thunder Tiger to me. [link]http://www.acehobby.com/ace/showpic.asp?imagepath=images/engines/enlarge/TTR9801.jpg[/link] older version but still has most of the same shapes.

Could be a lot of .91 four strokes. Would help to see the other side. Guess you will when it gets to you.

Yup, probably. Got a guy at work that I have bribed to strip it down and check it out (The Johnny who does the jets).

I got confirmation it was a TT, thanks guys.

definetly not SAITO- THEY have one piece head /cylinders.