450/426 frame swap

have a 2002 426 and a 2003 450, because of red sticker season, want to swap just the main frames so that when they read the vin numbers it comes back as my 426, green sticker, has this been done by anybody,thanks

You'll end up having to, in effect, put the 450 engine in the complete 426 chassis. None of the '03 bodywork will fit without quite a bit of work. Then you'll have a 426 with two more horsepower and a four speed. Seems like a lot of work to get there. :)

Part number's are "oh so close" 5SF-21101-00-00 for the 426, and 5TA-21101-00-00 for the 450. Not too sure...

Yamaha uses a part numbering system that is based on "basic numbers". The second group, the 5 digit string after the first 3 characters, is the basic part number. All ***-85550-**-** are flywheels, all ***-21101-**-** are frames.

The first three characters indicate the particular model they were made for. 5TA is the '03 YZ450F; 5SF is a YZ426; 5NL is an '01 YZ250F, and so on.

The first of the two groups of trailing digits are used to indicate different sizes of the same part, or other variations, like the 3LD-12168-W1-00 and the 3LD-12168-Y1-00, which are #180 and #185 valve shims, or the 5UN-22212-50-00 and 5UN-22212-60-00, which are 5.3 and 5.5 kg/mm rear springs.

The last I believe is to indicate that the part has been revised. Two zeros means it's the first one issued, a 10 or 20 would mean a first or second revision.

5PA-21101-10-00 is pretty close to 5TA-21101-00-00, too, but that's a frame for a YZ85.

5PA-21101-10-00 is pretty close to 5TA-21101-00-00, too, but that's a frame for a YZ85.

So you are saying a 450 motor is a slip in fit to a YZ85 frame? :)

Let me say, as politely as possible, that after reviewing your question and the information previously given that lead you to ask it, there exists the possibility that, although I am certain that your concern is sincere, you may perhaps have misinterpreted my response. Or, to rephrase.....

Eh, no. :D

Although, many years ago, I helped a friend install a 427 Ford in a Nash Metropolitan (yes, as a matter of fact there was a LOT of cutting involved), and Service Honda apparently offers CRF250 engines in CR85 frames now, so who knows??? :)

do a search. They are not interchangable.

Do the mounts line up? (450 engine to 426 frame?)

do a search. They are not interchangable.

So the little winky smile didn't convey the joke? :)

Must have been the wrong part number. :D

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