1979 YZ 250 and YZ400 frame differences

[loosecannon]

Hi guy's

I just checked the numbers on my 1979 YZ250 frame, and it's a YZ400 number, is there any differences in the frames?, I have been told there isn't

Would this cause any dramas come time to race it in any classes , once I'm ready to race it, I haven't raced yet, so I just thought I would ask

Regards
Dave

[vandy010]

I'll say no drama at all Dave,
frames are from the same year (evo) and the engine size
decides what class it runs in..
No probs...
I have a swing arm and airbox to suit the 250/400F if yourself or anyone
reading this is interested...
Cheers,
Vandy

[loosecannon]

Thanks for the info Vandy ,

I did read somewhere they are the same frame, even part number with Yamaha,


Regards
Dave

[Viper666]

Frames are identical. The only differences between 250/400F is the engine (obvious), pilot, needle, main jet & slide in carby & tube from carby to air box (400 shorter), expansion chamber, CDI & spark plug coil. (250 use magneto, 400 flywheel), rear rim & spoke set (250 2.15 rim, 400 2.50 rim) but you can use either.

[loosecannon]

Thanks a bunch for the info Viper 

I did hear they were the same, but wanted to confirm it, incase I needed different parts...anyway mine will be a race bike, not a concourse/show bike, the fact the frame number is different won't make a rats to me, I only want to race it

[Viper666]

If you were to buy a new frame, back in the day, it wasn't stamped. I have new cases for my YZ125E & it so you can restamp your own.

[loosecannon]

Ok, cool that's interesting to know too 

one more coat of paint and you won't see my frame number anyway...lol...