Topic: Front Wheel and Forks off a CB250N or T and rear wheels, do they fit the CB400F?

[Peter K]

Gentlemen and Ladies,
I'm sure that I have read somewhere that it is a straightforward swap for the front and rear wheels and the forks from a CB 250 or 400 T or N (late seventies, early eighties) to a 1978 CB400F2. Does anyone know if this is true? Obviously if you do a straight change from one of the 400's you need to change the forks at the same time because of the dual discs. I'm not looking at this as being a permanent change so would only consider doing it if it is relatively straightforward.
Any comments would be most welcome.

[Tim2005]

Nope, it isn't a straightforward swap. Rear end- you just need to modify spacers, add the 250n/400n brake plate & find a 400f-size sprocket (tricky). Front end - you need N forks, yokes, caliper(s) brake hoses, disc(s), speedo drive, mudguard, spindle. And you end up with a 400F with too soft forks and a 19" wheel. And a speedo that doesn't read correctly. As you can tell, I'm not a fan of this....

If you can get an 18" CM400 wheel, an CB250RS speedo drive, uprate the fork springs, fit last model CB400N-C yokes, make up clock mounts, change the master cylinder, add a CM250 mudguard, get reverse (black) comstars and play with the oil, you do end up with a 400f with twin discs & tubeless tyres,  but it's not exactly worth the effort in my experience.   An interesting learning experience though!

[Peter K]

Thanks for your advice, its much appreciated. You have obviously looked into this in some detail or have done it yourself. Invaluable experience, thanks again.