1982 CB750 F fork tube mystery

[Bo82CB]

Hey all.
I am working on putting my 750 back in use after being dormant for a while. Besides all other stuff you all are aware of I am trying to get new TNK fork tubes for the the bike since original ones have some pitting, not terrible but why not replace them if /while they are available. Well this is where I hit the wall, when I look at parts microfiche for my year and model it comes up as 51410-445-631.
So when I check that part in description says “tube diameter 35mm”! My bike has air assist forks and tubes are 37mm measured with caliper, I have been searching everywhere to no avail in attempt to dig info about 1982 CB750F with 37mm fork tubes. Has anyone had issues like this and if yes what was solution or do you guys have any pointers…
I have not taken fork’s apart, also need to mention already talked to Race Tech and no help as of right now and Franks forks, they can make me set but I need to send original to them and cost is more than TNK.
Any help would be greatly appreciated!

Bo

 

[jpdevol]

I'm coming up with a different p/n (don't know if 37mm)
https://www.cmsnl.com/honda-cb750f-1982-c-japan-rc04-103_model50230/partslist/

https://www.cmsnl.com/honda-cb750f-1982-c-japan-rc04-103_model50230/pipe-frfork_51410mb7611/

 

[SenseAmidMadness]

It's my understanding that all CB750F's came with 37mm fork tubes starting at the 1981 model year. You will have to order 37mm tubes to replace yours.

My buddy has a 1980 CB750F and it has 35mm fork tubes, just like my 1980 CB750K. I've been ordering parts for him from VintageCB750.com and every parts description for the forks seems to have a split between "1979-1980" and "1981-1982".

 

[Bo82CB]

It's my understanding that all CB750F's came with 37mm fork tubes starting at the 1981 model year. You will have to order 37mm tubes to replace yours.

My buddy has a 1980 CB750F and it has 35mm fork tubes, just like my 1980 CB750K. I've been ordering parts for him from VintageCB750.com and every parts description for the forks seems to have a split between "1979-1980" and "1981-1982".

I understand that but nobody is showing 37mm fork tubes for ‘82 750f, they do show them for 900f…question is are those tubes used on 900f same as tubes used on ‘82 750f!?

 

[Bo82CB]

I'm coming up with a different p/n (don't know if 37mm)
https://www.cmsnl.com/honda-cb750f-1982-c-japan-rc04-103_model50230/partslist/

https://www.cmsnl.com/honda-cb750f-1982-c-japan-rc04-103_model50230/pipe-frfork_51410mb7611/

I appreciate your info, my dilemma now is do I own bike for Japanese market here in the US. By the look of the Japanese market bike forks I don’t think so but not certain. I sent inquiry to CMSNL and hopefully they can give me an answer to that question and solve mystery about my forks.

 

[Bo82CB]

CMS wasn't much of the help, they said my bike was modified and that’s it!
Weird thing, I found on Frank’s Forks website, there is listing for 37mm fork tubes for ‘81-‘82 CB750- XR250… some confusing stuff for sure!