Topic: Looking to replace my 1978 CB750 front fork tubes.

[1080]

Looking to replace my 1978 CB750K  front fork tubes. It appears that the after market only lists '72- 76. I have a pair of CB 750 1977 front tubes ( one is bent) and they measure to a length of 23 inches, I have not removed the 78 forks yet. I want to replace them because of the constant blowing of the new fork seals. this has been a problem since I bought the bike new ( I am the original owner) they were replaced twice ( Can't remember if they did one side at a time?) under warranty back when the bike was new. The forks seals last for maybe a year or so and then they start to weep again. Just before replacing last fork seals I had inspected the tubes for nicks & used a fine grit stone on any road chip surface that I had found on the tubes. Just as in the pass replacements were good for a while then the weeping of the starts again, the disc side was always the first one to go. Question is why is there no mention of replacement tubes for the 1977/8 front forks? Does any one know if they are still available from Honda?  Fork tube part no. 51400-393-003.

[Gurp]

You may look into a forks by frank. They make some very quality replacement tubes for various models including our beloved single overhead cam Hondas

Sent from my LE2127 using Tapatalk

[Don R]

 I'm assuming they are for a K. Partzilla says they are the same as the tubes on a Hondamatic and I've used generic replacement forks off of ebay in my 750A tubes. I also used F1 fork lowers with 550 tubes because they are shorter.
https://www.partzilla.com/product/honda/51400-393-003?ref=f834de6832553c14ac39208a2f883065e2bb7021

[bryanj]

Here in uk we have a few rirms that will grind them down and diamond hard chtome them back to size for about £200 perhaps see if anybody over there does the same

[1080]

Partzilla  shows Currently Unavailable. I will check with local Honda Dealer. Thanks Don R, yes it is CB750K (Corrected).
bryanj  the closest I came years ago was a company that rebuilt heavy equipment hydraulic ram tubes.  I lost the business card and I do not know if they can do 35mm tubes?
I looking into Forks by Frank, any part no. to go by?
Thanks.

[newday777]

51400-393-003 is Discontinued from Honda

David Silver Spares has aftermarket tubes

https://www.davidsilverspares.com/CB750K7-FOUR-1977/part_305038/

[newday777]

https://www.vintagecb750.com/products/3/suspension-wheel/52/fork-tubes-springs-seals-boots

[1080]

So the best replacement from Vintage CB750 is the Fork Tube Set/2, Length (580mm or 22 13/16"), 35mm OD.

Fits: Honda CB750K (1972) Higher then Frame# 2093730 Only,CB750K (1973-76)
Before ordering Please Confirm 22 13/16" is the Length you would like
Part #: 73-1148

Which is 3/16" shorter and the other choice is 13/16" over stock Fork Tube Set/2, Length (605mm or 23 13/16"), 35mm OD.

NOTE: LENGTH is 23 13/16", one Inch Larger then Stock Length for these Models below.
Honda CB750K (1972) Higher then Frame# 2093730 Only,
CB750K (1973-76)
Also Fits These Models, Confirm the 605mm Length is what you Require Before Ordering.
Honda CB750K (1977) Higher then Frame# 2707508 Only,
CB750K (1978),
CB750F (1977-78) Supersport
CB750A (1976-78) Hondamatic

Before ordering Please Confirm 23 13/16" or 605mm is the Length you would like
Part #: 73-1080

Any feed back on which one was used by members.

[HondaMan]

I have some overlength fork legs (lowers, too) from a K7 I rebuilt long ago. I think they are 6" over? The owner had another stock front end and had me splice it on.

CMSNL shows some still on-hand?
https://www.cmsnl.com/honda-cb750k7-four-1977-usa_model495/pipe-front-fork_51410393003/