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Discussion Starter #1
I have a 78 Honda hawk cb400t I was wondering if I can put a heavier from fork and triple tree from maybe a 750. 650 thanks
 

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Yes, that's been done several times. I'm running an '81 CB900F front end on the road bike, '79 CM400T.
This is the starting point https://www.allballsracing.com/forkconversion/ which handles the stem bearings, fill in the blanks an you get a list of potential front ends to choose from. Note they don't tell you the lengths of the fork ass'y so you may end up higher/lower than stock. Also missing is the stem length.
This list gives you the fork diameters, you've got 33mm forks right now. Fork tube Diameters list
This one has axle diameters JAP bikes Fork Tube Sizes, Neck Bearings, axle Diameters - Club Chopper Forums
 

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Plenty of factors come into play when choosing a new front end. i start with wheel size to match the original or something new that i'm looking for, wheel style is important if you want it to match the rear. Another important issue is front brake, that factor alone can disqualify plenty of potential donors. Different steering stem lengths can become an issue, a good machine shop can swap your old stem into a new lower triple tree if needed, longer stem length can sometimes be overcome simply with added spacers.
 

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Discussion Starter #4
I have a 78 Honda hawk cb400t I was wondering if I can put a heavier from fork and triple tree from maybe a 750. 650 thanks
Plenty of factors come into play when choosing a new front end. i start with wheel size to match the original or something new that i'm looking for, wheel style is important if you want it to match the rear. Another important issue is front brake, that factor alone can disqualify plenty of potential donors. Different steering stem lengths can become an issue, a good machine shop can swap your old stem into a new lower triple tree if needed, longer stem length can sometimes be overcome simply with added spacers.
Thanks all that replied . I am looking for a direct swap . bearings no problem Do you know anything that would work. What I am trying to do is to beef up front end.
 

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The CB900F front end was pretty much a direct swap. Had to make steering stops on the lower triple. Gives you 39mm forks, 19" wheel and dual disc brakes.
It also raises the front end @1.5" so longer rear shocks are in order to balance the suspension geometry. I think the same vintage CB750 is close to the same
 

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perhaps some preload spacers will do the job? i added 3/4" spacers to my CM400C forks and it worked great.
 

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The CB900F front end was pretty much a direct swap... ...It also raises the front end @1.5" so longer rear shocks are in order to balance the suspension geometry. I think the same vintage CB750 is close to the same
What is the fork length difference between the CB900 and say my 79 CB400T?
There are a couple of clues right there
 

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Discussion Starter #11
I might look into the vintage 750 to swap my cb400t. I know that the fork lock would still work. I believe somebody mentioned that the bearings would need to be changed.
 

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I am considering approaching Cognito Moto about custom triples. My bike is a 79 CB400 TI I want to retain spoked wheels so I would need to use forks for which there is a spoked wheel/axle that works with said forks.
 

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I think the front end from the 1980-1982 CB650 is just what you need. Spoked wheel, single disk brake, modernist trailing caliper design, and the caliper can easily be upgraded.
 

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I just happen to have a complete dual disc front end and wheel (minus fender and calipers) for a CB650C. Even has headlight ears
 

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Did Honda have a dual disc spoked wheel front end in those days or is that a comstar or cast wheel?

I'm sure there is a dual disc spoked cruiser front end out there that will accept shorter fork tubes & innards from another Honda, but I haven't stumbled upon it yet. Single disc works fine for my kind of riding.
 

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I was actually considering swapping that onto my son's CB450K. I believe they shared the samme fork tube size. I would thik All Balls has a solution for mounting the 650 triples onto the 400 frame. Not sure of the stem.
 

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Did Honda have a dual disc spoked wheel front end in those days or is that a comstar or cast wheel?

I'm sure there is a dual disc spoked cruiser front end out there that will accept shorter fork tubes & innards from another Honda, but I haven't stumbled upon it yet. Single disc works fine for my kind of riding.

I am not aware of a dual disc spoked setup from Honda that would work with CB650 forks. A single disc would work, paticularly if I could also go with upgrades caliper, pads and a braided brake line.
 
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