Topic: 1973 cb750 forks interchangeable?

[avoca]

I have a 1973 cb750 I just bought with chopper forks on them and I dislike them.  I need a standard, stock pair and I was curious if they had to be ones from 1973 or could I put other model years on the frame, say from 1972, 71, 75, etc.  Thanks

[70CB750]

Yes, they are interchangeable to some extent.  The main difference is the brake bracket, 1973 was the first year for the T-shaped front brake bracket, while earlier bikes had a C-shaped bracket.

That said, you can get lowers 1974, 1975 or 1976 and they will fit.

I found these schemas very helpful researching parts and compatibility:

http://www.cmsnl.com/honda-cb750-four-k3-usa_model481/partslist/

[ekpent]

If you still have original fork lowers and just extended or longer fork tubes which was a common way to make a cheap chopper back in the day than you can just replace the tubes. Make sure the front steering neck has not been raked out at some point. Post a pic if you can.

[70CB750]

Oh man 

Thank you Eric, you are absolutely right, I got carried away.

Finding tubes in decent shape is not easy, you might want to check CycleX:

http://www.cyclexchange.net/Honda%20Cafe-Front%20End%20and%20Suspension.htm

[ekpent]

Somebody here may have some also---Hey Bill, Mr Benton you out there ??   

[avoca]

If you still have original fork lowers and just extended or longer fork tubes which was a common way to make a cheap chopper back in the day than you can just replace the tubes. Make sure the front steering neck has not been raked out at some point. Post a pic if you can.

Yes, they are interchangeable to some extent.  The main difference is the brake bracket, 1973 was the first year for the T-shaped front brake bracket, while earlier bikes had a C-shaped bracket.

That said, you can get lowers 1974, 1975 or 1976 and they will fit.

I found these schemas very helpful researching parts and compatibility:

http://www.cmsnl.com/honda-cb750-four-k3-usa_model481/partslist/

Hey, thanks guys!  I tried cycle-x but they seem to be sold out at the moment.  Also, since I'm completely new to this, I couldn't tell you (and neither could the guy I bought the bike from), if the front steering neck has been raked or if the fork lowers are original (maybe it's the same thing as the steering neck :/ ).  I'll upload a picture and hopefully you guys can tell me!   I appreciate the help.  Oh and some guy has a pair from 1970 that said will fit; I don't have a front brake at all (it's completely missing), so will the brake bracket still be an issue here?

[ekpent]

The lowers 'look' to be original 750 from what I can see. Lots of swapping on some of these over the years. It does not look raked but then again very hard to tell in those pics. Look the steering stem area over well for what looks like non-factory welding, cutting etc..

[avoca]

The lowers 'look' to be original 750 from what I can see. Lots of swapping on some of these over the years. It does not look raked but then again very hard to tell in those pics. Look the steering stem area over well for what looks like non-factory welding, cutting etc..

Yes I'm sorry, the bike isn't here at my house and these were the only pictures I had.  Thanks for the information though!  Since it has no brake caliper assembly, do you think it's still pretty vital to get the T shaped ones from 1973 or does it really matter?  Thanks

[martin99]

The lower frame rails are pretty near parallel to the ground on a stocker. With extended forks, and if it hasn't been raked, you might expect them to be at an angle? As said, hard to tell from the pics, try and get one side-on and facing forward if you can.

Just a thought, some builders used fork top extensions instead of extended forks. Before you source new ones, worth removing a fork to see if there is a joint hidden somewhere? You never know your luck!

[70CB750]

The lowers 'look' to be original 750 from what I can see. Lots of swapping on some of these over the years. It does not look raked but then again very hard to tell in those pics. Look the steering stem area over well for what looks like non-factory welding, cutting etc..

Yes I'm sorry, the bike isn't here at my house and these were the only pictures I had.  Thanks for the information though!  Since it has no brake caliper assembly, do you think it's still pretty vital to get the T shaped ones from 1973 or does it really matter?  Thanks

I mentioned T brackets as a way to identify, the earlier lowers are not compatible with newer fork tubes - first you need to find tubes that will work for you, lowers are easier to find.

The T brackets are easier for dual disc setup and also more available = cheaper than the early C bracket brakes.

Hope this is not too confusing for you, check out the CMSNL schemas too.

[754]

 And machinist still should beable to cut them down for 100.00 or less, I have done quite a few..takeout the cap, pull spacer out..the length of that is probably how many over the fork is.

[seanbarney41]

Look closely at your fork lowers' caliper and fender mounts.  If they look like these, you need the C bracket...

here is what the c bracket looks like...

this is what lowers look like that use the t bracket...

[avoca]

And machinist still should beable to cut them down for 100.00 or less, I have done quite a few..takeout the cap, pull spacer out..the length of that is probably how many over the fork is.

Say, thanks!  I may end up doing that if I either get confused or am unable to find cheap forks.

The lowers 'look' to be original 750 from what I can see. Lots of swapping on some of these over the years. It does not look raked but then again very hard to tell in those pics. Look the steering stem area over well for what looks like non-factory welding, cutting etc..

Yes I'm sorry, the bike isn't here at my house and these were the only pictures I had.  Thanks for the information though!  Since it has no brake caliper assembly, do you think it's still pretty vital to get the T shaped ones from 1973 or does it really matter?  Thanks

I mentioned T brackets as a way to identify, the earlier lowers are not compatible with newer fork tubes - first you need to find tubes that will work for you, lowers are easier to find.

The T brackets are easier for dual disc setup and also more available = cheaper than the early C bracket brakes.

Hope this is not too confusing for you, check out the CMSNL schemas too.

No no, you actually did a great job of clearing that up for me so I appreciate it too!  I'm definitely going to check out the schematics for a better understanding of what I'm looking at and what I need.  The guy threw this bike together with spare parts from all different bikes so it's a bit of a challenge for me to identify this part and that in regards to the model they came from.  Now I know I can just find the forks and worry about the lowers after and that took a lot of weight off my shoulders   I'm a fairly young person (25) which means I never grew up with these bikes so my understanding of all this is limited, and this is my first bike build too so I probably sound pretty stupid 

The lower frame rails are pretty near parallel to the ground on a stocker. With extended forks, and if it hasn't been raked, you might expect them to be at an angle? As said, hard to tell from the pics, try and get one side-on and facing forward if you can.

Just a thought, some builders used fork top extensions instead of extended forks. Before you source new ones, worth removing a fork to see if there is a joint hidden somewhere? You never know your luck!

I'll be disassembling the bike here in the next few days so I'll take a look to see if this has been done.  Hoping so because that would make my life a whole lot easier at this point! 

Look closely at your fork lowers' caliper and fender mounts.  If they look like these, you need the C bracket...

here is what the c bracket looks like...

this is what lowers look like that use the t bracket...

thanks so much for the pictures!  This will help me identify what I have, and as well as the other posts on this thread, you've made it a lot easier/stressless for me so thank you so much!  I have a visual reference now and that is always a plus 

[70CB750]

And machinist still should beable to cut them down for 100.00 or less, I have done quite a few..takeout the cap, pull spacer out..the length of that is probably how many over the fork is.

I wish you were closer, Frank.  I have nice tubes 3 or more inches over - which will not fit in my small Logan - and local machine shops I checked don't have the tap, is it M24 on top?

[ekpent]

First you need to determine if the bike has the early or later fork lowers to get the correct tubes. With some better pics of those the guys should be able to tell you. If for instance you have 73 lowers these would be a good option as they are new and do not have any rust where the fork ears mount like used ones can have. Better if your doing a custom build.  http://www.ebay.com/itm/Honda-CB750-K2-K6-Front-Fork-Tubes-51410-341-702-CB750K-K2-K3-K4-K5-K6-/141409250710?pt=Motorcycles_Parts_Accessories&hash=item20eca5ed96&vxp=mtr

[avoca]

First you need to determine if the bike has the early or later fork lowers to get the correct tubes. With some better pics of those the guys should be able to tell you. If for instance you have 73 lowers these would be a good option as they are new and do not have any rust where the fork ears mount like used ones can have. Better if your doing a custom build.  http://www.ebay.com/itm/Honda-CB750-K2-K6-Front-Fork-Tubes-51410-341-702-CB750K-K2-K3-K4-K5-K6-/141409250710?pt=Motorcycles_Parts_Accessories&hash=item20eca5ed96&vxp=mtr

Ok thanks.  I thought the other guy said it didn't really matter what fork tubes you get?  I appreciate the link, though.  I might buy those once I figure out my lowers.

[Don R]

The tubes and lowers must match each other. Once matched you may bolt either onto your Honda.

[754]

 I don't tap them,  just single point thread them..ie cut new threads..

[Patrick]

Since it does not appear you are not trying to go strictly model specific, you could do a major upgrade to the front brakes on your bike by swapping out the whole front fork, including triple tree, for a DOHC 750 from the late 70s or early 80s. If you use the whole front end it's a bolt on replacement. The DOHC forks have dual-disks and dual-piston calipers. I did this on one of my earlier 750s. It makes a major difference, brakewise.

I'm also sensing that you don't have a whole lot of cash to throw at this bike right now. Parts of DOHC Hondas are not near so dear as parts for our bikes. Those bikes just are not as sexy. I got a whole fork from an '79 or 80 750, including working calipers and master that didn't even need to be rebuilt, for $50 off Craigslist. Check it out. A lot of posters can't give the stuff away. If you do it, be sure to get the front wheel. Only the wheel from the 77-78 F model 750s fit the later fork.

Patrick

[avoca]

Since it does not appear you are not trying to go strictly model specific, you could do a major upgrade to the front brakes on your bike by swapping out the whole front fork, including triple tree, for a DOHC 750 from the late 70s or early 80s. If you use the whole front end it's a bolt on replacement. The DOHC forks have dual-disks and dual-piston calipers. I did this on one of my earlier 750s. It makes a major difference, brakewise.

I'm also sensing that you don't have a whole lot of cash to throw at this bike right now. Parts of DOHC Hondas are not near so dear as parts for our bikes. Those bikes just are not as sexy. I got a whole fork from an '79 or 80 750, including working calipers and master that didn't even need to be rebuilt, for $50 off Craigslist. Check it out. A lot of posters can't give the stuff away. If you do it, be sure to get the front wheel. Only the wheel from the 77-78 F model 750s fit the later fork.

Patrick

Ok I think I got it   Thanks!  I really appreciate the help guys because this is my first build and I hardly know what I'm doing but it's more fun that way   ANd yes slightly strapped for cash but I'm going to do the best I can.  The late 70's front ends sound like a great idea and I just might do that!  Thank you

The tubes and lowers must match each other. Once matched you may bolt either onto your Honda.

Perfectly cleared up.  Thanks!

[avoca]

OK so now I don't know what I have because my lowers don't look anything like the two pictured earlier with the c and t clamps

[754]

Looks like some mounts were cut off.. How many tapped holes do you have,  just count the blind ones.

[avoca]

Looks like some mounts were cut off.. How many tapped holes do you have,  just count the blind ones.

looks like 3, and it looks like I'll be getting a new set of uppers and lowers!  Haha.  Oh well, thanks for the help guys.

[avoca]

What do you guys think about these on the 73?

http://www.ebay.com/itm/1974-Honda-CB750-CB-750-Front-Forks-Shocks-/360990924981?pt=Motorcycles_Parts_Accessories&hash=item540cbc60b5&vxp=mtr

[seanbarney41]

looks like a fair price for condition and those are correct for 73, uses the T bracket