Topic: 1977 CB750 K7 Resto-mod, Knoxville

[AintNoEasyWay]

Clamp the tube in a vice and work the lowers like a slide hammer. compress and yank, compress and yank...it will eventually come apart.  Maybe shoot some penetrant in the bolt hole on the bottom in between workouts.

Awesome. Thanks, Desert. Makes sense now.

Just got my drilled rotor from Godffery's Garage. I'll post pictures later but this thing looks awesome. Excellent customer service too!

[Desert-SOHC]

Awesome. Thanks, Desert. Makes sense now.

Just got my drilled rotor from Godffery's Garage. I'll post pictures later but this thing looks awesome. Excellent customer service too!

Cool, I've been looking for an aluminum A wheel for mine

[AintNoEasyWay]

Clamp the tube in a vice and work the lowers like a slide hammer. compress and yank, compress and yank...it will eventually come apart.  Maybe shoot some penetrant in the bolt hole on the bottom in between workouts.

Guys, this worked great. Got the old tubes out & im getting everything cleaned up.

[Desert-SOHC]

Yeah....they get some nasty built up crap in the forks when not serviced regularly. I used 10w fork oil in mine and the ride is better than using what the manual recommends.

[SOHC4 Cafe Racer Fan]

Nothing quite like the aroma of 40-year-old fork oil.

[Desert-SOHC]

Nothing quite like the aroma of 40-year-old fork oil.

EWWWW, I just remember smelt it, that's a smell that you NEVER forget, like burnt wiring.

[AintNoEasyWay]

Nothing quite like the aroma of 40-year-old fork oil.

EWWWW, I just remember smelt it, that's a smell that you NEVER forget, like burnt wiring.

Why hasn't Yankee candle made a scent for it yet?

On the search for some K7 headlight brackets. My originals have small pits of rust on them from age. If I kind find a pair in better condition, I'll soak these in rust remover & try to get them looking as decent as possible.

[AintNoEasyWay]

Alright guys, still at work on the front end. I've repainted my triple tree & front caliper & they turned out great. A few questions:

The tubes I ordered from Cycle X are about an inch longer than the originals. They measure out at 23 13/16 inches, & Cycle X claims these are the standard for 77-78. Anyone have an idea why they're longer? As long as there won't be a significant difference in ride, I don't mind.

I also bought new progressive springs (far right on photo), which you can see are shorter than the original springs. So my new tubes are longer & my new springs are shorter. I wasn't prepared for this & am not sure how this will change everything. Any input would be great.

Fork seals are stuck in the fork lowers & I haven't had any success prying them out after a WD40 soak. How have you guys removed these?

Last, I don't have the original tool for removing the cap over the steering stem to replace the bearings there. Do you guys have a method you recommend for removing that?

[Godffery]

Clamp the tube in a vice and work the lowers like a slide hammer. compress and yank, compress and yank...it will eventually come apart.  Maybe shoot some penetrant in the bolt hole on the bottom in between workouts.

Awesome. Thanks, Desert. Makes sense now.

Just got my drilled rotor from Godffery's Garage. I'll post pictures later but this thing looks awesome. Excellent customer service too!

 Thanks Nate, glad your dig'n the Rotor work! 

[RAFster122s]

A screw driver driven part way into the seal and thin pad of hardwood for it to wedge against the top opposite edge can work sometimes. The circlip on top of the seal that holds it in place is removed, right?
I have seen seal pullers for auto use that have a hook But, it is easy to have it dig into the side of the seal surface pulling a seal with one of them. I believe Lisle makes them. But, like I said, if not careful you may need new fork lowers using one of those...or even the screwdriver. The seal may be stuck to the fork lower, so smacking it around the edge and fork interface to break that grip might work to free it up, or heating the fork lower in that area on outside of fork lower might help.
Try smacking it around and see if it helps, ...before getting medieval with it.

[AintNoEasyWay]

Thanks RAF. I managed to get the seals out tonight by tapping a screwdriver with a mallet to break the rust around the old seal. Reassembling the forks now as soon as I get some feedback on the forum of how to configure these new Progressive springs.

I also need to find a 48mm pin spanner or some tool to remove the top thread nut on the steering stem. Then I can finally move on to getting the new steering stem bearings in.

[RAFster122s]

On the CX500 we use a section of pvcplumbing that slides into the fork with very little freeplay on the sides. A washer where it contacts the spring. This allows you to preload the springs and you fill the tube with a good quality fork oil with the manuals recommended amount.

David

[AintNoEasyWay]

On the CX500 we use a section of pvcplumbing that slides into the fork with very little freeplay on the sides. A washer where it contacts the spring. This allows you to preload the springs and you fill the tube with a good quality fork oil with the manuals recommended amount.

David

Cool, thanks David. The Progressives I have did come with pipe & washers. My dilemma is that my springs are about an inch shorter than the stock springs while my new fork tubes are about an inch longer. I'll use the PVC provided to make up for the difference in spring length, but will having longer fork tubes matter?

[RAFster122s]

It can change the rake and trail measurements on the CB750.  The CB750 is a totally different beast in handling than the 550. The 550 has it beat hands down on handling.  The 750 has to use counter pressure on the turns as you are aware, or weigh shifts that are not as smooth.  May want to ask the question over on the tech and high performance section to see if others can offer some info. 
An easy way to counteract the longer forks is to have them stand proud of the tops of the triple trees Or, you can get longer shocks. But, the shocks need to be suitable for the load so that the compression difference doesn't add issues to the handling.  The shocks are an easy way to counteract the longer forks. I think the GL1000 have been used by some.  Others go for Works Performance custom shocks (they are built to order) or IKON (KONI shocks new owner's) and there are other good quality shocks.  If you want to make the springs handle even better than consider installing emulators in the front forks for ideal setup with the stock forks.  A fork brace and fork damper are advised if you want to push the handling of the bike in the twisties...
The emulators are great bang for the buck and work well on street bikes or even race bikes with restrictions on stock forks.

David

[AintNoEasyWay]

Alright guys, finally set up & measured old fork tube/spring assembly vs new assembly. The old spring comes just above the old fork tube, as everything I've read suggests should occur.

The new setup, with the longer new tube but shorter Progressive spring leaves enough room for me to screw the fork cap completely in without touching the new spring. After cutting a piece of pvc, I've made up for that gap, pictured below. The pvc measures out to just under 1.5". Does this sound sketchy to anyone? Will frequent suspension engagement wear down the pvc, forcing me to have to this over again? Just want to get some thoughts before setting these back up.

Also, should I only use a washer between the spring & pvc or should I use two, adding another between the pvc & fork cap?

Thanks for helping me out with this. Really appreciate input!

[RAFster122s]

The PVC should not wear much if at all. You want it long enough to provide some compression of the spring so it doesn't have any slack.
You can use longer length and fork oil to tune the spring response.
The RaceTech gold valve emulators provide improved dampening in compression and rebound. They are far cheaper than grafting most other front forks onto your bike.

[SOHC4 Cafe Racer Fan]

The PVC should not wear much if at all. You want it long enough to provide some compression of the spring so it doesn't have any slack.
You can use longer length and fork oil to tune the spring response.
The RaceTech gold valve emulators provide improved dampening in compression and rebound. They are far cheaper than grafting most other front forks onto your bike.

The Race Tech gold valve emulators are a nice improvement over stock springs and progressive springs.  Of course, they do not measure up to modern USD forks tuned to the bike and rider's weight.

[AintNoEasyWay]

Thanks guys. I set the forks back up yesterday & spring response seems okay just testing by hand. I'm waiting to get a spanner wrench in to remove the top part of the steering stem so I can get my All Balls bearings installed. Then I'll get the front end back together & really test out the springs.

[AintNoEasyWay]

Alright guys, something I'm curious about is the D washers that should go in the triple tree in its tiny gaps. Hondaman's guide claims these are a necessity to prevent undue mechanical stress on the tree.

However, when disassembling my tree, there were no D washers to be found. I assumed this was a PO's fault until I looked to a K7 diagram to find the washer size. But the diagram shows no washers either.

Do I need a washer or not? 

[danyo]

No washers in k7, k8

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[AintNoEasyWay]

No washers in k7, k8

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Interesting. Thanks, danyo. Any idea why?

[danyo]

No idea why, I was very surprised  seeing them on earlier  models.

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[Stev-o]

No washers in k7, k8

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Interesting. Thanks, danyo. Any idea why?

Upgrade

[SOHC4 Cafe Racer Fan]

That and 8 years of broken upper triple trees. . . . 

[AintNoEasyWay]

Just started work to install my All Balls steering stem bearings. If I'm in town this weekend, I should be able to finish that up & start getting the front end back together.

Also, when I purchased the bike, it didn't have the original side cover emblems. I bought an unpainted pair off 4into1.com & found some lettering paint on Amazon. They're turning out pretty good so far (need to paint the 'K' & do touchups). We'll see how they hold up under riding/environmental conditions.