Topic: Early Replica cb750 Shock.

[BenelliSEI]

I have a nice set of new replica black body shocks on my latest project. They are very accurate replicas, but have 5 position preload ring. Has anyone ever moved the  three position ring from the originals? I’m going to try, unless I get warned off. Thanks!

Oops! No shocks in my photo. Will take one next time.....

[Dunk]

Source for black body shocks like originals? When I restored my K1 back in 2013 I went with Ikon, chrome like the newer bikes but only a discerning eye can tell and I ride the bike.

[Don R]

   Dunk,  Z1 parts has some nice repros and last time I looked, they had a set of original ones also. There are two different K0 type shocks on their site and ebay so shop accordingly. I intended to try the adjuster swap but my spring compressor wasn't up to motorcycle shocks so I haven't yet. 
 There was a price increase this year so I offered last years price for my second set and they accepted it. They did have make an offer as an option.  I think the valving is a bit stiff but hope they loosen as they break in.

[BenelliSEI]

   Dunk,  Z1 parts has some nice repros and last time I looked, they had a set of original ones also. There are two different K0 type shocks on their site and ebay so shop accordingly. I intended to try the adjuster swap but my spring compressor wasn't up to motorcycle shocks so I haven't yet. 
 There was a price increase this year so I offered last years price for my second set and they accepted it. They did have make an offer as an option.  I think the valving is a bit stiff but hope they loosen as they break in.

Don.... Thanks, I’ll have a look. I stand the shocks up in my drill press. Chuck a 1/2” X 8” brass drift (helps if the end has been faced and smoothed) and push down on one half of the lock ring. It usually only takes a bit of effort to pop it out. It would be much safer if I just made a tool that fit in my press, but I’ve been getting away with this for so long.......

[BenelliSEI]

These are the replica “black body” shocks. 4 into 1 and Vintagecb750 sell them. Unlike the originals, they have a 5 position spring preload adjuster ring. The early bikes have three settings. I removed one ring from the original shocks (sitting on the swing arm). This required cutting the eye off the top end (no problem as they were completely useless). Maybe the replicas have a screwed on top? Anyone ever taken one apart? We’ll see...... how

Failing that, I have a brand new set (purchased from Honda by a previous owner, eons ago) of originals on my K0. They will get swapped in.

[Ujeni]

Yamiya sells a set of replica shocks that are a near-perfect. They claim that they are made by the same manufacturer as the original. I have used these on several sandcast restorations and many other have as well:

https://www.yamiya750.com/index.php?main_page=product_info&cPath=246_251_142_93&products_id=131

[BenelliSEI]

Yamiya sells a set of replica shocks that are a near-perfect. They claim that they are made by the same manufacturer as the original. I have used these on several sandcast restorations and many other have as well:

https://www.yamiya750.com/index.php?main_page=product_info&cPath=246_251_142_93&products_id=131

These are identical too. I think they will go on my K0 and I’ll use the NOS Honda units on the SC.

[Kook652]

Yamiya sells a set of replica shocks that are a near-perfect. They claim that they are made by the same manufacturer as the original. I have used these on several sandcast restorations and many other have as well:

https://www.yamiya750.com/index.php?main_page=product_info&cPath=246_251_142_93&products_id=131

 

Newbie here. 1969 Diecast CB750K with 13,000 miles on it - but sat for over 20 years in a hanger/barn. Shocks look to be in good shape, visually. Can they be rebuilt?

[BenelliSEI]

Yamiya sells a set of replica shocks that are a near-perfect. They claim that they are made by the same manufacturer as the original. I have used these on several sandcast restorations and many other have as well:

https://www.yamiya750.com/index.php?main_page=product_info&cPath=246_251_142_93&products_id=131

 

Newbie here. 1969 Diecast CB750K with 13,000 miles on it - but sat for over 20 years in a hanger/barn. Shocks look to be in good shape, visually. Can they be rebuilt?

I don’t think so, the unit inside is like a small, separate cylinder. They screw into the bottom saddle bracket and there is a nut on the stud. If you remove the nut, you will set the threaded plate has four punch marks to lock the stud in place. I’ve no idea how you would dismantle that..... The replicas from 4 into 1 (and others) are relatively inexpensive. If yours look good, use them. If the back end bounces uncontrollably you’ll know you need new ones right away.....

[Kook652]

Thank you!!

[Ujeni]

Most likely, your 50+ year old shocks are not going to perform well. They might look nice, but there is a high likelihood that the internal seals have failed and you are essentially just riding a spring. The way to find out would be to remove the spring and see if there is damping when compressing or expanding the shock. If so, you are in luck. If not, time to find a replacement.

[BenelliSEI]

Most likely, your 50+ year old shocks are not going to perform well. They might look nice, but there is a high likelihood that the internal seals have failed and you are essentially just riding a spring. The way to find out would be to remove the spring and see if there is damping when compressing or expanding the shock. If so, you are in luck. If not, time to find a replacement.

+1. Mine just make a noise but offer almost zero dampening on rebound....

[Kevin D]

Here is an inexpensive and safe spring compressor. The hardest part of using it is threading the strap correctly. It only took a couple pumps of the ratchet handle to pull the springs down just a bit to disengage the keepers.
My original shocks had zero damping and the springs were weak so I opted for new Hagons a while back. The shocks are good but 23kg springs are too much for my 220 lbs so I refitted them with 20kg springs.
The current Hagon supplier is British Cycle Supply in Nova Scotia for Canadians and also in Maine for Americans.

[Ujeni]

This is a great tip! Thanks!

[Don R]

 Thanks guys I appreciate the info and the spring trick is way cool Kevin!

[BenelliSEI]

Thanks guys I appreciate the info and the spring trick is way cool Kevin!

+1 on the strap. The method I described with the drill press is a bit dicey. I will try this instead!

[Kevin D]

Well, thanks guys but I’m not the first one to use a ratchet strap for a spring compressor.
I got it done without cutting any hooks off or tying a knot using the long strap.
I left a little slack so there was a turn of strap on the drum before it tightened.
Having the bottom clevis keeps the strap in line.
If I was doing a mono shock I might use a heavier strap.
and I have done this exactly twice, once removing the old springs and again installing the new.

[ekpent]

I've done it with a woodworker's bar clamp and a couple of wood blocks taped to the clamp surfaces. Had a furniture repair biz at one time so used what was handy.    Strap method looks good though.
  Wonder if a little gentle pressure from a cheapie hydraulic press if you had one would do the trick also ?

[scottly]

My original shocks had zero damping and the springs were weak so I opted for new Hagons a while back. The shocks are good but 23kg springs are too much for my 220 lbs so I refitted them with 20kg springs.
The current Hagon supplier is British Cycle Supply in Nova Scotia for Canadians and also in Maine for Americans.

The Hagons I just bought came with 18kg springs, and the seller, who weighed the same as you, felt they were too soft. He could have just bought new springs, but as he thought the shocks were too long for his Moto Guzzi, he ordered a new pair with 20kg springs and sold the old ones to me. BTW, I noticed that the bushings aren't centered in the eyes very well, and I'm going to have to address that before installing them.

[PeWe]

I'll try that strap trick on a set of Marzocchi AG Strada in need of a restore.