Author Topic: Recondition CB750 K2 rear suspension dampers (Read 8728 times)

coolgoose · « **on:** March 25, 2010, 11:47:01 AM »

Can stock rear suspension dampers on CB750 K2 be reconditioned? I am wondering whether I can recondition my rear dampers? Anyone in this forum has done it before? Tips please!!!

Duke McDukiedook · « **Reply #1 on:** March 25, 2010, 12:50:31 PM »

Are you talking about rear shocks?

If that is what you are asking, the answer is no.

coolgoose · « **Reply #2 on:** March 25, 2010, 01:16:37 PM »

Thanks Dukiedook!

Yea I was talking about rear shocks. Dang! can't recondition the stock ones.

I heard Honda discontinued the old ones and finding similar dampers so that I won't ruin the stock look appears difficult. Can anyone suggest any non OEM dampers where I can still use my stock springs and chrome plate (chrome cup thats present on the stock shocks) on them?

Thanks for response guys!

Duke McDukiedook · « **Reply #3 on:** March 25, 2010, 01:30:00 PM »

http://www.davidsilverspares.co.uk/parts/part_105084/

David silver spares sells a replica shock, it will cost a few quid though.

Yamiya might sell some repro shocks also, I think their website is down though.

Old Scrambler · « **Reply #4 on:** March 25, 2010, 01:34:47 PM »

How many miles? If you can find a set of low mileage used shocks for a K2 or K3 they may help. Later years will fit but have black shock bodies. I am in the same situation. My K3 has close to 70k on the shocks with a lot of 2-up riding. After sitting for a few years they had little dampening, but after riding a few hundred miles some of the dampening seemed to come back. Maybe I just got used to the feel of pogo-springs.

coolgoose · « **Reply #5 on:** March 25, 2010, 02:12:36 PM »

How do you check whether the damping is good or not? I have my damper removed from the rear shock absorber, when I try to press the damper rod down with hand it offers little resistance. However, there is a significant amount of resistance when I try to pull back the damper rod. My K2 had close 42K mile on it. The springs appear good.

Duke McDukiedook · « **Reply #6 on:** March 25, 2010, 02:30:03 PM »

Don't worry, your stockers are shot, the question then becomes what will you replace them with?

coolgoose · « **Reply #7 on:** March 25, 2010, 08:45:28 PM »

That is the big questions..With what should I replace my stockers? $:-\$

I don't want to change the stock look on my K2! The replica shocks by Yamyia are expensive...now I am in a big dilemma

Magpie · « **Reply #8 on:** March 25, 2010, 08:56:39 PM »

These have always interested me, they look good
http://cgi.ebay.ca/HONDA-CB-750-SHOCKS-1969-1970-SAND-CAST-DIE-69-70-CB750_W0QQitemZ160414392815QQcmdZViewItemQQptZMotorcycles_Parts_Accessories?hash=item25597161ef

Cliff.

coolgoose · « **Reply #9 on:** March 26, 2010, 05:13:40 PM »

Thank a Ton Magpie for pointing me the shocks!!

I got them from ebay

Swoop · « **Reply #10 on:** March 27, 2010, 04:14:12 AM »

Quote from: coolgoose on March 25, 2010, 02:12:36 PM

How do you check whether the damping is good or not? I have my damper removed from the rear shock absorber, when I try to press the damper rod down with hand it offers little resistance. However, there is a significant amount of resistance when I try to pull back the damper rod. My K2 had close 42K mile on it. The springs appear good.

From what you describe these shocks that you have appear to be good. Why did you think that they needed to be replaced? Looks or function?

Steve

754 · « **Reply #11 on:** March 27, 2010, 08:08:13 AM »

I know of a method used to rebuild Girlings.
So i asume it could work on Honda shocks, if theyy were not leaking..

Can fill you in ,
if anyone wants to try it..(involves welding..

)

coolgoose · « **Reply #12 on:** March 27, 2010, 04:42:19 PM »

Thank You 754!

Could you please let me know that method of yours for reconditioning? I am all ears!

MCRider · « **Reply #13 on:** March 27, 2010, 05:39:56 PM »

Quote from: coolgoose on March 25, 2010, 02:12:36 PM

How do you check whether the damping is good or not? I have my damper removed from the rear shock absorber, when I try to press the damper rod down with hand it offers little resistance. However, there is a significant amount of resistance when I try to pull back the damper rod. My K2 had close 42K mile on it. The springs appear good.

generally speaking, production shocks of that vintage do not have, or have very little, oil damping on compresion by design. The spring is responsible for compression damping, the oil in the shock body on rebound. The oil degrades over time from heat cycles.

The springs can get sacked from use over time. And there is an element of fatigue from time alone.

And beyond that, it is generally considered by those of us who care about such things, that the stock dampers on 70/80s era bikes were junk from the factory. Good shocks have oil damping in both directions (dual dampening) and higher quality springs that don't sack from heat cycles.

But I understand the need/desire to have stock looking shocks on repro and semi repro bikes.

Shocks, tires, etc were places the manufacturers could cheap out

754 · « **Reply #14 on:** March 27, 2010, 06:47:00 PM »

Dont laugh but here it is.. may or may not work..

In the old days they blamed everything on the fishoil, they claimed was in the shocks, and broke down in 5K. You need a shock, not ltaking out of the seals.

Anyway this is what they did to the Girling shocks, drill a small hole near the bottom of shock body (not aiming at chainguard), and drain shock. Then thru that hole rinse out the shock, then weld a small nut (say 6mm) over the hole, leaving thread in the middle. Then add a copper washer like that on the fork drain, and use the bolt/washer to seal it up. You have to play with the amount of shock oil put in, to tune it.

Try it on a set you dont care about, cant guarantee it works, but seems to have on some shocks..

wdhewson · « **Reply #15 on:** March 28, 2010, 05:27:41 AM »

754:

I like your oil fill idea. Sounds like it should work. When welding the nut on the lower shock tube body, I suppose the damper rod bits should be aways from the heat. Does this mean full extend the shock while welding?

old76cr · « **Reply #16 on:** March 28, 2010, 07:13:00 AM »

Here is a link to the technique described by 754. http://www.superhunky.com/articles/Saveshocks.php I did this on my Can-Am shock that had leaked out. Not having a welder I used JB weld to hold the nut on. Has been in use for 2 years now.

coolgoose · « **Reply #17 on:** March 29, 2010, 01:00:33 PM »

Thanks a lot 754 for explaing your idea!

Thanks old76cr for pointing the link. I will try it on some unused scrapped dampers before actually attempting on my stock ones

Thanks MCRider for the info on production shocks and damping.

Guys I have found after market shocks that look like stock ones from ebay. You can see them here http://cgi.ebay.ca/HONDA-CB-750-SHOCKS-1969-1970-SAND-CAST-DIE-69-70-CB750_W0QQitemZ160414392815QQcmdZViewItemQQptZMotorcycles_Parts_Accessories?hash=item25597161ef#ht_1822wt_1165

This solves my problem from the stock look perspective!

Thanks a ton for all the responses guys!

Duke McDukiedook · « **Reply #18 on:** March 29, 2010, 01:34:56 PM »

I hate to poop on those shocks but what kind of shocks do you really think you will get for $120US?

Odds are they'll be horribly cheap and worse than your stock shocks.

petercb750 · « **Reply #19 on:** March 29, 2010, 02:08:39 PM »

I have installed a set of the David Silver repro shocks on mine and, apart from them giving a bit harder ride (maybe not that hard, just a lot harder than the old saggy ones), they seem quite good and look no different to the originals, apart from lots more shine and no rust! Quite happy.

coolgoose · « **Reply #20 on:** March 29, 2010, 09:30:48 PM »

Thanks petercb750!!

I am not planning to use my K2 for long distance travel. At the most I would be riding 4 to 5 miles for my work that too weather permitting here in Seattle

I don't want to ruin the stock look!! Stiff ride is ok for me

Your bike looks gorgeous

What year is it? Could you please share some more picture? I am thinking going with same color theme.

petercb750 · « **Reply #21 on:** March 31, 2010, 01:34:44 PM »

Hi - it's a 72 K2. Thanks.
This is a fairly low res shot.

AshimotoK0 · « **Reply #22 on:** April 01, 2010, 04:45:53 AM »

I recently bought new (not NOS) K0/K1 genuine Honda Shocks for my K0 I am in the process of rebulding (expensive - ouch!!) Anyone know if the build quality is OK? At least Honda still make them - for K2 and above (341?) I think they are obsolete.

Cheers

AshD

Brown Bomber · « **Reply #23 on:** September 12, 2010, 06:06:09 AM »

I hate to bring up a dead cat, but I did refurbish the rear shocks on my 750K2, and it worked great. Here's a link to my thread on the Honda Twins forum; http://www.hondatwins.net/forum/viewtopic.php?f=19&t=4133

Trav-i · « **Reply #24 on:** September 12, 2010, 06:28:38 AM »

Quote from: Brown Bomber on September 12, 2010, 06:06:09 AM

I hate to bring up a dead cat, but I did refurbish the rear shocks on my 750K2, and it worked great. Here's a link to my thread on the Honda Twins forum; http://www.hondatwins.net/forum/viewtopic.php?f=19&t=4133

Thanks for that awesome link. I need to redo the shocks on my CL and I actually have an old set laying around, so I know what I'll be doing this week. Plus Fabricator needs to redo the shocks on his 750, if this works for me hopefully it will work for him.

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Author Topic: Recondition CB750 K2 rear suspension dampers (Read 8728 times)

Swoop

wdhewson