Author Topic: Difference between shocks on CB750K0 and K1 (Read 6521 times)

markb · « **on:** February 18, 2008, 02:40:45 PM »

I'm looking for shocks to replace the ones on my K0. They're no longer available (#52400-300-010XW) but I think I can get #52400-300-020XW which were used on K1's. Anyone know what the difference is?
Thanks,
Mark

754 · « **Reply #1 on:** February 18, 2008, 03:11:33 PM »

Early ones have a black top , and springs have more coils.

The others shoukld work but might be near price of a better performing shock?

HondaMan · « **Reply #2 on:** February 18, 2008, 08:14:50 PM »

The K0 shocks were 12.940" long, while the K1 were 13.060" long.
That's one of the reasons why the K0 had a more "squat" look to it.
That's the only difference I ever saw. Both had 110 lb/inch springs.

Terry in Australia · « **Reply #3 on:** February 18, 2008, 11:15:23 PM »

Well there you go. I've just bought a shiny new pair of 52400-300-020XW shocks offa EBay and they're the same length as the 52400-300-010XW that I bought from Kevin Hahn. (Hahnda) In fact, the shocks I bought from Kevin were probably one each of the 010XW and 020XW, and they're the same length too.

The springs are different (the K1's are shorter and with more space between the coils but come with steel spacers to make them the same length as the tighter wound coils on the K0 shocks. Otherwise, they're identical.

The all chrome/alloy (or non black top, whatever you want to call them) shocks on the late K1-K6 were longer I believe, and weren't gas/oil "upside down" dampers like the K0/early K1 (52400-300-010XW/020XW) items, but more conventional hydraulic dampers.

Good news is you can still buy the 020XW items, there's a set on EBay now, for $399.00 "buy it now" plus shipping. If that is too much money, I'm gonna put Kevin's back on Ebay with matching springs once I install the new ones. Cheers, Terry.

markb · « **Reply #4 on:** February 19, 2008, 03:00:03 PM »

Well, there seems to be a difference of opinion here as far as the length and the springs on the K0 & K1 shocks. Any other opinions? I might be able to clean mine up OK but what are the chances that 33+ year old shocks are still good (I've had the bike since '75 and they haven't been changed since then)?

Terry, are you saying you'd have to change the springs on one of your other pair to make them match? How much would you need for them? I saw that pair on eBay and that is a little spendy but I'm tempted.
Mark

HondaMan · « **Reply #5 on:** February 19, 2008, 06:34:10 PM »

Quote from: Terry in Australia on February 18, 2008, 11:15:23 PM

Well there you go. I've just bought a shiny new pair of 52400-300-020XW shocks offa EBay and they're the same length as the 52400-300-010XW that I bought from Kevin Hahn. (Hahnda) In fact, the shocks I bought from Kevin were probably one each of the 010XW and 020XW, and they're the same length too.

The springs are different (the K1's are shorter and with more space between the coils but come with steel spacers to make them the same length as the tighter wound coils on the K0 shocks. Otherwise, they're identical.

The all chrome/alloy (or non black top, whatever you want to call them) shocks on the late K1-K6 were longer I believe, and weren't gas/oil "upside down" dampers like the K0/early K1 (52400-300-010XW/020XW) items, but more conventional hydraulic dampers.

Good news is you can still buy the 020XW items, there's a set on EBay now, for $399.00 "buy it now" plus shipping. If that is too much money, I'm gonna put Kevin's back on Ebay with matching springs once I install the new ones. Cheers, Terry.

Different length springs?

I don't remember that part...
Now, I'm wondering...are there different versions of the 750 springs, too? When I saw those "preproduction 750s" in a post here last year, I saw what looked like 450 shocks on those.

The reason the length I mentioned above sticks in my memory (for better or worse, aging memory...) is because I swapped shocks with 2 K0 riders to get their shorter bodies, so my K1 springs would be preloaded an extra bit while lowering the rear. They got my slightly longer bodies and I got their shorter ones, because they liked the K1 "look" of being more "level" in the back. I got the lower rear and the added trail up front. (Not much, I'll admit, but in those Production Racing rules, every tiny "legal" bit helped, or so we believed.

).

OK, "K0" gurus...is there a consensus? I just GOTTA know, it's gonna keep me up nights...
(See what you do to me, Terry?).

Jonesy · « **Reply #6 on:** February 19, 2008, 07:13:07 PM »

Here's what I can glean from my Honda comparator, FWIW... (afraid it doesn't solve the mystery of the early K0 dampers, though...

)

The cited "differences" in the K1 shocks:

I thought I had specs on the K0 shock, but the it;s one of those things that the shop manual denies ever changing in the K0...

Terry in Australia · « **Reply #7 on:** February 19, 2008, 11:10:29 PM »

Quote from: markb on February 19, 2008, 03:00:03 PM

Well, there seems to be a difference of opinion here as far as the length and the springs on the K0 & K1 shocks. Any other opinions? I might be able to clean mine up OK but what are the chances that 33+ year old shocks are still good (I've had the bike since '75 and they haven't been changed since then)?

Terry, are you saying you'd have to change the springs on one of your other pair to make them match? How much would you need for them? I saw that pair on eBay and that is a little spendy but I'm tempted.
Mark

G'Day Mark, nah, you don't want mine mate, the dampers are gone and that's why I'm selling them, they're only good for someone who can get 'em rebuilt, or someone who doesn't ride around bends, ha ha!

Still, I've stripped and cleaned them right up, acid dipped all the rust off and painted the dampers black again, and with the correct K0 springs I'll still get over 100 bucks for them, good old K0 bullshiit "sandcast" prices, ha ha!

markb · « **Reply #8 on:** February 20, 2008, 05:33:32 AM »

Other than riding with them (I am a ways from that) how can you tell if the shocks are OK? Mine would probably clean up OK if I could take them apart so what's the procedure for taking them apart?
Thanks for all the input,
Mark

Terry in Australia · « **Reply #9 on:** February 20, 2008, 03:47:30 PM »

You can rest assured that your dampers are buggared too mate, once the seals go, the oil runs down the shafts and the pistons are just a pumping up and down..........

You'll need a shock spring compressor (a motorcycle one, not a car one) to compress the springs, then pop out the two alloy "collets" and you can then remove the chrome covers and the springs from the damper assembly.

Now the "damping" effect can be tested by just pushing the damper rod in and out, and like mine, yours will have virtually no resistance after all this time. It's the "damper effect" that stops the shocks from acting like pogo sticks when you go around bends.

Steve K0 and I are working on a cunning rebuild service for K0/K1 shocks, they'll be oil damped only, and not oil/gas like OEM, but they will still work fine, so don't throw out your old ones, we might do a "changeover" service! Cheers, Terry.

DONZIE · « **Reply #10 on:** February 20, 2008, 04:50:28 PM »

TERRY
I don't meant to highjack this thread but I have to ask what are you talking about when you say you acid dipped your shocks
DONZIE

Terry in Australia · « **Reply #11 on:** February 20, 2008, 07:41:15 PM »

Quote from: DONZIE on February 20, 2008, 04:50:28 PM

TERRY
I don't meant to highjack this thread but I have to ask what are you talking about when you say you acid dipped your shocks
DONZIE

Hey don't worry about it mate, I'm always jacking someones thread, ha ha! (er, sorry, I don't mean to..........)

I've got a big 16 gallon tub of Phosphoric Acid, diluted 1:4 with water. I dumped in the chrome covers, springs, and lowered the chrome bottoms (on wire, so the damper bodies didn't submerge) and the acid just washes the rust away, leaving the chrome like new. Most chrome cleaners and polishes contain Phosphoric Acid. Cheers, Terry.

754 · « **Reply #12 on:** February 21, 2008, 07:48:16 AM »

We use Citric acid to take rust off oil tins w/o hurting the paint.

Have not done it myself, but many have... but it may be safer...

HondaMan · « **Reply #13 on:** February 21, 2008, 06:56:18 PM »

Quote from: Jonesy on February 19, 2008, 07:13:07 PM

Here's what I can glean from my Honda comparator, FWIW... (afraid it doesn't solve the mystery of the early K0 dampers, though... )

The cited "differences" in the K1 shocks:

I thought I had specs on the K0 shock, but the it;s one of those things that the shop manual denies ever changing in the K0...

Thanks, Jonesy! Cool post, I don't remember seeing one like this... It clearly shows the spring length changes and the diameter changes, even if the verbage is a little clipped. It's interesting that the overall length is shown at 13.07" while I'm used to measuring them as 13.06". Hmmm...production tolerance issues? I seem to also remember the Betor and Koni catalogs listing several lengths for these, too, in the 12.880", 12.940", 13.060" and 13.125" lengths, about 1972 or so (non-Honda, of course.)

Jonesy · « **Reply #14 on:** February 22, 2008, 10:32:54 AM »

No prob, Mark... It's in the K1 shop manual suppliment. I can send you the PDF of it if you want. The screen shot didn't post at the same size I uploaded it, making it tricky to read.

HondaMan · « **Reply #15 on:** February 22, 2008, 07:32:04 PM »

Quote from: Jonesy on February 22, 2008, 10:32:54 AM

No prob, Mark... It's in the K1 shop manual suppliment. I can send you the PDF of it if you want. The screen shot didn't post at the same size I uploaded it, making it tricky to read.

Thanks!
I "reconstructed" it with the Brother software, got a good print.

markb · « **Reply #16 on:** February 23, 2008, 10:01:18 AM »

Thanks all for the interesting posts. After looking at my shocks I agree they may not be good so I bit the bullet and bought the pair on ebay. Why compromise handling, I want a safe rider. If they were still available I probably would have to pay at least $150 a piece anyway. Whats another $100 when I couldn't find anything new anywhere and who knows what kind of shape used ones would be. Actually I did find one source on the internet (Bekkoame) by searching using the part number 52400-300-020. It's a Japanese site and if I'm calculating the exchange rate right they would be about $220 a piece. I couldn't figure out how to order from them. Anyway ever use them? Terry, if you end up doing some kind of rebuild I would be interested in refurbishing my old ones.
Thanks for all the replies,
Mark

Terry in Australia · « **Reply #17 on:** February 24, 2008, 03:18:25 AM »

No worries Mate, I received my new shocks last week but haven't had a chance to fit them yet (I was away all weekend) and I want to pull them apart and check the damping, but they sure do look nice compared to my old ones, and 400 bucks is still cheaper than a new pair of Ikons, although the Ikons are far better shocks, but what price originality? Ha ha, Cheers, terry.

Venturous · « **Reply #18 on:** July 25, 2008, 03:56:42 PM »

I have on eBay now a set of new 52400-300-020XW with a buy now of $375 if anyone interested. I ordered these from my parts guy then found out with the sidecar attached I really should use aftermarket specialty shocks.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=170243919550

toycollector10 · « **Reply #19 on:** July 26, 2008, 04:00:25 AM »

Nice work boys, you can trust Terry and HondaMan to cut out the crap and give us the good oil....

Terry, how's about some pics of your K0 resto mate?

6adan · « **Reply #20 on:** July 26, 2008, 06:06:42 AM »

And speaking of KO's,is there a book or books or anything else to guide one on the restration of the KO? Thanks Dannie

troppo · « **Reply #21 on:** July 26, 2008, 06:25:31 AM »

Quote from: 6adan on July 26, 2008, 06:06:42 AM

And speaking of KO's,is there a book or books or anything else to guide one on the restoration of the KO? Thanks Dannie

I think the most helpful book for the complete restoration of a K0 would be a fat cheque book

HondaMan · « **Reply #22 on:** July 26, 2008, 08:50:39 AM »

Quote from: troppo on July 26, 2008, 06:25:31 AM

Quote from: 6adan on July 26, 2008, 06:06:42 AM
And speaking of KO's,is there a book or books or anything else to guide one on the restoration of the KO? Thanks Dannie
I think the most helpful book for the complete restoration of a K0 would be a fat cheque book

And, if your K0 is sandcast, look around for CL450 parts when working at the back end. A lot of the real early ones seemed to have come from there.

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Author Topic: Difference between shocks on CB750K0 and K1 (Read 6521 times)

troppo