79 CBX1000 OEM Rear Spring Rate

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RickKean
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79 CBX1000 OEM Rear Spring Rate

Post by RickKean »

Hi from Houston 77064

I've come up empty in my rear spring rate searches, so I'll ask:.
What rear spring rate was delivered on the 79 CBX1000 SS?
Was the factory rate included in any Honda manuals or bulletins?

I won't be using the unknown aftermarket blue coilovers (helper + load spring inline setup) that my Project came with. I've obtained a pair of on-the-bench rebound adjustable Koni 76K-1413 Special D's with linear wound springs that WAG/Calculate at 120lb/in (2.1kg/mm). I'll set the rebound initially at full soft, and probably leave it there. The springs are White/Green/Red color coded; anyone know Koni spring codes?

Thanks
Rick

steve murdoch icoa #5322
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Re: 79 CBX1000 OEM Rear Spring Rate

Post by steve murdoch icoa #5322 »

Contact Nils.
He does shock rebuilds and probably has some old Koni manuals.
viewtopic.php?f=5&t=10498

RickKean
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Re: 79 CBX1000 OEM Rear Spring Rate

Post by RickKean »

Thanks Steve

I've PM'd Nils

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NobleHops
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Re: 79 CBX1000 OEM Rear Spring Rate

Post by NobleHops »

The modern Ikon 7610-1413 uses the same spring spec as the older Koni you have - a progressively wound spring with three effective spring rates - 18/25/33 kg/mm. That will translate to a range of 100-155 lbs/inch. They are 255mm long. We have other springs in that length, heavier and lighter and we freely exchange and install them for our new shock customers, FYI.

I do not however think that my springs will fit your 76-series shocks off the shelf - the spring clips/collars used on the 76 are slightly different in some way. The factory knows what is needed (I don't recall what the issue was) and they can certainly be procured for you if you wish to respring those old shocks. I"m going to guess you'll get into $50 of machined parts plus $100 for a pair of black powdercoated springs, $150 for chrome.

In anticipation of your next question, I cannot rebuild those - the seal is a different OD than that used on the newer Koni and Ikon 7610 and is not available from us or from Koni. I do have a collaborator that is attempting to make a bushing to size them down so our seal will fit the 76, but it's too soon to say whether or not that will work long term.

Best,

Nils
Nils Menten
Tucson, Arizona, USA '80 CBX, sort-of restored :-)

RickKean
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Re: 79 CBX1000 OEM Rear Spring Rate

Post by RickKean »

Thanks Nils for summarizing the Ikon offerings. The Konis I've acquired look to me to have a few miles left before requiring rebuild attention. The seal bushing sounds like a great idea! Let us know how that develops.
Please correct me if I'm wrong, but don't each of the 18/25/33 kg/mm rates need a decimal?
tx
Rick

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Re: 79 CBX1000 OEM Rear Spring Rate

Post by RickKean »

I emailed RaceTech about the Stock Rear Coilover Spring Rate. Their Technical Support Response was quick and to the point:
"The website says to call because we do not have specs on this model. Hopefully you are local and would like to bring the bike in so we can spec the machine and figure out what fits. This model is very rare and old so we have not had the chance to record the specs. Would you like to bring yours in?

Mike Crow
Tech Support"

While I'd like to send them the bike, my plans remain primarily DIY.

tx
Rick
Houston

steve murdoch icoa #5322
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Re: 79 CBX1000 OEM Rear Spring Rate

Post by steve murdoch icoa #5322 »

I am assuming they would want the bike at their Corona Ca. site?
Maybe somebody local could lend them a bike.

RickKean
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Re: 79 CBX1000 OEM Rear Spring Rate

Post by RickKean »

steve murdoch icoa #5322 wrote:I am assuming they would want the bike at their Corona Ca. site?
Maybe somebody local could lend them a bike.
Yes, Corona CA.

I found these coilovers on kijiji.ca https://www.kijiji.ca/v-motorcycle-part ... nFlag=true
Does this appear to be from an '80 CBX, as described by the seller? :
Image
This spring's wound diameter has a fairly pronounced taper as it nears the lower seat, so I'm guessing the spring rate wouldn't be linear, but progressive, as Nils has said of the Ikons.

Calling SoCaliCBXers :)

steve murdoch icoa #5322
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Re: 79 CBX1000 OEM Rear Spring Rate

Post by steve murdoch icoa #5322 »

Yes, those are '80 CBX shocks.

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