Topic: Aftermarket Boge shocks

[cbjunkie]

given the clevis mount and the measurements i think it's up to you - i have been looking for a slightly shorter shock for my K1 since i'm running a 16" on the rear and have enough daylight between the fender and rubber to pass a wombat through...

[ohiocaferacer]

i fold...i don't even know what you're talking about.

A progressive rate spring is usually a spring, that as the spring is compressed its resistance to force changes (increases) the more it is compressed. What this does is give you a nice stock spring rate during normal use, but as you push harder with the bike and compress the spring deeper into its stroke....you will get an increased spring rate or a stiffer spring. Kind of like having 2 spring rates in one spring.

You can usually tell progressive rate springs, due to the coils being wrapped closer to one another at one end of the spring.....which these shocks appear to have. Just wanted to double check if someone knew for sure......i'm betting they are.

[eldar]

Progressive dampening shocks are nice too. Start off light but more dampening as the shock compresses yet rebound is the same through the entire range!

[nomadwarmachine]

So are these longer or shorter than stock, and by how much?  Sorry, I don't have my CB handy (in storage at the moment)

[Terry in Australia]

Yepper, they're progressive rate springs, I've got my four pairs sitting here on the lounge room floor as I type this, they'll apparently work with all the CB sohc4's, and certainly will fit all 750's from the K0 to the (urrggghhhh) K8.

I can't say if they're longer or shorter than the OEM shocks as I don't have any to compare them to. Tom will probably know though, I sent him a pair of Boge's, and he's got a few CB750's so I imagine he's got a set of stockers to compare them to?

I got an email back from Tim, the seller, he's got cases of these shocks, so watch out for future auctions, looks like there'll be plenty to go around! Cheers, Terry.


 

[cbjunkie]

eye-to-eye stock is 13" i thought...

[SteveD CB500F]

Shocks are quite heavy Terry.

What was the freight cost like??  Probably still a good deal though at $50

[cbjunkie]

Colorado to Sain'Louie Missery was 10 bux...which is beans.

[Terry in Australia]

Shocks are quite heavy Terry.

What was the freight cost like??  Probably still a good deal though at $50

According to the box for 4 pairs to Oz it was $66.00 Steve, so at less than 20 bucks a pair I reckon that's pretty good? Should be about the same to Britain? Cheers, Terry.

[TwoTired]

I measured one of my used CB550 shocks.  The older kind with the metal shields on them.  (74, I think?)

Eye to extended length-  12.5 inches plus or minus 0.1 inch.
Eye to collapsed length-  10 inches plus or minus 0.1 inch.  (bottomed on rubber snubber)

Spring weight fully extended and compression adjuster at maximum - 105 lbs.
Spring weight fully extended and compression adjuster at minimum - 70 lbs.

I've had difficulty finding shocks for the CB550.  Progressive replacements were listed as 13 or 13.25 Inch length.  Which was exactly the same as the ones listed for the CB750.

A story for those who care to read such things...
I bought a 1975 CB550K with Koni shocks on it.  Though pleased with the markings, I removed them very soon as I thought they were horrible.  They kept banging at full extension on every tiny change in pavement evenness (single rider).  These shocks are 13 3/8 eye to eye and clearly were ill suited for the Cb550.

Here's the data I measured on the Koni's.
Eye to extended length-  13 3/8 inches plus or minus 0.1 inch.
Eye to collapsed length- 10.25 inches about.
The springs have a stripe of red and a stripe of white paint on them, unknown significance
Spring weight fully extended and compression adjuster at maximum - 20 Lbs !?
I can't compress them at all with 140 lbs applied! (My stability limit on the test scale)  However, the shock didn't argue with my 12 ton shop press!
I'm guessing these need to be rebuilt, at least.
External markings
Koni  Holland
Special "D"
76F-1296
8-74

Are they worth rebuilding?

Cheers,

[Terry in Australia]

You can't buy rebuild kits from Ikon (Koni's successor) for the older Koni shocks TT, however, I think (and I'll know for sure once I get KGhosts old Koni's apart) that the 7610 rebuild kits kits will fit the older shocks, as the shafts are the same OD, but the bodies on the older shocks appear to be narrower.

Up to you whether to rebuild them or not, if you weren't happy with them then you'll probably sell them, but while Tim is selling the Boge shocks for 50 bucks a pair, (which I suspect can be rebuilt with the Ikon kits as the shafts appear to be the same size and the bodies will be easier to open than the Koni's with the special tool provided) you probably won't recover the cost of the rebuild. Cheers, Terry. 

[TwoTired]

My Koni's look good on the outside.  But, while compressing them in the press, they made "crunchy" sounds.  I'll make a tool to get them apart. (lefty Loosey?) But, if the internal bores are rusty, they'll go to the dump.  The shaft seals are all cracked, so there might not have been any fluid in them for years.  That couldn't have helped, if indeed they are dry.  Can't expect them to work well after abuse.

Wonder if my MC shop buddy has the tool for these...

Cheers,

[Henry Dorset Case]

FWIW, I am paying $30USD for shipping one pair of shocks from the US to sunny New Zealand.  Since its about as far in the world you can go (unless he was sending them to Scott Base in Antarctica), I am just living with it...

[TwoTired]

(unless he was sending them to Scott Base in Antarctica).

Hmmm,  I think I'd want a full vetter with lowers and spike tires, too...  Wonder how you preheat an SOHC4?
 

[clarkjh]

50 Gallon drum on fire under the pan

James

[eurban]

Two Tired-

In case your interested, Ikon's website has the color coding for Koni spring rates.  I think it's in the technical section.  Basically you should be able to magically transform  the colors on your springs into spring rate numbers.  I have an NOS set of the special D 1296s (this is the number for the 750) that I am using on my project bike. These did come with some crude instructions on how to change the compression/rebound dampening.  Let me know if the instructions would be helpful.

[nomadwarmachine]

If anyone can quickly run a tape measure along their stock CB750 K0-K6 springs, please let me know -- I am 1500 miles away from my K2 but would love to get a set of these to replace the stock springs!

[Terry in Australia]

My Koni's look good on the outside.  But, while compressing them in the press, they made "crunchy" sounds.  I'll make a tool to get them apart. (lefty Loosey?) But, if the internal bores are rusty, they'll go to the dump.  The shaft seals are all cracked, so there might not have been any fluid in them for years.  That couldn't have helped, if indeed they are dry.  Can't expect them to work well after abuse.

Wonder if my MC shop buddy has the tool for these...

Cheers,

That's it mate, lefty-loosey. There's not much inside them, I recently rebuilt a set of the 7610 series shocks and they surprised me with their simplicity. The hard chrome on the shafts rarely rusts, and the "cylinder" is just a mild steel tube. I used about 70ml of ATF to replace the rusty gunge that was once oil, and the "rebuild kit" only consists of the shaft seal and an "O" ring under the threaded "nut", so they're a piece of cake to do, once you get the "nut" off. Cheers, Terry.  

[Gordon]

If anyone can quickly run a tape measure along their stock CB750 K0-K6 springs, please let me know -- I am 1500 miles away from my K2 but would love to get a set of these to replace the stock springs!

The stock shocks off my K1 are 12 7/8" fully extended. 

[78 k550]

so from the little shock thing I had a couple weeks ago. I found out I had a pair of 750 shock's on my 500. they measure 13 1/4" center eye to eye. The springs off measure 9 15/16th"

Paul

[eldar]

I would not mind these shocks but I kinda like the height. These would drop about 1 inch off or so.  But if they work really well, then I probably would not mind too much. Terry, you gotta get a pair on and let us know how they work. Ikons and all the others are rather expensive right now for me and if these work better than the nameless brands being sold and are cheaper, well that is all good!!

[Terry in Australia]

OK Eldy, if I get time today I'll stick a set on my F2 and fit KGhosts tank so I can take it for a ride, and I'll take some pics. Cheers, Terry.

[nomadwarmachine]

Please do, Terry!  I would like to repalce the springs on my 750K2, but I would love to see how they look/ride, first!

[Terry in Australia]

Man, the things I do for you guys, ha ha! Ok, so I "shelved" the K1 seat fix to to do this, I dragged out the F2 and washed a good 6 months worth of dust and crap off it, then took a pic with the NOS S&W "Street Strokers" that have been on it since I resto'd the F2 from the Ebay junker I paid 500 bucks for in the summer of 2003, and have done less than 100 miles since. The Street Strokers are real long, 14 inches from eye to eye, making the centre stand a gamble, and the sidestand completely redundant, ha ha!

Now it wasn't just a case of "slapping them on" as I'd ordered the Boge's from Tim with different springs, unassembled, so I had to select a pair of springs, and assemble the shocks. Hmmnnnnn.......... Problem is, my home made shock compressor was made to rebuild a set of old Koni's on my Cb350F 10 years ago, and required extensive modification to accept the wider Boge shockers, but after an hour or so of screwing around on the milling machine, I got them together again, and as I'd gone mad with "anti sieze" compound when I restored the bike, it only took 30 minutes (if that) to remove the S&W's, and fit the Boge shocks. Now someone was saying that these Boge shockers are an inch shorter than stock, but that can't be right, because on the centre stand the tire sits approx 1 inch above the concrete, which is just about where I'd expect it to be?

Now the F2 hasn't fired a shot in anger for a good 6 months, and 3 months or so ago I discovered that the tank was rotting out with rust, so I carefully removed the bubbly tank and replaced it with Tim Kasper's (KGhost) tank that he sent me all the way from Texas, all those months ago, that finally arrived just before Christmas, and gave it 20 or so kicks with the ignition off to circulate the oil and get some fuel into the carbs. I re-fitted a charged battery and hit the starter, and surprisingly, it went VAROOM straight away!

Okay, I let it warm up, and worked the clutch lever a few times to get the oil circulating between the plates and by the time I got my ol' open face helmet on, was happy with it "snicking" into first gear, and casually took it through the gears as I cruised around the block, testing the new shockers over the speed humps in my street, and even though the springs were on their lowest position, they felt good. Firm, but not hard.

The bike was running pretty good, so I decided to go for a decent run, so headed north and I can say the shocks were working really well, no wallowing in corners or sweeping bends, when I noticed something hot and wet stinging my (bare) left leg? Turns out that I've got a massive(ish) oil leak, and the hot oil was spraying all over my leg? Hmmnnnn, not good.

Ok, I turned the bike around, and "gave it the berries" all the way home, seeing a tad over 100 Mph as i watched hot oil running over my left boot and up my shin, which smelled a bit like baked potatoes? Oh well, I got home in one piece, degreased the engine (and my leg) while it was still warm, drank a couple of bottles of icy cold Strongbow cider to dull the pain emanating from my roasted, but still manly leg, and had a shower. here's come pics, Cheers, Terry.   

[Terry in Australia]

And some more................