Author Topic: Anyboy did a mono shock modification???  (Read 6490 times)

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Offline Lumbee

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Anyboy did a mono shock modification???
« on: November 12, 2005, 07:06:23 PM »
...playing around with some ideas, wondering if anyone has modified a stocker (CB750) to use a monshock.  Anybody see a problem with doing this?
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Offline Sam Green Racing

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Re: Anyboy did a mono shock modification???
« Reply #1 on: November 12, 2005, 10:04:03 PM »
It's looking like a no Mark. Have a go at it, you may be the first person in the world to own one. ;D
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Offline SteveD CB500F

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Re: Anyboy did a mono shock modification???
« Reply #2 on: November 13, 2005, 02:45:07 AM »
There's a monoshock 500/4 out there somewhere.
I read about it in an old magazine.
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Offline Einyodeler

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Re: Anyboy did a mono shock modification???
« Reply #3 on: November 13, 2005, 06:24:44 AM »
The 500 would be easier because you would only have to relocate the battery , but the 750 has the oil tank there too.
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Offline JonnyHonda

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Re: Anyboy did a mono shock modification???
« Reply #4 on: November 13, 2005, 06:47:06 AM »
There would be a lot to consider, would a stock mono shock suspension from say a GPZ750 of CBR bare the weight, the 750 SOHC weights in at over 500 pounds, balancing, alignment C of G. Like to see it done though ;D

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Offline MRieck

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Re: Anyboy did a mono shock modification???
« Reply #5 on: November 13, 2005, 06:49:59 AM »
I thought the guy that put the 900RR front and rear end on the F used the mono set up?  Maybe he just welded shock mounting brackets on the swingarm for the 2 shock set up. I can't recall. Anyone remember the bike I'm talking about?
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Offline Einyodeler

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Re: Anyboy did a mono shock modification???
« Reply #6 on: November 13, 2005, 07:03:03 AM »
It`s not a SOHC but you gotta check this out this radical CBX :o
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Offline Sam Green Racing

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Re: Anyboy did a mono shock modification???
« Reply #7 on: November 13, 2005, 01:24:15 PM »
What a waist of a nice motor ::) ::)
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Offline MRieck

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Re: Anyboy did a mono shock modification???
« Reply #8 on: November 13, 2005, 02:46:33 PM »
What a waist of a nice motor ::) ::)
.....and alot of effort! ::)
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Offline 6adan

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Re: Anyboy did a mono shock modification???
« Reply #9 on: November 13, 2005, 03:42:34 PM »
  Looks like he got the tank from part of a F117 jet fighter.
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Offline Sam Green Racing

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Re: Anyboy did a mono shock modification???
« Reply #10 on: November 13, 2005, 03:46:16 PM »
I did'nt see the tank  ;D
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Offline paulages

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Re: Anyboy did a mono shock modification???
« Reply #11 on: November 13, 2005, 06:09:14 PM »
a mechanic at my local parts shop has converted a cb500/4 to a monoshock. don't think it looks all that hot, but i'll ask him about the specifics...
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Offline Geeto67

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Re: Anyboy did a mono shock modification???
« Reply #12 on: November 13, 2005, 06:53:02 PM »
There are a few SOHC cb750 monoshocks floating around japan. Can't find the pics now, but I have seen them in the past. Most of the bikes are SOHC 69-76 K bikes, I think I remember only seeing one monoshock supersport. I think there is a black SS monoshock conversion in canada also.

I have considered the conversion on other bikes and the one thing I have learned is get the whole back end system. Sometimes a little thing like the shock can make a system not work, I friend of mine in england had an fzr600 rear setup on a kawasaki h2 and when he used an R6 rear shock the suspension wouldn't work, he put the fzr600 shock back in and the suspension worked fine. Get a whole system and try to duplicate the shock angle as the stocker it came from. For older bikes I hear cbr600f2 and fzr/fz 600 also work well as a starting point. I like the fzr600 because the upper shock mount in the fzr60 frame is steel and can just be cut and welded to the bike frame you are converting. 
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Offline Lumbee

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Re: Anyboy did a mono shock modification???
« Reply #13 on: November 13, 2005, 07:12:44 PM »
...hey Gee, r u saying there are aftermarket kits for this?  I was thinking of fabbing something up my self.  Grabbing a late model sport bike shock off ebay and fab it up...
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Offline SteveD CB500F

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Re: Anyboy did a mono shock modification???
« Reply #14 on: November 14, 2005, 02:25:42 AM »
I haven't found much on this, but did find this note:

www.bikerworld.co.uk/tech/probs/CB750monoshock.html

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Offline Geeto67

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Re: Anyboy did a mono shock modification???
« Reply #15 on: November 14, 2005, 03:00:34 AM »
...hey Gee, r u saying there are aftermarket kits for this?  I was thinking of fabbing something up my self.  Grabbing a late model sport bike shock off ebay and fab it up...

If there are kits for this, they exist only in the bowels of japan, and I can't read enough japanese to find out. It would not surprise me though. Spondon and Harris in england  might have more information about it. For the time being you are in severly custom waters.

I assumed that in converting to monoshock you would be using a rear swingarm setup off another more modern bike, espically since the rear stock swingarm may be inadiquate for this conversion (the K bike flexes too much, don't know about the F). All I was saying is if you are going to convert, get the whole setup off the donor bike, the wheel, swingarm, shock, shock mounts, dog bones, etc. You can't just weld mounts to your existing swingarm and frame and then grab any old shock and stuff it in there, there is a science to it. Norton used to have a monoshock swingarm in the 60's that the tz750 copied, they were laydown shocks that ran across the top of the frame at an angle and were huge, the swingarm was also extremely heavily braced. That is probably the only way you will get your old swingarm to work with a monoshock. For modern bikes, the shock drops below the swingarm and is attached with some dog bone linkages which can be used to tune the suspension. mismatching the shock with the dogbones can have disasterous results. The way involving the least engineering is to just adapt what already works on another bike to your bike, and by adapt I mean the whole thing.
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Offline Lumbee

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Re: Anyboy did a mono shock modification???
« Reply #16 on: November 14, 2005, 05:56:48 AM »
....good article steve...thanx...
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Offline cb(r)

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Re: Anyboy did a mono shock modification???
« Reply #17 on: November 14, 2005, 06:50:24 AM »
I was going to do the mono shock thing.  but it is not the look I really want at the moment.  I have 74 cb 550.  I have an cbr hurricane 600 swing arm shock and rear rim with disk brakes and rear sets.
here is some pros and cons.
the 600 swingarm is not as wide as the 550 at the pivot point, thus you need to make special spacers about two 1/4" gaps roughly.  also the pivot bolt for the 600 is larger than the 550.  so one option is to drill out  the mounting holes  to accept the bolt. 

the 600 wheel centerline to sprocket centerline is very close so slight  change there. *very important  alignment issue*  because of tracking probs and chain alignment.  once these two forementioned centerlines are correct then you get spacers to align for tracking.
 also the bearing diameters of the 600  wheel are smaller then the the 550.  bolt and spacer issues again.

If you still want to put the swing arm and shock on your bike  then here is some good advise I recieved from geeto67.  do research! take all you current and exact dimensions of your related bike parts. write them down and keep them with you especially at a bike salvage place.
there is alot of work but it is a very cool look.

what I have learned is that you should try to stick with honda parts. when doing the conversion.  alot of the dimensions either have not  changed or changed very little. 

I will try to find pics from my post on the subject.  hope this helped and not discouraged.?

Offline cb(r)

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Re: Anyboy did a mono shock modification???
« Reply #18 on: November 14, 2005, 07:00:26 AM »
 search  "mono shock" on this site. it will put you to my post "changing to newer swingarm and monoshock. comments or ideas?"

 read that.  there is a couple of links to pics. 

one more thing with the project I was going to do,  another pro is a 2" extension with  the  cbr swingarm

good luck

Offline Lumbee

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Re: Anyboy did a mono shock modification???
« Reply #19 on: November 14, 2005, 07:28:33 AM »
...thanx CB...looks like we already went through all this huh?   ::)  I'm got a few swingarms I'v already modified with about 6" of stretch (over kill???)  That I'd like to use if I tryed this...
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Re: Anyboy did a mono shock modification???
« Reply #20 on: December 05, 2005, 02:04:27 PM »
I have done four monoshock conversions on the CB750

Offline ProTeal55

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Re: Anyboy did a mono shock modification???
« Reply #21 on: December 05, 2005, 02:11:34 PM »
Got any pics of what the end-product looked like ?
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Offline cb(r)

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Re: Anyboy did a mono shock modification???
« Reply #22 on: December 05, 2005, 02:26:49 PM »
ya send some pics!  I pesonally like the look.