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I'm not "picking a fight" either. Seen 1000s of people come through here and do exactly what you did, still have yet to see someone finish. Why? because the "sequencing" as you put it doesn't set them up for success. Believe it or not, most of the people here want you to have a long lasting and satisfying experience in the hobby, but we have also seen this a dozen times and you aren't special or different, and we already know how this is probably going to turn out (because that's the value of experience).

Since you seem pretty oblivious, let me clue you in to a couple of things about this site:

1) most of the regulars here are vintage racers, racing enthusiasts, industry people, or general performance motorcycle people. There is a very low tolerance for bikes that are to be seen and not ridden, and honestly so far all you have posted is that you care more about how it looks than how it works.

2) Unless you are an engineer working in the motorcycle industry (and it's pretty safe to assume you are not), you are not smarter than the honda engineer that designed the frame for your bike. just hacking stuff off behind the shocks because you think it looks cool is a pretty wrong idea. Don't get me wrong, I am not against frame mods per se, but there are ones smart people who know what they are doing do, and ones that people do because they don't know any better and they saw it on the internet. Guess which you are.

3) you build every custom bike twice (sometimes 3 times). Only the jackasses on TV take bikes all apart and do everything all at once because it looks dramatic. Actually I don't even think they do it, I think producers cut and edit the footage to look that way because they can make it seem more dramatic. All the people I know who modify bikes for racing make their mods on fully running ride-able bikes because they can then immediately test their modifications to see if it was a good idea or not. It also helps them with clearance for other items, because it is easier to adjust the part you are fabricating than it is to fabricate pieces for two different sections. Everything on a bike is part of a system, change one thing in the system you have to change the whole system. You changed the seat so now your bar position and foot control position have to change. And by the way, the way those things behave on the stand vs how they behave in motion are very different. So you build it up and make sure it all works and it's ugly as hell and that's when you take it all apart to do cosmetics. Trying to do them both at the same time is setting yourself up for failure (hint: you should probably ask how).

4) Don't put anything on the internet you aren't ready to receive criticism about. If this is precious to you, then probably find another hobby - motorcycles are dangerous and amateur dipshits who watch a youtube video and think they can just cut sections out of their frame are not making it any safer. Having a defensive attitude only hurts you, being emotionally tied to your decisions only hurts you. You have to be objective about your modifications. If you post a few pics on the internet of you hacking off a piece of frame, and pretty much all the regulars come out and laugh at you it's probably a sign you should ask about why it was a bad idea, to get defensive and say "it's my choice" and shut down is just a good way to end up on your back in the middle of the road wondering what happened while you wait for an ambulance.
 

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Discussion Starter #23 (Edited)
Thanks for taking the time to put your thoughts in writing.
No offence intended but I'm sure you will understand that presumption on your part can read as prejudice to me.
Huge negative judgements made off a couple of photos followed by a load of insults. Welcome to caferacer.net ��
You say you 'already know how this is going to turn out, that's the value of experience'. What do you know of mine?

Using your numbers:

1. I chose to register on this site precisely because it has the membership and expertise you describe. You've decided somehow that I care more about how it looks than how it works. The seat mock up is to ensure that it will work - place for battery, electrics, suspension etc. All vital.

2. Good to know you're not against frame mods - if you're up for it, you might enjoy/endure this build. Again no need to close with an implied insult.

3. All makes sense but my plan is not unique, I'm here for constructive inputs and enthusiasm, insults I can get anywhere.

4. My personal work is entirely about creative ideas. To have an idea puts you in a minority of one, otherwise it's not an idea. It's then about converting people to the value of the idea. I work in an environment of continual challenge and criticism. A few one liners on the Internet are a non issue. More than happy to trade.

Read this somewhere - Ever tried. Ever failed. No matter. Try again. Fail again. Fail better. Kinda liked it.

Enough of the banter.

I'll post a couple of photos/doodles - you'll see where I'm going but if you can resist the immediate temptation, I'm all ears.
 

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Discussion Starter #24 (Edited)
A couple of sketches -

1. the hairy one to understand the risk of suspension going 'over centre'. A wheel in the ass scenario.

2. Swing arm/mono-shock - suspension travel/spring compression.

As an initial sketch, 4"/100mm suspension travel equates to 1.6"/40mm spring compression and critically not over centre.

Interested in thoughts around these issues please and ideas on an appropriate shock for this orientation and compression (size 10"/250mm). Bike wet weight 445lbs/200kgs

image.jpeg image.jpeg image.jpeg

Thanks
 

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Read this somewhere - Ever tried. Ever failed. No matter. Try again. Fail again. Fail better. Kinda liked it.
Yeah, nice quote but when you're talking about cutting shit out of motorcycle frames and converting shitty twin shock frames to mono shock the time where you fail is usually at full throttle and it can be game over. Try again may not even be possible.

Your call, but from my perspective you need to stop doing hipster shit because you just saw it on Pipeburn.
 

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Discussion Starter #26
Quote is Geeto67 tag line - just looking for common ground with him/her after a frosty start.

I’m sure he/she will appreciate your comment.

If you’re willing, I’m after informed options on a mono-shock conversion:

Have I actually lost structural integrity?

If so,
What to reinforce?
Where to reinforce?
How to reinforce.

No idea what Pipeburn is unless it’s what my grandfather complained of when hiding his pipe whilst still lit.
 

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What swing arm are you going to use for your mono shock? The stock one is not up to the task of supporting weight without the twin shocks. With the bike torn down get that head off the motor and do a valve job. Super easy and will wake the motor back up. As long as the rings are good and rings on these last for many miles. Over the past 3 years I've done 14 custom CB500/550 rebuilds and if you don't do it just right you will hate it. You will ride it for 10 miles and then post it up for sale
 

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your bike and I could care less what you do to it. but I got $5 that says it never sees the road. (under its own power)
You of course realize there is no way you could ever collect on that bet... never is a mighty long time...

As for the frosty reception, I have to admit, when I saw this thread my first idea for a reply was 'What, no monoshock?" but decided to not say anything (then). I iterally LOL'd when I saw that little feature added. While it's new ground for the OP, it's more of the same around here. If you wander through past threads you'll see a lot of new projects where guys dove in head first and maybe lasted a couple weeks or so, but rarely have they amounted to anything.

Maybe yours will, who knows. None of us have any first hand knowledge of what you're capable of, but your thread has started out like so many others that go nowhere and just end up with another Craigslist ad for some CBwhatever parts.

I hope you surprise us, we could use that around here. As for the monoshock... in my book it's not worth the effort. The bikes that I consider to be the ultimate cafe racers (everyone has their own definition) have dual shocks. Nothing wrong with dual shocks on an older bike. Kinda like when people put single sided swingarms on their bikes. Why? Because they can. Ok... so what? As much of a Ducati fan as I am, I lost my fascination with SSS's years ago. But to each his own.

BTW - I also fully admit I'm jaded on the whole cafe racer thing. I hang around here to procrastinate from doing real work for the most part. Having said that, there's an Aprilia in my basement that could really use some race bodywork installed, I should get my lazy ass off the couch...
 

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Discussion Starter #31
What swing arm are you going to use for your mono shock? The stock one is not up to the task of supporting weight without the twin shocks. With the bike torn down get that head off the motor and do a valve job. Super easy and will wake the motor back up. As long as the rings are good and rings on these last for many miles. Over the past 3 years I've done 14 custom CB500/550 rebuilds and if you don't do it just right you will hate it. You will ride it for 10 miles and then post it up for sale
Plan is to reinforce the current swing arm - triangulate the length in line with mono shock with prop(s) at lower shock mount.

Won't be the first but I'd like to get it right.

1. I understand the principle of load following the line of the twin shocks.

2. The proposed mono-shock picks up the load along another axis and will need to be a different spring rate to carry the load.

What have I missed?

Terrific to hear the engines are tough. This one's done 44,000 miles.

Can I see any of your builds on line?

What do you consider 'just right'?

Thanks
 

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Discussion Starter #33
You of course realize there is no way you could ever collect on that bet... never is a mighty long time...

As for the frosty reception, I have to admit, when I saw this thread my first idea for a reply was 'What, no monoshock?" but decided to not say anything (then). I iterally LOL'd when I saw that little feature added. While it's new ground for the OP, it's more of the same around here. If you wander through past threads you'll see a lot of new projects where guys dove in head first and maybe lasted a couple weeks or so, but rarely have they amounted to anything.

Maybe yours will, who knows. None of us have any first hand knowledge of what you're capable of, but your thread has started out like so many others that go nowhere and just end up with another Craigslist ad for some CBwhatever parts.

I hope you surprise us, we could use that around here. As for the monoshock... in my book it's not worth the effort. The bikes that I consider to be the ultimate cafe racers (everyone has their own definition) have dual shocks. Nothing wrong with dual shocks on an older bike. Kinda like when people put single sided swingarms on their bikes. Why? Because they can. Ok... so what? As much of a Ducati fan as I am, I lost my fascination with SSS's years ago. But to each his own.

BTW - I also fully admit I'm jaded on the whole cafe racer thing. I hang around here to procrastinate from doing real work for the most part. Having said that, there's an Aprilia in my basement that could really use some race bodywork installed, I should get my lazy ass off the couch...
Thank you, all of that I can live with.

Just looking for informed understanding/experience. Many minds etc.
 

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Discussion Starter #34
Before I lose out to the KZ thread, any thoughts on earlier questions re implementing mono-shock conversion?

Have I actually lost structural integrity?

If so,
What to reinforce?
Where to reinforce?
How to reinforce.

Swing arm/mono-shock - suspension travel/spring compression.

4"/100mm suspension travel equates to 1.6"/40mm spring compression and critically not over centre.

Any ideas on an appropriate shock for this orientation and compression (size 10"/250mm). Bike wet weight 445lbs/200kgs

Thanks
 

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You can search some of my posts that have some pics of a few of my bikes. The "just right"is the riding position. If your going clip ons and bump seat then clip ons are a requirement. Tarozzi and raask make amazing bolt on sets for your bike. Do go the cheap eBay route. Also suspension. Again stay away from cheap eBay specials. Great cheap shocks are Redwing. NO OVER SIZED TIRES. They have a vintage look but are very bouncy
 

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Discussion Starter #37
You can search some of my posts that have some pics of a few of my bikes. The "just right"is the riding position. If your going clip ons and bump seat then clip ons are a requirement. Tarozzi and raask make amazing bolt on sets for your bike. Do go the cheap eBay route. Also suspension. Again stay away from cheap eBay specials. Great cheap shocks are Redwing. NO OVER SIZED TIRES. They have a vintage look but are very bouncy
Thanks, I'll take a look and thanks for the useful advice and supplier/manufacturer names.

Assume you mean DON'T go the cheap eBay route.

Agree on tyres.
 

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Discussion Starter #38
Re: Kinetic Motorcycles suspension conversion kit - Absolutely NOT what I want.

I can not follow the logic of the design - so many flexible junctions in the configuration. One size fits all maybe?

The plan is stiff swing arm constructed to suit suspension travel and shock dimensions/capability.

Still hoping for informed answers to my earlier questions.

Anyone?
 

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Not sure where or why you think the junctions are flexible. It follows the same basic design that most are using for the modification, simply reinforcing the existing swing arm. It'd be money better spent getting XB33BSA or one of the Brit experts that frequent the site to build you a proper set of shocks for the rear.

You said earlier that you had a plan. So far you have stripped a non running bike, hacked the rear frame off and now are seeking advice on chopping and welding it into a mono shock. How is your back end modification going to affect front end geometry, are you changing forks? Are you sticking with the 18/19 rims, if so it limits tire choice or are they changing. Are you trying to improve the performance of the motorcycle or is this an exercise in what you think looks cool?
 

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Re: Kinetic Motorcycles suspension conversion kit - Absolutely NOT what I want.
I can not follow the logic of the design - so many flexible junctions in the configuration. One size fits all maybe? ...
Just as the woodsman said, that design has no more flexible junctions then the original stock setup, the heim joint connections are only there to make the geometry of the whole thing adjustable. Probably because the creator was faced with the same questions as yourself; what spring, travel and shock absorption rates are required to make it function. The Kinetic kit really isn't a mono-shock conversion, it's a rear shock relocation conversion only if it still utilizes 2 shocks simply mounted higher and forward on the frame. Handling is probably not improved in the least considering the shocks they are using, probably handles like a pogo-stick.

One of the key design criteria in a performance monoshock suspension is to locate the shock absorber mounting points as low as possible in the frame. This is why the linkage type monoshock suspensions are superior to the non-linkage type setups. Honda's latest and greatest linkage setup moves the mounting points even lower then their previous setup by eliminating the top frame connection completely:

The swingarm pivot and the lower linkage dog bone carries all of the stress.

Something else to note is that modern performance monoshock spring/damper units are light years more advanced in their construction and design then the original spring holders on your antiquated CB. ... If you can't figure out that Kinetic design, this one will drive you crazy.

 
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