71' CB500 monoshock with no name...O2 sensor success!

Re: 71' CB500 monoshock with no name...electrical hiccup?

MotorbikeBruno said:

Haha yep, stupid charging systems! Wait...without them we couldn't get far... haha.

Here's the results. I think the pictures speak for themselves. And my current thought is that there is something wrong with the battery. 14.5V at higher rpm. But when you let off that throttle, it dips right back down to 12V range with the headlight on. Somehow the battery can't handle that kind of draw...so I'm going to have it checked out. Borrowing a co-worker's car to get another one (should be warrantied....) Wish me luck.

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tear apart 3 of your meters and use the parts to fix the problem. A-team for the win!

no serious, ditch the stock crap and get the RR24 combined reg/rec for around 100 bucks. fix and forget. trust me, best buy you'll do on the bike.

Re: 71' CB500 monoshock with no name...electrical hiccup?

Bert Jan said:

tear apart 3 of your meters and use the parts to fix the problem. A-team for the win!

no serious, ditch the stock crap and get the RR24 combined reg/rec for around 100 bucks. fix and forget. trust me, best buy you'll do on the bike.

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Bert, I already have that! (see picture) Found the problem, it appears there is supposed to be 12V going into the Black line....and it was NOT, as my harness is now "custom" to my bike. Fixed that and we're all good. Waiting on needles for my machine to try the damn seat again. Working out the bugs as I go. Over 300 miles on her so far in her current state

Re: 71' CB500 monoshock with no name...electrical hiccup?

You'll probably hate me for saying this, this late into your build, but the monoshock angle you have is bad from a physics standpoint. It could just be the angle of pictures, though.
Maybe someone said something already, but I haven't real all 17 pages.

If you feel inclined, and have the time sometime, angle the monoshock mount struts on the swingarm up a few degrees, so that the angle of the mount struts and the shock do not pass 180 degrees at full compression.

I could go into why, but it's the common non-levered practice, and makes practical sense in terms of physics.

Fun build overall though, nice work.

Re: 71' CB500 monoshock with no name...electrical hiccup?

mlinder said:

You'll probably hate me for saying this, this late into your build, but the monoshock angle you have is bad from a physics standpoint. It could just be the angle of pictures, though.
Maybe someone said something already, but I haven't real all 17 pages.

If you feel inclined, and have the time sometime, angle the monoshock mount struts on the swingarm up a few degrees, so that the angle of the mount struts and the shock do not pass 180 degrees at full compression.

I could go into why, but it's the common non-levered practice, and makes practical sense in terms of physics.

Fun build overall though, nice work.

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I measured rake and trail and it falls within the guidelines for a good handling bike (it has surgical knive-like handling and great stability at higher speeds). As for full compression, the shock moves less than half an inch...with me on it/full load. It was designed for a 800lb+ motorcycle and is really almost as stiff as using a metal bar in there, I should have just made it a hardtail Thanks for the heads up though, I am fairly confident I won't have any issues in the future as this shock doesn't do what other much softer shocks would. (for example...compress! haha)

Re: 71' CB500 monoshock with no name...electrical hiccup?

Yeah, I wasn't talking rake and trail, was talking leverage, radii, stress and all that other good shit.

Re: 71' CB500 monoshock with no name...electrical hiccup?

mlinder said:

Yeah, I wasn't talking rake and trail, was talking leverage, radii, stress and all that other good shit.

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Ah, word. That isn't necessarily in my job title. Can you draw on a picture to show me what you mean by the 180degree comment?

Re: 71' CB500 monoshock with no name...electrical hiccup?

Sure, ill make a quick 3d sketch here in a few.

Re: 71' CB500 monoshock with no name...electrical hiccup?

It looks as if your lashup may have a falling rate,and is actually starting out "over center", well under center really but the rate is falling
the shock lower mount should be signifincantly above a line drawn thru the axle and top mount ,when shock is bottomed this should still be above that line
this insures a rising rate,even if nearly flat when seen on a graph
the modern single shock linkage has a carefully designed rising rate usually on a curve that climbs much steeper near bottom out, without a linkage the rate will be straight and not very steep, i think
but what you do not want is a falling rate this means as rear wheel travel progresses the shock has more leverage advantage applied to it, the opposite of what you want

Re: 71' CB500 monoshock with no name...electrical hiccup?

xb33bsa said:

It looks as if your lashup may have a falling rate,and is actually starting out "over center", well under center really but the rate is falling
the shock lower mount should be signifincantly above a line drawn thru the axle and top mount ,when shock is bottomed this should still be above that line
this insures a rising rate,even if nearly flat when seen on a graph
the modern single shock linkage has a carefully designed rising rate usually on a curve that climbs much steeper near bottom out, without a linkage the rate will be straight and not very steep, i think
but what you do not want is a falling rate this means as rear wheel travel progresses the shock has more leverage advantage applied to it, the opposite of what you want

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Let's put that ^^ into things that make sense. My "lashup" is not a term the average person knows. Here's what I'm asking for. A simple drawing. I used different colors so you could explain what you are talking about in layman's terms. From what I'm gathering, you are saying to have the bottom shock mount raised up above the line (BLUE line on drawing) correct? I chose to put it in-line because it would have less torque on the weld joints if they were sitting on top. They are in-line for that purpose, the picture makes it look like it's drooping below slightly, and it's not as drastic as this shot looks because of the angle it was taken at. I'd say it's almost perfectly in line but I'll go check when I get home. Thanks for the input!

Also, don't forget, this spring will never "bottom out" It's so insanely stiff for this bike that it BARELY moves under any amount of stress/bumps/potholes. And note again that the pictures aren't perfectly from the side, so you will see some "deflection". I'll take your thoughts into consideration, although this particular shock was not mounted like the other sport bike shocks you see, it was mounted similarly to what is there, both top and bottom are allowed to move, unlike the sportbike shocks that have ONE stationary point and use a linkage. This is why I chose this non-sport bike version over a CBR shock.

Re: 71' CB500 monoshock with no name...electrical hiccup?

xb33bsa said:

It looks as if your lashup may have a falling rate,and is actually starting out "over center", well under center really but the rate is falling
the shock lower mount should be signifincantly above a line drawn thru the axle and top mount ,when shock is bottomed this should still be above that line
this insures a rising rate,even if nearly flat when seen on a graph
the modern single shock linkage has a carefully designed rising rate usually on a curve that climbs much steeper near bottom out, without a linkage the rate will be straight and not very steep, i think
but what you do not want is a falling rate this means as rear wheel travel progresses the shock has more leverage advantage applied to it, the opposite of what you want

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Exactly. Thanks man, I'll stop CADing now

Re: 71' CB500 monoshock with no name...electrical hiccup?

mlinder said:

Exactly. Thanks man, I'll stop CADing now

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Haha, I'm cool with it, I love to learn. I just edited my above to see if that's correct. Check that again if you wouldn't mind. I'm heading home now. I'll catch your responses in the morning.

Re: 71' CB500 monoshock with no name...electrical hiccup?

MotorbikeBruno said:

Let's put that ^^ into things that make sense. My "lashup" is not a term the average person knows. Here's what I'm asking for. A simple drawing. I used different colors so you could explain what you are talking about in layman's terms. I appreciate it!

Also, don't forget, this spring will never "bottom out" It's so insanely stiff for this bike that it BARELY moves under any amount of stress/bumps/potholes. And note again that the pictures aren't perfectly from the side, so you will see some "deflection" I would think. I'll take your thoughts into consideration, although this particular shock was not mounted like the other sport bike shocks you see, it was mounted similarly to what is there, both top and bottom are allowed to move, unlike the sportbike shocks that have ONE stationary point and use a linkage. This is why I chose this non-sport bike version over a CBR shock.

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OK, that is a good photo and drawing of what I'm talking about. That should be a 180 degree, that is, straight, and mo more (though less is probably fine in this case) line fully loaded and coming down hard at 60mph from a 30 foot long jump you just did from a giant speed bump. The blue line is the only one we care about in this case.

The angle is the wrong way right now.

Angle the support bar up enough to get your angle of where it and the shock meet to an angle in the OTHER direction.

It has nothing to do with the fact that both sides of the shock are "hinged", it has to do with compression rate, compression depth, and greater linearity in shock compression.

You can weld, it's an easy fix, and should you ever decide to get a shock back there that makes sense, you'll be MUCH much happier.

Re: 71' CB500 monoshock with no name...electrical hiccup?

And really, xb33bsa is right, there should still be less than 180 degree angle (at the bottom) with you, your girl, and 100 pounds of camping gear on your back whilst jumping up and down on it, at it's lowest point. You never want the amount of force from the shock to decrease as the inside angle increases, which is what happens when your suspension setup is "upside down", like yours is.

Re: 71' CB500 monoshock with no name...electrical hiccup?


I would not worry about it tho until you get a shock/spring combo that actually moves, carry on and keep up the good work

Re: 71' CB500 monoshock with no name...electrical hiccup?

I'd do it now while the bike isn't complete

Re: 71' CB500 monoshock with no name...electrical hiccup?

Thanks for all the words. I'll see if there is a way for me to "fix" it when I fully weld the rear end together. I'm worried if I change that, all of my rake/trail stuff will change, which would be bothersome...because it handles like a dream...it just hurts my back! hahaha

Just to be clear. I think you are saying the lower shock mount should go UP slightly from where it is at now (in-line) correct? Or did I read that wrong and it should go DOWN towards the ground? I'll do what I can, but like I said before, that spring is solid. haha

Re: 71' CB500 monoshock with no name...electrical hiccup?

yes up
why not get a shock that works ? or at least a lighter spring ?seems a shame you did such nice work but the ride sucks

Re: 71' CB500 monoshock with no name...electrical hiccup?

xb33bsa said:

yes up
why not get a shock that works ? or at least a lighter spring ?seems a shame you did such nice work but the ride sucks

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Well it's actually not THAT bad, which is why I kept it. The main issue is space and shocks that are designed to be mounted and used like this. All of the CBR and sportbike shocks are designed for the linkages, they are also 4+ inches longer than this bad boy. The other issue was price. At the time, any of the shocks that were designed to be used this way were pretty expensive. I'm relatively happy with it overall, I'm just not as young as I used to be, and the sportbike is taking its toll as well haha

Re: 71' CB500 monoshock with no name...electrical hiccup?

designed for a linkage ? don't worry about that,try and find one that has correct spring, travel and length whether or not it is used with linkage is of no matter

Re: 71' CB500 monoshock with no name...electrical hiccup?

xb33bsa said:

designed for a linkage ? don't worry about that,try and find one that has correct spring, travel and length whether or not it is used with linkage is of no matter

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From the myriad of posts that was something that was very notable. Do NOT use a linkage type shock in a straight design. I suppose I'll keep it as-is for now and try to change the mounting point a bit as mentioned. I do not see it being a problem, but there's a difference between good and bad design I suppose :-\ Onward! ;D