Topic: Café/brat CB500 K3 -77, can't hold my fingers from it

[SOHC4 Cafe Racer Fan]

Did you replace the 40-year old fork springs?

[AlBundy]

No I didn't. It has progressive springs. Is that stock and should I replace them?

[AlBundy]

A better picture of the bike. Need to install the plug for tacho wire. Arrives next week I hope. Need to order new handgrips also.

What do you guys think about the design? Want some feedback

[AlBundy]

A video of the exhaust sound

[SOHC4 Cafe Racer Fan]

No I didn't. It has progressive springs. Is that stock and should I replace them?

Not stock. Hard to say if you should replace them. Yes, if they are not providing sufficient dampening.

[AlBundy]

No I didn't. It has progressive springs. Is that stock and should I replace them?

Not stock. Hard to say if you should replace them. Yes, if they are not providing sufficient dampening.

The dampening feels pretty good. Compared it with my friends new Z800. It´s not as good as his but it works. The rear shocks feels hard as stone though. Should they be like that?
 

[SOHC4 Cafe Racer Fan]

No I didn't. It has progressive springs. Is that stock and should I replace them?

Not stock. Hard to say if you should replace them. Yes, if they are not providing sufficient dampening.

The dampening feels pretty good. Compared it with my friends new Z800. It´s not as good as his but it works. The rear shocks feels hard as stone though. Should they be like that?

I think you might be overly optimistic about your front end.

The rear should not be either overly stiff or soft.

[AlBundy]

No I didn't. It has progressive springs. Is that stock and should I replace them?

Not stock. Hard to say if you should replace them. Yes, if they are not providing sufficient dampening.

The dampening feels pretty good. Compared it with my friends new Z800. It´s not as good as his but it works. The rear shocks feels hard as stone though. Should they be like that?

I think you might be overly optimistic about your front end.

The rear should not be either overly stiff or soft.

Okey. The bike has not been on the roads since 86. If  the springs isn't stock, they can not have been used so much I would guess. Or do they become less good when just standing and aging wthout being used?

[SOHC4 Cafe Racer Fan]

It might be okay.  I was just kidding because there's no way it could be in the ball park of a modern sport naked bike. 

Seals and fork oil degrade over time.  Make sure to service your forks if you haven't with new oil, cleaning and seals.

If the shocks feel too stiff, wooden or too soft, replace them. 

[AlBundy]

It might be okay.  I was just kidding because there's no way it could be in the ball park of a modern sport naked bike. 


Seals and fork oil degrade over time.  Make sure to service your forks if you haven't with new oil, cleaning and seals.

If the shocks feel too stiff, wooden or too soft, replace them.

Thx for the answers. It's okey :p I have replaced the seals and the fork oil. The Honda dealership here in Swe told me to use 15W Motul oil, so I bought that.

[AlBundy]

Did a compression test today to be sure that the engine is in good condition. Bike was warmed up and I used the starter button and it was dry.  Got these numbers #1 150psi, #2 155psi, #3 155psi and #4 160psi. What I've understand the difference should not be more than 10%, but what about the pressure? What should the numbers be?

Thx in andvance. This forum is the best!

[SOHC4 Cafe Racer Fan]

Al.  Your bike is looking and sounding great.  I ditched the 77-78 exhaust on my K4 because it was rusty, but yours looks and sounds nice. 

[AlBundy]

Thanks guys. Will ride it for sure! More questions will be asked at the winter period when I tear i down. 

[AlBundy]

Anyone who knows what the float height should be on PD46B carbs? Read somewhere that PD46A has 14,5mm but I can't find anything about the B version.

[AlBundy]

Hi,

Anyone who knows if the drain tube (number 22) should be connected like I have drawn in the attached diagram? If not, what should be connected to the pipe from the chamber comp (number 12)?

[AlBundy]

No one that can answer?

[AlBundy]

Anyone who can tell if it is necessary to seal the inlet manifold rubbers when reassembling them? I noticed that the ones (OEM) I had on the bike were leaking so i bought new. Installed them with new clamps but it is still leaking (or sucking air). Sprayed some carb cleaner on them and the rev raised. I also hear some kind of "spitting" noise from them sometimes.

This is the ones I bought: https://www.davidsilverspares.co.uk/CB550K3/part_144351/

Maybe I should have bought the oem ones? Or do I need to seal them with some kind of grease or gasket seal?

[AlBundy]

Hi. It's been a while since a posted. Have been enjoying the bike I have decided to rewire the electrical since my main fuse keeps blowing. I have a short circuit and the best fix for the future is an M-Unit, so I got one. Before i start the wiring I need some help with my wiring diagram I have drawn. Calj?? I want to know if there are some errors in it. It is my first time I'm doing something like this. Is it okay to connect the brown wire that goes from key ignition to the p-light? And also, how do I connect the the neutral switch so the bike don't start if it's not in neutral?

I also got these parts: Ricks reg/rec, momentary push switch for start/kill and horn, latching push switch for high beam, on-off-on switch for turn signals.

[AlBundy]

The BROWN from key does not need to be used. Instead, run a BROWN from AUX (as it should be). This accomplishes the same thing (powers P without starting bike) and adds fused circuitry protection.

As for NEUTRAL, you can run the GREEN/RED wire to the START push button on one side, and the other wire to M-UNIT START input (left side). This provides the "ground" for that momentary switch to convert the signal at the M-Unit. Make sense?

I also don't like to use the M-UNIT ground studs for the Reg/Rec or the power tap. I prefer to take these directly to the frame and battery respectively. This reduces any potential leaks or reduction in charging voltage. Everything else looks pretty darn good.

Thank's Calj. I really appreciate it. I think I understand. I have ditched the brown wire from key switch and also grounded the reg/rec to the frame. When you write green/red I presume that you mean the one from the starter solenoid. I added the clutch switch also. Is it correct to put it on the green/red?

The quality of the jpg is not the best since I converted it from pdf.

[RAFster122s]

Recommend you not cheap out on the shocks as it pays to invest in a good set of rear shocks. 
The front can be vastly improved using Racetech gold valve emulators if you do not want to do a modern front fork replacement.  A set of new front springs to go with the emulators are the best combination. 
But, you will probably spend $1000 US to do a modern fork upgrade to the bike and the Up-Side-Down (USD) fork conversions are not really required to get much better dampening and brake system for the bike. There are many conventional fork designs that have sufficient tuning and vastly superior braking performance that are the conventional fork design.
Some go with the Suzuki GSXR forks and others have used the CBR600 or the Yamaha R1 or FZ600 forks with good success.

Since stopping is pretty important it could be considered a worthwhile place to spend money on the bike, as are tires and suspension.  If you can't keep the tires on the road they can't do what they are suppose to do.  Not that you are going to need to be riding where you are pushing them to or near a limit, but in a panic move or required reaction to hazard, etc. it is always a good thing to have that capability in reserve.  That's my thought process on it.

The 4 into 4 pipes are nice and it is a combination many like and want...
So if yours are in great shape, either hang onto them or consider that when and if you decide to change.

[RAFster122s]

Hi,

Anyone who knows if the drain tube (number 22) should be connected like I have drawn in the attached diagram? If not, what should be connected to the pipe from the chamber comp (number 12)?

The intake box doesn't connect to the drain like that... The end of the drain has a squeeze fitting that allows you to open that drain line by pinching it. It has a foam element/filter in it to help hold or collect the water. SohRon has a very very detailed build thread where he rebuilt his 550...worth looking up and taking the time to read and re-read.  Very very detailed stock restoration to better than factory condition.   I think he is creating a book for the 550 restoration from that thread and additional information.
The carbs connect to box 12 and it connects to the filter box which has the re-breather circuit and the filters in the bottom help separate the liquid vapor before getting back to the filter element.
David

[RAFster122s]

22 connects to the bottom of 13 and the other tube 17 connects to 23? which is another port in 13 if I recall correctly.  I haven't looked at the parts exploded diagram to see if they give you a stronger clue as it looks like SwedishParts had those figures from the parts manual.
 

[AlBundy]

So for clarification:

The GRN/RED is the stock NEUTRAL switch wire color. Run it to the momentary switch that will also be your START button, on one of the poles. This is your button "ground". The other pole runs to the START input. This will require that the bike be in NEU to operate START.

As for the clutch switch hooked to the solenoid, that creates another "ground" for the solenoid to operate.

So, to use push button START, you will need to be in NEUTRAL and the clutch lever pulled in. I don't like this condition personally. If you happen to stall the bike in traffic, you will naturally pull the clutch; thats good behavior. BUT, you don't want to have to gear shift to NEU to also start the bike.

If it were me, now that you added the CLUTCH switch, I would leave NEU switch wire as you have it; running only to the gauge. I would run the solenoid to CLUTCH switch as you have it and just wire the push buttons normally. But, this also creates another situation where you MUST pull the clutch to start the bike. Fine if you're riding, but what about first thing in the AM in the garage? As long as the bike is in NEUTRAL, I personally don't want to have to pull my clutch. I want to verify the gear position of neutral, then push a button and start it up while I fasten my helmet and zip my jacket and pull on my gloves. Then off I ride.


Wiring up your bike requires you think through your riding behavior to decide which switches are involved and how they effect your operational requirements.

Confused yet?

A little bit confused, but I think I got it or hope so at least. You have a good point with the staling. So to clarify. I want to be able to start the bike without it being in neutral if it stalls. Also U made me think about the clutch switch. I was not clear enough but I will not be using the original clutch lever. The new one I got operates the other way. If I pull it, there is no connection. If I understood you right, the best way is to ditch the clutch switch. With that being said gets me this: Bike will be able to start even if it's not in neutral and the start will not be depending on the clutch lever if it's pulled or not. Is that right? New diagram is attached.

[AlBundy]

Recommend you not cheap out on the shocks as it pays to invest in a good set of rear shocks. 
The front can be vastly improved using Racetech gold valve emulators if you do not want to do a modern front fork replacement.  A set of new front springs to go with the emulators are the best combination. 
But, you will probably spend $1000 US to do a modern fork upgrade to the bike and the Up-Side-Down (USD) fork conversions are not really required to get much better dampening and brake system for the bike. There are many conventional fork designs that have sufficient tuning and vastly superior braking performance that are the conventional fork design.
Some go with the Suzuki GSXR forks and others have used the CBR600 or the Yamaha R1 or FZ600 forks with good success.

Since stopping is pretty important it could be considered a worthwhile place to spend money on the bike, as are tires and suspension.  If you can't keep the tires on the road they can't do what they are suppose to do.  Not that you are going to need to be riding where you are pushing them to or near a limit, but in a panic move or required reaction to hazard, etc. it is always a good thing to have that capability in reserve.  That's my thought process on it.

The 4 into 4 pipes are nice and it is a combination many like and want...
So if yours are in great shape, either hang onto them or consider that when and if you decide to change.

I think I will get the Hagons for rear or the cheaper ones from Cyclexchange. Are they any good? The brakes I also want to upgrade but don't know if I should do an dual disc conversion or get an new front end. I can get an front end from an modern bike pretty cheap  for around 100$ or so, with brakes if I'm lucky. So the best would be maybe to change the front end. But then I have to get an new steering stem and triple tree and also new front wheel? I don't know if I want to spend those money right now since it's my first bike. I can't decide since I already spent around 2000$ on various part's and there is more to come.

I really like the 4 into 4 pipes and they sound so good. They are in great shape and I will not have them on the bike. Will keep them preserved for future value. I have an another half way custom built 4 into 2 that looks good. Have not tested them yet though since the bike's in parts.

[AlBundy]

Bike will be able to start even if it's not in neutral and the start will not be depending on the clutch lever if it's pulled or not. Is that right? New diagram is attached.

Per diagram, you have it shown as you describe it.

You don't need to tie the key BRN and BRN/WHT to BLACK. Thats all taken care by BLACK to LOCK. Just saying... And you only need now to ever move the key 1 position to have either TAIL and P or TAIL, P, and IGN.

Lastly, there are 3 programming features in the M-Unit you might think through. You can have all 4 indicators glow at a percentage of full to perform as running lights at all times. Some like to do this for visibility. Depending upon whether you ride in traffic mostly, you might want this activated.

You can set the TURN to auto cancel on a 10- second interval from 10 to 50 second delay. I set at 10, but also manually cancel. Up to you.

And you can force the behavior of the BRAKE light to strobe, flash then solid, solid, fade in to solid, etc. I like strobe to solid because my LED brake lights are VERY bright and you can't help but notice them. Makes me feel a tad more protected from being smashed into.


Final input: Any wire into the left side is purely a "ground" with the exception of LOCK. So you can use 22AWG from the push buttons. (Actually you could use thinner still, but 22 works well for handling and connecting). All the ports on the right side are switched power runs, so I use 18AWG directly to the components.

From AUX, you'll need basically 4 service runs: TAIL/License plate bulb, Ignition, Gauge back light, Coils. You can only stuff 2 total wires into AUX, so I use a 4-way Molex connector out of AUX. I then use separate wire colors for each run that are standard to Honda to each service segment (BRN to TAIL) BLACK to Ignition, BLK/WHT to Coils, BRN/WHT to gauge) to keep me oriented with stock "wiring" service. It will make troubleshooting and future ownership a lot easier. You can scavenge your stock harness for some of this special stripe wire coloring since you only need short runs. (Same for GRN/YLL, BLU/RED, GRN/RED) etc.

Hope it all works out as easy as seems. You've planned pretty well, so you should be set. Tripping the M-Unit into CONFIG mode can be tricky but its pretty simple once you get it there.

Thank you Calj for taking the time to analyze the diagram! Now I feel confident with my wiring. I will change the colors in the diagram to match the OEM better. Also ad a table with wire sizes. The program I use don't have dual color wires so I had to complete it with a second program. The reason why I have tied the BRN and BRN/WHT (black acc) is because I want the same function in position two as one.