Author Topic: 1972 CB500 - Rebuild Project (Read 31998 times)

Puffin · « **Reply #125 on:** October 14, 2015, 05:14:47 PM »

Popped down to see how my tank is getting on and couldn't resist posting a few pictures... Final clear coat is waiting for a light sand and a buff then it's all ready.

Been thinking of various colour schemes for the last 12 months and I must have changed my mind 50 times but in the end only one colour was sticking in my mind which was...... Honda Repsol Orange.

Given the rest of the bike is Matt Black and Chrome I think this is gonna look awesome..

Fun Fact: Repsol first got into Motorbike GP racing in 1971 which was the same year the CB500 was introduced...

To be honest I only learnt this yesterday so it's more of a coincidence than an official tribute but it's gonna make a good story if anybody goes "Hey man nice tank colour" or "why the hell did you paint your bike Orange bro?".

Restoration Fan · « **Reply #126 on:** October 15, 2015, 08:14:03 PM »

Beautiful paint, Puffin! Looking good, man.

RAFster122s · « **Reply #127 on:** October 15, 2015, 10:12:09 PM »

Very nice Puffin! The Repsol Orange really pops. I like it.
A top coat of a urethane clear like the Spraymax 2k would protect the paint from gas.

David

Puffin · « **Reply #128 on:** October 25, 2015, 09:48:05 PM »

Tank is done and all assembled.... Looks amazing with white badges and the new gas cap

Puffin · « **Reply #129 on:** October 25, 2015, 09:56:43 PM »

My phone camera pictures don't really do it justice but adding the tank really pulled it together... the bike really is starting to look so cool...

I find myself standing in the garage just staring at it

Puffin · « **Reply #130 on:** October 25, 2015, 10:13:39 PM »

Going back a step I have also finished off the electrics.

I wrapped up the wiring loom using some TESA cloth tape... It's really easy to use and made a really nice neat job. Held it on the bike using extra wide cable ties and used Dielectric grease on all the connections to prevent corrosion later.

Puffin · « **Reply #131 on:** October 25, 2015, 10:22:14 PM »

The Electronic ignition attaches to the Black & White switched wire from the coils using the supplied splicing device.

I static timed the ignition using a test light with one lead grounded to the body and the other attached to the corresponding -ve coil wire. The difference with the Dyna ignition to standard points is that you have to time it to full advance so make sure you read the instructions carefully.

It's a little fiddly holding the cam to full advance whilst looking through the view hole and rotating the engine all at the same time but I got the hang of it pretty quickly.

Puffin · « **Reply #132 on:** October 25, 2015, 10:38:07 PM »

I am so glad I labelled each cable back at the start of this project... it saved me sooooooo much time. There was only really the idiot lights than needed connecting and these were pretty straight forward.

I only had to de-bug the horn and the oil pressure light.

I was puzzled by the horn not working as it was working fine when I mocked everything up at the start? A check of the wiring diagram however showed that the horn grounds at the switch and in a moment of clarity I realised that my new handlebars were powder coated as opposed to the chrome ones I used originally. A bit of sandpaper and I cleared some paint off at the switch and again at the clamps and the thing fires every time.

I had bought a tiny black horn that I was going to use as a replacement but the sound it made was just so quiet I doubt anybody sat in a car would have heard it.. the original one however sounds like a truck horn ... it's ridiculously good and I kind dig it's retro vibe so it stays.

Puffin · « **Reply #133 on:** October 25, 2015, 10:53:04 PM »

My other problem was the oil pressure light not coming on when I turned on the ignition..

It was easy to diagnose that the oil pressure switch was faulty. With no oil pressure the switch should be closed or ''on" so there should be continuity between the little metal part at the top where the wire attaches and the metal body of the switch which goes to ground. No continuity means the switch is stuck open which means the circuit is not complete which means your oil light will not come on.

Rather than pay over-the odds for an original switch you can search the part number and it lists a load of Honda Cars that use the same switch... I think Preludes, Civics and Accords for example.

I picked a new switch up for $9 NZ which is crazy cheap.

If you are going non-original the thing you need to watch is thread types and the actual pressure the switch activates. I believe the original was an M10 x 1.0 taper thread that activates around 7psi....?

My switch activates around 5.5psi and the thread was 1/8 GAS (I think that is a British non-tapered type thread?). Either way it fits just fine.. I did use some plumbers tape (teflon or PTFE tape) around the threads as a precaution.

Apparently this switch fits all the cars in the photo if that helps anybody...

SOHC4 Cafe Racer Fan · « **Reply #134 on:** October 26, 2015, 08:43:05 AM »

I like how the paint came out. It'll make for a unique 500. Very REPSOL orange.

Wiggy_NZ · « **Reply #135 on:** October 28, 2015, 01:53:05 AM »

Hi Puffin.... I have just finished reading you full story... You are going well for an old pom. lol. Where are you in New Zealand.... I am in Christchurch... I own a K5 750

Regards Brendan

Puffin · « **Reply #136 on:** March 10, 2016, 03:23:38 PM »

Wow so it looks like I haven't posted here since October last year...!

Christmas, New Year, starting a new job and a 6 week holiday touring around the country has meant the CB500 has taken a bit of a back seat. Now that things are settling down again it's time to get this thing finished and update this build thread. I have actually got quite a bit done and despite being crazy busy, the bike has made some significant progress and passed some big milestones.

The last time I posted it looks like I had just got the tank back so I'll back track to that point and bring you up to speed

Before I show you the bike some of you might be interested in this if you need to move your bike around... particularly if you have a van.

I bought a cheapo motorbike front wheel brace from the autoparts shop. Next I got some (free) flat bar from a fencing manufacturer and some eyes from a rigging store.

I drilled some holes in the bar to attach the eyes and a couple more to attach the wheel brace. I then bolted the whole assembly to the existing holes in the van floor where the seats used to mount - hey presto a removable bike transporter with mounting points.

Puffin · « **Reply #137 on:** March 10, 2016, 03:40:46 PM »

Now for the 1st bit of big news....the exhaust.

I was introduced to a guy who had a lock up near my office who was starting up a pipe bending and welding business. He worked over at the University in the day and was building up his business in the evenings and weekends. I mentioned that I needed a new exhaust for my bike and he reckoned he could do it.

Anyway we chatted a bit more and I ended up taking the bike over to him one evening along with a load of pictures and a couple of old rusted sets of headers so he could see how the original set-up worked.

My brief was that I wanted 4-into-2 headers with an up-sweep and to retain the center and side stands if possible. I also wanted to access the oil filter without taking the exhausts off. I wanted Stainless steel and I wanted to use the reverse cone mufflers I already had.

Anyways he seemed confident so I agreed to leave the bike with him and see what he came up with. It took him a couple of months but I eventually got the call to say they were ready...

This was what he came up with...

Puffin · « **Reply #138 on:** March 10, 2016, 03:53:09 PM »

.... I'm pretty happy with the result

It's unique, hand made and he nailed every aspect of what I wanted. He cleverly fabricated a little bracket underneath which acts like a stopper for the center stand. The side stand moves freely. He got the mufflers exactly where I wanted them which means I can still adjust the chain.

His welds are immaculate and i can also access the filter easily.

If I was going to be hyper-critical I would say the bottom of the headers don't quite hug the engine as close as I anticipated but this could be adjusted by altering some of the bend angles or adding another bend in the down pipes. The result of this however is that it gives the headers quite an angular and aggressive look so I'm leaving it for now and will make a call once the bike is done.

Puffin · « **Reply #139 on:** March 10, 2016, 03:55:43 PM »

Some more pictures...

SOHC4 Cafe Racer Fan · « **Reply #140 on:** March 10, 2016, 05:41:21 PM »

Pretty damn good looking. How does it sound (running video)?

MickB · « **Reply #141 on:** March 10, 2016, 07:19:07 PM »

Fantastic, they look great!

Puffin · « **Reply #142 on:** March 14, 2016, 07:56:48 PM »

Quote from: CB750 Cafe Racer Fan on March 10, 2016, 05:41:21 PM

Pretty damn good looking. How does it sound (running video)?

Well... an excellent question and one that leads to my next milestone. I have managed to get the bike started and even drive it down the road. The first attempt she was only running on Cylinders 1 and 3 which I thought was unusual but after it had cooled down and I tried again all 4 cylinders were firing away nicely. The exhaust notes are really nice and deep without being too loud. I'll try and get some video posted soon as she does sound amazing.

I even took her down the road. She went through all the gears, took off and stopped just fine and actually rode pretty nice. Only issue was that I couldn't get it over about 3,000rpm without it bogging. I have not done any tuning or carb syncing yet so for now i'm considering this a great success...!

Puffin · « **Reply #143 on:** March 14, 2016, 08:14:03 PM »

Couple of minor jobs got completed after being further enthused by having a running bike..

- Cut out a grill for the air filter cover to keep out the leaves and stones and oiled up my uni-filter
- Addressed a leaky and sticking front caliper with a new seal and some Dow Hi-Vac grease that is often recommended in by this forum.
- Tarted up the original black metal plate

SOHC4 Cafe Racer Fan · « **Reply #144 on:** March 14, 2016, 08:27:00 PM »

This is a clean, great-looking bike.

Puffin · « **Reply #145 on:** March 14, 2016, 08:41:42 PM »

I spent a long while looking at Speedo and Tacho options.

Having swapped out the original CAM for a 650 CAM, my original tach was no use as the drive ratio on the cam gears is different. This meant I needed to go electronic or get a new analogue tach plus new drive gear.

Unfortunately I really struggled to find a mini analogue speedo in kms, that had a matching electronic tach, that looked any good.

I considered a fancy all-in-one dial but I'd never use half the functions and I just didn't think it was the right choice on this bike. My other problem was that my top clamp did not have the original mounting points as it had been modified to be used as a police bike which originally had the speedo mounted in the headlight bucket and no tach at all.

Anyway eventually I found these simple, black mini dials on Alibaba for $20 USD each including postage. Unfortunately the electronic tach didn't come with any wiring instructions but I eventually figured it all out and they seem to work just fine.

I'm not sure how accurate they are, or how long they will last, but they look really good.

I mounted them by simply installing longer bolts in the handlebar clamps which provided something for the brackets to secure to and allowed the guages to sit at the right height.

Puffin · « **Reply #146 on:** March 14, 2016, 08:54:15 PM »

Quote from: CB750 Cafe Racer Fan on March 14, 2016, 08:27:00 PM

This is a clean, great-looking bike.

Thanks, I'm so pleased how this is actually turning out. My next step is to get a seat hoop from Harisuluv and start getting a seat made up.

Puffin · « **Reply #147 on:** March 16, 2016, 01:29:26 PM »

Quote from: calj737 on March 15, 2016, 06:19:29 AM

If your electronic tach is drawing a signal from the coils, then it will be highly accurate provided you have a clear, strong signal.

Thanks Cal, Yes it does. I took the tach wire and connected it directly to the coil terminal.

Puffin · « **Reply #148 on:** March 19, 2016, 05:13:54 PM »

Quote from: Wiggy_NZ on October 28, 2015, 01:53:05 AM

Hi Puffin.... I have just finished reading you full story... You are going well for an old pom. lol. Where are you in New Zealand.... I am in Christchurch... I own a K5 750

Regards Brendan

Hey Brendon, Sorry I've just seen your post. I'm up in West Auckland mate.

Was riding around your neck of the woods earlier this summer as I have some family down in Christchurch. How's the 750 running?

Puffin · « **Reply #149 on:** March 19, 2016, 05:30:29 PM »

Right... video of the first test run.

As I mentioned the carbs are not synced yet so you can hear it bog down at around 3,00rpm but otherwise no smoke, no explosions, no fires, no sudden grinding of metal.... generally pretty happy.

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Author Topic: 1972 CB500 - Rebuild Project (Read 31998 times)