Topic: 1972 CB500 - Rebuild Project

[Puffin]

So steps 1 and 2 are completed.

Got the back end cut up and brought the bike into work where our friendly maintenance guy took some time out one evening and welded on the hoop which I got from Harisuluv on this forum.  He cut a couple sections of box steel up and fashioned a couple of triangles to fill in the undersides of the hoop where it meets the frame and tie the back end in nicely.

He also gave me a few welding lessons and some advice and I got super enthusiastic and went out and bought a welder.  Hopefully with a bit pf practice I should now be equipped to tackle the rest of the welding requirements on my own...!

I'll tidy up all the welds once I have a the final mounting tabs and cross member installed.

[Puffin]

I wanted to keep the internal plastic mud-guard in place to protect the electrics and try and keep road splatter off all my nice clean engine.  It's well designed and fits better than anything I could fabricate and because I'm keeping the side covers you really can't see it at all. 

The only issue was it used to mount on the fender mount 'arched' section on the back of the sub-frame that I just cut off.

Fortunately it slides in between 3 metal tabs and so I just slid a couple of Speed Clips over the tabs, drilled a few holes and held it together with some washered self-tapping screws.  Holds it in place really well. 

[Puffin]

So for the rear end I'm leaning towards 2 options:

Option 1  (as per mock up below) - Reinstall the original rear fender but have it so just maybe 100-150mm is sticking out past the hoop.  (That's 4 - 6 inches for you 'mericans and Brits over 40!), Install a small single 'bates' style brake light on the fender and have a side mounted licence plate.

Option 2 - Have no rear fender, mount a cats-eye type brake light under the kick-up of the hoop.  The plate can either sit under the light or be side mounted.

Thinking Option 1 at the moment... but I'm fickle so by tomorrow it could be some 3rd option I've yet to consider.

[Stev-o]

Definitely option 1.

+1. No fender on rear looks odd to me.

[Puffin]

Well it looks like another 6 months has passed since I updated my build thread, I have however been pretty active however so for the sake of completion here is an update....

First off I used my new welder and 'never welded before' welding skills to install mounting tabs for the indicators and the rear fender. 

[Puffin]

I then knocked up a licence plate bracket that mounts off the rear axle

[Puffin]

I spent a bit of time working out how I was going to mount the seat pan and decided to go for a couple of overhanging tabs down the side of the frame.  In order to bolt these in I needed to add some triangular sections of steel to the frame.  Might look odd for a minute but I'll show you how this works in a couple of posts...

Once I was all happy and the welds cleaned up I painted it all black to match the frame

[Puffin]

Next I needed a seat pan... and this is where I lost about 3 or 4 months.  I decided to take the bike to a custom fibreglass bloke who I knew as I figured he'd be able to make something pretty quickly.  Turns out I was wrong and it took him weeks and weeks to get it done.  In hindsight I should have just done it myself but in the end he did a pretty good job. 

He built in some metal strips for support and to mount the pan to the frame.  It's pretty robust as well so no fear of it breaking anytime soon.

A front tab sits under a lip on the frame by the tank which stops it lifting and the side tabs go over the frame onto the two triangular sections I added.  It's solid as a rock when mounted

[Puffin]

Next I got the seat covered.  Again I farmed this task out to professionals... got put in touch with an old gent who ran an upholstery business in his garage who was great to deal with.

2 days later, and for a really decent price, I ended up with a sweet hand made black leather seat.

[Puffin]

As the bike has been off the road for 25+ years I need to pass a compliance test before I can get her fully legal.  This means I needed to add a rear reflector.

I made up a bracket which mounts to the underside of the fender using the tail light mounting bolts and attached a stick on trailer reflector.

Looks good and you can only really see it from directly behind the bike.

[Puffin]

So that's me up to date with the build and she is now pretty much complete..

I got me newly rebuilt carbs on and she fired right up and so took her for a spin.  Unfortunately she was running really rich and only managed to get a few km's down the road before stopping.  I took her back to the garage and checked a few things over and decided the fuel level was still too high.  I took the carbs off again and lowered the fuel level in the float bowls a bit more.

This time she ran much better and managed a 5km run with no real problems but an inspection of the plugs showed it's still too rich...  I tried a vacuum sync and all 4 cylinders were pretty well balanced but I've also got a bit of a hanging idle problem now.

I guess now comes the common problem of figuring out how to get it running right....!

That's this weekends task and I imagine I'm going to need some help from the forum gurus

[Puffin]

Thanks as usual for your constructive feedback Cal.

Yes I definitely do need some welding practice so thanks for the tips.

I have been using the clear tube method and have the fuel levels currently at 4.5mm from the gasket. I had them at 3mm but the bike was running so rich it was stalling after only a few kms..

I shouldn't have an air leak as I have all new orings in the intake manifolds plus new rubber boots on both sides of the carbs... I say "shouldn't" but I guess to be safe I really need to do an aerosol test to make double sure.

I can't help but think I need to swap out the Keyster pilot jets and the keyster valve needles and seats and go back to stock? At least with everything stock I will have a known base to start with. 

[Puffin]

So I have spend the last few weekends trying to get the carbs sorted and the bike running right... in summary this was my process:

1)  Swapped all brass in the carbs back to the original Keihin items and set everything back to stock.  Needle 4th Clip, Air screws 1 + 1/8th turns, floats 22.5mm (3mm from gasket seam)
RESULT: Way too rich, only able to do about 10kms before plugs fouled
2)  On advice from an old bike mechanic fella I know (who used to assemble these bikes in the 70's) I swapped old needle and needle jet for new ones.  I already had aftermarket so I installed these.  His logic was that modern unleaded fuel causes the needles to wear faster and the jet orafces to oval out after about 20,000 kms  causing more fuel to enter carbs.
RESULT: Started better and idles better but still way too rich.  Plugs still fouling.
3)  Moved the needle up a notch to the middle slot and turned out the airscrew out to 2 turns
RESULT:  Bingo! (I think)

Done a couple of 30km runs and she ran really good, no deterioration in running quality by the end.  Checked the pugs after and they are a little dark but no soot deposits. 

[Puffin]

With the bike actually rideable I went back and addressed a cosmetic issue that was bugging me.  I never really liked the scrambler bars so ordered a lower set of bars and swapped them over and installed a set of bar end mirrors.

The new bars were a little thinner than usual which meant I had to drill out the internals a little to get the bar ends to fit.

I also had to punch out a hole in the grips to install the bar ends so I used an old set of bars, sprayed on some silicone for lubrication and pelted the grips with a rubber mallet.  This left a nice handlebar sized hole in the ends. 

[Puffin]

so after 2 years and 2 months here she finally is....

[Puffin]

some more pics

[Puffin]

few more...

[Puffin]

Last lot...

[BallAquatics]

Very nice indeed.  Great job!

Dennis

[MickB]

Puffin it looks great, well done. BOTM.


Sent from my iPhone using Tapatalk

[Puffin]

Shameless plug...

My bike is nominated for Bike of The Month, feel free to pop over and vote for my bike... or any of the other nominees of course  ..

http://forums.sohc4.net/index.php/topic,168354.msg1951953.html#msg1951953

[Puffin]

Some updated pics with my new Drag Bars below...

... and a wee video of her running.