Author Topic: 1972 CB500 - Rebuild Project (Read 31316 times)

Puffin · « **Reply #200 on:** March 14, 2017, 12:57:44 AM »

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 · « **Reply #201 on:** March 14, 2017, 01:00:15 AM »

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

Puffin · « **Reply #202 on:** March 14, 2017, 01:04:40 AM »

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 · « **Reply #203 on:** March 14, 2017, 01:13:48 AM »

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 · « **Reply #204 on:** March 14, 2017, 01:25:21 AM »

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 · « **Reply #205 on:** March 14, 2017, 01:39:45 AM »

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 · « **Reply #206 on:** March 14, 2017, 01:58:29 AM »

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

calj737 · « **Reply #207 on:** March 14, 2017, 04:25:40 AM »

Use the Clear Tube method to dial in your fuel level.

A hanging idle is probably attributed to a vacuum leak around the intake manifolds. A common source is the O-rings between the head and the intake manifold itself. Spray some aerosol in that area while the bike is idling to see if the RPMs change.

A little bit of feedback on your welds: They're cold. Especially looking at the license plate bracket, you can see how the edges are not burned in to either surface. That means you have no penetration or fusion. Probably, you could nearly hand snap those apart. I get that you're nervous about melting through, but hard wire MIG starts cold, and only gets warm after you get running, but that requires you have the correct voltage set up. Next time, bump your volts up and slow your travel. And hold your tacks longer and nozzle tip closer to the metal

I do like the look of your solutions, but am curious if the reflector won't get smacked under suspension compression?

Puffin · « **Reply #208 on:** March 15, 2017, 02:21:19 AM »

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.

calj737 · « **Reply #209 on:** March 15, 2017, 04:21:37 AM »

Quote from: Puffin on March 15, 2017, 02:21:19 AM

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.

Thanks for stating the constructive acknowledgement of your solution before the balance of us climbed onboard the "Kick the Keyster" jets train

calj737 · « **Reply #210 on:** March 15, 2017, 04:35:30 AM »

Quote from: Puffin on March 15, 2017, 02:21:19 AM

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.

So this (^^^) leads me to believe your hanging idle from fuel starvation now that your fuel level is so low. The "rich" condition you experienced at 3mm was more likely due to jet discrepancies than fuel level.

I'd encourage you to reset the fuel level to ~3mm per stock, then jet and tune with stock brass. I suspect you'll be happier and have a better running bike.

Puffin · « **Reply #211 on:** May 12, 2017, 08:02:13 PM »

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 · « **Reply #212 on:** May 12, 2017, 08:14:09 PM »

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 · « **Reply #213 on:** May 12, 2017, 08:27:42 PM »

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

Puffin · « **Reply #214 on:** May 12, 2017, 08:28:57 PM »

some more pics

Puffin · « **Reply #215 on:** May 12, 2017, 08:30:10 PM »

few more...

Puffin · « **Reply #216 on:** May 12, 2017, 08:31:08 PM »

Last lot...

calj737 · « **Reply #217 on:** May 13, 2017, 04:02:20 AM »

Nice result!

BallAquatics · « **Reply #218 on:** May 13, 2017, 04:20:20 AM »

Very nice indeed. Great job!

Dennis

MickB · « **Reply #219 on:** June 08, 2017, 12:45:35 AM »

Puffin it looks great, well done. BOTM.

Sent from my iPhone using Tapatalk

Puffin · « **Reply #220 on:** September 22, 2017, 08:09:35 PM »

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 · « **Reply #221 on:** September 22, 2017, 08:12:10 PM »

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

... and a wee video of her running.

News:

Author Topic: 1972 CB500 - Rebuild Project (Read 31316 times)