Author Topic: My first complete build 72 CB750 - completed for now... (Read 56084 times)

Terry in Australia · « **Reply #125 on:** May 04, 2018, 05:45:13 PM »

Hmmnn, well I like the yellow and the white mate, but not keen on the battleship grey. Good job, and as long as you like it, that's the main thing.

algophobe · « **Reply #126 on:** May 04, 2018, 06:55:58 PM »

For some reason I've been on this kick for nonmetallic browns and greys. Its to enhance the yellow and white. Once the black comes in it'll pop even more.

Godffery · « **Reply #127 on:** May 04, 2018, 09:06:23 PM »

I'd say it works pretty well together.
A daring move, well executed.

algophobe · « **Reply #128 on:** May 08, 2018, 09:45:42 AM »

Quote from: Godffery on May 04, 2018, 09:06:23 PM

I'd say it works pretty well together.
A daring move, well executed.

thanks godfrey. well as nice as that paint was. I always manage to find a way to screw it up. I had a local sign shop cut a vinyl stencil to form the number plate and "Honda" lettering as well as the Chinese character which will be the signature of the bike. I knew they tend to leave glue residue and can come off with some encouragement. but what really ruined things was that I painted white, then masked to paint the black. a single edge with two paint colored layers don't work to well. so I had to wipe it off and start over. fortunately the layer of catalyzed clear on top of the grey and yellow shielded the mistake and can work over it again.

here's the pic of the seat completed since it didn't require too much stencil work. there's a final flow clear coat so it makes it extra shiny. the flow coat was intended to avoid having to do fine sanding and buffing to get rid of minor orange peel, but there are some runs that i'll have to remove so now buff and sanding is a must to finalize the paint.

only the tank remains to be painted. i'm going to have to hand cut transfer/masking films to make the lettering. this is going to be interesting.

Godffery · « **Reply #129 on:** May 08, 2018, 07:08:19 PM »

No sweat Man, that's just a little thing we call "the learning Curve".

algophobe · « **Reply #130 on:** July 11, 2018, 09:37:09 PM »

Haven't posted lately as I have been struggling with painting the last piece of the bike. The gas tank has more layers of artwork and lettering that I had quite a bit of trouble with. specifically painting the Honda letter, the number and surrounding black frame. had some issues with putting on decal stencils that left glue residuals that ended up requiring wiping them off with acetone and starting over. fortunately the clear coat sealed the yellow and grey layers. the last few months of painting had been plagued with bad weather from rain, temps <60, and >120 degrees in Southern California which slowed down my progress. But I've finally finished the paint job. PHEW!!!

I learn a few things the hard way. 1) minimize tape time with decals/stencil and line tapes (it helps reduce glue residues) 2) always buy new vinyl tapes for each project as expensive as they are (if they're old they also leave glue residues) 3) when there are contaminants on the clear coat (fisheyes), check the connectors for the spray guns, even with new moisture/dust filters contaminant hide in plain site.

algophobe · « **Reply #131 on:** July 11, 2018, 09:40:10 PM »

below are some hurdles I sorted, thru. fisheye contaminants, failed vinyl stencils led to trying to make my own stencil, the lettering was horrid.

algophobe · « **Reply #132 on:** July 11, 2018, 09:59:37 PM »

I decided to give the custom cut vinyl decal/stencil another try and breaking down the black elements and painting them separately to minimize tape time, and it worked like a charm! no glue residue

I decided to use the #7 instead of #72 was it would be simpler and less cluttered, 7 being a homage to my wife being the 7th of 8 children.... and the only daughter amongst 7 sons. with all the patience to handle 7 brothers and the many hobbies of her husband.

The black framing was quite another challenge as well, as it was taped by hand and the tight turns pushed the flexibility limits of the masking tape. in the end, i clear coated after all of the black elements were painted, and cleaned up the black and white lines by hand with a fine brush and lettering enamel, followed by a final clear flow coat.

Then sanding from 1500 to 3000 grit and buffing it with cutting compound. and VOILA!
Its gonna get a little wax tonight and then on to reassembly this weekend.

Godffery · « **Reply #133 on:** July 15, 2018, 08:33:29 PM »

Well done Man! Painting itself is a real challenge, then to add multi color, stripes AND lettering is an over-achievement for attacking a first time paint project. Well Done Indeed!!!

algophobe · « **Reply #134 on:** July 16, 2018, 09:41:52 AM »

Quote from: Godffery on July 15, 2018, 08:33:29 PM

Well done Man! Painting itself is a real challenge, then to add multi color, stripes AND lettering is an over-achievement for attacking a first time paint project. Well Done Indeed!!!

Thanks Godffery, though i have to confess, not my first body paint that's why I was ambitious enough to use all the layers, definitely the most complex I've done so far. I used to rattle can paint all my riding buddies' race/track plastics back in the day, i'll post some pics up later when I get home. the two component paints are a bigger headache but gives such beautiful results when you put in the time.

SOHC4 Cafe Racer Fan · « **Reply #135 on:** July 16, 2018, 10:11:37 AM »

Good job on the paint. It is reminiscent of the Edwards/Rossi Yamaha livery/helmets used at Laguna Seca

algophobe · « **Reply #136 on:** July 16, 2018, 11:14:03 AM »

subconsciously maybe inspired by Collin. but this was the main inspiration.

algophobe · « **Reply #137 on:** July 16, 2018, 11:46:53 PM »

i'm back and forth on what to do with the fuel petcock. the stock petcock has two outlets, i'm assuming intended to go to the two fuel inlet on the stock carbs. the bike was a mess when I got it so never really see how it fits stock, and the parts images don't necessarily say it. i'm using CR specials carbs which has one larger fuel inlet in between the 2-3 unit. should I plug one and run the other line to the CR carbs OR use both and a Y connector?

02z06dave · « **Reply #138 on:** July 17, 2018, 04:26:41 AM »

Quote from: algophobe on July 16, 2018, 11:46:53 PM

i'm back and forth on what to do with the fuel petcock. the stock petcock has two outlets, i'm assuming intended to go to the two fuel inlet on the stock carbs. the bike was a mess when I got it so never really see how it fits stock, and the parts images don't necessarily say it. i'm using CR specials carbs which has one larger fuel inlet in between the 2-3 unit. should I plug one and run the other line to the CR carbs OR use both and a Y connector?

Use a Y

SOHC4 Cafe Racer Fan · « **Reply #139 on:** July 17, 2018, 08:52:17 AM »

Nice paint inspiration.

Use a "Y" connector for your fuel output to the carburetors.

algophobe · « **Reply #140 on:** July 17, 2018, 07:48:13 PM »

Doh! The pain of mods... Anyone make lower profile petcock for stock tank for 72 cb750? Or just finish balancing the carb then plug up the holes.

algophobe · « **Reply #141 on:** July 17, 2018, 10:55:53 PM »

I'm on the final stretch of this build. So running into these little set backs are a little frustrating. Things that remains to be done are:
1. Treating the slight rust that built up within the gas tank from a year ago at the seam between the bottom and walls of the gas tank. for some reason the por 15 did not seal off in this area. I have the tank partially filled with the non-acid rust remover currently.
2. Figure what to do with the rubbing between the petcock and nipple on the carb boot and finish fuel line
3. Finalize carbs. Probably lower the clip on needle a couple of notches.
Can't wait to see how she rides!

calj737 · « **Reply #142 on:** July 18, 2018, 02:48:58 AM »

Remove the nipples and install a screw after synching.

algophobe · « **Reply #143 on:** July 18, 2018, 10:45:52 PM »

thanks for input gents.

by the way, I just use the Metal Rescue derusting solution for all the minor areas that POR 15 didn't cover well, i'm trying to rise out that solution. since its a water base solution, I was thinking of using acetone to rinse it out and evaporate faster without damaging the POR 15 coating.. anyone know if acetone has any detrimental effects on this coating?

either that or I was thinking of using gasoline to rinse the tank out. water based fluid aren't immiscible with gasoline, but maybe with multiple cycles of rinsing it would replace the water.

calj737 · « **Reply #144 on:** July 19, 2018, 02:15:48 AM »

Rinse with diesel, not gas, and definitely not Acetone.

algophobe · « **Reply #145 on:** July 19, 2018, 06:12:31 AM »

Quote from: calj737 on July 19, 2018, 02:15:48 AM

Rinse with diesel, not gas, and definitely not Acetone.

I known some people recommend storing unused tanks with a small amount of diesel, but why diesel? do they mix better in this case with water? I'm planning on filling the tank with gas soon to start her up anyways.

SOHC4 Cafe Racer Fan · « **Reply #146 on:** July 19, 2018, 08:41:20 AM »

Yes, acetone will simply dry without leaving any protective layer/film to prevent oxidation. Ideally, if you could store it in an oxygen free vacuum, that would prevent any rust. Rinsing it with diesel is a good idea. Liberal WD-40 will suffice in a pinch. Then, try to keep it out of the elements.

calj737 · « **Reply #147 on:** July 19, 2018, 10:39:36 AM »

You lined the tank with POR-15 and want to displace the water. Diesel will do this without damaging the liner. Thats why diesel.

algophobe · « **Reply #148 on:** July 20, 2018, 11:59:02 PM »

Thanks for the input gents... working on the final carbs adjustments. There was this awesome guide in the tech section.. it was pinned to the top but for some reason i can't find it anymore. It list the common symptoms and what to do to correct it on the carb. Anyone know where it went?

Nm.. found it in Faq

algophobe · « **Reply #149 on:** July 22, 2018, 05:36:57 PM »

so the CR31 was built by Dime City according to the set up I'm running. K&N Pod filters with 4:1 exhausts (spitfire from Cycle X), otherwise stock motor. damn that thing is loud. Ignition advanced to +5, I played with +10 but doesn't seem to improve much. The manual states she should idle below 1000 rpm, but she seems to struggle if I back out the idle screw. I'm curious how accurate these aftermarket tachometers are, also from DCC. you can see it in the video.

the air screw adjustments were done and idle speeds seem to settle at about 1/2 turn from fully closed. I haven't worked with these older carbureted bike in a long time, but noticed that after rev'ing. it seems to be a little slow to come back to idle, but doesn't need to be "blipped" to get back to baseline.

the needle they installed were YY9's, i had to bring the clip down to the 5th notch to get what seems to be good throttle response at 1/2 and 3/4 throttle turn. when it was at the 4th notch, the engine stalls.

take a look at her running, any observations/suggestings welcome!

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Author Topic: My first complete build 72 CB750 - completed for now... (Read 56084 times)