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Messages - Robert W

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1
CB500/550 / Re: CB550 Lost Ignition - Help Needed
« on: January 15, 2025, 01:48:38 PM »
Open up the handle bar switch by undoing the 2 screws. From the inside you can access the contacts. Probably have to loosen up the cable lock nuts as one interferes with the screw removal.

2
CB500/550 / Re: CB 500 Four Gast Tank Painting
« on: October 09, 2024, 07:56:57 PM »
Lots of black particles may be rubber from alcohol in the petrol. Dumbest government mandate.

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CB500/550 / Re: Paint disaster / new colour
« on: June 06, 2024, 06:29:10 PM »
All fast drying spray cans are lacquer based. They have a high amount of lacquer thinner in them. In order to do multiple coats and multiple colors, they need to be sprayed within an hour or so or you'll get the dreaded wrinkling effect. These paints are not gasoline resistant. The high lacquer content is used to slightly dissolve the 1st coat for 2nd coat adherence. If you wait too long, like a day, you will get the wrinkle effect.

There are enamel paints which are oil based and can take up to a day or 2 to dry enough for a second coat or second color. They are more gasoline resistant but color choices are limited. These paints do not wrinkle because they don't have the same solvents in them.

The best paints would be automotive paint and a HVLP paint sprayer setup. Unfortunately, most people don't have this. I used to paint with lacquers and then finalize my paint with several coats of clear lacquer to resist gasoline spills. It worked to a certain degree if you wiped it off immediately. But now that I've gotten used to spraying automotive paints, urethane based, it's really the best and most durable way.

What you could do is paint either lacquer or enamel with spray cans, and organize with an automotive paint shop to finalize your paint job with a urethane clear coat. It won't react with either. You may have to lightly wet sand your paint job with 600 grit just to give something for the urethane clear coat to adhere to.

I am not a paint guru but I have lacquer painted a lot of motorcycles in the past like 40 years ago and just restarted painting motorcycles after teaching myself how to paint cars.

4
CB500/550 / Re: top end gasket set recomendations
« on: May 14, 2024, 06:41:02 PM »
I always used a light film of GE Silicone (pure Silcone caulk, not the paintable goop) on the head gasket and the O-rings for the oil passage. It was a poor design relying on the O-ring alone between the head and the cylinders. Why they didn't have a similar setup for the cylinder to crank case with the oil jet is a mystery. However I've got Yoshimura big bore kits with higher compression pistons in both my CB500's and they never leak at the cylinders or the oil passage. You have about a half hour before it starts to set too much so make sure you get the head on and torqued within that period. The silicone also makes for an easier cleanup the next time you change the gasket. Paint thinner or mineral spirits seems to slowly eat the film left behind.

5
CB500/550 / Re: CB550 Cylinder 1&2 not firing
« on: April 30, 2024, 02:24:52 PM »
Since governments have mandated alcohol petrol blends, we have a problem. How could they is another question. Ethanol will deteriorate everything that was not made with this compatibility in mind. it basically eats rubber, plastic, fiberglass, etc. Carb 1+2 fed from line 1 and carb 3+4 fed from line 2 both from the dual outlet petcock. I suspect you have little rubber bits blocking the idle jet, which is a lot smaller orifice than the main jet.

6
CB500/550 / Re: Float height 500 k1
« on: April 30, 2024, 01:33:13 PM »
1. Float height is the manual is 22mm. But this is just a guide. The tang on the floats when new are tangential to the pivot pin. However after mangling them several times, you may notice that they are no longer tangent. So feel free to adjust the float height to 23 or 24 mm. That little offset is magnified by the ratios of tang to pivot and float height to pivot. As long as your covering the jets it should be fine. Measurement of the amount of fuel in the bowl is a pain and not easily done unless you use a drain screw modified with a clear tube to view the fuel height.
2. If your having trouble with the overflows barfing out fuel, one thing for sure is the needle valve springs over time become unequally compressed and less resistant giving you all kinds of different measurements. I suggest buying new needle valve sets. You will notice the difference immediately when you set the carbs on the bench. The floats will touch the needle valves and not compress the springs at all. Also these stock Keihin carbs use a lot of o-rings which over time will not seal. Especially the o-ring on the needle valve seat. If this one is bad, your carbs will eventually overflow. These needle valves are brass on brass. Some are rubber on brass. So there is no substitute for a good spring in the needle valve.

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