Topic: Barnyard CB550 - Questions?

[zgould]

I found a 74 CB550 in my grandpa's old barn. I played with it a bit to see if it would start or not. It wants to, but it doesn't want to stay alive (Using starter fluid). Pulled the carb off and it looks really really clean. I then pulled off the tank, set it to drain out the petcock....nothing came out. Now I'm having the hardest time figuring out how to get the petcock off of the fuel tank. It seems like the petcock is actually part of the fuel tank? There is nothing to take off, it seems like it's pretty much rip a whole in the bottom of the rusty gas tank in order to pull this thing out.

Any ideas? I'll post pictures if needed. I'm very excited to start working on this bike. I just want to make sure it runs before I start doing anything to it. If I can't get this petcock off, I'll have to opt for getting a new one; or I'll just hook up a 1g fuel can to it just to see if it will run or not and worry about the tank later.

Anyways...any help would be greatly appreciated.

[Puntas13]

Unscrew the bowl. Take out the metal screen and and there should be 2 screws behind it. That's what holds it on.

[wowbagger]

Yup, sounds like an early petcock. Here's the fiche to give you an idea of what's inside:
http://www.cmsnl.com/honda-cb500-500-four-k0-1971-usa_model459/partslist/F++10.html#results

[zgould]

Ahhh perfect. I went to unscrew from the bottom and the whole "Nut" part of the bottom just ripped off. I saw the screen in there but figured I just already fugged it up enough for one day.

HA! glad to known that the 2 bolts are hiding under that filter. Going to have to cut the entire bottom bowl out to get to it though. Thanks so far guys! Going to check it out when I get home this evening.

[Stev-o]

Do you have a good battery? Need it for a good spark...

[zgould]

Meh, enough battery to crank the charge up on it and supply enough amps to get the starter to fire. Point blank there is absolutely no fuel coming out of the petcock.

Not to mention when I poured the gas out it come out red, and so did a few big chunks of rust as well. I'm going to start with the tank/petcock, try to fire it up after that, and see where I am from there.

[skidooextreme]

Red means gummed up carbs.  Surprised your even getting that far...its going to be a project mark my words

[zgould]

Red means gummed up carbs.  Surprised your even getting that far...its going to be a project mark my words

I thought the carbs would be gummed up too, which is why they are the first thing that I pulled. I cracked open the carbs and my eyes went (O_O). The carbs were completely free and clean. This bike is in extremely mint condition once I got all the dust off of it. It has flat tires, and a few cracked lights from being leaned up again things, but no body damage at all.

I really think that the petcock got itself clogged and then it was just left. The carbs show no signs of gumming. Only the fuel tank.

[Stev-o]

It is possible that the float bowls were drained. 

[mcswny]

Pictures?!


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[Duanob]

Yes pictures or it doesn't count

Sounds like the bowls were drained, good one on gramps. You're looking at a tank cleaning and possibly a new petcock but in the end worth it.

There are lots of threads on derusting a tank. Just remember if you want to save your paint job be super careful not to spill any acid based liquids on it. Wrap the tank in plastic wrap or something like that.

If I remember right the petcock on your tank isn't overly expensive, Like mine on the 75-76 tanks its almost $100 for a new one. Google Part number: HONDA 16950-300-020

If you don't have clean fuel running through the engine it will cause all sorts of problems. Clogged and leaky carbs, runability problems, etc. And don't forget to do a 3000 mile tune up first.

[zgould]

Great advice to read. My weekend started this evening. I was able to drop some air gun pellets in the tank and jiggle them around. Almost removed all of the rust I could see. Now it's sitting with some vinegar in it. Going to order the Petcock tomorrow and get read to try to fire up tho bike again next weekend.

Best thing on hand to prevent flash rusting for a week?
What brand oil to use?
Are the sparks plugs still readily available or is there a better modern kind?

Thanks for the help so far everyone. I mean to take pictures, just get to busy working on the bike.

[goldarrow]

Use any dinosaur oil.  10w40 cheapest you could find

I commute a lot of freeway miles and use denso x24es-u, for around town short distant rides x22es-u is good