[Alex79]

Ok, I just got my permit on Thursday. I am in California on the central coast (in the middle of the state) and the family I live with has allowed me to register a 1979 Honda CX500 they don't use anymore in my own name. I am 26, and know hardly anything about motorcycles, so bear with me.



Thursday night was the first attempt to fire it up since it had been sitting for 9-10 months. It had some old gas in the bottom of the tank I believe, but I went and bought 1 gallon of premium since the compression rate was 11:1 I was told. Gas is poured it, held the choke out a little bit, and gave her a go. The engine started to wind up as if it wanted to kick over, but just didn't make it.



We checked the spark plugs, cleaned out the chambers (found some gunk in there), made sure they are firing and put them back in. Tried it again, same thing. The engine got right to the point of 90% almost turning over, but still something wasn't right. We took the seat off, checked the air filter. It looked "ok", but we took it out and lined the box with starter fluid and tried to turn it on once more. It went about 95% this time but still wasn't turning over.



Next we checked the gas line, it was dripping so that was good. Oil, coolant are all normal levels. The dad in the family I live with whose bike it was says that since the gas was sitting for so long and we tried to start it, it could have gone bad and turned to varnish. How valid is that?



So right now, we took the gas tank off, drained all of the gas out of it. I got new spark plugs just in case, and I cleaned the air filter (its a black cylinder sponge looking thing). Tomorrow he wants to put the gas tank back on and test it with a fresh gallon of gas to see if that will fire her up.



What do you guys think? Is there anything else we need to check/drain to clear it out before turning it on again? He said it started last year, and by the sounds of the engine now, it's like right there and wants to turn over. I think it just needs some love and it will kick in.



Thanks in advance!



-alex

 

[CXPHREAK]

When you've got the tank back on with fresh fuel open the carb float bowl drains and flush out the last of the old fuel.

 

[Alex79]

Where are the carb float bowls and how do I drain them? (sorry im a rookie at this stuff)



To clarify.



1. Put tank back on

2. Pour in new gas

3. Locate carb float bowls and drain them



Is that correct?

 

[CXPHREAK]

I'd think the feller who's bike this is can probably identify the carb float bowl drains for you.



They'll be the lowest screw located on the carbs and they're flat head not any of the phillips head screws. Unscrew 2 or 3 turns and let the fuel run from the drain for 10 to 20 seconds.



Make sure you have a drain tube on the nipple on the bottom of the carb and drain into a tin etc. for disposal.

 

[Blindstitch]

It's the screw on the left side bottom of each carb.

A shot of starting fluid in the airbox might help too.

 

[Alex79]

It's the screw on the left side bottom of each carb.

A shot of starting fluid in the airbox might help too.

Where are those located on the bike? If I am looking at the left side of the bike? Where the spark plug goes, that's the carb right or the piston? Sorry if I am saying the wrong labels.



We did put several shots of starter fluid into the air box, it didn't help much.

 

[Alex79]

Ok, I found them, but which screw? Screw B is only on the left carb, it didn't match the right carb EXACTLY.

 

[jtswenson]

No option C? I always answer C. Then I'll have to go with B. The answer is B.

 

[Blindstitch]

Option B.

Get low and look from the left side of the bike with a flashlight at the other side and you will see a screw in the same spot that can only be accessed with a long screwdriver.



If it has sat long enough the gas in the carbs will turn into a jelly like amber substance and plug the jets.

 

[Alex79]

Option B.

Get low and look from the left side of the bike with a flashlight at the other side and you will see a screw in the same spot that can only be accessed with a long screwdriver.

So both screws are only accessed from the left side of the bike?

If it has sat long enough the gas in the carbs will turn into a jelly like amber substance and plug the jets.

Will draining it clean the jelly like amber substance automatically? Or do I need to clean the jets out somehow?

 

[Blindstitch]

Both screws on the same side.

and

If there is dried gas in the carbs that won't drain out. If you can't get the bike to start eventually you will have to pull the carbs and see if the jets are truly plugged.



Some bikes just need a bit of help and they're good.

 

[Alex79]

Ok, from looking at the bike, the left screw closest to the outside looks like it will drain much easier. Is the screw that is harder to get to as easy to drain? What method would you suggest of how to angle drain the 2nd float bowl?

 

[Blindstitch]

11 inch screwdriver. I always keep one on my bike. Right from the left side.

 

[Alex79]

I meant the way to drain the 2nd float bowl? The one farther back. Whats the best way to drain this?

 

[Blindstitch]

I meant the way to drain the 2nd float bowl? The one farther back. Whats the best way to drain this?

Get a long 11 inch screwdriver and get on your knees from the left side of the bike and stick it through to the right side carb and turn the screw.

 

[bandit]

hiand welcome from spain.

i think your problem is two fold.

1/yes,you really do need fresh petrol to give your engine half a chance.do as described above.

2/i havent see you mention your power source.make sure your battery is fully topped up with distilled water,and,fully charged.if there is any doubt,hook up jump leads as well to a car.



then pull out the choke 3/4 way.turn your kill switch to off......spin the engine over fast,and as your engine is spinning,flick the kill switch to run.

good luck

 

[Alex79]

UPDATE



Put the gas tank back on, sealed up the float bowls, poured in a fresh new gallon of gas, put some starter fluid in the air box, and attempted to start the bike. It engine started right up, but quickly died when trying to idle. We attempted this several times and got it to open throttle just fine using only starter fluid. We checked the spark plugs and they were completely dry, no gas was hitting them.



We came to the conclusion that the jets are probably plugged up and we need to take the carbs off and clean them out. Is there anything else I can check before having to do this? We went through all of the steps to check everything else, but the engine is not getting the gas since the jets are probably plugged up. Is this pretty easy to just take the carbs off and unplugg the jets? Will I have to do anything else?

 

[Blue Fox]

Alex, first make sure that fuel is actually reaching the carbs. Open the bottom drain screws on the float bowls and see if gas comes out. It is possible for the petcock to be gummed up and no fuel is getting to the carbs. Likewise is it possible that the float needle has been stuck in the closed position and this doesn't allow for gas to get in.



There is a lot more to cleaning a carb besides "unplugging the jets". I would suggest you read all the posts in the Quick Reference section of this forum and follow their advice. That means carbs off, all removable parts removed, all rubber parts out, a good soak in carb cleaner or better a ultrasonic cleaner, then another pressure rinse with canned carb cleaner. Finish by compressed air and that all passage ways are clear.



This is not a slam bam, thank you madam process. If you are well experienced in doing these carbs, you are looking at a full 8 hours to check everything and get it right. You will only frustrate yourself by doing it half-assed.

 

[Alex79]

Alex, first make sure that fuel is actually reaching the carbs. Open the bottom drain screws on the float bowls and see if gas comes out. It is possible for the petcock to be gummed up and no fuel is getting to the carbs. Likewise is it possible that the float needle has been stuck in the closed position and this doesn't allow for gas to get in.

Did this, float bowls are getting fuel, and the line with a fuel filter is good to go. I am thinking the jets aren't allowing fuel to the engine, they are ambered up from the old old gas that sat in there before we clean out the fuel tank with new gas.



I want to make note that the carbs were cleaned/rebuilt last year before it started sitting for 9-10 months. So I am thinking they don't need to be FULLY recleaned right? We should be able to take the carbs off and just clean the needles and make sure everything else is clear of passage ways with a air compressor and blow it out.

 

[Blue Fox]

You might get by with a cursory cleaning, Alex. It wouldn't take long to try that. Some of the internal passage ways are about the same size as the jets tho, and they may be blocked. Also you might just try putting some Seafoam in the carbs and let it set for a couple of days. Then drain it out of the bowls for lawnmower use later. That may also take care of some of the crud.