Another Carb Rebuilding Thread

[PAULYBOY]

So, over the weekend, TheCafekid and N1elkyfan came down. I told them about my fear of taking the carbs off my bike and rebuilding them. Hahaha, they said. Heeheehee they twittered. It's not that hard they intoned. Of course, I replied, you're right. I felt em bar assed to admit I was just chicken. Josh told me he'd come down sometime and help.
Well, last night I took my b@!!s in one hand and some tools in the other and went to work. Airbox came out easily enough, although I noted the snorkel was just kinda jammed in betweent it and the battery box. I also b\noticed that all the clamps that held everything onto either side of the carbs were all pretty worn out. Out come the carbs, up on the bench. Whack with the impact screwdriver to loosen up the screws. Hah! Got every single screw out, and replaced with the polished stainless allen heads.
When I bought the bike, the guy that sold it to me seemed to be a fairly competent bike wrencher, and he had told me he had gone through the carbs, but not dialed them in. The carbs were surprisingly clean, but i used my carb kits and replaced every o ring i could get to. The only thing I noticed about the carbs were these two things- the air screws, or idle screws or whatever they were called were only out less than one turn, and the butterflies on #1 and #4 carb were not adjusted to be closed all the way. Hopefully i did right by adjusting the butterflies so they would all be closed at the same point. I turned the screws all the way in after replacing their tiny o rings and then backed them out 2 full turns.
As I was doing all this, I had my fuel tank on top of a 5 gal bucket, because no matter which way I turned the petcock (vacuum operated petcock) fuel still ran out.There seems to be my main question, other than if anyone has any more hints on the carbs. Isn't the petcock only supposed to feed gas when it is opened by engine vacuum? And, more importantly, isn't one of the side positions, either 3 oclock or 9 oclock, supposed to be OFF?

[tkent02]

Your petcock has a slight leak, fuel should only come out with vacuum unless it's on prime.

Not sure about the screws on your model, usually they should be more than a turn out, and as for the butterflies, bench synch and then vacuum synch them when you get it back together.

[Nessism]

Petcock has three positions: ON, RES, Pri. Prime means fuel flows all the time. ON and RES require vacuum to pull the diaphram open to allow fuel to flow. Based on what you have said, your petcock is bad and should be replaced.

Regarding your carb rebuild, it's best to take the carbs down all the way and soak the bodies in the dip solution. You need to un-gang them for this of course - something newbies are often hesitent to do. There are typically o-rings on the interconnection tubes between the carbs which sometimes leak - on the carbs I've worked on, the o-rings have crumbled as soon as I touched them. You can not replace these if you don't seperate the carbs from one another. Also, replacing the factory brass jets with aftermarket jets of unknown quality is risky. Some people have good results but others report problems - particularly on the float seats. General rule of thumb is to order an o-ring kit from Robert Barr at cycleorings.com and reuse your old brass. Get new bowl gaskets as needed seperately.

Sorry if this sounds like I'm raining on your parade. Just want you to have success when it's all complete, and a little extra work up front typically pays off in the end.

Good luck.

[PAULYBOY]

As to the petcock, I guess I'll have to replace it. I ordered a set of carb orings last year from that place. That's what I used. Didn't do any rejetting, just repalced o rings and float bowl gaskets. Thanks for the input, though. I used the intertube orings, although the fittings were really in there, which to me meant the orings were still fine. I guess it's good that the only extra parts i ended up with wrre the screws i replaced, huh? Do you have any tips for bench synching? The only reason I put it all together last night was because I didn't want it laying around in pieces for too long. I have VERY limited time during the week to do stuff like this, and if I let stuff lie for a week, who knows what would happen to it>

[chef1366]

I bench sync with a thin flexable feeler guage. Open the butterflies with the idle screw until the feeler guage slides under the #3 butterfly and set the rest the same way.

[PAULYBOY]

I bench sync with a thin flexable feeler guage. Open the butterflies with the idle screw until the feeler guage slides under the #3 butterfly and set the rest the same way.

Let's put it this way, Chef. When I 1st looked at the butterflys last night, #1 and #4 were even with each other as the other two were closed. 1 & 4 were still open enough to almost slip a toothpick under, and all the way through, the gap. I looked for my 35 year old feeler gauges to no avail.

[chef1366]

Use a paper clip then. Just file off any sharp edges.

[PAULYBOY]

Use a paper clip then. Just file off any sharp edges.

As they say in the beer commercials- "BRILLIANT!"

[PAULYBOY]

update to carbs/petcock

I replaced the o'rings for the intakes, and the stainless allen head screws. The guy I bought the bike from must have really done what he sadi he did, because the intake o rings were still very pliable, not even squished into square cross segment yet. So, I made my water bottle cum gas tank idea, with new clear fuel hose, and tried to set the idle, both hot and cold. Of course, stupid me, I tinkered with it for 15 minutes before I realized I'd have to plug the vacuum port for smooth idle. No carb sync yet, but the bike is running a lot smoother, and close to the 1200-1500 rpm at idle. Then, I changed the oil. Hmmmmmmmm, 5 quarts of runny, gas smelling stuff came out, and when I took the filter out, the last person to change oil filter must have smeared half a tube of goo on the oil filter o ring to keep it in place. Anyway, that confirms what you all have been telling me about my petcock leaking. Now that my tank is off being repainted in the day of the dead motif, I did previously order a rebuild kit from bikebandit that said it was supposed toi fit my make and year. Only about 1/2 the seals fit, and the main vacuum diaphragm assembly didn't quite look the same. I guess if it doesn't fit, I'm out the 21 bucks and will have to get a replacement. So, next question is this-
Can I replace it with a non vacuum type petcock, and just cap off the vacuum port? What about an inline, chemically inert ball valve so I know the fuel is off when I'm not around and don't have to worry about the gas in the oil thing again?

[Nessism]

The main system keeping fuel out of the oil is the float needles, if they are not sealing properly (as yours apparently are not) you are going to continue to have problems. The number one reason for float needle problems is contamination from the tank getting stuck in the needles. Assuming the tank is clean and the needles are sealing, the petcock is a safety device of sorts when the engine is off. A shut off valve would be better than nothing if the petcock has failed, but don't expect it to solve your gas in the oil problem.

[PAULYBOY]

The float needles looked good when I took the carbs apart, and there was an inline filter along with the rather tall filter element attached to the petcock. I'm assuming that when I cleaned the carbs out, I would have gotten any junk out as well. Thanks for your reply though. I just hope the problem is gone. The inside of the tank is in really good shape, almost no rust anywhere that I can see. All nice and shiny inside. I'm still puzzled about the other outlet coming out of the tank on the left side of the tunnel just ahead of the fuel sender. I guess it is some type of vent, but since the hose attached to it when I took the tank off the first time last year was attached to the vacuum port of the carb setup, and nothing attached to the vacuum port of the petcock, it might not be. Maybe I can get some pix tomorrow.