Carb line question: Octopus?

[Mace Bronco]

I have a 79 SF and I think the guy before me put an 80's model carb ont it, based on discussions I've read here. The Cylmers shows my petcock valvues as needing the octopus. It wasn't on the bike when I rode it home from NC. So my question is do I need to put it back? and if not what are the correct hose attachments?

Thanks in advance for your wise counsel/


eric

[natemoen]

You do not need the octy, lots get rid of it anyways. If you still have the special tank on the bike then the rear most nipple on the petcock needs to be plumbed to one pair of carbs and then the other rear nipple needs to be plumbed to the other pair of carbs. The lower T on the carbs is the T that the fuel goes to, the upper T is for the bowl vent and needs to go to the airbox, or open to the air (filtered though) if you dont have the airbox.

The front nipple on the petcocks will not be used when the octy is not in place.

[BA80]

I personally like having the octy because I'm either too lazy or too forgetful to remember to shut off the petcocks every time.

If the carbs you have are 80 model carbs there won't the the upper nipple for the bowl vents, just the lower fuel inlet nipples. If they are newer carbs make sure the vent hose nipples on the airbox are capped off or you'll be sucking dirty air in there.

[Mace Bronco]

OK Thanks. I still have a question though. The carb ony has one set of t's in the lower section of both pairs. I do have the box and am putting it back in. I'm pretty sure it's the special tank it has two nipples. the way it was on I believe is each nipple had a linethat leads to a 'Y' that then went into each 'T'. Does that sound right or can I jst do what you've suggested? If so, should I cap the non used nipple?

[Mace Bronco]

Greg,

So if I don't shut off the petcock gas will keep flowing? I need the octo for that? and the vernts you're talking about are the two brass tubes coming out of the top of tha air box right?

[BA80]

I'm at work right now or I would find a diagram of the fuel lines with the octy. I'll look for one when I get home to post for you unless one of these fine fellows he would do it before that.

I don't know what "brass tubes" you might be speaking of. The vent nipples on all the airboxes I've seen are molded into the plastic in the upper half.
in the top corners facing the carbs.

If your float valves are working perfectly you won't have a problem but if they sit open for a long period (overnight) the valves can seep enough to cause problems.

[natemoen]

Greg,

So if I don't shut off the petcock gas will keep flowing? I need the octo for that? and the vernts you're talking about are the two brass tubes coming out of the top of tha air box right?

The gas will only keep flowing if things are not working right. But shutting the gas off is the BEST way to keep things when not riding because it keeps gas from flowing IF something goes wrong. If there is only 1 T in between each pair of carbs then yes you have later model carbs but since you have the early airbox you need to plug those 2 brass tubes coming out of the airbox or else you are letting unfiltered air into the carbs (bad thing).

[BA80]

Here you go Mace, HERE in this online manual in chapter 6 on page 155 there is a diagram of the octy fuel lines.

I suggest putting inline filters in there also. I found some small (1"-1 1/4" dia.) lawn mower fiters at ORiellys and installed them just before the inlets to the octy. they lay nicely on top of #2 carb.

If you need to look anything else up in the manual look in CBugs signature and click on the link to his website. He has manuals in there. I find a paper one easier to use though.

[Mace Bronco]

hey thanks a lot everyone.I'm going to try the singel line thing, and let her rip. I'll let you know what happens unless I get blown up or somthing. lol

[Mace Bronco]

well it's up and running but running rough and backfiring a bit. I've gone through the carbs already dipped all the non rubber parts and reassembled. any suggestions?

[BA80]

JAT.......have you checked the pickup coil wires?

[Mace Bronco]

I did put new coils on (used from a parts bike) and they are firing. At leaset there is spark on each cylinder with plug out. it appears that numbers 1 & 2 are not firing and it's only running on 3 & 4 (based on the exhaust on 1 & 2 not being very warm and 3 & 4 being hot hot) but I didn'thave the vacuum line attached to the carb (slaps self in forehead) so I'm going ot try that. If that's not it I'm stumped. your thoughts?

[BA80]

As was stated actually the only thing tha 1 & 2 share is fuel supply. I mentioned the pickups because you said it was running rough and back firing. A symptom of pickup coils with a wire going bad.

The only other thing I can think of right off is carb sync. Try adjusting the center sync screw and see if it smoothes out. Do you have access to a set of sync guages?

[DGXSER]

If it is 1 & 2 , then it is the fuel line or your petcock on the left side. First check your petcock is working. Then make sure you do not have a kink in the fuel line. I often find I have to reach under the carbs and pull the fuel line a bit to get a kink out of it after lowering the tank.

Also, make sure you have enough gas in the tank. If it was low when you removed it, when you put it back on more gas might be in the right side and able to run in the ON position. Try putting the petcocks to Reserve it it is close on fuel level.

[Mace Bronco]

Thanks again. It was indeed a kink in the line. I got this blue line that is not very sturdy and kinked when I got everything jammed in there. That airbox is a nightmare. Do I have to rejet if I put on single filters? Caused I'm definitely not going to go through that crap again. Anyway it seems to be running ok with an occasional back fire. How can I check the coil wires aside from grabbing hold and getting a taste of the electric chair?

Oh and I don't have access to a set of sync gagues. any suggestioins for finding a set in the Detroit area?