What have I done????

[skids]

Re: Could be

Take the bowl off and clean out the starter jet. It may be plugged.

Originally posted by planedick
Maybe the synch isn't right and #1 is working harder than the rest.

[Toolmaker Tim]

Carbs

Thanks everyone. I now have some things to look at. I'll dig into it after work and see what I've got.

[ridinghard]

toolmaker tim, I started mine this morning, ran it for about 10 minutes at full choke, pretty high idle and I didn't see any glow.

[Toolmaker Tim]

Thanks for checking for me ridinghard. I looked at the plugs and it appears cylinder one is running rich. Not much, but enough to go digging in the carbs again. Just for an opinion, does anyone think that the pain in the a$$ top support on the airbox is really needed? I mean if you are using the 2 screws on the side, why couldn't you cut the section that has a screw thru the top out leaving the part that holds the screws that everyone knows(LOL) not to take out, intact. Alternately C-clamp a mending plate on both sides of the center screw, drill two holes thru and tap them, then cut the support between the screw holes. That way you could take the middle piece out before trying to drop the airbox down while prying the top support over the mounting hole. I bet someone has already done this, I just didn't look for it in the right place. Got the work bench cleaned off tonight with the encouragement of all the mosquitos in the general area. Guess I'll smell like gas and bug juice tomorrow nite.

[ClarkGriswald]

I dont use the top support only the two side bolts. I left the bracket unmodified cause I can hang it there while the bolts are out.

[XSPastor]

A PO of my bike cut the to mounting bracket in half at the mounting hole. It can still be secured but just loosening the bolt allows the bracket to spread and the air box to drop.

[bikerphil]

airbox

I totally eliminated the top bracket and cut off the snorkel about 1" from the top of the airbox. Comes out now in about 2 minutes. Drilled holes in the bottom too and now it gets plenty of air.

[Toolmaker Tim]

Jets

No, I'm not talking about the squadrons of skeeters that were lying in ambush in my cave. Took the carbs off and looked at a couple things. First the starter jets, where are they? Are they the little spoogie holes in the side of the bowl? Second, if I bump the pilot jets up to 45 is that going to balance things out as far as the jet, K&N filter,header combination I have? The tech tip suggests that the you go up one in pilot jet for every 2 main jet steps, but I understand that hot pipes are caused by over-rich mixture. No, I haven't synced the carbs cause I don't have a set of mercury sticks and can't really afford them now. I do have a vacuum gage, but there seems to some debate on how accurate they are. Now what?
Bikerphil, made the mods to my airbox that you have, except for the holes in the bottom. Want to try to get what I have now working before I go throwing a monkey wrench into works. I have a extra airbox bottom I can change back to if it causes problems.

[bikerphil]

airbox + jetting

Try checking the color of your plugs. This will give you an idea if you are rich or lean. On my 79 Special w/ BS34II carbs, I have the modified airbox, 42.5 pilot + 145 main jets, 25.5 float level, + 4-1 mac exhaust. Runs great this way for me, mabye a bit lean at lower RPM's.

[Toolmaker Tim]

Plugs

Bikerphil, plug #1 is black on the tower and grey/tan on the electrodes, the rest are tan. Would a plug that isn't firing properly cause a rich condition? I'm trying not to overthink this but....
That might be caused by a bad wire or coil. I honestly don't know at this point.

[bikerphil]

plugs

Tan/grey is mabye a little lean, but ok. Put in a new plug, run some Seafoam in the tank. Carb 1 idle circuit might be partially blocked.

[Toolmaker Tim]

Carbs

I pulled the carbs and made sure the starter jets were clean. Didn't find anything, but that doesn't mean there wasn't something. Put in the 45 pilot jets, figure it can't hurt, and I can always change back if I need to. I've decided to get the extra carbs fixed up so I can make changes and still have the bike running. I am going to need a set of floats and valves. Does the slide springs sold by Mikes XS work? I'm probably going have a laundry list of parts to get. Any recomendations on a carb sync tool? Guess you can't have to many tools.

[bikerphil]

diaphragm slide springs

I recall reading that the XS650 diaphragm springs are shorter than the ones the XS11 uses. As for sync tools, they range from about $60 - $125. You could make your own for much less than that if you want. If you are replacing your brass floats with plastic, the height setting will probably be different than the recommended 25.7MM. If there are no pinholes in your brass floats, I'd re-use them, JMHO. I'm assuming that you are working on the BS34II (early type) carbs?

[mro]

Any recomendations on a carb sync tool?

I still use a single vacuum gage which works just fine to synk the carbs. Just takes longer.

header glowing = a serious lean condition
I'd check that you don't have a broken pilot screw tip in the carb (because it's fast/easy to check)

Enricher circut
Starter "jet" is located in the float bowl
fuel flows up thru this jet thru the carb to a small chamber (it picks up air from the top of the float bowl (other holes in float bowl rim)
In this small chamber there's a plunger with a sorta needle on one end. When you pull the "choke" all the way out the enricher circut is "wide open" allowing maximum fuel flow for a rich mixture,
push "choke" lever in half way and the needle on the plunger reduces the mixture but is still rich. All the way in and the enricher circut is closed off allowing no extra fuel mixture.

Long story short
Sounds like this circut be clogged.

The enricher circut dumps the fuel into the carbs throttle bore.
The hole it comes out of is located on engine side between 10/11 o'clock.

The choke lever needs to be pulled out when cleaning to let carb cleaner to pass thru. (unless you total disasembled the carbs)
Using the straw on the carb cleaner spray thru the hole or thru bottom of carb to see if it comes out other end.


mro
(then agin.....
your problem could be something totally different )

[Toolmaker Tim]

Thanks for the simple expliantion mro. Haven't put the carbs back in yet, so I'll check the pilot hole. Gonna buy a can of carb cleaner on the way home to make sure the enricher circuit is clear. I didn't think about that little brass tube going down into the float bowl when I was cleaning things out. Thanks