little o-ring on elulsion tubes

[angus67]

so, any ways, ive been working on a friends 71, and got it all sorted, and eventually starts with alot of kicking. It will warm up fine, then when I take off the choke, it will idle for a few minutes I can revit up, but it quickly floods out. It wont restart, and the plugs are soaked. the mix screws are 3/4 out, needles 3rd notch, Battery at full charge, strong coils.
when I had the carbs apart, (bs38's) I noticed the small o-ring around the emulsion tube is deteriated. could fuel be finding itway around the jet/needle flooding it out? I ordered new rings from mikes. I hope its that simple. Ive got the poionts dead on, timming right. when it starts, it sounds great, welll ballanced rite/left.
if that isnt it, then what? drop the needle a notch?
floats are not sinking.

 

[XSLeo]

Yes, fuel can leak past that o-ring. making the mix very rich.

 

[angus67]

gawd, I hope so. ive been wanting my garage space back. cant give it back unless it runs.

 

[5twins]

Your needles are already set a step leaner than stock by being in the #3 slot. If the new o-rings cure the flooding and rich running, you should probably re-set the needles to the stock position or you may end up running too lean.

 

[angus67]

o-rings from mike should be in tomorow. hope its whats needed I need to get this bike back to my friend.

 

[angus67]

nope, the o-rings werent it.
It still is hard to start, idles fast when warmed up on choke, turne choke off, floods out.
so I should put the needles at the second slot from the top, 5twins?

 

[5twins]

Stock setting for the 4JN19 needle in the XS1 and 1B is 4th from the top. Mikuni needle slots are always counted from the top down .....

If it's already running too rich in the leaner #3 slot, moving it to 4 (which is richer still) isn't going to help, it'll make things worse. There's something else wrong with those carbs if it's flooding out like that. I would make sure everything is correct for that carb set - jets sizes, needle, float setting, clean choke feed jet. Sometimes a carb set is just bad. If it had gotten really gummed up at some point, the gas residue could have eaten away at the internal passageways. It can also do the same to the jets, the needle jet in particular. If you have another set of carbs you could try, that may help pinpoint the problem. If it still floods out with another set, then I would be looking for motor or ignition problems.

 

[angus67]

update.
tore the carbs apart AGAIN- made sure every passage was clear. replaced the choke plungers, cleared out the idle mix, main jet, pilot jet, eeverything. good spark full battery, points at 3. valves set. in .003' out.006"
full battery, blast of carb cleaner for a little help, choke it, started on about fifth kick, it idled fast,3k let it warm up, the head right behind the exhaust flange was 155/ 175, seemed hot enuf so I took the choke off, and idled longer than before, so, thought i was making progress. its idling around 2100, and when I turned down the idle, to 1500, it died. so I jump on and start kicking, no start. pull the plugs, dry.
the only thing I can think now is its fuel starved, and running off wat enters the bowls when it isnt running. my fuel filters are new, the tank shows a little scale, but isnt like, flakey with huge chunks of rust. I want to see what happens without filters, but am afraid i will have to clean them carbs again, and again, and again(no pain, no gain?)
i give up for now. next weekend, I'll get bigger filters, the ones I have are small, but have seen them on bikes here, the clear cone ones with the sintered bronze(?)
if I can spray some carb cleaner, and keep it from dying, i will know its fuel delivery problem, but I really have gone thru everything.
any ideas?

 

[angus67]

needles in forth slot, BTW

 

[chopfather]

You could try running it with a small bottle of fuel hooked to the fuel line wthout filters to see if they are impeding flow without having to worry about dirt from the tank getting into the carbs.

 

[angus67]

ooh, yeah, thanks.

 

[xjwmx]

bigger filters, the ones I have are small, but have seen them on bikes here, the clear cone ones with the sintered bronze(?)

I have a real tiny clear sintered bronze one on mine feeding two BS34s, so doubt your filter is the problem, unless it's plogged up. It's mounted straight up and down, with the bronze cone attached to the lower side. It's easy to check for a clogged filter - does gas come out of it

 

[flyboy]

I think Chopfather's idea is best to identify whether or not the fuel is contaminated. Might want to check the float levels too.

 

[chopfather]

I was gonna mention float level this morning but flyboy is quicker on the draw. I know I've sometimes gone over things several times only to find it was something simple all along.

 

[pyroman]

Angus, it is obvious that bike is broke beyond repair....You can ship it to Me, and I will give it a good home......

 

[angus67]

floats are at 25mm. any lower, and it pees allover my garage!

 

[XSLeo]

Try setting them higher, as in 26 mm. The spec as listed in my factory book says 25 mm +or- 2.5 mm. So the floats can be from 22.5 to 27.5 and still be in spec. I doubt that going to a shorter spec will help but a higher spec will fill the bowls to a lower fuel level. this makes the carbs runs leaner.
If you use a clear tube from the drain plug as the book talks about, the fuel level is supposed to be 4 mm below the gasket surface.
Try it, what can it hurt.

 

[angus67]

ill try 26 this weekend. glad 38's are easy to get out.
also, when I replaced the choke plungers, the one on the left has two slots, one to activate the left choke, and the other to activate the right choke. the plungers that came with the rebiuld kits has only one slot, and will actuate the rite carb, but i have to push down on the plunger arm to turn both off. can I just choke the left carb? ive heard of this done. I think ggggary only chokes one carb.

 

[angus67]

uhhhh...... figured it out.......
Cruzin the forum here, and some one was looking for the spec on piont gap, so since I like to verify the right info before i tell someone, I grabbed my manual, flipped to chapter 3, and it says to turn engine until mark on rotor is at 'f' mark............ive been putting it at the 'T'.
all this time, ive had it fire at tdc. duh. sometimes i amaze myself. i always tried to deny my polish heritage, but it rears its ugly head now and again
after getting it 'rite' , it fired on third kick. warmed up, took off the choke, and kept idling. i thru a timing light on it, one cylinder is smooth, but the other is missing alot. these coils are the originals, and they test good, but im gonna buy new coils and wires.
I did sync the carbs, it is very snappy above 2krpm's, and idles back down smooth, but the irratic idle, I'm pretty sure the coils are crapping out.
any thoughts on the choke plungers?

 

[XSLeo]

Doesn't the 71 carb link the chokes with a metal strap? In 72 they went to a choke on the left carb with a rubber crossover to choke both cylinders. They used it that way till 76 when they linked the carbs with the angle iron and used one throttle cable. They went back to a choke in each carb, linked to one lever.