Street fighter/ Bobber build 2.0

[bikerphil]

Are you 100% sure the fuel supply lines are going to the LOWER carb T's and not the upper venting T's? What about the fiber washers for the seats, are they torn and not sealing? When you initially fill the carbs after installing, are you tapping the float bowls with a screwdriver handle to prevent the floats from sticking on the bottom and causing flooding?

[skids]

I don't know, but you might need to explore the need for a different float valve needle to work with those plastic floats.

[Fearthepack]

OK, the extra floats I have are the 1980 plastic ones. Read through your posts on adjustments needed for the plastic floats did what I thought was needed to use them. Set height at 26mm and getting a good seat. Tried blowing into the gas inlet and couldn't get the seats to fail.....this is good.

Start caranking and gas shooting out the enricher (10 oclock hole on bell) on 1 and 4 carbs...BTW I have never had flooding out the back of carb this whole time except only when cranking.

Reset height to 27.5mm just to omit fuel height as a problem. Shoot the bowl should be only have full by now.

Same results except 2,3 carbs decided to randomly jump into the action.

Side note plugs are bone dry I would expect them to be wet. Going to see if anything crawled into the carb boots.

Just seems like the carbs are not delivering fuel into the motor but instead throwing it out the back. This bike maybe possessed.

Not sure how I go from last jet change and a great running bike to no mans zone....

[donebysunday]

Very interesting, thanks for that. Think I tried this years ago on a XS650 and did not work out. Now I'm thinking I just did not have the technical knowledge at the time.

[Schming]

Will the plastic floats work in carbs designed for the brass ?

If you decide to get the plastic floats there is a really low price on some good plastic floats, eBay auction # 113336776088 # 113336776067 # 113336776086 and # 113336776049

Lots of threads that answer your question here:

http://www.xs11.com/forum/search.php?searchid=2858700

Bottom line is that, yes they will work and seems like folks have the best results with matched sets of needle/seats, viton tipped or brass, but there is a small clearance issue mentioned between the plastic float and the early carb innards, in this thread:

http://www.xs11.com/forum/showthread.php?t=43692&highlight=plastic+floats+early+carbs

[donebysunday]

yep valves in spec...
Ok after letting the carbs full of fuel on the bike overnight i removed and dropped the bowls as fast as i could and 2 of the floats had minute amount of fuel in them after shaking them. For observation I followed DiverRay recommendation marked the 2 bad ones and put all in a pot on the stove. One known bad one bubbled fairly well the others did nothing even the other known bad one never bubbled....at this point i can't trust any of them. I have some extras hiding somewhere i will try, then may order plastic ones.

Will the plastic floats work in carbs designed for the brass ?

If you decide to get the plastic floats there is a really low price on some good plastic floats, eBay auction # 113336776088 # 113336776067 # 113336776086 and # 113336776049

[DiverRay]

If you marked the spot that the bubble came from, you can fix that float! Just use a solder iron and a bit of solder to seal it. DO NOT try to use a torch!! You will have the float in bits if you try. DAMHIKIJK....

[Schming]

Seems like you found the culprit.

Checking the threads, looks like the XV920 float seats and viton tipped needles with the plastic floats are the way to go in the early carbs.

[Fearthepack]

yep valves in spec...
Ok after letting the carbs full of fuel on the bike overnight i removed and dropped the bowls as fast as i could and 2 of the floats had minute amount of fuel in them after shaking them. For observation I followed DiverRay recommendation marked the 2 bad ones and put all in a pot on the stove. One known bad one bubbled fairly well the others did nothing even the other known bad one never bubbled....at this point i can't trust any of them. I have some extras hiding somewhere i will try, then may order plastic ones.

[Schming]

Valve Adjustment ?

Fearthepack, have you checked the valve shim to cam lobe clearances ?

IMHO this should be the first step in the tuning process, 'cause it affects how well the carbs will work.

I just reread the whole thread and maybe I missed it but no mention of a valve adjustment.

BTW your bike is a looker and hats off to ya for your attention to detail, really nice.

JAT, the forced air by mouth into the bowls may be too much pressure that may be displacing the fuel, also the 2hr. interval may have let the fuel evaporate a little letting the floats drop some.

[motoman]

With floats installed, would check that each one is parallel with carb boby as there is minimal clearance room. This causes many a float to hang up a bit dragging on float bowl.

[Fearthepack]

Yes vents are clear....
Did shake and no audible fluid was present....
However that is not always the case being to hear something.....
I cant think of any other items in the carb but floats that can fail...its either clogged passages or not for the most.
I've never done what you have suggested about the floats should be interesting...

[DiverRay]

OK, first are the vents clear? if the vent is blocked, you WILL overflow!
After your test, you should have pulled the two floats and shake them near your ear. You can hear if there is liquid inside the float. Or, follow this:
To check the floats, put them in a pot of water on the stove, and turn on the heat to slowly bring up to a boil. Look for any small air bubbles from the floats as the temp rises. If you don't see anything, pull the pan off the heat and add a couple of ice cubes to bring the temp back down somewhat quickly. Do NOT just pack ice into it, as you can cause the floats to collapse. When done, again shake near your ear and listen for liquid.

[Fearthepack]

Trying to omit culprits....
1. Dropped 4 brass floats in a bucket of water for an hour....all floated so held under water for five minutes and all popped up fine.
2. Polished up the needle and seat...
3. Reassembled and bench tested by blowing in the fuel line while upside down and worked perfect, rotated to open up the seat then closed again while blowing and all worked as it should.
4. Reinstall the carbs and only ran fuel to #3,#4 till it stopped flowing in clear fuel lines. Disconnected the gas tank line and put a line I could blow into. First attempt hard to tell if air is getting past the seat. Wait a few minutes and repeat and could notice air bypassing the needle/seat. Wait 2 hours and easily blow into the tube....WTF, WTF, WTF

Was thinking bad (contaminated fuel) was keeping the needle from seating but why would the forced air by mouth get easier over time with no new gas flow.

A betting man says the floats are failing over time causing the needles to seat worse and worse yet they float fine in water...

I know something close to nothing at this point......

[Fearthepack]

p.s. this has created a no run condition just a little pop now and then.