carbs and petcock

[fireburster]

So my 93 b4 doesn't idle without choke. I bought some fuel cleaner from a shop here and they said to ride it around. I went for a ride thinking i had plenty of gas. I ran out and the petcock doesnt seem to work. I switched over but it wouldnt fire. Had a buddy bring me some gas and i had to pop it because my battery was dead from trying to start it to much. Should i take it off and clean it or any other ideas? Im pretty sure its hooked up right. I have the long straight tube on the gas tank going to coolant run off, i think thats right.

Also im thinking of building the carb tool but Im new at this. Could someone who has done this on a b4 explain it like im a 4 year old? I found that i need 1/4 tubing and i think i see where it hooks on the carb. But the manuals pic of the screw to turn isnt very helpful. Anyone got a pic? I think i will just do the 2 carb way as im not sure how to make a 4 one.

Also i changed my rad coolant since there wasnt almost none in there. I got it full but i still dont have any extra in my res that you check the full line on. Could i have a vacum issue or something. I filled it up with the proper amount of coolant just the res tank is empty.

Sorry this is a lot of questions in one thread.

[mosquito]

There's a catch-22 with the petcock: The engine has to be running for the valve in the petcock to open.  If you run it out of gas then you can't start it get the fuel to flow into the carbs to start it.  The workarounds are to

- remove the screw on the face of the petcock and turn the petcock lever to 12 o'clock (ON is 6 o'clock, RES is 9 o'clock) or
- pour fuel into the carbs via the fuel line (half a pint or so should do) or
- keep starting (up to 10 or 15 seconds at a time to not overheat the starter) or
- put another hose on the vacuum nipple of the petcock and lightly suck (you're providing the vacuum the motor normally does)

"The carb tool"?  A manometer?  For synching two carbs, it's pretty much just a long tube with some fluid that you can easily see inside it.  Sorry don't have photos or measurements.

Once you get the carbs off push on the bit where the throttle cable connects.  You'll see the parts it turns on the between the carbs. There's a big-ish round spring and then little compression springs between the carbs.  With the compression springs there's (only one) screw.

I can't think of any vacuum issue that would affect the coolant level (short of vacuum fairies sucking away your coolant in the night).  But, if you were nearly empty (!), adding coolant usually winds up leaving air pockets inside, so filling it doesn't really leave it full.  The thing to do is fill it then run it for a few seconds and fill it again.  For me it takes two or three times to get it full-full.

[fireburster]

where are the 1-2 3-4 screws? Do i get to them from the top, or front.I know i have to remove the tank so i assume i see them from the top.

[mosquito]

It's easiest to find / see them with the carbs off, but they have the same description:  between the carbs there are parts moved by the throttle, including two springs and the (only) screw.

Can't access them from the front, the engine's in the way.  It does take a little practice to get the screwdriver in the right place and to turn them without pushing down.

Oh, here's a caveat for liquid manometers:  don't rev and release the throttle 'cause it can suck your fluid out.  If you do turn the throttle close it slowly.

[fireburster]

Ok ill look for them when i get there. Will a 1/4 tube fit the carbs or do i need another size?

The bike seems to run great just doesnt like the choke off. Guy i bought it from said he rejeted them and synced them but you never know if they did or not.

[Ken Hill]

If it won't idle without the choke it's not a sync issue, it's plugged pilot jets. The pilots in these bikes are tiny, doesn't take much to plug them. If the bike sat for a while with gas in it with no stabilizer the pilots are probably plugged.

[interfuse]

or if you have a rusty tank.

[fireburster]

The PO did a dynojet kit, He told me the carbs were clean when he opened them. I have no doubt that there is crud in the tank. I need to clean that out.

Is it typical that when i start the bike with full choke that it revs to like 4k for 5 mins, then i start slowly letting off the choke it goes down. I then can let it idle with no choke but when i drive it and come to a stop it will dip way down and die unless i leave the choke on. Maybe something just isnt set right and Im looking at the wrong part.

This is my first bike so I'm pretty new to all this.

[Ken Hill]

I'm a dealer and one thing I've learned is never assume the customer knows what they're doing. Just because the PO said he cleaned the carbs doesn't mean he did it right. I've had alot of people tell me they cleaned them when all they did was take the float bowl off and spray some carb cleaner around. I would go thru the carbs thoroughly, take every jet out, make sure you can see lite thru all the jets and make sure every passage way in the carb body is clear. If you squirt carb cleaner in a hole it's supposed to come out somewhere. I would also check float ht. and pilot screw settings, don't assume anything is right, I've seen people really mess things up. If you're not confident in doing it yourself find a shop / person you trust that knows carbs and pay them to do it. You'll be further ahead by starting with the basics, knowing that the carbs are 100% right.

[mosquito]

I totally agree with Ken Hill.

--

Five minutes of warm up at 4k sounds like a long time to me.  Now that it's cooler, I'll start it, adjust the choke so it's going 2 - 2.5k for a minute or so and then ride it and turn the choke off within a mile or when I get on the freeway (about half a mile for me).  My bike has done the dying at stops and getting the carbs right made that go away.

FWIW, I was arguing with my carbs a month ago.  It wouldn't run under 3k (it would just die, in some cases slowly, other cases immediately).  Turns out I had each of these problems at various times:

- Plugged idle jets -- cleaned the puppies

- Inaccurate and inconsistent float heights -- I built a tool out of several small steel rules, where I'd eyeballed them with just one ruler before.  They had varied by 2+ mm and now I can get them within 0.25 mm.  (A 2 mm float height change on my bike is a HUGE change.)

- Inconsistent idle screw turns.  --  Carefully turned them all back to 'zero' and then back out again.  One of the last times I cleaned the idle jets I was in a hurry and left the carbs attached to the cables and then adjusted the idle screws with the carbs installed when I had been doing it off the bike.  I got confused and turned two of them half a turn the wrong way and that left two cylinders starved.

[fireburster]

Ok i may look at them but it is probably over my head doing carb work.

Any tips on putting the airbox back on? I noticed it wasnt on right and took it off but its not easy to get them all back on correctly. Im sure there is something im missing.

[mosquito]

Nope, you're not missing anything.  It's a pain.

Get all four clamps nice and loose.  Align the airbox with the carbs, catch the top edges on the carbs, push down to catch the bottom edges.  Curse.  Think about baseball.  Rinse and repeat until it works.

[bonanaza]

A little WD-40 on the insides of the rubber sleeves helps

[gsxr400 racer]