complicated carb problem

[Squishy]

Buddy your beating a dead horse if your trying for good mileage. If you want mileage get a passport 70. The best you will get on a "properly" running 400 is mid 30 mpg. Period! This engine puts out more specific HP than the Gsxr1100 of the same vintage. Don't be so "F"ing  lazy and search out the hundreds of posts on here about jetting and mileage!

Where did I mention anything about wanting to get good mileage? You're the one who brought it up out of no-where.
Btw I did read the jetting info topic but literally nobody is running 110 mains. Only found 1 post about 110 from the old topic and it appears to be from you (Theif400).

[Thief400]

Cause your tracing your mileage by jetting!!!! Read the whole jetting thread. Everything you squids want to know has been documented on here years ago! Stop being so lazy!! Nothing happening now isn't new and has been we reported on here

[Squishy]

Cause your tracing your mileage by jetting!!!! Read the whole jetting thread. Everything you squids want to know has been documented on here years ago! Stop being so lazy!! Nothing happening now isn't new and has been we reported on here

Dude, you need reading glasses..
I never even mentioned the word mileage until you brought it up.
I'm not tracing my mileage. I don't even care about mileage... 

edit: I think you're confused with poster gallant_pilot (OP). He mentioned fuel economy...

[greg737]

Everything you squids want to know has been documented on here years ago! Stop being so lazy!! Nothing happening now isn't new and has been we reported on here.

Wrong.  The B400 is aging, it's getting older.  That's what I was pointing out earlier in this thread. 

All of your old jetting information just assumes the carbs have healthy emulsion tubes in them, but as the B400 ages this is less and less likely to be true.

[interfuse]

The bandit 400 was old when the jetting thread was started. You can't tune around worn emulation tunes. The only solution is to replace them. And forget about trying 110s if you're running a jet kit. The needle taper on the jet kit allows more then enough fuel with the supplied jets.

[Squishy]

The bandit 400 was old when the jetting thread was started. You can't tune around worn emulation tunes. The only solution is to replace them. And forget about trying 110s if you're running a jet kit. The needle taper on the jet kit allows more then enough fuel with the supplied jets.

I'm running stock carbs with stock airbox and slip-on exhaust.
I got the needles with adjustable clips. (set to +1 richer)
Gonna try 110 .. only cost €7,50 so

[Squishy]

So I tried 110 but will post results in jetting thread

[gallant_pilot]

hello again guys!

after a long time, i finally stripped the engine,got the head and barrels skimmed and lapped the valves.
there is no leakage from the valves and everything looks fine.

1- i did the timing exactly same as what manual says.( 20 pin from 3 on EX to 2 on IN)

2- spark plugs are good and i have purple,blue spark.

3- set the carbs to stock setting.

4-new battery is on the bike.

now the bike doesnt wanna start at all.the starter turns the engine but there is no single sign of starting.

i have no idea anymore.

do u guys have any suggestion for me?


its GK75 engine

[Squishy]

Could be anything.

1) Check compression first
2) Recheck timing
3) Check spark on all 4 plugs
4) Make sure the carb gets fuel, and don't forget the vacuum hose. Check choke mechanism.
5) Make sure airbox is clean.

If you have compression, correct timing, 4 healthy sparks, fuel and air, it must start.
So one of the 5 is wrong.

[gallant_pilot]

i checked everything !

spark is there,fuel is enough in the carbs,timing is exactly as the manual shows,i tried it with and without air box.compression is good as i did recon on head and valves,rings and pistons are in very good condition.

if any of these is not write,i must at least get a very tiny small combustion.but there is nothing at all.

[Squishy]

i checked everything !

spark is there,fuel is enough in the carbs,timing is exactly as the manual shows,i tried it with and without air box.compression is good as i did recon on head and valves,rings and pistons are in very good condition.

if any of these is not write,i must at least get a very tiny small combustion.but there is nothing at all.

Well, I would recheck the above 5 points.

1) What were the compression numbers?
2) Double check timing
3) If it sparks it doesn't mean it can spark under compression. Make sure the sparks are in good condition.
4) Check everything on carbs: vacuum rubbers, choke mechanism, throttle valves, vacuum hose, intake rubbers.

You could also check the valve clearances, even when compression is good they might open too far or something?

[ventYl]

try to check spark with two nails with ends 8mm apart instead of spark plug (manual show how exactly). you should still get spark. if not, shorten the gap and test how small will fire the spark. especially in case you have original, untouched, stock ignitor which tends to fail often. In colder weather even replacing previously working spark plugs for equally heat-rated new ones can do miracles and replacing HT wires can do even bigger ones. (if it was not already performed).

and one note: check if you have HT wires connected correctly. i know it is dumb but i happened once to me when I was fiddling with one of my B400s that I swapped wires between coils. I suddenly got no spark for no apparent reason. Also, If carbs sat dry for some longer period bio-ethanol probably present in gasoline might clog passages inside carbs.

[gallant_pilot]

today i replaced all plugs with new ones and i have spark on all 4.
tested the compression and it is alryt.
checked the timing and its also perfect.
cleaned the carbs again.

still nothing

[greg737]

Sorry to hear you're still having problems.  Here's something to consider and check.

I just scanned back over all of the posts in this thread and I didn't see any mention of the bike's Ignition Control Box.

The Bandit's Ignition Control Box can easily be the source of your problem.  The most delicate part of the Bandit's ignition control system is the two very small wires that connect it to the Signal Generator (which is a variable reluctance pulser located under the engine's left-side cover). 

The Signal Generator was obviously produced separately by a sub-contractor (probably Nippon Denso Corp.) and this parts provider constructed it with only enough wiring to get a couple of inches (centimeters) past the rubber oil-seal stopper.  When the Suzuki assembly technicians built it into the Bandit's wiring harness they used crimp-on connectors.  These crimp-on connectors are rigid while the rest of the Signal Generator wiring is flexible.  This creates a point at which the wire naturally flexes when any bending force is applied.

The Signal Generator wiring can fray and split at these crimp-on connections.  You should carefully inspect the Signal Generator wiring to determine the condition of its wiring to the Ignition Control Box.  Inspect the wiring from where it comes out of the upper-rear corner of the engine's left side cover to where it reaches the two-wire connector plug in the main wiring harness that leads to the Ignition Control Box.

   

[greg737]

Also, the Bandit's Ignition Control Box is very sensitive to the amperage spikes.  It's okay to "jump start" your Bandit from a car battery as long as the car's engine isn't running.  If you do this with the car's engine running the amperage is too high for the Bandit's Ignition Control Box.

During your maintenance difficulties and trouble-shooting if you have attempted to "jump start" your Bandit from a car with the car's engine running the capacitors on the circuit board inside your Bandit's Ignition Control Box will be blown out and it will not function.