400, problems

[Big_Ging]

Hi Its my first post here sadly with problems 
I've looked in the forums for a answer but I cant find spot anything So I'll ask here :)
I have a Jap import 1992 bandit 400, When I bought it, it ran fine apart from stalling when hot. So after a nice ride back home i checked the Fuel Air screw's they went from 1.5 turns to 5.5 

So I turned them all back down to 1.5 turns and the bike started and idled fine, Also while I was there I tried to balance the carbs, which where quite away out, Now, I can balance the left and right banks fine, But when ever I try to balance them togeather the revs fly upto 4000rpm. Over the Last few weeks I have tryed a few things

1) replacing the seals in the carbs
2) putting some WD40 around the carbs looking for air leaks
3)Cleaning the carbs out

Nothing seems to work, Any Ideas? I must be missing something simple, I know my Guages are fine as I balance my cbr1100xx the other day and that runs sweet as a nut.

thanks

Chris

[andrewsw]

okay, just to eliminate the simple problem... does it rev *while* you are adjusting? I ask because pushing on the screwdriver will do that...

[Big_Ging]

wow quick reply thanks, By 'reving' I mean as I sync the two banks it picks upto 4000rpm and stays there more in sync the banks are. More out of sync they go lower the revs get, this happens with little to no down force on the screwdriver.

Just a thought, the last owner said he striped down the carbs and rebuilt them, not sure if something could of been put back wrong?

[frankenzuki]

You may to back off your idle adjustment screw, as you sync.

[andrewsw]

I second that. THe more in-sync the carbs are, the easier the bike runs and the higher the revs will go. THe climbing revs is a sign that you're improving things, IMO.

A

[Big_Ging]

the idle screw is backed all the way off, I'll pull the carbs off tommrow and check nothing is fowling the linkage.

[pmackie]

Based on what most the 400 guys run, you wil likely need to turn the air screws OUT to 2-3 turns? This could be part of your sync problem.

[PitterB4]

What Andrew means is that when you're working on that middle screw, you can be opening the throttle by pushing on it.  IIRC, that happens really easily on that one.  And, I would start your A/F screws out at least a little further.

[Big_Ging]

well day two lol I have tryed a few things you have said

1) I turned the A/F screws up from 1.5 to 3.0 by 1/2 turns and tried to rebalance, What I have noticed is be blue/white smoke which gets less higher the a/f is turned, the bike seems happier more turns i give it.

2) I have checked the linkages, choke etc all are free and working correct,

The only thing I know i have not checked is the float hights, would these be worth a look? what sort of settings am i looking for?

On removing the carbs a few times I have spoted a pool of fuel in the inlet rubbers I dont realy think thats normal? Also the spark plugs seem a little damp when i removed them for cleaning

Thanks for all your help so far

[andrewsw]

sounds like you might have stuck floats or perhaps a bad fuel petcock. Both of these problems are common on B4's. Likely you'll need to pull the carbs and give them a once over. If your floats are stuck, fuel will flow constantly (even if slowly) and overflow the carbs into the cylinders.

open those float bowls and pull the floats. You're looking for bits of grit sitting right at the top of the float needle preventing it from closing. Or worse, you'll get a piece of grit down the side of the float needle itself causing it to jamb in it's housing (don't ask how I know this ). You can pull it apart, but be careful. And you'll definitely need to adjust the float height when you're done. Set them to stock (search this forum for information on doing this) and most likely leave them there. Non-stock adjustments to float height should be the last on the list of tweaks, IMO.

A

[Big_Ging]

Hay there, been a while since i have posted on this topic, I checked all the carb's, checked the valve clerance's (they where all tight ) and tryed to reblance the carbs.

 It still idle's at 2000-4000rpm and wont rev over 6000(ish) its also pumping out lots of blue/white smoke, even when its just turning over!! I want to test the commpresion but I cant find a tester with a 8mm tread to fit the plug holes (I'm in the uk anyone know where i can get one?)

To be fair i am stumped, any ideas on what to do next, I'm starting to give up on this bike 

thanks chris

[Big_Ging]

update she will rev over 6000 now, dont know why, she just started to