revs hanging

[lozza]

Am having real trouble with my H1, depending on how i adjust the idle, i either get revs hanging - anywhere from 4000 downwards, and then eventually dropping to lumpy idle. or lumpy idle that eventually ends in stalling.

I think it is running lean so I checked like this.
https://www.youtube.com/watch?v=ZXVXMK1Fy8I
Also if i apply the choke at any point, even when fully warm the revs will shoot up to 8k

note that when it finally drops to the normal idle speed, it runs really lumpy and will eventually stall.

i have had the carbs apart numerous times to clean them, replaced all parts that needed it, and put in new pilot screw o-rings.
Cleaned all jets and parts and blown through them with carb cleaner. the pilots were set to factory and the float heights too.
I have tried adjusting the pilot screw anywhere from just 0.5 turns out to 2.25 turns out (factory for H1) and it still behaves exactly the same as in the video there.
In fact, adjusting the pilot screw does not seem to make any difference at all.

I have had the carb holders off of the head and cleaned the head surface, then cleaned the rubbers and replaced them on the head with sealant. all rubber parts carb, manifold airbox were clean and sealed properly with silicone.

i have sprayed carb cleaner all over and around the intake and carburetor with the engine running, revs did not change, i think its pretty safe that i can rule out an air leak.

I'm stumped now. Any ideas anybody?
Any chance at all that this might be something electrical.

all help is much appreciated.

[KwakKwak]

Have you balanced the carbs????

[lozza]

One thing i noticed when i had it running earlier, is that if i cover the two breather pipes coming from inbetween the carbs (part no 92059A http://www.zxrworld.co.uk/images/hmicro ... ternal.gif) - the revs increase, similar to the way they do when i cover the airbox intake.

I know these are meant to be breathers, but I wouldn't have thought that the engine should be sucking air in through them? and obviously enough to alter how it runs...

[lozza]

Have you balanced the carbs????

Haven't balanced them yet, but have some balancing guages hopefully on the way, thanks to ross.

[lozza]

Right, checked the carbs and they're all balance up nicely.

What can I try next, please any suggestions...

[lozza]

Rigged up an aux fuel tank to try to check fuel level in the float bowl using the tube method, but i can't get a consistent reading.

I get the same problem on all four bowls, I loosen the bleed screw, it fills up to some point - sometimes below the service level, sometimes spot on and sometimes even above it. then i tighten it back up, drain what was in the tube, and then repeat the process and then it gives me a different f*cking reading! usually lower than the first one U got, each time i tighten it and open it again it gives me a different reading, alot of the time when its a low reading I somehow end up with a bubble at the BOTTOM of the tube, wtf is going on.... Has anyone else had this problem?!?!

Really would appreciate some input from anyone here cos i'm seriously losing my patience with this f*cking machine!

[KwakKwak]

If you drop the zero point below the carb and bring it back up you will get an inconsistent reading, footery as fook doing this.
Are you sure everything in the carbs is okay, seals etc. Are the float valves seating smoothly, ie has someone removed the seats before and scratched the insides, I've managed to scratch a few before when removing with long nose pliers and on checking the valves, they can occasionally stick.
Seems odd that the choke will make your bike rev to 8000 when warm, mine will just cut out if I use choke once warm.
Are the fuel lines all good??

[ross46]

Try taking the carbs off an measuring the float directly, take out the pilot screws and check everything is in the right order and not damaged and set back to standard settings, have you done your valve clearances?

[KwakKwak]

Try taking the carbs off an measuring the float directly, take out the pilot screws and check everything is in the right order and not damaged

Last two sets I've stripped, one had the washer and O ring missing on carb 4, set I'm working on at present had no O rings to all four pilot screws Reckon either when people are adjusting them, they must be removing them first rather than reseating them, and losing bits, would explain why people have so many problems with setting these.

[banner001]

im giving them a look for lozza.

[lozza]

Have had all the parts out of the carbs, cleaned them and put them back in properly numerous times, all parts are there - new o-rings on mixture screws. Originally it wouldn't even idle - fixed this by clearing a blocked pilot jet. Measured floats with a ruler and set them to factory before i tried the tube test.
Was getting different readings each time I tried the tube test even if i disconnected the tank, drained all the bowls and started again.

Fuel lines good as far as i know.
Valve clearances claimed to be done by the previous owner but even if they were bad I wouldn't have thought that would cause the revs to raise when I cover the intake or apply choke? points to a lean mixture to me but I've tried everything I can think of...

Not sure about the float valves I guess they could be a possibility - seems unlikely all 4 would be bad though - as i was getting inconsistent readings on all bowls. but as banner said I have now sent them off to him and hopefully we'll find the problem.

[ross46]

Valve clearances out will cause the engine to be fighting against each other, so could cause problems, mine was so much smoother after doing valve clearances, reminds me, need to do mine