idling problem....

[doqq]

does anyone know what size diameter is the fuel line?  i found some inline fuel filters by purolator at pepboys but theres three different sizes.

[doqq]

yea... i dont have the bike with me at the moment thats why im asking

[Kenyan01]

Hi! I went to the nearest autopart shop and asked them to show me all the inline filters they had. The smallest was one for one of the Peugeot cars... I took it and fixed it in, cutting some length off the fuel pipe to reduce kinking that Inoticed occurred when I'd fixed it with the whole length of the tube.
Bike's running well... Tho' a bit hesistant in the idle. (Nothing to do with the filter. It's been like that for a while.) It loves to idle on choke! I have not adjusted my revs yet. I'll do that and get back withthe situation.

Cheers,
Patrick.

[doqq]

would a clogged jet cause it to be running rich?  or is my problem elsewhere?

[Kenyan01]

Hi!

The B4 is upto its tricks again! It's revving at 7000rpm on idle, with the idle screw adjusted until its out of its place!

It's been running well, then one day I noticed it was sounding rough an unbalanced and found that Cylinder four was cold. Idling was okay.

I checked the spark plug - it was clean, firing but not the fat nice blue ones, so I replaced it with a good one that was firing. Nothing! I opened the carbs to check it out and found clogged main and pilot jets in the 4th carb which was dirty. So, I cleaned all the carbs. I made sure not to adjust anything since the bike had been running fine.

On reassembly, the bike is running at 7000rpm, and I don't know what to do!!  I've tried checking the choke, the accelerator, and clutch cables... They are all well.

Can someone give me an idea what to do?

Best regards,
Patrick.

[pmackie]

For your bike to be reving at 7000 rpm at ilde, something has to be holding the throttle open. Check you cable routing and make sure you have slack in the throttle cable.

High and erratic idle can also be caused by air leaks in the intake system. Check all carb mounts and manifold bolts.

[Kenyan01]

PMackie,
The throttle had been my first suspect and I confirmed it was okay.
I took the carbs out for a cleaning, and found that two of my pilot jets were clogged by copper rust (due to the bike having been grounded for a while as I collected all my requirements for it to work without problems - loom, new CDI, new voltage regulator, new battery, digital multimeter etc). I feel good about the bike coz one of it's major problems has been sorted out, and as soon as I'll be through with these carbs, I'll have the perfect Bike!

I cleaned the clogged jets, etc but it still has erratic idling... I have all 4 cylinders firing equally, and that means it has something to do with dirt, air leaks, etc. I'll have something good to report tomorrow or by Monday.

I just love this bike! What would I be doing with all the time it takes from me if it was just smooth running?!

Best regards,
Patrick.

[pmackie]

One way to help diagnose a air leak to spray something like kerosene (or WD-40) around the intake manifold area while the engine is idling. If it is sucking air, it will tend to suck the kerosene as well, which will tend to make the engine run slower/stall or at least smoke out the exhaust.

You should also check the vacuum line to the petcock, as it will run erractically if it has cracks or sucks air.

In both cases, this assumes that the bike will idle at roughly the correct rpm.

If you still having 7000 rpm idle, you need to look at the carbs again. I'm not familiar with the carbs on the 400, but ensure that the slides are not hung up in their bores and/or that the butterflys are not sticking.

[Kenyan01]

The revs at idle are in the 1500 - 2000 range, fluctuating up and down. If you sat round a corner you'd imagine there are two bikes talking to each other... and it is not smoking or running rich. Every so often, one particular cylinder is not firing...

Cylinder four: I've moved it's spark plug elsewhere and it's firing. I also swapped it's floats elsewhere, and that cylinder is okay. This could mean something wrong with compression in this cylinder?

I am going to check for some air leakage somewhere in the carbs. Perhaps an o ring torn or lost... but I remain convinced it is the carbs.

If it were the vacuum leaking air would I not have problems with fuel flow?

Cheers,
Patrick.

[pmackie]

Given the symptoms your describing, maybe you ARE having problems with fuel flow. Check both the vacuum lines and fuel supply lines to each carb, make sure nothing is pinched, twisted, cracked, etc.

Surging at idle is usually a symptom of an overly lean condition on one or more cylinders. This can happen if your not getting enough fuel to the carbs.

Some additional suggestions:

1. Make sure the carbs are clean, especially the pilot jet and air screw circuit. If youv'e picked up crud in them before, you may have to clean out the fuel tank and add an inline fuel filter.
2. Make sure you have no air leaks. Look at the manifold to cylinder connections for any damage or gaskets that are poking out. Check the manifold to carb boots for cracks, etc.  As I mentioned previously, you can do the WD40 or kerosene routine to help.
3. Once your sure the carbs are clean, adjust the air screws to their factory settings as a starting point.
4. Do a carb sync. (syncronize the vacuum of all carbs at idle)

[Kenyan01]

Hi!
I have spent 4 hours cleaning my carbs, starting with an exterior cleaning, interior cleaning, then checking of each carbs, jets with a thin needle (appropriate), cleaning of each butterfly, checking the state of the needles, floats, etc.
This is the third cleaning these carbs have had in 4 days. This time, I included a bit of compressed air to flush out any possible dirt.

I already have an inline fuel filter [/i]in situ.

I checked the spark plugs and they've turned out clean - greyish, no soot. And they have equal fat blue sparks.

There is no cracks on any of the tubes and manifolds, and I made sure to tighten all the carb and airbox screws - I usually ignore to tighten the 2 in the middle.

I have also changed my 1.4 coil to another spare I have had a long time.

At the end of it, I expected a good musical sound of the Bandit...
Yes it sarted right away without me touching the throttle... but it was still rough... but much steadier at about 1800 rpms. The only catch was when I dared touch the throttle... It shot it revs upto 4300, stuck there for a while and then gradually came back down to 1800.

And cylinder 4 is still not firing. Yet the spark plug was good before I installed it!

Why am I wrong to think compression failure? How do I test compression when I don't have the gauge? I'm really itching to sort out the small niggles so that I can fire the bandit on its first long trip in 18 Months. Do I check the clearances especially for cyl 4?

I have a carb synchronizer that I've never used before but I bet the manual should be useful in making sure I do the right thing...

[land-warrior.rus]

Saunds like your mixture screws are out too much . Try screwing them back in equaly to see if that will make a difference to throtle response better...
And  since you have carb sinch gage do the sinch straight away, at least that way it'll ellimenate that problem...

http://forums.banditalley.net/viewtopic.php?t=209

[Kenyan01]

Hey Land warrior,
The carb synch was done, and I adjusted the mixture screws on all carbs 1.75 turns... and we now have an improvement... carb 4 is firing equally to the others.

But after behaving well, later when I went to take it out for a spin, it was revving at 4000 rpms at idle (without choke, with or without the airbox), consistently for over 15 minutes, and I left it there to  relax. The exhaust is clean.

What does this mean? Is it saying it is lean? Or do we have some clogged jets in my idle system again? There is no air leak - I used paraffin to check.

Please help, I want to go for my long trip on the bandit.

[land-warrior.rus]

That sounds strange. Iy was running well and then the idle just went up...
Since it was ok for a while may be you are riht about jets cloging up again. I'd check that again. I used comresed air at the golf club where i'm chefing, they you it for cleaning there shoes after the game(it very very powerful thing) when was claning my carbs.After i put everything back together it was behaving similar to yours, so i just adjusted the screws like i told you and its fine ever since...
Have the fuel filter now as well. All well...
Cheers...