1100et running on 3.

[Spelli]

I would have thought that if the low speed idle circuit was blocked, at 3000 rpm the main jets have would kicked in.

Am I wrong with this presumption?

is it more to do with throttle opening than rpm?

I can see how it would be difficult to clear the thin channels of the idle circuit but the main jet is easy to see and it is obviously not blocked.

just trying to understand what might be going on. 

[Guest]

3 hours ago, Spelli said:

I would have thought that if the low speed idle circuit was blocked, at 3000 rpm the main jets have would kicked in.

Am I wrong with this presumption?

is it more to do with throttle opening than rpm?

I can see how it would be difficult to clear the thin channels of the idle circuit but the main jet is easy to see and it is obviously not blocked.

just trying to understand what might be going on. 

I can't remember the exact figure, I'll try and remember to have a look tomorrow. But 3000 rpm is still roughly in the idle circuit's range. Idle circuits generally swap over about 2,200 to 3,200 depending on the carb. To be sure you're on the mains but not yet on the correction I aim for 3,500 - 4,000.

Oh, and that's the reading on a 'proper' tach rather than a 40-50 year old cable and gauge. 

[Toecutter]

Just a thought, have you checked the float bowl on that particular carb that's giving issues? Have a look at the brass bowl spigot, the long one and the hole that this leads to. I had a similar issue a few years back with a blocked hole on a katana inhibiting the bowl to 'breathe' thus not allowing fuel to pass kind of creating an air lock in that particular carb. Had me flummoxed for a while. Swapped bowl with a known good item and problem solved.

May not be the issue but worth a go. Hope that made sense, sorry have had a couple...

[Spelli]

Hi Toecutter

Thanks for your input. 

I presume you are referring to the brass dip tube that goes into the hole into float bowl casting. 
 

The hole in the float bowl is clear. I can blow through it with an airline. I think the brass dip tube is clear as well. I used one of the clear plastic insulated sheaths that go over the bullet electrical connectors as a sort of a funnel / seal over the diptube so I could use the blowgun to blast air down it and air was coming out the other end. 
 

So I think I have got that one covered although if it is partly blocked it would still pass air but reduce fuel flow.
 

So still no guarantee.

[coombehouse]

Try spraying a small amount of wd40 into the intake of the cylinder that's dead, if it fires up then it pretty much guarantees that the problem is carb related 

Edited October 26, 2024 by coombehouse
Spelling

[gsxwill]

On 10/25/2024 at 4:22 PM, coombehouse said:

Try spraying a small amount of wd40 into the intake of the cylinder that's dead, if it fires up then it pretty much guarantees that the problem is carb related 

As said above, I prefer brake Cleaner, but if it comes to life after you squirt a bit in then you know it's a carb problem 

More and more these days it is 

[TLRS]

Careful with burning brake cleaner as some of them will generate very poisonous gas when burned!

[ArcanumOne]

I had a similar issue with my 1991 USA spec GSXR1100.  I cleaned the carbs a few times. checked the cable properties, even bought new OEM coils and cables.   I have a spare set of OEM CV carbs and installed those--nothing.    I had two cylinders not firing.  The bike had NGK iridium plugs that ran fine for a few starts, then some stopped firing.  Replaced those with new Iridium plugs, same results.  I finally dumped Iridiums altogether and have gone to NGK  platinum-tipped plugs and never had another issue since.  

 

 

Edited October 28, 2024 by ArcanumOne

[Spelli]

1 hour ago, ArcanumOne said:

finally dumped Iridiums altogether and have gone to NGK  platinum-tipped plugs and never had another issue since.  

I have heard others complaining about NGK plugs. Is there a better brand ?

[Gixer1460]

Denso's or NGK's are std. fitment but Iridiums aren't and they really aren't suited for use with carbs!

[Guest]

44 minutes ago, Spelli said:

I have heard others complaining about NGK plugs. Is there a better brand ?

Denso or Bosch equivalents. There are a lot of knock off NGK plugs which are poor quality, but NGK themselves have let quality control slip in recent years and the genuine ones are very hit and miss. I won't use them in a lawn mower never mind a bike, too many failures and not working straight out of the box.

[Guest]

I've never had any problems with NGK, despite Internet hysteria, and have used them on everything, cars, bikes and even lawnmowers with no problems.

Just have to be careful where you buy them. 

[ArcanumOne]

When I was troubleshooting my GSXr1100 (and my Bimota SB6 with H20 cooled engine), I replaced the NGKs with Densos.  But, I also used the Iridium Densos, and they failed after a short while too.  I agree with Gixer1460, the IRIDIUMs are not suitable for the bikes for some reason.  Only one exception:  I have been running an Iridium in my 2001 KTM LC4 with a 40mm CV Mikuni without any issues after 5000 miles.   The IRIDIUMs also failed in my '95 Triumph Speed Triple and after replacing with NGK Platinum plugs, my problems with the Triumph resolved as well.  None of my injected bikes have issues with Iridiums.

Edited November 7, 2024 by ArcanumOne

[andyroach]

I've had a lot of problems with Iridium plugs. My guzzi ran as sick as a dog after changing to them. Changed back to normal plugs and the problem vanished.

I also had an ER5 which I bought as a non-runner. Changed the Iridiums for normal plugs and it cracked up straight away.

I would change to a normal plug and see what happens. 

I kind of feel this problem might come under the banner of the old adage, "95% of all carb problems are electrical".

All the best and hope you get it sorted soon

[Spelli]

On 11/7/2024 at 4:20 PM, andyroach said:

95% of all carb problems are electrical".

Oh no… just when I was thinking I had narrowed the causes down to the carbs 

[Spelli]

I have eventually managed to get the old girl back together after having cleaned the carbs yet again. 
 
complete strip ( apart from the butterfly’s) Slow running gallery’s blown through with carb cleaner and then 20 minutes in a heated ultrasonic and then this same process repeated 4 times ( total of 160 minuets in the ultrasonic for each carb ) then blown out with compressed air.

Assembled back together, and what do you know …Still nothing from the no 4 cylinder !

what now ?

Do I go through the same process again or is there something else I have missed. ?

Where should I go from here?

[Gixer1460]

is #4 plug wet or dry? if wet likely electrical, if dry then you know what the answer will be! Plus if plug is wet - change it for new as they rarely get better!

[Spelli]

9 hours ago, Gixer1460 said:

is #4 plug wet or dry? if wet likely electrical, if dry then you know what the answer will be! Plus if plug is wet - change it for new as they rarely get better!

Gixer1460,  thanks for that. 
The plug, I would say is a bit damp certainly not wet as I would have expected if there it was just an electrical problem. 
 

Having seen this myself I tend to doubt my own judgements, so I appreciate your input, it helps. 
Thanks.
 

I think I  am going to try find a way of filling the slow running galleries with carb cleaner by somehow blocking off the exit holes and leave it to soak for a while. 
 

Just not sure what to use to stop the cleaner running out the bottom. Could try masking tape but I thing it will quickly dissolve the glue and just fall off. 
 

I am trying to avoid dismantling the the butterfly’s . This is preventing me just going for a full soak in cellulose thinners.  Might have to just bite the bullet if this fails. 

Edited November 15, 2024 by Spelli

[Spelli]

7 hours ago, TonyGee said:

without reading the whole thread !  have you checked the compression on all 4 cylinders ? 

Hi Tony,

Yes I have checked the compressions. 
I was getting between 150 and 170 psi across all 4 cylinders.

i think Gixer1460  is right. The plug doesn’t  seem very wet. I would have expected the plug to be drenched in fuel if it was a spark issue ( spark looks good when I test it ) so it looks to me like a really bunged up slow running system. 

I am very open to suggestions from the incredibly knowledgeable people on this forum. 

 

Edited November 15, 2024 by Spelli

[Spelli]

12 hours ago, TonyGee said:

it looks like some more carb work is needed   can you get hold of a good set of carbs to try on ?  

No, sadly I don’t have access to such a luxury.  I have looked on Eblag but they aren’t cheep so I think for the moment I am going to have to keep cleaning.  
 

I have seen a Video explaining how the remove the brass balls that block the drillings for the galleries so they can be cleaned but that sounds a little extreme to me and would only be a very last resort. 

[Spelli]

[Spelli]

Well Flipping eck… looks like I should have gone to spec savers !! 

Looks like I might have got the old girl running on all 4 at last !

Before stripping the carbs yet again for another clean I decided to have a closer look at what was happening. 

The no 4 cylinder seemed to be doing very little when the plug lead was removed the lumpy tickover remained unchanged. However the header pipe was getting a bit warm although no where near as hot as the others. 

So in desperation I decided to slip the vac gauges on to see if that might show something and indeed it did !!!

The no 4 cylinder vacuum was well up on the others. 

I balanced the carbs and she started to run a lot sweeter. The header temperature evened out and she responded positively when the plug lead was removed. 

Took her for a short run and she is now running  just as sweet as  I remember back in the day  when I had black hair and a waistline.

it seems my attempt to align the butterfly’s by eye is no longer a reliable guide. I think the no 4 butterfly must have been virtually closed. I think the last clean must have cleared the blockage and my poor assembly skills tricked me into thinking that the problem was still there.

Like I said…” I should have gone to specsavers “

[Spelli]

Thanks everyone for your input. 

What an incredibly valuable resource this is to have access to such a pool of experience.

Absolutely Fantastic !!!

 

Edited November 16, 2024 by Spelli

[andyroach]

20 hours ago, Spelli said:

Well Flipping eck… looks like I should have gone to spec savers !! 

Looks like I might have got the old girl running on all 4 at last !

Before stripping the carbs yet again for another clean I decided to have a closer look at what was happening. 

The no 4 cylinder seemed to be doing very little when the plug lead was removed the lumpy tickover remained unchanged. However the header pipe was getting a bit warm although no where near as hot as the others. 

So in desperation I decided to slip the vac gauges on to see if that might show something and indeed it did !!!

The no 4 cylinder vacuum was well up on the others. 

I balanced the carbs and she started to run a lot sweeter. The header temperature evened out and she responded positively when the plug lead was removed. 

Took her for a short run and she is now running  just as sweet as  I remember back in the day  when I had black hair and a waistline.

it seems my attempt to align the butterfly’s by eye is no longer a reliable guide. I think the no 4 butterfly must have been virtually closed. I think the last clean must have cleared the blockage and my poor assembly skills tricked me into thinking that the problem was still there.

Like I said…” I should have gone to specsavers “

that is really cool. so glad you got the old girl running on 4 again.

 

[Spelli]

On 11/17/2024 at 3:24 PM, andyroach said:

that is really cool. so glad you got the old girl running on 4 again.

 

Thanks Andy,

Me too. I have been trying to post a pic of her as a little thank you for all the help I have received but all I get is a blank page. 
 

I will give it another go …