1100et running on 3.

[Dezza]

4 hours ago, Spelli said:

Just shows how bad ethanol based fuel is. Not like the days when I was running on good old 3 star. 
if anyone else remembers that perticular brew ?

Fuel was Esso superunleaded, which is supposed to be ethanol free

[ral]

Is  or does number 4 kick in at higher revs when the fuel supply through the carb changes from idle to main jet, From memory the emulsion tube has small holes along its length, these need to be clean so ensure you remove the emulsion tube for cleaning, did number 4 carb have fuel in the float bowl prior to pulling the carbs off? Also confirm the tiny passage in the float bowl is clear, they are a arse to check and clean as can be fairly gunked up. Again from memory the brass tube at the rear of the carb locates into a passage when the float bowl is offered up for re assembly, this passage has to completely clear all the way through.

I find that you have to completely remove all the brass type components I.e jets,emulsion tubes, choke slides and not rely on the ultrasonic to clean them, if any are blocked it’s unlikely they will clean in the bath.

Use a mild acid ( like liquid aluminium cleaner ) and swill the brass parts in this, just don’t leave them in to long, they should come up like a new penny, remember to swill them off to remove any trace of acid after, clean fuels good at this.

If you can get hold of a number 9 E string of a guitar this is perfect for passing through the tiny holes in the float bowl passage.

Good look, they are a bugger to get perfect.

 

[Spelli]

2 hours ago, ral said:

Is  or does number 4 kick in at higher revs when the fuel changes from idle to main jet

Thanks Ral

No it doesn’t.  I tried that and I spun it up to around 3000 rpm and is still didn’t kick in. 
May be I should try that again before I remove the carbs yet again.

I should get chance over the weekend. 

[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. 

[imago]

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, it it fire up then it pretty much guarantees that the problem is carb related 

Edited 13 hours ago by coombehouse