Hanging Idle and poor throttle response.

[Sesman]

Bet you can’t. Try passing a 0.2mm then .3mm wire through a clean jet. If it goes through, there is no spiders web.

exactly push any wire through and there will be no spiders web left I know what I can see in my jets it’s definitely there 😊

No not really. I’m not talking about pushing or ramming a probe….just passing. Until somebody shows me physical evidence I’m convinced it’s an optical illusion due to light refraction at the drilling reduction.

[Sesman]

Incidentally, if the ‘imaginary’ structure in the jet could not resist light pressure from a soft wire, it could never withstand the persistent pressure from a changing vacuum strong enough to vapourise fuel.

Being a pragmatist, I tend to only believe what I can observe and a 0.3mm wire effortlessly passing through a 0.38mm new jet tends to suggest my observations are accurate.

My jets are squeaky clean and the bike runs perfectly.

I’m not saying your jets don’t have some kind of sophisticated internal structure, I’m just saying your analysis may be flawed…visually.

[Oddjob]

I take on board the idea of the web being an optical illusion BUT all the probes I did were halted in exactly the same place on every jet. I measured the wire and it was identical from either end, they all showed some obstruction where the diffuser part met the threaded part. The wire was thin enough to pass through the obstruction IF you wiggled it but not if you just pushed.

However this could also be caused by how they are machined, if the upper part (the part stamped with the number) bores are larger than 40 size and only where it meets the lower part is actually drilled 40 that would mean a small step where the larger and smaller bores meet (you following me) this could be the obstruction, it hits this step and you feel it must be the web, a little jiggling and it finds the smaller hole and passes through. Which could mean the web is an optical illusion. I mean in the pic showing one dissected there doesn't appear to be any sign of the web BUT I can't zoom in on those pics so maybe it's there but too small to see?

[Laverdaroo]

I get the theory as to why they might be there but cant for the life of me sort out in my head how they would manufacture them to such a minute tolerance in such a small area. Surely that's impossible to cast (think they were machined from solid) and even more so to miss whilst machining the insides,  irradicating it before completion.

I had a good look in all the old Honda jets I've collectedover the years and some are for the 550 but I've nothing in mine but easy to get the results as per your description.

Not saying anybody is mistaken and always bow to superior knowledge but finding this a bit hard to work out mentally!

Nothing new there I hear the masses shriek!

[deltarider]

Folks, I hope I can convince you, there are NO structures in there. Numerous times I've thought there was a web. On all occasions, just by changing my distance in POV, I came to the conclusion there wasn't. Only you need either glasses or a magnifying glass and you need to vary the distance. The pic below was taken right after I thought there was a web. I did NOTHING and just made a pic. See for yourself. Besides, what use would a web have there? I mean, not even the main jets have one. Please don't allow the hoax to be the next nonsense story. We already have plenty of silly claims in the international forum which I've tried to fight for years. Some are very persistent because Mr. so and so made the claim and not many dare to contradict him or even ask him to clarify.
Here's a question though. The first (and only) time I've pulled the float needle valves from their seats, I remember I've seen in there a very thin, almost felt like gauze or was it mabey very thin aluminium? Some sort of filter? I'm not sure. Maybe I was misled and was it just collected dust. Has any of you seen what I 'saw'?

[Sesman]

All. I think the difficulty getting a wire through is due to the significant step in the drilling. The step is present on both sides of the jet. The .38 or .4mm drilling is very short relative to the length of the jet (28mm).

Iv’e now inspected several old original, new original and new pattern pilot jets and arrived at the same conclusion….it’s a drilling only. I’m not convinced any kind of engineering intervention within the jet is required to effect correct running…..I’ve proven this empirically.  Unless somebody can demonstrate it’s possible to pass a .3mm wire past the mythical spider in a .38mm jet it doesn’t exist. In my mind at least.

Show me the spiders web….

My visual observations to date have simply observed the refractive effects at the internal drilling step. Try viewing the end again with a wire inserted….you will see what I mean.

[Laverdaroo]

Ka Pow!

I'm in no position to question on things I know nowt about but I've found this really interesting from the off. In my addled head I couldnt fathom the manufacturing process involved in the making of the jet to allow the web to be present. It simply didnt compute for Honda to manufacture such a fiddly scenario, no mtter what technology they held at the time. I'm not sure you could do it now tbh, happy to be enlightened though.
At the end of the day, this has been a really good use of brain cells to conclude an issue/topic/myth or however you want to lable it. This is what the forum's for and just emphesises what a great thing it is to be involved in.


Disclaimer: I dont get any form of commission from SOHC and not a 'crawly bum lick' either, just highlighting what we already know

[Bryanj]

Wasnt Honda that made them, they bought in carbs from Keihn who made for lots of manufacturers

[philward]

Just read this whole thread and with my none Honda engineering background, my logic says this debate hinges around how the spidery web structure could be manufactured - if it could, then there can then be a debate as to its use - if that structure could not be engineered, then the discussion ends? Original post where the bike runs well after clean out seems to be the proof of the pudding in the absence of this?

Sent from my moto g(50) using Tapatalk

[Sesman]

Incidentally, to close this out. I replaced all four pilot jets with new replacements…..it didn’t change a thing and the bike performs just like it did after the clean…..perfectly. I can now go on to check sync the vacuum, but to be fair it seems fine. It might quiet the clutch down a little, but as it’s a 500 I’m doubtful.