Honda-SOHC

SOHC.co.uk Forums => CB500/550 => Topic started by: PennoK3 on November 17, 2024, 01:01:35 PM

Title: PD46 Idle Jet
Post by: PennoK3 on November 17, 2024, 01:01:35 PM
Simple question, should the hole in the idle jet be clear its full length?  Trying to work out if its blocked or correct.
Title: Re: PD46 Idle Jet
Post by: McCabe-Thiele (Ted) on November 17, 2024, 01:07:02 PM
The jets in my 400 & 500 were clear right through.
There is an optical illusion imho that makes some folk think there is a fine mesh inside.

I used a long wire taken out of a wire brush to make sure it's unobstructed - I then pop it in the Ultrasound bath again for an extra clean.
Title: Re: PD46 Idle Jet
Post by: Johnny4428 on November 17, 2024, 02:03:29 PM
Definitely should see light all the way through, also important for the side holes to be clear. High E guitar string works too to clear these jets, very small passage through at the thin end.
Title: Re: PD46 Idle Jet
Post by: PennoK3 on November 17, 2024, 02:16:17 PM
Thanks guys.   Yes, blocked solid.   Had a quick look on the internet for new ones (Size 42) but they all seem to be in Germany.   Any UK sources that anyone could recommend?
Title: Re: PD46 Idle Jet
Post by: Bryanj on November 17, 2024, 02:51:05 PM
They are press in jets not available from Honda, only place i ever found them was Sirius Consolodated in Canada but their website is a nightmare
Title: Re: PD46 Idle Jet
Post by: Laverdaroo on November 17, 2024, 03:27:12 PM
Currently in the US if anyone needs any bringing back. Back late December.


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Title: Re: PD46 Idle Jet
Post by: K2-K6 on November 17, 2024, 04:55:48 PM
The jets in my 400 & 500 were clear right through.
There is an optical illusion imho that makes some folk think there is a fine mesh inside.

I used a long wire taken out of a wire brush to make sure it's unobstructed - I then pop it in the Ultrasound bath again for an extra clean.

I remember discussing that Ted, and thought I could see something of that order.

I researched that further (but forgot to post anything about it) with this link  https://www.telescope-optics.net/diffraction_pattern_and_aberrations.htm I think, explaining more about it.

If you go approximately halfway down that page, there's illustration of "primary astigmatism " with attendant longitudinal cross section, accompanied by end on optical effect, this i believe accounts for that effect in the viewer's visual interpretation.
It seems to produce a cross from light diffraction through that tube type view you instigate by looking through the idle jets in the scale they are.

That's quite deep into optical theory, phew  ;D

Title: Re: PD46 Idle Jet
Post by: Sesman on November 17, 2024, 05:50:19 PM
Heat them over a flame that give them a light tap. Most of the resin comes out as ash. Then clear with the E string. Or give Superbike Surgery a nudge. He has a super duper carb cleaning formula…he say.
Title: Re: PD46 Idle Jet
Post by: deltarider on November 18, 2024, 08:18:35 AM
The design of the PD46 carbs differs fundamentally from the oldstyle carbs on previous CB500/550 models. The idle jets of the PD carbs see less fuel passing than the slow jets in the oldstyle carbs. Gasoline (petrol) has changed also. Best advice I can give: either use your bike regularly or add a maintenance dose of a socalled fuel system cleaner additive at every tankfill and hope the best of it.
Title: Re: PD46 Idle Jet
Post by: Johnny4428 on November 18, 2024, 01:10:06 PM
I replaced my pilot jets with 45’s. Just give a little extra fuel to improve starting and running. I have had a reasonable success so far and to compensate have been tweaking the mixture screws ((closing about an eighth of a turn at a time). Unfortunately the bike is now in hibernation until next spring. But the last run I had there was still some adjusting to do on two of the cylinders. I do work an addative too (Frost Ethomix) longer periods between runs.
Title: Re: PD46 Idle Jet
Post by: Bryanj on November 18, 2024, 03:43:05 PM
Attached is a screen shot from Sirius  web page, their site seems to have improved.
I have bought from them and found service quick and not phenominaly expensive
Title: Re: PD46 Idle Jet
Post by: Laverdaroo on November 20, 2024, 06:18:26 PM
Still heer if you want em bringing back?…….,


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