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Author Topic: Help! 82 Honda CB750F Filter Pod dimensions.  (Read 337 times)

Offline Pontus85

  • Posts: 6
Help! 82 Honda CB750F Filter Pod dimensions.
« on: Dec 26, 2017, 11:52:27 »
Hello everybody, hope you all had a great christmas.

So, once again I'm here with a standard noob question, what is the outside carburetor intake diameter on a 1982 HONDA CB 750 F RC04?

And I know what you are thinking "Just measure it?", yes I know but my lovely CB750 is in my friends garage and because of both of our work scheduals we meet maybe once every third week. During that time I mostly plan my build and order things. And yes, I did measure the outside diameter of my carburetor intake and took some photos of my ruler against the carb intake.
However, the camera picture looks a bit scewed, almost as if it's a cross between 52-54mm. I've been googling my arse off so now I turn to you guys.

I know switching to airpods might cause some problems with air/fuel ratio but I've read that if you spend a little more on K&N filter it might make it easier to adjust that afterwards, don't know if that's true but if you know anything more about this, please let me know.

Thank you all for helping this amateur with his first Café Racer build!

Best regards
Pontus
1982 Honda CB750F

Offline J-Rod10

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Re: Help! 82 Honda CB750F Filter Pod dimensions.
« Reply #1 on: Dec 26, 2017, 12:31:31 »
It's not true.

Offline TheCoffeeGuy

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Re: Help! 82 Honda CB750F Filter Pod dimensions.
« Reply #2 on: Dec 26, 2017, 12:50:53 »
Well I don't know the dimension you are looking for but u have some Pod experience.  if you are switching to pods,  ONLY do those.  if you are changing exhaust as well do that after you have sweetened up the set up with pods...One thing at a time.   I have pods on my 850, K and N were better than the cheapies, but in the end only Uniflow worked well enough for my liking.  I do understand that some bikes are easier to set up with different brands than others.   Get a selection of much larger jets and be ready to play around with sizing.

remember to have fun.  dont fret over small problems.
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1968 Harley Aermacchi ML 125 Rapido, restored
1972 Honda Cl 450 engine rebuild, a day rider soon, now sold
1980 Suzuki GS850GL Street Brat  My other day bike
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Offline teazer

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Re: Help! 82 Honda CB750F Filter Pod dimensions.
« Reply #3 on: Dec 26, 2017, 17:54:05 »
Just so you know, those carbs on DOHC Hondas are notoriously hard to get fueling correct with pods. Experts with dyno facilities and exhaust gas analysis find them almost impossible, so expect to find it not running as well as stock after you fit pods.  The late Leon Moss ended up fitting all manner of compensation devices on to get them right.

Most bikes with pods don't run right. but the good news s their owners have no idea how much better they could run and consequently are happy with the less than stellar results.  Hence teh saying "Ignorance is bliss"...   :-) 

Offline CrabsAndCylinders

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Re: Help! 82 Honda CB750F Filter Pod dimensions.
« Reply #4 on: Dec 26, 2017, 22:01:50 »
I understood that it is only the CV type of carbs that don't work well with pods, not so?
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Offline teazer

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Re: Help! 82 Honda CB750F Filter Pod dimensions.
« Reply #5 on: Dec 27, 2017, 01:24:59 »
Not entirely.  They just happen to be among the worst.  Ask PJ how much time it took him to get CB360 carbs to work with pods and how hard they are to jet correctly with other changes to the motor and exhaust. 

Mikuni BS series CV carbs by comparison are quite easy to run with pods or trumpets or stock airbox.  Still not easy to get the right and they have dips in the air-fuel curve that are hard to tune out especially where circuits overlap.

Offline Pontus85

  • Posts: 6
Re: Help! 82 Honda CB750F Filter Pod dimensions.
« Reply #6 on: Dec 27, 2017, 07:25:51 »
Thank you all for you answers. I know the diameter for the pods now. 52mm.

Yeah, I've heard it's going to be a real test to get the engine to run properly. I'm dreading it.

I found this on the "Vintage and classic Hondas" forum. He got it to work with K&N pods, taping each pod up 75%, changing the jets to 75/110s and 3 1/2 turns out on the pilot screws. Unfortunetaly there's no video or sound of how it performs.

http://vintage-and-classic-honda-s.456789.n3.nabble.com/I-GOT-PODS-TO-WORK-td4039223.html

Thank's again for all the answers!
1982 Honda CB750F

Offline J-Rod10

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Re: Help! 82 Honda CB750F Filter Pod dimensions.
« Reply #7 on: Dec 29, 2017, 08:23:14 »
That may work for him. Highly unlikely it does for you. Do you have the same exhaust as he did, are you at the same elevation? Many, many factors go in to that. It's not quite that simple.

Offline Pontus85

  • Posts: 6
Re: Help! 82 Honda CB750F Filter Pod dimensions.
« Reply #8 on: Jan 12, 2018, 16:55:52 »
Damn, this might be an expensive lesson for me. Oh well, live and learn.
1982 Honda CB750F