Author Topic: Mystery Carbs (Read 4825 times)

csendker · « **on:** June 20, 2006, 03:18:08 PM »

Pardon my intrusion on the tech board with an SOHC2 question, but this is driving me nuts and I'm about to split for a long weekend camping where it will continue to drive me even more nuts. 48 views and no progress. I have a mystery carb that I thought was for my CB175, but there's some differences from my stock carb. Some mystery jets & ports. I've searched a ton of models thru the parts fiche and come up empty handed. Anyone have a clue?? --> http://www.sohc4.us/forums/index.php?topic=10949.new#new

Thanks.

Sam Green Racing · « **Reply #1 on:** June 20, 2006, 03:26:05 PM »

What size bore is the carb with the extra jet.

The extra jet is a power air jet, this type of carb was fitted to sports models in the sixties.

Sam.

csendker · « **Reply #2 on:** June 20, 2006, 03:28:28 PM »

Where do I measure? Venturi inlet? There's a "20" stamped on the flange, and a "20" stamped on the slider cover and a "20" printed on the choke flapper if that makes any difference. And they're Keihen's. And what's a power air jet?

Sam Green Racing · « **Reply #3 on:** June 20, 2006, 04:21:58 PM »

Chris I am at work at the moment and can't confirm what the carb is, dose it have letters and numbers on the side other than the 20 ?
the 20 is the choke size so you don't need to measure it.

Sam.

csendker · « **Reply #4 on:** June 20, 2006, 04:29:25 PM »

Nope, just the 20 cast into the flange and stamped on the choke. I stand corrected on the cap, it's blank - my other set has the 20 on the cap, not this one.

Sam Green Racing · « **Reply #5 on:** June 20, 2006, 04:37:47 PM »

OK not to worry, the carb looks like one I have from a CA95.
This was the 150cc tourer (Dream or Benly) in the States.
I don't know much about them but the air jet is a perfomance booster.
Dose the CB175 have twin carbs, and the spare you have, is it one of a pair ?

Sam.

csendker · « **Reply #6 on:** June 20, 2006, 04:58:14 PM »

It was billed as belonging to a CB175-twin carb SOHC-2, but it was e-bay, so who knows what it really is? I have a matched pair, right & left. I was hoping that I blindly stumbled on a kick-ass set of racing carbs that would allow my 175 frankinbike to toast anything that it comes up against. When it ever gets on the road that is...

csendker · « **Reply #7 on:** June 20, 2006, 05:04:20 PM »

Better pic?

Sam Green Racing · « **Reply #8 on:** June 20, 2006, 05:30:21 PM »

Honda have been useing these power jet carbs since 1958 that I know of, maybe 1957 on the very first small twins (CB90/92/95).
The touring versions of these bikes did not have the power jet.
I am not sure what carbs your bike should have but I will check for you when I get off work in the morning.
Some of the early Hondas could varey in specification because Honda used the parts bin method, if they ran short of a component they would fit a different one if it would fit.
I know this sounds strange but it's true, perhaps Hondaman could confirm this.
It could be that the carbs on your bike are not the spec ones, and the ones you have bought are.
I'll get back tomorow when I have checked my workshop manuals.

Sam.

Jay B · « **Reply #9 on:** June 20, 2006, 07:18:01 PM »

The carbs in the pics are identical to those on my '73. I've owned it since new so I know they haven't been changed.

Sam Green Racing · « **Reply #10 on:** June 20, 2006, 07:28:14 PM »

Thanks Jay, Chris maybe in for a power boost with his new found carbs.

Sam.

csendker · « **Reply #11 on:** June 20, 2006, 07:34:47 PM »

The carbs without the air jets came with the bike. They look like and match the tune-up description from the Service Manual, Owner's Manual, and look like the ones on the parts fiche, etc. so I'm pretty sure they're original. I looked at the parts fiche for all CB175's and didn't see the additional jets indicated anywhere.

So, regardless, will these work on my bike with minimal fuss? - I realize anything can be done with enough time, effort and money - I just don't want that route. And if so, is there a performance advantage to these? And what do I do with the extra jets? Anything? Just leave them? Adjust them? Why is mystery jet #2 hidden behind a gasketed screw-cap? Sick of the questions yet?

Thanks.

Sam Green Racing · « **Reply #12 on:** June 20, 2006, 08:07:30 PM »

No, not really.....in my workshop manual for CB92/95 it shows the power jet, but dosn't tell you anything about it

I'm in the dark as much as you are.

Are the power jet carbs handed ?....can you post a pic of the pair.

Sam.

csendker · « **Reply #13 on:** June 20, 2006, 09:04:38 PM »

1208: The pair - yes, they are handed L&R

1209: the internal port

csendker · « **Reply #14 on:** June 20, 2006, 09:05:13 PM »

1211: mystery jet #2, hiding behind the gasketed screw

1212: fuzzy, but small port from mystery jet #1 to #2, inside #2's hiding spot

csendker · « **Reply #15 on:** June 20, 2006, 09:06:13 PM »

1214 & 1215: side views

csendker · « **Reply #16 on:** June 20, 2006, 09:07:37 PM »

1216: manifold side

1218: top - note the casting for the internal port between the two mystery jets...

Sam Green Racing · « **Reply #17 on:** June 20, 2006, 10:10:54 PM »

Will see what I can find when I get home, see ya tonight.

Sam.

Sam Green Racing · « **Reply #18 on:** June 22, 2006, 04:41:58 PM »

Well Chris, Iv'e checked out in all my workshop manuals (Haynes and Honda) all bikes from 125 through to 200cc and these carbs didn't come up.
Strangley enough, the CB 200 Benly as it's called over here only has 18mm carbs.
Looking at the pics you posted these carbs definitley fit onto an intake manifold as on the 160 and the 175.
The carbs I have with this power jet are for the CB92 Benly Sport 125, the CB95 Benly Sport 150 and the American CA95 150 tourer.
The carbs I have bolt onto studs coming out of the head through a heat insulator, with a nut behind the flange. Irespective of what they have come off Chris, the carbs you have should fit your CB175 and should be an improvement over the ones fitted as they are more of a performance carb. I have only seen power jet carbs fitted to sports machines, other than the CA95
but I don't want to have to explain that one.
It maybe an idea to sort the bike out with the carbs it has on, then swap them over to see if there is a performance difference.
Best of luck, hope you will be able to let me/us know how they turn out.

Regards Sam.

csendker · « **Reply #19 on:** June 25, 2006, 05:07:41 PM »

Sam, hanks for all the digging. I couldn't find them in anything I have either. I think I can dig up the guy I bought them from, and try to see if he can ID them.

-Chris

Sam Green Racing · « **Reply #20 on:** June 26, 2006, 05:15:01 PM »

Hi Chris, it would be great if you could do that, I realy would like to know what they came off.

Sam.

csendker · « **Reply #21 on:** June 26, 2006, 06:22:04 PM »

e-mail's away, lets see if I get a response.

Sam Green Racing · « **Reply #22 on:** June 26, 2006, 06:34:49 PM »

Super

csendker · « **Reply #23 on:** June 29, 2006, 08:59:35 PM »

Response is in, he has no clue as to what he sold/I have. He did narrow it down to only having 160/175/200 stuff though. Suggested maybe a CD175, which doesn't seem to exist in the parts fiche. Some more scrounging thru the fiche and I did see a couple of models that insinuate the casting for the air jet, but have no parts associated with them, such as the actual jets themselves. The search continues.

Nevertheless, what, if anything, does one do with the air jets? Any adjustments or do they just exist?

Hmmmmmmmmmmmmm...............

Sam Green Racing · « **Reply #24 on:** July 04, 2006, 06:12:01 PM »

Like you said, they just exist

They won't be off a CD175, as this model only has a single carb.

The plot thickens.

Sam.

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Author Topic: Mystery Carbs (Read 4825 times)