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Discussion Starter · #1 ·
Hey guys,

I'm putting together another set of carbs for my 360, thanks to a member here. I have several sets of used #100 main jets (are they called 'mains' on these carbs? dont want to be throwing around bad terminology) and a new set of keyster #100s. I am going to run some shorty mufflers and pod style filters. Is this enough that I will need to up the jet size? I was thinking of running a .040 drill bit through a pair of 100s to effectively make them a 101.6-102ish.

Would it be wise to richen it up a tad this way, or will I be just dandy running the 100s?

And before you chastise me, yes, I know I should get it together and see how it runs first. And I will, but if I have a better chance of getting it right the first time with a richer jet, I'd like to know.

Are the keyster jets really junk like I have read in various places on the internet?

Thanks again!

TJ
 

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Sensei
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There are TWO mains in a 360 carb, the primary and the secondary....According to my reference, stock BOTH are #68 jets... The stock pilot jet is a #35....
However, We just went through a similar situation with another member....I'll post a link to his topic as soon as I locate it....

The link: viewtopic.php?f=17&t=1833&st=365&sk=t&sd=a&hilit=main+jets&start=10
 

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Discussion Starter · #3 ·
Ok,

Secondary Main Jet (at base of Needle) is marked 100.
Primary Main Jet is marked 68.
Slow Jet (under the screw) is marked 35.

What is strange is that the secondary mains that came out of BOTH sets of old carbs were 100s. One set matched the font and markings of my new keyster jets, the other set was marked with the KeiHin logo and measured just about exactly 1mm with my set of gauge pins. I guess both sets had been changed to the improper sizes that come with the rebuild kits at some point in the past? EDIT: The KH marked jets came out of carbs that had certainly not been opened since 1983, and looked to me like they had never been messed with, no tool marks on the jets or the bowl screws. END EDIT.

Bikebandit.com's list that accompanies their scan of the Honda microfiche lists the "Jet, Main" as a 100 for the CB360.

Also, the service manual that I found via Hondatwins.com on http://web.ebscohost.com/serrc/[email protected] lists the Secondary Main as a 100.

Anyone have an original Honda service manual that might yield some light on this? Maybe a typo in the original manual is what created all this hubbub in the first place?

I'm not trying to doubt your expertise, I just don't want to hunt down a pair of 68s only to put some extra holes in my pistons with an overly lean condition.

Thanks again,
TJ
 

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Discussion Starter · #4 ·
Well, after some hunting in a couple of manuals...I am happy to report that I STILL have contradicting information.

I got a scanned copy of the Honda Service Manual from repairmanualclub.com. It has the figure that 66Sprint posted in the other thread.

However, in the Supplement for the CJ250/CJ360 it lists a 110 Secondary Main, 68 Primary, and 35 Slow. This also lists a different carb setting mark of 759B as opposed to 745B for the CB360. 745B is stamped on the bodies of my CB360 carbs.

The CJ360 carbs LOOK the same as my CB360 carbs, but perhaps there is some internal difference? I always thought the CJ and CB's used the same engine. Was the CJ a hotter bike?
 

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Yeah...this is a snafu that I've come across myself whist searching for new jets. All the rebuild kits I've seen contain a #100 or #110 secondary main jet. When I contacted one seller about the incorrect listing of said jet, their reply was a standard "what you see is what you get" shove off. I dont know where those sellers are getting their information, but they sure as **** aint gonna listen to anyones fault finding.

If you simply refer to the Clymers repair manual page 99 all the jetting specs are there...and the CJ model carbs are jetted the same as the CB and CL models.
 

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Sensei
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I referred to both a Chilton's and the Honda service manuals... Both say twin 68's.... However, if you ran the 100's, the worst that would happen is you would flood/foul the plugs when that jet "kicks-in"...WAY better than leaning out and burning something.... Since it was apparently running with those jets, try that first......
BTW... The CJ was the "econo-model"... 5-speeds and drum brakes as opposed to the 6 speed and disc on the CB....
Note that some non factory manuals show the primary and secondary positions reversed as in this same discussion about the CB/CM 400 carbs....

viewtopic.php?f=5&t=461&st=365&sk=t&sd=a&hilit=main+jets&start=90
 

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Well I guess the eternal question is which 360 would ever have had anything other than #68 mains? Why are re-build kits mis-informed?
 

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Discussion Starter · #8 ·
I would say the rebuild kit manufacturers have the wrong idea because a couple of the manuals are wrong.

The Honda Shop Manual lists a #110 in the CJ250T/CJ360T Supplement. The other link I posted claims to be from a Clymers manual for 360 twins, and it lists a #100.

The only place I have seen the 68 for both places is on page 66 of the Honda Shop Manual which is the chart that 66Sprint posted. You say Chilton's lists a 68 for both locations as well?

Something is wrong somewhere.

I'll put these 100s back in my bike and do some plug chops, once I get my new tires. They'll be stupid sooty and black at WOT, possibly even soaking wet with that much extra jet size, right? Probably get some hellacious shut throttle backfiring too.
 

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Sensei
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TJ... I'm not sure what your results will be... If you check the similar circumstances with the CB/CM 400 carb it worked fine with the larger secondary.... (You are the Guinea Pig for this information as it relates to 360's,.... but MANY in this group will benefit!)..... Steve
 
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