Cafe Racer Forum banner

1 - 14 of 14 Posts

·
Registered
Joined
·
12 Posts
Discussion Starter #1
Forgive me if this has been discussed.

I am looking for one of two things.

First I'm trying to find a jet & needle kit for my '74 CB750K. I tried to put on the high flow K&N filters on the stock carbs and my mechanic said that he would be unable to tune the bike with out the jets and needles, which he informed me know-one makes, but I think thats bullshit. Not to mention that the stock setup runs rich anyway. A friend of mine thinks that you can just adjust the needle on the clip on the stock carbs, but I havent taken one apart to see if that is correct. I did find a jet kit online but no corresponding needles.

So if I cant find a jet & needle kit for the stock carbs. I wonder if there is anyone out there that makes a carb kit that I can just screw straight into my manifolds. This way I bypass the whole problem.

I have been scouring the Sudco wesite all morning. I saw the vintage carb kit section but did not see anything for my bike. I even checked the manufactuer websites to see if there was anything but no luck.

Anyone already solve this problem and can point me in the correct direction?
 

·
Registered
Joined
·
23,303 Posts
SUDCO has the needles and jets, you are going to have to call them and identify your carbs since they don't list stuff for older bikes by make (only by carb type). I don't think you are going to find a "kit" since that is more of a sport bike thing so you may have to buy four individual needles and f our individual jets.

Also try rage performance:
http://www.rageperformance.com/carburetorparts.asp

I'm pretty sure Sudco also has the CR carbs for sohc cb750s but they are like $1100.

Honda also has all this stuff but you have to order it individually and will pay a lot.

Second, get rid of your pods and go back to a stock airbox with a K&n replacement filter. No jetting and the idle is smoother. From what I understand the performance is about the same plus you get your ability to ride in the rain back.

get acquainted with the SOHC4.net resource list:
http://www.sohc4.us/forums/index.php?topic=743.0

Edited by - Geeto67 on Feb 26 2007 6:53:21 PM
 

·
Registered
Joined
·
12 Posts
Discussion Starter #3
Bingo! Thanks dude. Funny you mentioned that I shouldnt get rid of the air box. Every time I bring this up to someone, the first question is, Why would you want to get rid of your air box?

I email and left a voice mail message for the guys at Sudco. However maybe I will just keep my air box, as suggested.
 

·
Registered
Joined
·
23,303 Posts
your carbs are keihin's BTW, and I am pretty sure there are only two styles of Jets for Keihin carbs (page 167 of the sudco catalog BTW), you need to figure out which one.

The stock airbox on a cb750 was specially designed to work with those carbs, espically at idle. The motor needs to be a lot hotter (cam, bore, etc) before I would think about the airbox being limiting. K&N makes a replacement filter for the stock airbox that rocks. It is pricey but it is also reusiable for life. Flows tons more air too.



Edited by - Geeto67 on Feb 26 2007 7:05:09 PM
 

·
Registered
Joined
·
23,303 Posts
quote:
Does the K&N air filter for the air box, lean out the bike a little?
you may have to adjust needle position (there are 4 or 5 positions) but I didn't have to change jets in my bike. Actually I didn't have to change needles either but I had a stumble when you whacked it open that went away when I changed filters. Because honda dicked around with emissions on these bikes year to year (there are 4 different carb types) some don't need it others might. the only way to know is to put her on and see. That is with stock pipes however, if you are running aftermarket pipes (a 4 into 2 or 4 into 1)you will have to rejet.

Also, it is the idle quality the suffers most with the switch to pods. some bikes only need minor adjustments when switching, others a little more, but getting the idle and off idle proper that is what often makes the carbs hard to tune.

Edited by - Geeto67 on Feb 26 2007 7:26:21 PM
 

·
Registered
Joined
·
23,303 Posts
quote:
Ya I am using the Kirker 4 into 1
did you already rejet for the kerker? The kerker is an awsome pipe and usually requires a rejet even with a stock air box. I'd say you would have to go up 1-2 sizes in jets and may need to go 1 size in the needle.
 

·
Registered
Joined
·
12 Posts
Discussion Starter #9
no I havent. I was told by my mechanic that knowone made needles and jets for the bike. So If you know where to get them. Please do tell.

Thanks.
 

·
Registered
Joined
·
23,303 Posts
quote:
no I havent. I was told by my mechanic that knowone made needles and jets for the bike. So If you know where to get them. Please do tell.

Thanks.
I am pretty sure your jets are: Keihin Round Main Jets 99101-393-XXX

(look on rage perf site).

There are more than enough links on this page for you to get jets. If you want to know what size you can either wait until I clean out the garage so I can crack open a set of 75 cb750K carbs or get out the shop manual and read what the stock size jet is.
 

·
Registered
Joined
·
8 Posts
The stock jet size on a CB750K5 - CB750K6 is 105.

I'm trying to find out if anyone has put pod filters on a CB750K5 - CB750K6 and if so, did they rejet (what size?), adjust the needle position, or new install new pilot jets? I have original exhaust. Thanks for any help here.
 

·
Registered
Joined
·
23,303 Posts
quote:
The stock jet size on a CB750K5 - CB750K6 is 105.

I'm trying to find out if anyone has put pod filters on a CB750K5 - CB750K6 and if so, did they rejet (what size?), adjust the needle position, or new install new pilot jets? I have original exhaust. Thanks for any help here.
you could have started a new thread on this...

well that is kind of a loaded question. Depends on a couple of things:

Where do you live?
What kind of pods?
what exhaust are you running?
what kind of riding do you do?

If you bought those cheap emgo metal filter pods do your self a favor and run nuts first into a doorknob....that way you remember not to ever buy them again.

Ideally you want K&N filters or at very least a paper fliter pod. Personally the K&Ns are reuseable so I lean toward them.

If you have an aftermarket exhaust and pods I would suggest going up 1 jet size. If you still have any hesitation after that I would move the needle up one notch.


Edited by - geeto67 on Jan 04 2008 5:06:16 PM
 

·
Registered
Joined
·
1,523 Posts
i fitted pods to my 1976 model cb750. also had drag pipes on it. i went from 105 main jet to 110.
with the 105's it would miss and sputter at full throttle from being too lean. I bought the 110's and was able to go full throttle without the sputters. I haven't done any other carb adjustments aside from idle air screw adjustment. i live at about 2000' elevation.
I feel like i should have gone with 112 jets though.


'72 cb750
'75 cb750
'76cb750
'82 cx500 (but mine is cool, i swear. Why don't you believe me?)
 
1 - 14 of 14 Posts
Top