Topic: Carb year changes? CB 750 - 72

[persson-johan@hotmail.com]

Hello!

Recently got my CB 750 together after two years of renovation. Bone stock. Everything is new/overhauled and the bike runs almost perfect. Done about 400 miles, very meticulous about the break in and done 3 oil changes

So to my problem. It has a small small stutter/stumble just when coming of idle and barely touching the throttle. It's almost solved by adjusting the pilot screws 2 turns out. I'm 99% sure this has to do with worn throttle needle and seat since I reused all the stock brass carb parts. I want to use Honda parts but the needle and jet is out for my 72. I found the parts new locally here in Sweden for the price of 100$ but it is for a 74-75. Same as this: http://www.cmsnl.com/cb750-four-k4-1974-usa_model482/needle-set-jet_16012300014/#.V3NxmvReDCQ

Will this work for a 72 also or did the carbs change over those years?

Regards
Johan

[persson-johan@hotmail.com]

No luck here

Well I think I'll try it. Since the aftermarket rebuild kit fits k2-k6 I think this would be fine to use. And definitely better than the keyster kits!

[chewbacca5000]

This is what I use in my own bikes.

http://4into1.com/replica-keihin-2-0-float-needle-valve-assembly-16011-375-004/


If the pilolt jet is in question I buy 4 more from same place.

http://4into1.com/replica-keihin-slow-jet-honda-cb125s-cb350f-cb400f-cb500-cb550-cb750/

Can you post a pic of your air screws?  The solid ones where original to that bike and provide a nice idle at 1 1/4 turns out.

I set the floats to 24 1/2 to 25mm with these float valves as the springs are a little stiffer.

I get good results using this combinations with a stock air box.

[persson-johan@hotmail.com]

Thanks for the answer! I'm talking about the throttle needle, not the float needle

My floats and float needles are good and the level is set with a clear tube to 4 mm under float bowl mating surface as per Hondaman.

[persson-johan@hotmail.com]

Update on the subject.

Ordered the throttle needles and the seats as a set from Honda and it was the same as on my K2, 27201 needle if i remember the numbers correct.

Bike runs super smooth now, no more stutter coming from idle, pilot screws at about 1 turn out instead of 2. Needs choke on start (never has before). Easily worth the 100$