Author Topic: 1978 cb550k only runs with choke nearly fully closed (Read 1313 times)

screemn2 · « **on:** May 30, 2015, 05:48:52 AM »

ive been tryin to build a cafe racer ...i am stuck right now i put a mac four in one exaust on the bike have the carbs jetted to 105 main all fresh and rebuilt ...timing set to spec ..valves set to spec ..planned on running the pod set up but right now there is nothing on the carbs they are wide open ...i can not get the bike to run proper .. i will start up on the first kick as long as you hold the choke closed ..will not stay running with the choke turned off ....please any help will be appreciated .. would like to move on

Stev-o · « **Reply #1 on:** May 30, 2015, 08:43:33 AM »

First off, welcome. 2 quick thoughts:

- these bikes typically run like crap w/o the airbox in place.
- only runs with choke sounds as if the pilot jets could be clogged.

Have you properly cleaned the carbs?

screemn2 · « **Reply #2 on:** May 30, 2015, 10:02:38 AM »

yes .. the insides of the carbs are flawless from e guitar string to compressed air alll is spottless...just replaced the jets from the stock 90 to the 105 to compisate for the exhaust and pods ...that did help a little bit on running conditions but still not even close to drivable.. driving me nuttss... i dont know what to check next ...alll cylinders run at even temp plugs are dry now with the new jets ...could fully open carbs really make this run this bad?

scrapvalue · « **Reply #3 on:** May 30, 2015, 06:24:22 PM »

You are going to have to bump up the jetting a lot!

I had to go from 110's to 170's to make my 750 run right,(and it does), with pods and exhaust change.

screemn2 · « **Reply #4 on:** May 30, 2015, 06:32:49 PM »

thanks for the help guys ...i havnt put any pods on yet could you guys recomend what kind to buy?...and they are that crucial to have on the carbs to make run with out choke on ?...i do have a couple of bigger jet sizes but was just going on all the information ive been getting from the forums about jet size for the set up ive got...i would put the stock airbox back on but the ripped up old boots from box to carb are now gone but looked like junk anyway...

screemn2 · « **Reply #5 on:** May 30, 2015, 06:34:18 PM »

hi cal ...lack of induction control? .. what is it you mean by that?

screemn2 · « **Reply #6 on:** May 30, 2015, 06:37:08 PM »

the float height is set right at the 13mm mark....and all are right on...78 pd46c carb spec is 12.5

screemn2 · « **Reply #7 on:** May 30, 2015, 06:39:13 PM »

so the foam pods are the best for easier tuning ?.....thanks for all the info

guys

screemn2 · « **Reply #8 on:** May 31, 2015, 04:51:54 PM »

well i ordered some uni pods today ... i hope that that will be a start on drivability $:-\$

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Author Topic: 1978 cb550k only runs with choke nearly fully closed (Read 1313 times)

screemn2

1978 cb550k only runs with choke nearly fully closed

Stev-o

Re: 1978 cb550k only runs with choke nearly fully closed

screemn2

Re: 1978 cb550k only runs with choke nearly fully closed

scrapvalue

Re: 1978 cb550k only runs with choke nearly fully closed

screemn2

Re: 1978 cb550k only runs with choke nearly fully closed

screemn2

Re: 1978 cb550k only runs with choke nearly fully closed

screemn2

Re: 1978 cb550k only runs with choke nearly fully closed

screemn2

Re: 1978 cb550k only runs with choke nearly fully closed

screemn2

Re: 1978 cb550k only runs with choke nearly fully closed