Also be aware that to get the manifold to seal to the heads the brackets must be installed with the carb secured to the heads. Then
align the manifold gaskets and secure them to the heads.

 

That is a very good point because i did not do that so i will do it again the right way.

Thanks.

 

After making sure the manifold is refitted right my Harley runs rough when i start to slow down i am now thinking it is over fuelling i have fitted a 46 slow running jet but what size main jet should it have it has standard linked pipe's with open fish tail silencer's.

 

[QUOTE=Yankee Dog;21714966]Can you swap the ignition wires from front to back to see if the problem moves? Next question would be what is your jetting. I assume carb is a cv-40? I have changed the slow running jet to a 46 but still running rough when slowing down, a guy i know thinks it is over fuelling and has even lent me a box of jets but what size should the main jet be for strait through pipes ? do you know.

 

[QUOTE=worldtraveler;21721247][QUOTE=Yankee Dog;21714966]Can you swap the ignition wires from front to back to see if the problem moves? Next question would be what is your jetting. I assume carb is a cv-40? I have changed the slow running jet to a 46 but still running rough when slowing down, a guy i know thinks it is over fuelling and has even lent me a box of jets but what size should the main jet be for strait through pipes ? do you know. there is a 180 main jet.

 

If I remember correctly 46 is an aftermarket size. 42 or 45 came from the factory depending on the year. 45 and 46 are so close that I'm not so sure that is your issue.

 

I'm not sure what the issue is, or how well defined:

Does the engine start when cold?
Does the engine idle once warmed up?
Does the engine accelerate without hesitation or stumble?
Does the engine cruse without stumble or backfire?
He did complain about coast down from speed but didn't say what condition existed at idle after he came to a stop.

On that note:
Are the cables from the twist grip to the carb adjusted correctly? Pull cable to WOT; push cable to adjust free play. (Push cable not seated or spring mis-aligned)
Does the slide come down to the marks in the carb when the throttle is in the idle position? Pull cable adjustment.
Is the enricher(choke) completely closed when in the closed position? Check cable attachment at carb, as well as shut off valve for fitment. (Possible air leak)
Is the idle screw(not low speed jet) correctly adjusted? And, do you know how to get this correct? Has to be adjusted with engine at room temp. Works in conjunction with low speed jet.

Not being critical, but sometimes people are to quick to blame the jetting when it is an adjustment problem. His problem intrigues me and I personally would like to see him resolve this. And would really like to know what solves the problem.

An example: My twin cam started to run poorly, at first thought it was a carb problem, but found out that one of the adjustable push rod nuts had come loose and the exhaust valve was slowly closing itself down.

 

Yes the engine starts from cold some times first time, i have to hold the throttle open a little for the engine to keep running so not realy but it keeps running while the choke is pulled out, yes the engine pull away as it should even accelerating when in top gear,when i start to slow down it miss fire's,when i stop the Harley again i have to keep the throttle a little open to keep it running or the engine will stall, yes the cables are adjusted ok and the throttle and smooth, I am sure the throttle is closing as it should, The problem i am having happened after the Harley had beed unused for a few weeks the fault did not show while out on a ride. The engine had done approx 500 to 600 miles after a full rebuild by a Harley trained mec who is booked up till sept so cant do it now.
I hope this gives you a better picture of the problem i am having.
John

 

Road king still not right i have looked at the sparkplug and the tip is grey and black round the edge that tells me it is running rich.so i need to rejet the carb, Right ?

 

I have fixed my Road king poor running problem it was caused by an air leak on the choke i put a little PTFE tape on the fitting before screwing it into the carb body and it now runs very well .
Many thanks for your help in sorting the problem
John