Choke Ineffective?

First some background...You can see my motorcycle details in my signiture. But This problem has existed since I bought the motorcycle, before putting pod filters on. My motorcycle has always taken a couple seconds to start up, and I have to give it a bit of throttle or I do not think it would ever start. Struggles to idle until warm. I have cleaned the carbs multiple times and they are very clean. Once warm the motorcycle runs great all through the rpms. Once warm it will start right up with no throttle. I am pretty sure the valves are out of spec and need to be adjusted, I would also imagine the carbs need to be synch'd. With those two things, I would think that it would start easier and idle cold.

But my main question is that the choke does not affect the idle speed until the motorcycle is very warm, and even then it only raises the idle by about 500 rpms. In videos I have seen the choke usually raises the rpm's by about 2k. I have checked for vacuum leaks before and found none.

Thanks

In the bottom of the choke well is a jet. hard to see. Also the choke dip tube has a jet and a mixer hole at the top. Use a guitar string, the smallest you can get to clear them. My 550 post shows how I cleared jets.
Steve

Hi
2 things to check for
Take off the pods on carbs 1 and 4 and operate the choke lever. I had a problem with the choke linlage a few years ago and the lever moved but the choke flaps.butterflies didn't. Usually you can flip the lever to full choke and hear the click as they go vertical.

Second thing is to check your pods. Look at the picture below and then look into one of the Emgo pods and look for a rim which might obstruct the red circled openings in the pic. Some cheaper pods are shaped so that they will block those openings. K&Ns are fine but not sure about Emgo

Failing that all I can say is that with everything in spec including valves (do this first), carb fuel level and mix screw my 750/4 will usually start cold with full choke no throttle and a push of the start button. I need to turn the choke down a bit after a minute and after a few minutes I'm ready to ride reducing the choke in the first few miles/kms. It does take about 10 minutes ridng before bike is fully warmed up.



PS dont know if you saw my reply to your post last week but I'm not the guy on instagram

If these are on the bike in your sig, im pretty sure you have the Kehin Cv34s. those carbs have a VERY wimpy spring to move the choke butterflys. I had to add a spring to get mine to work. EDIT: not sure but it looks like they may have changed the spring in '81 so you might have something different.

Thanks all for the responses.

DoctoRot - Yeah it is different. They do not use a spring.

JR - The butterfly's definitely open and close. Also yeah I have seen pictures like that before while I researched about buying pods and their possible issues. My pods partially block those but I think it's safe to rule that option out since the problem existed before getting pods correct? I do need to adjust the valves, I'm sure that contributes to the problem. I will try to check the float levels tomorrow. Also, I did see your post, sorry to confuse you :blush:

Swest - I will try to clean the idle circuit tomorrow as well. I think it might be partially blocked.

The motorcycle started up a little better today and idle'd (barely, wanting to die but didn't) with no throttle with the choke. I then slowly opened the choke to see what would happen and it started to die, so it was working how it should. I think the idle circuit may just be a bit dirty in one or more of the carbs.

I don't think you will be able to get it running correctly with those ports partially blocked. CV carbs already don't like pods, and partially blocking the port that leads to the diaphragm will cause issues.

You can cut a little with a utility knife to take the sharp edge down like a slope.
Steve

Yeah, before I installed the pods I decided that if it ran crappy I would cut them. However it runs great all through the rpms so I decided not to mess with a good thing. The starting problem really was just as bad before pods. In fact it was worse. Because now when it's warm it starts right up. With the air box it still took a minute when warm or cold. It runs better now than before, so that's why I do not think pods have anything to do with it.

Clear those jets in the choke well and you should be good to go.
Steve

swest wrote: Clear those jets in the choke well and you should be good to go.
Steve

You are talking about the one's under the plastic plug right?

No, I'm talking about where the brass tube goes. Do you have a pic of your carb. might be different.
Steve

fpdavis4 wrote:

swest wrote: Clear those jets in the choke well and you should be good to go.
Steve

You are talking about the one's under the plastic plug right?

Under the plug is your pilot, I believe...