1981 Kz650 CSR Dies when throttle turned

hello,

I am a new member to this board. I am new to Kaw's but not new to fixing bikes. All bike makes have their quirks so I am trouble shooting the one I have and looking to you all for advice or a simple knod to the carb gods.

up on the chopping block for the panel is a CSR 650. It has the carbs that look like towers, and where the slides are seeming mechanically linked to the throttle, not free like on early honda's. These particular carbs have an accelerator link and pump but did not have a cover for the vacuum sensor, it does hav two brass outlets at the bottom of the vacuum sensor though. From some of the searching I have done this seems to be one of the real possible carb models. Please correct me if I am wrong.

The main symptom I would like to focus on is the fact that when I turn the throttle it pretty much dies. I took it out a couple of days ago and was able to get going but that was about it.

if the choke is turned on during idle it dies
if the choke is on when trying to start, it will barely start and then die.

it seemingly idles fine with the occasional put put

I sprayed starter fluid on all carb boots (before and after the carb with no increase in engine speed, so I don't think that an air leak is part of the issue(at idle)

pulled all of the spark plugs know I am getting spark from the boots, need to check the plugs though.

Things not checked:

1. Timing, I pulled off the right side cover and it doesn't have points at first glance, just a cam and some small blocks(which are cruded up a little). I'd like to verify that this is most likely an electronic ignition?

2. I have not tested compression yet (today is the day)

3. I have not done a full carb strip down and soak yet, but it is on the list.

I have read some things about air screws at the top of the carbs that was of interest and wonder if that is a good place to start while I still have them on, (because I know how all of you feel about carb boots, especially when they are hardened like mine)

I will keep you all updated on the progress, solutions, and questions etc...

Thanks in advance,

Mike

Your main problem is dirty carbs. If the bike has set for a long period of time with the old gas left in the carbs all the small passages and jets will varnish up as the gas evaporates. Take the carbs off and clean them really good, including all the small passages and jets. Do not just pour carb cleaner in the tank and think this will work because it won't.

Thanks for the reply. I actually had to Kreem the tank. Although I absolutely agree the carbs are an important factor, here is an update with the work I did today:

1. Tested all the spark plugs, I need to replace all of them to get the best results. They were all about equally sooty.
2. cylinders 2-4 had great compression all around 150lbs or higher. cylinder 1 on the other hand when i first tried only went up to 120. I tried a couple more times with the same results. I put a little oil to see if the rings would seal and it went up to about 130, still not good enough. I thought it might be the seal on the compression tester so i pulled it off reseated it etc... and with a little more puts put sound like air rushing out from somewhere in the engine the compression spiked up to 145 and held. i am thinking that a valve adjustment is definately in order or cleaning of the valve seat. I also heard some intermitten clanking in the motor.

other observations:

when testing the spark plugs (out of the head) the motor would start and run with each out (one at a time) with all except cylinder 2. Anyone care to take a stab at why cylinder 2 is so special?

I also did some reading and am convinced that the ignition advance unit needs to be pulled, cleaned, and lubed.

I would rather try to find other big things before I have to take the carbs of again....

Thanks for the input Baldy, a carb soak is on the to do list.

Mike