The Ongoing Chapters of the 650B2A.

Let's get everyone up to speed. Picked up my first bike ever about a month ago and have been working on it ever since! With the tires alone being older than I. And a empty garage I have set forth attempting to make this 650 run like it should and get on the road! Here is what the bike looked like when I first got it.

Here is video of the current project!



Currently painting and waiting on airbox. Notice those odd exhaust baffles, I have no idea why they are designed like that. Going to clean them up straighten them out and repaint the muffler black.

Welcome John.
Nice project you've got there.
She looks to be in decent shape, and with the help of those here, you should be able to get her road worthy again.

Airbox Arrived today, Installed on those VM22 carbs. All needles at 2 1/2 turns. Idles rough for a minute or two. Then idles pretty well at exactly 1000. 15 Jet, 102 Main. The moment I touch the throttle it stalls and drops rpm similar to when It was getting to much air when I dropped from 112.5 to 102 main. Im stuck in a bit of a loop on what exactly to do. Not to mention that airbox was the most painful thing to install. Will have video available tomorrow showing the problem. With some luck it will magically work!

Probably a dumb question, but did you have the air filter element in the airbox and the round cap on the airbox? Ed

Yes I did. In fact I even made sure that there were no leaks in the airbox as it was an ebay purchase. All new hoses and everything was clamped up.

cool project. couple things to check in your trouble shooting efforts;
Is it still running on points/condensers? if so I would check that the points are good and timing set correctly.
while you're in there it would be good to check the advancer to make sure the springs are in good condition and it is functioning properly. have you checked the valve clearance?
Have you checked the carb float heights?

I have never seen the inside of a Mac muffler and now that i have I want one even less. good luck.

Johnbug wrote: Airbox Arrived today, Installed on those VM22 carbs. All needles at 2 1/2 turns. Idles rough for a minute or two. Then idles pretty well at exactly 1000. 15 Jet, 102 Main. The moment I touch the throttle it stalls and drops rpm similar to when It was getting to much air when I dropped from 112.5 to 102 main. Im stuck in a bit of a loop on what exactly to do. Not to mention that airbox was the most painful thing to install. Will have video available tomorrow showing the problem. With some luck it will magically work!

Since the stock air box and filter are in place (a good thing) if it was mine I would install the stock jetting. Take a look at the image below, notice it shows a 90 main jet for the VM22 carbs. Those are the original jetting specs. Ed

Yes the bike still is running points, but it would seem that either no air has ever gotten into that area or the last owner replaced it. Because they seem alright from a quick visual inspection. Valve clearance is something that although I feel confident in my ability to do there is a place not to far from me that only charges a bit and they only work on vintage bikes. So not yet. As for carb float height yes I have and they are all set to be the exact same. Advancer spring? That's something I'd have to research before messing with. As for stock jetting, That is the next step right now the original 90 jet should be coming in the mail today. I also have the 107 jets just in case. I recently got my hands in a little in line spark checker to see if they are all getting spark. I'll put a video up later of the bike running with both the cover off the points and see if everything works as it did yesterday.

Regarding valve clearances -

Before you consider having a shop work on it I highly recommend you first check the clearances using the Kawasaki Service Manual as your guide. Having owned my 1977 KZ650-C1 since it was new I have found the valve clearances have changed only the very slightest amount over the past 40 years. In fact, I have only made an adjustment to 1 shim in all that time, and that was when the bike had about 500 miles on it; it now has more than 60,000 miles.

Checking the valves is a simple task that only requires a set of feeler gauges and the manual. It is smart to have a new valve cover gasket in hand just in case you discover a previous owner has cemented the existing one in place. In that case it may be damaged when removing the valve cover. No sealant is required when installing the gasket, but for some strange reason some folks feel compelled to glue them in place.

If you find some shims need to be changed you may want to do that yourself or have a shop do it, but if you have a shop do it be VERY careful that you find a shop who knows these bikes and has a Kawasaki Service Manual for your specific model. Personally, I don't know of any shops in my area that I would trust to do the job correctly since I doubt anyone working at them has ever seen much less worked on a KZ650. Ed

If these are 22 mm carbs I think the air screws you talk about are really pilot screws...... my manual shows 24 mm carbs with air screws (what I have up high and pilot screws (which are on the bottom of the bowl)...... Ed's chart shows that the 22s have pilot screws..... it says in my manual to set em at 1 and a 1/8 th turn out not 2 and a half but then again that is for 24s and you need a proper factory manual for yours to know what 22s are to be set at.

The bike now starts in a different way every time. One startup it would only maintain idle with almost full choke. Now it with full choke will shoot up to 4k then attempt to die. I'm stumped. Although the 90 jets are here so I'm going to attempt to instal those and try this again. Video of strange idle behavior will be up soon.

As for the idle screws. I recall in a pervious post centered around my carb trouble and from some research most recommended that it would be set at least 2. Although I sadly do not have the original service manual for a B2A. I will attempt 1 turn in after I reject this to the 90 jet size.