Mark,
So are you saying the item marked as "Starter Jet" in this photo is the air inlet for the pilot jet that you speak of? This is the item we've been drilling out to 0.018" to improve cold starts.

 

Obviously I'm the guy who presented this "fix" quite some time ago. It was pulled from my vast, treasure trove of knowledge in all things motorcycle that I am imminently known for on this and other forums.



OK, OK, it was something that Kawasaki sent out under the radar back in the late 70's/early 80's era for the KZ650 to dealerships for cold starting problems on those bikes.

 

Remember I said I'd admit when I'm wrong... I am wrong. I have made an error. Such is life ..it happens.

I did a bit more searching and found the #77 drill mod for the starter jet to ease starting, from back in 2011 and the cheap mods I found and documented before has drilling a hole in the slide with a #32 drill, along with this link and this one, third post backing up the modifications.

I still believe neither circuit will, without damage, do anything in the range described no matter how big the holes are. One is plugged by the stopper piston when the button is pushed closed, pretty sure it is spring loaded too, the other is only active up to a max of about 1/4 throttle.

I'm bowing out at this point, since I don't have my carb off to look at stuff and I'm not so sure that is the problem area, but have no idea. Still I'm waiting to see if the cdi is the ticket.

 

Alright...
Carb out and choke setup inspected. Here's my pics of the choke set up:

https://goo.gl/photos/qf44VAMMzqNKpsjQ7

And as per IDR or Richard, can't remember... I went for quick 5 minute drive with a dead cold engine and kept it in that bad range for the entire drive, riding the brake if necessary. Here's the spark plug (with less than 2 hours on it BTW)

https://goo.gl/photos/p4TrpEQoDcVHDFDZ8

I grabbed a short piece of vac hose and tested the choke circuit. It was letting some air passed ever so slightly in both directions (sucking and blowing - heheh). I took it out and inspected it - nothing abnormal that I'm aware of, there's a clear indent of where it's been resting and rubber looked decently soft - no cracks. I applied a little bit of grease to it and inserted it back in.

I again tested for a leak using the vac host pressed to the barrel vent (whatever its called - where the vacuum draw would be) it was much more difficult to blow and suck air - some is to be expected as the cylinder itself won't be a tight seal with the vac outlet and the diaphragm passage.

Test ride: NO difference. Wow, Very bummer.

At this point I feel I can safely say that at the very least, the UPPER portion of the enricher circuit is not the culprit.

Test drive then turned into a spark plug test and those pictures can be found above.

Another member of the forum who lives within 2 hours of me has graciously offered to lend me his space, time and parts to help determine the source of my problem. I'm going to try and pay him a visit tomorrow and first item on the list for a swap will be the CDI.

Thoughts on that plug guys?

 

Special thanks to RayCour. He is, no doubt, one of the few people on the planet that knows the KLX CDI inside and out. Marginal CDI - testing data- only Ray would know such things. We are lucky to have his membership.

Also, he offers the only programmable CDI for our bikes - KLX CDI module

 

The plug doesn't show any evidence of what's wrong does it?

 

Richard, nice to see you back to play. I hope all is well and you're keeping control over SE Asia.

Later...
Mark

 

There is another way that some CVK's could run richer than others - the MAJ (Main Air Jet)..

My thinking is : Could a few CVK34's have a smaller MAJ installed?

A smaller MAJ would richen the entire primary fueling circuit (3k RPM and up).
A smaller MAJ would cause a disproportionately rich AFR in response to an increase in main jet size.

A smaller-than-normal MAJ would work just fine, but it would not respond very well to "known working setups". Increasing vacuum (MCM) AND increasing main jet size to a known working setup would be a One Two knockout punch..

Here is a pic of the MAJ(From IceBikeDave )that has been modified (drilled and tapped) to accept main jets for tuning purposes. The PAJ (Pilot Air Jet) is to the left. I would suggest that we compare our MAJ sizes.

 

That should be a major help. Even a carb swap would work if time allows.

 

Well, we know his bike will run without stumbles if reset with what would ordinarily be considered lean fuel curves..