Nice snowy night with big flakes coming down. 28 degrees. The roads were dry at least, so I got the test ride in.

My, my. Its actually quick now. Klxster's recipe is pretty dang close for this bike. I'm pretty impressed with the power from about 5k to 8.5k. Still seems a bit anemic under 5k, but I'll suss that out over a few more miles. Thats just my first 10 miles impression. Tame and calm at in-town speeds. After 5k - definitely pulling power! I'm really impressed with the top end wail.

I still need to add the quick turn throttle tube. I think it will be better yet for my riding style. After that taste of the new engine attitude, I definitely want to get it on the local dyno. If its got a mid-range fueling issue, I want to dial it out. The moto mechanic we have here is a Kawasaki expert and he races them with good success.

Here's some pics from the night. Bike is bantam weight style for testing purposes.



Replaced a few worn parts as the bike went back together.





Right now I'm looking at some inexpensive action cameras on amazon. Seems like these days you get 1080p @60 fps for around $100 bucks. Me and my buddy want to get some dual footage of the rides. Anyone have recommendations? I'm kinda liking the Yi Lite.

 

Here's a few pics of the other machines we'll have on the lake this winter.

1978 Yamaha DT125 w/175cc top.



1978 Yamaha SR500



1985 Honda ATC 200 & 1984 Yamaha tri-moto
Another DT going together in the back cause we have the parts.

 

I am assuming you are using the stock slide spring with a stock slide lift port. If so, see below. If not, this must be done before any analysis can be performed.

While in lower gears, accelerating at WOT, starting from 3.5k-4k rpm, if you are getting a jolt of additional acceleration in the 5k-6k area you should change the clip setting to the specified 1N (top notch with both washers super glued to the top of the clip).. Run the test again - Acceleration below 5k-6k should be enhanced and it should pull hard, and completely linear, from 3.5k-4k rpm to 10,500 rpm.. This is assuming the Barker system is not killing lower RPM power or introducing a "power hit" at some point on up, compared to the Megabomb + PC4 system..

Don't be surprised if your "kawasaki racer" has no idea how to "hotrod" CVK carbs - or even how they work.. CVK's are street carbs, and not used in racing bikes.. Test his knowledge by asking him how the CVK creates an "accelerator pump like" shot of fuel when the throttle is "wicked" - even though it has no accelerator pump ... You know it does this as any carb that doesn't creates a horrible bog whenever the throttle is snapped open.. If he says it is achieved via the transition ports between the slide and the butterfly valve, he knows the CVK - otherwise, you should probably not let him monkey with it as not one component can be modified without it affecting all the other systems - dependency and proper interoperability between all components is how the CVK works..

If you put it on a dyno, make sure they can sense/capture AFR (air fuel ratio), AND take whatever measures are necessary to get your raw data files from all runs - not dyno charts - on a USB thumbdrive. Hints: Tell them to put all your runfiles under your name. If it is running WinPep 7, your files will be in a folder with your name and look like this: RunFile_0.drf for the 1st run, RunFile_1.drf for the second run, etc etc.. If the dyno is running WinPep 8, everything will be the same except the files will look like this: RunFile_0.wp8
Just ask if they are running WinPep 7 or WinPep 8, and then tell them you want ALL your DRF's ( or WP8's) loaded onto your thumbdrive.. They may "freak out" when you do this - but make it happen.. The DJ software is a free download and will let you view your data (charting) any way you want, any time you want. Plus, you can email me a copy of these files and I can create composite charts showing your results with the results of others.. I/we will immediately see how the Barker system is affecting power levels and my tune recipe.

 

Yep, stock slide spring. I used the dynojet 2152 spring for the 'stage 2', which I only ran briefly to see what it offered over full-stock.

Here is the current engine state:
CVK34
Keihin #40 pilot
Air mix screw 2 turns out
DJ144 main
DN0228 needle, 2N
Stock spring, stock slide lift port
__________________________
Airbox lid removed
Hi-Flo filter, lightly oiled
Crank case breather ported
Emissions delete
__________________________
Barker Exhaust Head pipe + Mid/Muff
MCM valve timing
Fresh NGK CR8E plug

This will be the first thing I do before the next test run. I think I need to move to 1N.

When I took my KLR705 to him for a dyno pull, I got a WinPep7 printout. He does add a tailpipe sniffer for A/F measuring. I will definitely bring a thumb drive and ask him to put all data from the runs on it. Even if he knows CVK carbs, I want to be the one monkeying. All I really need to know is where the fueling is now to make a good adjustment. I will post up whatever the results are so we can all take a look.
maybe I'll call the shop today to see if he can get me in this weekend.

 

Ok great!

Prior to dyno testing, all we have is your dynobutt for finding the CVK combo the Barker system seems to like best...
Once you thoroughly test 1N (and have a good "feel" for it) if you still want to try something else, there is one last "option" to test..

 

Just got off the phone with the shop, Farrell Performance. He is going to get me in for some dyno time early next week. He said he is now running the WP8 software.

I am going to move the needle clip to 1N beforehand and hit the street once more to see what that does for the 3-5k range. If the bike seems to like it, I might even consider moving up one on the main. The largest jet I have is a DJ148. I was reserving that one for when I get the Kibblewhite valves and do a little port work, but who knows? Maybe the DJ148 and 1N position is the ticket. Maybe the current DJ144 and 1N is the sweet spot. Or something completely different! We'll find out...

 

Well, to oversimplify the relationships just a little (since the lift port and slide spring are "set in stone" for now) - The needle ( and clip position) create the fueling curve shape - the main jet moves the entire curve up or down on the AFR chart. You slap in a DJ148, and you're certainly lowering the fueling curve to the point where some parts of it will be into "overfueling AFR's" - namely, the low RPM areas of operation will dip well below 12.5:1 and cause a loss of performance.. Straight to the point - if you like 1N, you are liking the new fueling curve shape, and the DJ148 is NOT the next move..

If you like what you get, going from 2N to 1N, and want to go "next level" in the same direction (fuel curve shaping), there is one more easy tweak to try...

Sidebar: During my tune development, I ran a DJ150 for quite a while. My dynobutt was absolutely convinced the bike was running better than it ever had.. So, as usual, I dyno'd it to check effectiveness. Horrible overfueling with power losses everywhere compared to all previous setups. But I was so happy with the way it ran and sounded with the DJ150, I actually kept it in for a while afterward !

If you are adamant, or the dyno indicates that your combo needs a main jet, such as the DJ148, so large that it overfuels the low/mid range ( but correctly fuels the top end ) - have no fear.. We will simply redo the fueling curve shape to allow the biggy main jet to properly (or better) fuel all areas of operations..

 

Also, if you are one that likes to take big leaps in hopes of big rewards, I can give you the "quick and easy" setup for using the DJ148, that stands the best chance of success..

 

If you're intention is to intrigue me into imploring further... its working. haha

Let's see what I've got to work with first. I need to get some dyno data in your hands.

 

Turns out, I didn't install the shift star backwards. The two locating dowel holes aren't identical and only one location fits the dowel. The star can only go in one way. This means that the Four Stroke Works star is machined incorrectly.

I leaned the bike over with a hoist so I didn't have to drain the fresh oil when going back into the shifter assembly.




I didn't get any pictures the first go-round. So here is the cover of and the shifter stuff exposed.



And here is the problem with the new shift star. This is the backside that goes against the transmission input. It is doweled to lock it in the correct location.



Here is the transmission input with two dowel locations. I thought I had chosen the wrong position with the dowel on the star, but upon closer inspection, they are not the same hole size or at the same radius on the shaft.




Instead what I found was the dowel on the front of the star that clocks the neutral signal disk was not in the correct position.
Original star is on right, FSW star is on left.



The neutral signal disk could be another variable, but its far less likely this part had changed over the years.






I was going to drill the FSW star myself. Its just a 9/32" countersunk hole. I wasn't having much luck coming up with the right tools to do a clean job. Now I'm going to have a buddy who's got a machine shop make quick work of it.
For now the stock shift star was installed again. I will contact Four Stroke Works to make then aware of the issue.