Hi Everyone,

Just thought I'd post up my config with the 351 kit. Pretty much all of my config information was found by searching through this form and hopefully this can help others easily find the same, if not verify other findings.

2009 KLX 351 SF with Stock CVK Carb
Elevation: 380' in Northern Virginia

Needle: DynoJet Stage 2 Needle (DNO228), 1N (clip at the top), 2 spacers on top of the clip, stock slide spring.

Jets: DJ148 Main Jet, 40 Pilot Jet, AF Screw 2 turns out.

Airbox: Lidless + UNI filter

Exhaust: Stock header + FMF Q4 (no spark arrester)

Clutch: 3 springs from EBC + 3 Barnett (501-40-06017 38lb springs), EBC DRC212 clutch kit coming in the mail today.

Gearing: 108 Chain with 13/45 and 15/45 combos.

Just some quick thoughts on the install. Pretty straight up install.

I have 12,XXX miles on my bike and it was a good time to also check the valve adjustments. Seems like the previous owner had the valves adjusted as I measured the shims at 3.05mm which I found odd since the clearance should have been tightening up. Anyways, checked for clearance and ended up running around 2.95/2.90 shims... Getting the HotCams kit will save alot of headache with the adjustments as I found running a smaller shim (ex.2.50) then measuring and repeating was very useful. I did find my tappet closest to the KAK (is that the spelling?) had alot of wear. I found similar posts on here referencing the same. The wear was in a circle pattern about half the diameter of the tappet, very rough vs the rest being smooth. Something I may replace during my next adjustment, cam lobes seemed to be smooth all around.

I ended up just using my fingers to compress the rings for install. Hardest part was keeping the gaps where I wanted them to be.

The front cam chain guide was weird for me, I took mine out since the manual said so, however I see some people didn't. Not sure if the clearance is ok with it still in, to pop off the head while on the bike. Anyways, I was struggling to get it back on correctly and contemplated taking the RH engine cover off. I took a break and my next few attempts allowed me to just pop it back in with some force, if your struggling just keep trying with different angles. Looks like it sits deeper than I would have imagined and the top of the guide should line up close to the line where the head meets the cylinder.

I ran the stock clutch with stock springs during the initial first ride. This resulted in tons of slipping. I was already aware of this and had the Barnett springs on the way already, so installing the 3 springs pretty much took care of that. I have the EBC kit on the way today. Hopefully that takes care of any other slippage if any. HAS ANYONE RAN ALL 6 BARNETT SPRINGS???. I can clutch up wheelie in 2nd, no clutch up wheelies in 3rd.

KLXster (SP?) comes to mind for the jetting. I browsed many threads with him and others going back and forth on the stock CVK fueling. I tried the above mentioned setting and it seems to be running very well. I still need to confirm if my fuel mixture screw should stay at 2 turns out. But it's fired right up and running strong, no hiccups or hesitations.

I also replaced my gearing/chain from the stock SF 14/39. I ran 13/45 initially which is nice for anything under 55 mph. 1st if very short running this gearing. 15/45 is what I'm running now, which I find pleasing and I can cruise just find at 60. I might run 15/39 just to have the high speed cruising but that won't be for awhile as I'm content with this gearing for now.

Fully recommend anyone on the fence to hop on the train with any big bore kit. I'll be keeping my eye on blowing any gaskets as I've read a few posts regarding this.

 

Very, very good job - and quite impressive !

Only three posts, a new member, and I've never had any contact with you - yet you've perfectly accumulated and applied/implemented the latest forum knowledge (recipe) for making a CVK'd 351 run perfectly and scream !

You probably already know this, but your next mod is to toss that restrictive stock header. Any large diameter KLX250 performance header will suffice .. Then just pop in a DJ150 or DJ152 main jet..

Alternatively, keep and test the existing DJ148.

And now, how bout some "new" information pertaining to "at home" testing of fueling..

In this hypothetical, we are testing the DJ148 after the addition of a performance header - assume a dyno session ( to verify fueling ) is not an option...
Perhaps you can carefully clean a large, visually accessible, portion of the Q4's "tailpiping"..
Without ANY choke usage, start to idle - and let engine warm to op temp...
Using smooth and low throttle, get to third gear, or 4th and begin doing snap-and-hold WOT runs from 3500 RPM ( in a remote area of course)..
On each run, there is no need to rev your 351 past about 8500- 9000 RPM, pull clutch and release throttle simultaneously for a "no engine braking" slow down ..
Once slowed to the correct speed, raise throttle to 3500 rpm, release clutch, and repeat another run..

The idea is to repeat this process until a "residue" is deposited onto the cleaned area of the "tail piping".. The exact color of the residue denotes WOT fueling - a somewhat "coarse" analysis can be made - safe vs non-safe can definitely be determined as well as a general determination of the quality of the fueling scheme for max performance. We are looking for "dry black" to "dry dark gray".. the lighter the gray, the more lean the fueling. Any "wetness" with black ( wet black ) denotes over-fueling ( which for you and your current CVK/Airbox setup, would mean the main jet is too large..)

Before anyone questions my "color chart" for this, please be able to describe how WOT fueling is/can be/should be used for component protection at the same time it provides max performance - as this will be my reply.

 

If that "testing scheme" seems too boring, just ride your bike, over many days, with a lot of full throttle usage, (and no choke usage) on a cleaned area of the tail piping.. With your CVK setup, the residue will mostly be from the WOT usage - in this case, dark gray to black (dry of course) is "good to go".. The lighter the gray, the more the need for a larger main jet..

As always, a quick, cheap, dyno pull with AFR sensing is the best option..

 

Klxster helped jet my 351 kit and my jetting is exactly the same as yours. I have the same setup as you except that I recently installed the FMF powerbomb header and I left the 148 MJ in. It is still running great and no signs of being lean. I checked the plug and it is a nice tan/brown color. Of course, it has been pretty hot recently so I will probably have to go to a 150 or 152 when it gets colder here in eastern PA. I also had a badly slipping clutch and went with the 38 pound Barnett springs. I installed all six and also I have gotten used to the extra pull it required in about 3 rides. No complaints and certainly no slippage now! Good luck getting yours sorted out-it sounds like you are close.

 

For anyone reading this thread, the CVk setup these guys are using is very precise, very concise, and cannot be deviated from. You must have all the correct parts, used in the specified way.
To recap:
There must be a aftermarket performance slipon OR a full performance system (header + slipon) used on the bike.
The airbox lid must be removed.
The CVK must be in perfect working order - the bike must be operating perfectly. FIx any carb/operational issues before doing a lidless recipe - as the lidless recipe on a faulting engine will make things much worse..
The slide lift port must be stock (undrilled) - the info about this is readily available on my links below.
The slide spring must be absolutely stock and uncut - find the specs for the stock slide spring in the forum. If in doubt, buy a new spring from Kawasaki..
The needle MUST be a DNO228 (2152 or 2182 kit) or a DNO352 (2206 kit). No other needle can be used - NEVER use the N1TC with a lidless 351 recipe.
The clip MUST be on the top most notch of the needle, and therefore, will require the two washers to be super glued on top of the clip - in order to keep them in place during reassembly.
The main jet must be a DJ148, DJ150, or DJ152, Depending on the header being run. Keihin equivalents are in a link below.
The pilot jet should be replaced with the #40 - and fuel screw initial setting of 2 turns out from lightly seated.

Do the setup "by the book" , and correctly - you get all the goodness.. Otherwise, your nightmare begins..

 

Where is a good place to order these jets and needle. I looked on their site but I could only find whole kits, not individual pieces. I just bought a klx250 with the 351 and has a 40mm carb. the stock one he broke the fuel screw off inside and I cant get it out. do you think the 40 is fine? thank you

 

Sorry, I only "instruct" on the stock CVK carb and its' usage as that is where my knowledge and experience lies.

I have no first-hand knowledge/experience with usage of any other carb on the KLX.

 

ChimmyChong,

Excellent post, thank you.

Can you comment on your mileage numbers pre and post big bore?