Not unrideable KLXster. Just off in that area where main jet should have little control. So a delay in performance, which in a cv carb CAN become a stutter if rich. I watched mine spit fuel droplets out the needle jet at small slide rises with a big main jet.
The stutter thread had one common denominator. Lower elevation reduced or eliminated it. Denser air even lidless? Maybe the only difference needed is a larger root diameter on the needle for the stutterer's or a larger than stock slide cutaway (I needed both). Pretty sure it wasn't repetitive errors.
Shifting at a different rpm point if available or riding above the point makes it all livable if you want but like an itch, you know it's there.

If you would like to know more about CV's on bikes, you can read a bit about lumpy cams and un-maintained Harley's. They've had Keihen CV's on stock and modified for a while too.
Also I was quite surprised at the mod world with scooters and their CV's. Different strokes for different folks eh but still the same game.
I don't consider it "crusading" just research. Just google stuttering and add CV motorcycle carb so you aren't directed to a speech impediment lol.

You wondered how my results from the MCM differed from dyno proof. Well I'm not the only one you have asked that am I. Maybe dyno proof is only good for that bike on that dyno? Maybe dyno ain't all that if I ride different than the operator of the torque ****.
For me the added issues for the shorter, but yes stronger, mid range was not worth it overall. I'll say that again. For me.
I always wondered why your dyno sessions showed so rich at low rpm and jumped in torque towards 5000rpm then finished shortly after 9000 in a stuttery quick fall until I tried MCM. I'm sure mine would look way worse with a fairly stock exhaust by the way it worked.
Maybe it is the cam profile. If you look you will find part #'s have changed. The '06 '07's originally came (exh. cam) with -1175 (unique to the 250's of those years) superseded to -0746. 300 exh cams are different #'s again even in the '06 '07 years.
Maybe too much overlap does come to play on some. Don't know why that is confusing to you KLXster since I swapped back and forth twice to make sure for me.

Looking at part numbers will also show you differences in the jetting parts over the years but won't tell you the actual differences. There has never been a change in manufacturer to Kawasaki for Keihen parts so no need to ever supersede part numbers.

Like I said before. I'm not telling anyone anything other that yours may be different even if not broken. Some parts may be different and someones definition of performance may be different too.
DJ's lidless 300 recipe is much closer than 1n, big main jet on mine, much closer, but if 1n, big main jet works for you, great. You'll never know until you try.

 

Don't know longevity. In fact my dog that helps me so much LOL in the shop, pawed the mallet off the bench to play fetch with me, and knocked the exh. cam to the floor.
I was un MCMing so the sprocket was off and it landed perfectly on a mounting ear and now I wait for a new un broken cam. Bummer.


The big stuff looks good IMO from a couple of decades in the biz. Gaskets included should be inspected. Mine were not punched correctly for coolant passages and went OEM.

After I put the circlips in my fingers I decided on OEM (kinda soft and OEM fits).
And,,, the final need-to-modify was the lower cam chain tensioner. Everything fits and is in the correct place but they stopped machining the internal relief 3mm short. So file, hacksaw or use the lathe to shorten the spring holding bolt 4mm shorter.

I'll try to make a point of a review here after 1000km of bush riding (Aug.?). I intent to do a complete borescope in the cylinder as I dial in jetting initially. If anything comes up before, I'll tell the world on Amazon .ca lol, but I,m expecting it's all good.

 

George, I bought one of those 300 kits a month ago. Same deal with the "not quite" gaskets. I was going to wait till the snow flies to install. Had read a blurb about the chain adjuster issue (maybe it was your blurb) and I was a little worried, but I guess it's not that big O deal. When are you going to be rolling again? Maybe we can plan a ride south or east of Kamloops some time.

 

Well, it's not confusion, it's curiosity about cam part numbers/timing differences.. And it turns out that '06 and '07 - with different EX cam part numbers - may in fact have different cam timings that affect how the MCM "acts"..

This was something brought up many years ago in the MCM thread by jeffward. He "warned" that MCM would not be as effective on pre '09's.. His English was so broken -
his explanations were not clear.. I just made a mental note of his "warnings".. From what you are saying, it seems to make sense that what HE was trying to say is that with different EX cams, the pre '09's won't respond as the post '09's do, to the MCM..

Yall can view his posts on this matter - MCM thread Post #336, #361, #435

So, with more DynoButt verification or one good Dyno chart, we may have new knowledge regarding pre '09 MCM results.

I guess, at this point, what we are looking for is verification that the MCM powerband enhancement is relegated to a relatively narrow RPM range of 5k-8K on pre '09 KLX's..


On to other issues.. My Dyno tuning charts were too rich in the low/mid low due to that area not being of any importance - at least at that time. Full slide opening @ WOT fueling (main jet sizing) was all I was trying to "dial in" ( As that is "Step 1" in performance tuning a CVK.) Adjusting everything about power/throttle response/etc below WOT and below "full slide open" is silly monkey work - fooling with springs/lift port sizing/clip positions/pilot jets/fuel screw settings/etc etc.. And a picky/OCD owner would likely want to dial all that stuff in to his/her own liking.. It just so happens that when I dialed all that in to my liking (with the help of Houstons4) it came out to be 1N+stock spring+stock lift port. I wanted as linear a pull as I could get - lessen or eliminate overfueling as best as possible - keep fuel mileage up..
Seems most others are quite happy with the "below 6.5K" results..

The lower elevation easing PWJM's stuttering - and use of "lean" main jets doing the same, always confounded me.. At one point, I was convinced his carb had different parts in it - we verbally compared every single component as best we could - all seemed "ok".. We even measured our MAJ's ( as best we could) ... Now I wonder if we missed something during these comparisons.. Oh well, there are two members that've replaced stuttering CVK's and at least a handful that have fixed theirs with careful diaphragm seating and testing.. Perhaps in the future, the next member to suffer such stuttering can verify his diaphragm seal and slide operation, then just use leaner main jets..

I have evidence that our KLX250 CVK34's will not stutter or exhibit any issues due to "over richness"- with AFR's down into the 10's:1.. With such low/mid AFR's (DJ150 main jet) my bike ran great for over a month before I dyno'd it.. What a surprise that test was - I thought the bike ran best with that combo.. It was actually down on power due to overfueling.. That experience also verified to me that dynobutts are not to be trusted - especially mine! lol

We do have evidence that aberrant slide behavior causes our CVK's to stutter.


We do, very much, need a better needle to fuel lidless KLX's with - a thicker and longer straight section, and a compound/dual taper to tip. With proper main jets, we need better fueling control below 6.5k RPM..

I've already given my views about dyno results on a stock mass produced engine only being valid for that engine/ or on that day / or on that dyno/... They are all uninformed "wives tales".. On other forums I'm active in (other motorcyles I own) it cracks me up when a chart is posted with "biggy" curves and numbers - and a STD correction factor.. The resulting "oohs and ahhs" are hilarious.. I say nothing though.. This forum and our members have my allegiance on such matters..

This post breaks my rule - never do-up a KLX678 style novel and post it.. I apologize - never again..

 

You're the one posting the ooh and ahh stuff here, power wheelies and all. If all those others are uninformed "wives tales" what makes you any different? Why are you any more believable than anyone else here? Please tell me Mr Know-It-All.

 

Oops, sorry I woke you up.. Ok, not really sorry - you're too much fun..

But, if/when you reach a level of knowledge to where you can tell me the exact reason why STD will always produce inflated numbers over SAE, we can talk..

But for now,,, Yeah, I kicked your sand castle,,,, and now I'm gonna run away - Can't get me..!

 

What you refer to as "stuttering" and what I'm talking about may be two different things, but it sure feels like something is stuttering.. you also can't lay claim to a word and say it only applies to a condition that renders a bike unrideable, especially when the word was originally used to describe a speech problem...

That being said, something isn't right. The bike is rideable, if I keep the revs up past 6.5k and travel at speeds in excess of the law... in fact, its even rideable at between 5k and 6.5k but I know it ain't right. Like I said, it feels like I"m dragging a rope and it catches every once in a while. I'm not blaming the the lidless recipe, but it doesn't happen with DJ stage 2.

Now that some more information has floated to the surface regarding MCM and pre '08 KLX250s, I feel sorta weird... like I ate too much ice cream. At this point, there is so much "up in the air" regarding carb differences between years, cam timings, and usable power in the rpm range that I ride... I feel like throwing in the towel and going back to stock cam timings and DJ stage 2 until I pull the trigger on BB. I'm the kind of person that won't stop wondering if what I'm feeling (lack of power, "stuttering", strange warm up time) is being caused by one of these variables. I know that the bike was smooth as butter albeit slower, with stock muffler and header and DJ Stage I...

 

5-6.5K @ WOT is where the slide it at the top of its' travel - full open. With the stock spring, full open occurs closer to 6.5k than with the DJ spring. But I think what you are talking about has nothing to do with WOT fueling..

I assume you are talking about a part throttle tuning issue. Stuttering, as defined in our threads, is a debilitating malfunction that occurs (usually) between 5-6K with WOT or part throttle with a strong "catch" as RPM's rise above 6K.. The bike is not really rideable in this "stutter zone". So I don't think you have the stutters..

You likely have a simple tuning issue or a little malfunction. Are you using the stock slide spring? Both DJ washers on top of the clip? Slide spring indexed properly within the cap? Has this issue been there constantly - from the moment you fired up the 1st iteration of your lidless setup - or did it appear suddenly?

 

There is no talking with you, as this thread is starting to show.

What I am pointing out is your total disdain for all those who do not immediately bow down and praise you. You are making yourself to be superior to everyone here and in the other forums by your own words.

As for your question, I don't really care. I am not working with any sort of equipment to read horsepower. So I truly don't care. If I needed to it wouldn't be hard to learn. I've learned harder stuff.

I ignored your attitude and presence for a while and will start again. Seems even showing respect for your knowledge in the one area of the CVK and DynoJet jetting for it, referring people to you wasn't good enough. You have to disrespect me and clearly that post shows you also have no respect for others.

Shows in playing semantics games in this thread, trying to lord your superiority over others when they' just want to fix a problem. I'd have told you to stuff it by now.

Stuff it!

 

I get what you're saying when you say "stutter" then clarify it with the term "surge".

When I started with jetting on my 250 I tried shimming the needle and doing a bigger main and pilot - going on the cheap. When I rode it the bike would surge (rpm variation) when held steady around 6000± rpm. If I gave it more throttle it would pull relatively cleanly. Remembering a bit from earlier days and the fact that Kawasaki has an enrichener circuit instead of a true choke, I reached down and opened the "choke", which slightly richens the mix. The surging smoothed out some. The bike was lean on the needle. If it got worse that would have meant too rich.

I bought the Kiehin N1-TC needle clip in the second notch from the top (1000 ft elevation) with a 125 main jet and a Dial-A-Jet. No more surging. I did the Kiehin parts mods done over the years by many, like Pippin. It was proven plus my brother did his 06 and it worked fine. My brother is using the same needle, but I think a 128 main jet running a KLX300 exhaust where I am running stock. He also did the Dial-A-Jet and found it smoothed out the power delivery filling in a bit when the brass was lacking. He isn't running the MCM, but I doubt that is any issue for you since they all use the same cams.

Seems from Partzilla that all the KLX250s from 1994-up run the same cams at least in the U.S. Look for your self. Also looked up 2006 and 2012 KLX250S exhaust cams on Kawasaki site and found same part number 12044-0746 . SnowCity showed the same part too 12044-0746. So no reason why MCM should be any different.

I think the MCM gave better power, but not huge. It is a 250 after all. I never got the power wheelie effect, but then again I ride it like an off roader - up against the tank. Off road it seems decent enough to get over obstacles with throttle and a tug.