Here's a question for klxster, does the DNO352 needle from the klx300 DJ kit reduce mid range overfueling better than the DNO228 needle?

Does a KLR650 CVK40 slide spring fit in the CVK34 and if so I wonder if it would be any stiffer.

I am struggling to figure out how a CVK40 can perfectly fuel the KLR650 but it seems the CVK34 has such an issue with mid range overfueling if you want the top end fueled right.

 

Yes, the DNO352 will better fuel the low/mid in a lidless setup. This is based not only on detailed measurements and comparisons between the DNO352 and DNO228, but, now, it is also verified through member "verification of effectiveness". The above information has been determined by me and other members and is posted in various threads for all to see..

I understand what you are trying to do - and the issues "at hand" - but please understand that the CVK34 (and your CVK40) do not have a problem with fueling.
The problem is that Cro-Mags apparently haven't developed enough brain matter to have figured out that lidless KLX applications, with a well fueled "upper mid - top end", unleash a tremendous power curve. So you've never developed proper needles for such applications..

The DNO352 was developed for a lidless KLX300R using small main jets (DJ132).. So, while its' straight section and initial taper are superior (for our needs) , it does have an overly aggressive final taper near the tip that we must "tune around"..


However, the DNO228 works just fine on 1N with stock spring and slide lift port - please know that both (352 and 228) need the stock spring and stock slide lift port.. The 352 requires it because that final taper cannot be allowed to "hit" the fuel curve until the RPM's are well into upper mid range (6.5k-7k) . And doing so also extends the RPM range that the 352 will keep the AFR more properly "leaned" over the 228.. But there is no getting around the fact that the AFR takes a big, quick, jump toward a "proper richness" when that final taper hits.

 

Hey Bryan, I missed this post of yours.. What you are describing isn't a fueling problem - it is the stereotypical diaphragm mis-seating fault. You may have a CVK with a "testy" diaphragm, which requires extra care to seat.. Sputtering/stuttering is known to be diaphragm related.

There is actually more that can "go wrong" - the diaphragm, cap, spring - all must be installed in the correct manner for proper functioning.. See the "CVK34 issues" link in my sig line for help..


I will get you the stock size for the lift hole - I believe it is 3/32 but I'll double check..

 

Thanks. I am going out to play with the bike tonight. It's been on hold. I have a honey-do list about a mile long. I'll pull the carb and look at the diaphragm while I'm in there. I double checked it when I put it back together, but you may still be right. I was thinking that at low rpms and heavy load, the hole was allowing the slide to rise too far and over fuel the bike. I'll look at it all and take it for a ride. Hopefully its that simple. I am planning on riding it to a clam bake tomorrow and it's a 110 mile round trip. Id like it to be running at peak. Plus all my buddies will want to take her for a spin.

 

Ok lets talk a bit about the details of the issue.

 

Tell me exactyly what RPMs is this happening? I assume a snap and hold WOT is what you are doing..? Is the issue 100% repeatable - exactly the same every time ?

Is the issue still present, to some degree, when you snap and hold WOT from other RPMs?

Awh screw it - just call me.. PM sent..

 

I am running 144/1N on my 330 kit and it runs very well. Went out to break the rings in and it pulled clean and hard up to 8500 where i was shutting it down. No stumbling issues to speak of (less than 144/1N on my 250) but that might just be the 330 kit covering up the lack of midrange torque. Either way it runs great other than the 38 pilot, i was 2-3/4 turns out and it is backfiring on decel like a hand grenade. In fact i am thinking I may had an air leak in the exhaust somewhere...

 

We've determined that Bryans' carb is not setup correctly - he has been running the DJ spring on a drilled slide! And it seems he created the "leaking diaphragm stumbles", during his last carb session.. He's going back into it tonite..

That backfiring - decel popping - is a sign of a lean idle circuit (Assuming no exhaust leaks).. If you are not using a #38 or #40 pilot jet, you really can't totally get rid of em.. A workaround is to go 3.5 turns out (on the stock #35) and reset idle speed to 1500 rpm..

 

I was between 2.25 and 2.5 out on the 38, went up to about 2-3/4 has significantly reduced the popping no more hand grenades out the tail pipe, but it will still shoot a ft long flame you the tailpipe sometimes lol, still needs a bit more, will go a full 3 out next.

I have now ridden the 144/1N and 38 combo on my 330 in a variety of temperatures and states of coolant temp, no bog anywhere, in fact, it responds much better than 144/1N did on the stock 250. It might not be perfect, but it is a great place to start tuning (I am at approx 1000ft asl)

 

It may be worth trying the #40 pilot. It is great in the 351. The 330 will probably like it to. I'm at 2 turns out with good results.

I just took my carb apart and put the stock spring back in it. Also jbwelded the hole and refilled to 3/32". I didn't take it out tonight. It did start, though. That's always a good sign. Haha. I'll update tomorrow after my ride. Also, I'm going to a clam bake so ill see if there's any difference in performance with 3lbs of clams, a lobstah, and all the fixins in my belly.