pinging, too lean or not enough octane?

[NWetRider]

with my needle on the top clip I get some pinging if loading the bike hard in low rpms. I tried lowering the needle but it feels like I lost some power and the bike loads up on slow trails. But it does take the ping away. I'm thinking the bike was not lean to start with by the results I got so do I need better then pump premuim?

Bike is a 99 cr250.

 

[john3_16]

Does it sound like the motor is surging (a strange rise in rpm's) when you let off the throttle and approach the lower rpm's ?

If it is it sounds lean...You can actually go to a fuel like VP C12 and it will automatically richen things up across the range and eliminate the pinging...With the increased octane you can also go to a pretty crisp jetting without the motor knocking.

Wether or not it's lean, good fuel should get rid of the ping.

 

[sick 96 250]

If your bike runs lean it will ping like you are describing. Instead of moving the clip up or down on the needle, set the needle back to factory specs and mess with the pilot and main jet. Although moving the needle up or down will lean out or richen the circuit it doesnt have the effect of the actual jets being correctly sized in the carb. While you have the needle at the top clip, your bike may run a little crisper but may be to lean, while when you move the clip down it will richen and make your bike a little fat. Try going back to stock jetting then work your way through the jets inside the carb and not the needle and see what happens

 

[NWetRider]

No surging. I've read all I can about what a lean condition is supposed to feel like and I really don't think it is at all lean. But I am no expert so the pinging confused me. I know some bikes just don't like pump gas but I don't know if mine should have a problem.

I don't want to start from stock jetting. According to everything I have read the bike came very, very rich stock. All the jetting recomendations I found on the net recomend the top position for the needle. I have 1 size larger then stock (which I assume is richer).

It doesn't ping on the first 1/4 throttle or wide open so I was assuming it is the needle. Is that a bad assumption? I played with the air screw last ride and even though it was about 35 degrees out I still had it out 2.5 turns for best response and fastest idle so I am guessing I am rich if anything on the bottom. It does idle a little more uneven though and was much more steady of an idle at 2 turns out. I like the response a lot better where I have it now but if that sort of idle is a bad sign I will put it back where it was.

 

[darringer]

I have a slight pinging with my 99 as well. I tend to notice it most on long hillclimbs. I also run a 1 step leaner needle in the top clip. During winter I run a 180 main and 48 pilot. This is for approx. 50-55 deg. Summer jetting is 42 or 45 pilot and 175 main. My bike came to me with stock jetting that was ridiculously rich on the main and lean on the pilot. It has always pinged a bit. As a side note, my compression is 220psi @ sea level, and I run 32:1 Motul 800 with 91 octane so-called gasoline in California. The bike has excellent throttle response, runs clean, and I have never suffered any ill effects from the detonation, as it is slight. I hope this helps you.

 

[hammy56]

I have 1 size larger then stock (which I assume is richer).QUOTE]

If you have one size larger needle, its leaner, not richer.......

 

[NWetRider]

Thanks, that was very helpful. Yesterday I hit the worst possible conditions, it was 10 degrees colder then normal, the air was really dry instead of the usual high humidity, and I was riding a little lower then normal. A turn in on the air screw made it decent but still was running lean. If I want the bike to survive a day like this I'll need to leave it as it is now, just a tad rich for my normal rides. I guess I have the right margin of error now.

Currently at 45 pilot, 2 - 2.5 turns out, 1 step leaner needle on 1st position, 178 main. Runs good on my normal riding conidtions. The slight pinging is only when I really load it in 3rd or a higher gear on a hill so I guess I will live with it.

 

[uts]

I have to run my old cr on 98 octane to get it to stop pinging. Even 95 octane pings a bit and I am pretty sure mine runs quite rich. You guys probably don't get BP fuels over there. They make a fuel called BP ultimate which is 98 octane pump gas. It totally rocks and no pinging. I would say try and get some more octane.

UTS