Please could the forum assist me with solving this pinging problem on my stock 2003 CR250. It might even be related to an earlier discussion of a 'knock' experienced by other riders in a another thread.
My CR pings noticably when I close the throttle at meduim to high revs, as in when jumping or shutting off at the end of a straightaway. This also occurs on partial throttle openings, under light load, for example when coasting.
I am mystified, as I have checked the timing marks, and they appear correct. The main jet mixture appears to be correct, as the plug is the right color, and the bike does not ping under load i.e. acceleration etc. In fact it runs really well, right across the throttle range under acceleration, although with the characteristic and much mentioned laziness off the bottom.
Id this be an it is a mixture/jetting issue, and if so, what circuits should I look at at? Going richer on the main has no effect. A richer idle jet seemed to have little benefit, and slowed down the off idle response.
As the bike runs fine otherwise, I am hesitant to mess with the jetting, but to my way of thinking, the most likely candidates are either a reduced needle diametre, larger nozzle or different slide cutaway. Which of these is the most likely to have the desired effect? Or is this phenomenon related to another issue, like maybe the bike needs a race gas mixture, even though it is stock?
Any help appreciated.
My CR pings noticably when I close the throttle at meduim to high revs, as in when jumping or shutting off at the end of a straightaway. This also occurs on partial throttle openings, under light load, for example when coasting.
I am mystified, as I have checked the timing marks, and they appear correct. The main jet mixture appears to be correct, as the plug is the right color, and the bike does not ping under load i.e. acceleration etc. In fact it runs really well, right across the throttle range under acceleration, although with the characteristic and much mentioned laziness off the bottom.
Id this be an it is a mixture/jetting issue, and if so, what circuits should I look at at? Going richer on the main has no effect. A richer idle jet seemed to have little benefit, and slowed down the off idle response.
As the bike runs fine otherwise, I am hesitant to mess with the jetting, but to my way of thinking, the most likely candidates are either a reduced needle diametre, larger nozzle or different slide cutaway. Which of these is the most likely to have the desired effect? Or is this phenomenon related to another issue, like maybe the bike needs a race gas mixture, even though it is stock?
Any help appreciated.
