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Discussion Starter #1
Hi all, i know there is another similar recent thread on jetting but i don't want to muddy the waters.

I have a CB250K3 and although it runs decent, i have 2 niggles i'd like to resolve:

1. Idle is ok, but not always stable. Can fluctuate in strength.
2. Can't help but think that it could have more power. As i say, runs ok but feel like it could have more.

I have done a lot in terms of setting up: all timing, bench synced carbs, new ignition components.

But i am running after market silencers (tulip type) with baffles. Even with the baffles, i feel the exhaust is probably less restrictive than the stock silencers and so i'm wondering whether rejetting may be required. If so, which way do i go (up or down) on jet sizes for a more free flowing exhaust.

Just another few pieces of info.

The one thing i haven't done is change the air filters (stock). I intend to do this imminently.

And despite the plugs being a healthy light brown, my bike never likes choke, even from cold. Initially making me think i have a rich mixture. Would this be logical that the idle is running rich but on a run, its running more lean hence the correct plug colour?

Any advice, greatly appreciated.

Thanks
 

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Idle mixture is set with the screws and is pretty much independent of jetting. A series of plug chops is one way to determine whether jetting changes would be appropriate. I'm not familiar with your particular carbs but chops performed at low speed, mid-range, and WOT usually tell the story. Even though you mention that the plugs currently show the correct color you may identify an area for improvement.

What makes you think replacing the stock intake would be helpful? Pods may look cool but getting them to work is likely to require significant jetting work. Even then most are fortunate to match stock performance let alone improve on it.
 

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Discussion Starter #3
Thanks, i dont intend to replace the stock filters with an aftermarket option. I meant replace like for like, so will remain stock.
 
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