Topic: cb350f Delkevic and Jetting

[574hondarider]

I have just done a full restore on a cb350f and put Delkevic 4:1 exhaust on her.  I am running slightly lean on idle, my machinest/engine guy agreed and said it's just enough to be annoying and I should go one size up on the pilot jet.  I understand each bike is different, but has anyone else running delkevic exhaust had to rejet?  My idle mixture screws have less than 1/2 turn until they are fully closed.  Everything else is stock and my jets are new keihin jets.  New old stock honda Std. piston and rings. Needle clips are second from the top, which should be stock.  Carbs synced with morgan carbtune pro.  New oem honda manifold boots from carbs to engine, new aftermarket boots from air plenum to carbs.  No air leaks are detected.

The issues I am seeing are prolonged cold start/excessive nursing of throttle needed, then once warm at stops it is idling high (around 2000 rpm with a very slight hunt), also when taking off from a stop with engine warm, really have to baby clutch/throttle or it wants to die.  Other than that she performs great.

[mr helicop]

I have the Delkevic system with megaphone muffler on my Cb550 and it runs fine on the standard jetting, idle screws are 1 turn out and the tick over is good once warmed up. I don't know if it is relevant to your carbs but I had similar idle problems which was sorted once I had thoroughly cleaned the idle circuits with carb cleaner and an airline.

[574hondarider]

Thanks for the reply, glad yours is running good!  I did a complete tear down of all the carbs, split and de ganged them, soda blast/chem dip/sonic cleaned, followed by air spray and then some carb cleaner and acetone bath for the small parts, so they were pretty squeaky clean.  Replaced all rubber parts with genuine honda gaskets and o rings, and brand new keihin jets.  I do think the issue is in the carbs, probably in the pilot jetting.