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CB466f
Erwin83:
--- Quote from: andut on June 15, 2017, 11:54:08 AM ---Good to hear that you're getting some progress Erwin !
Does the idle speed increase before it dies and do you still have the air screws at 2.5 turns ? If it isn't increasing in speed before stalling, it could be overfuelling slightly, so you may want to try running it a little weaker via the air screw adjustment and see if it improves - do the plugs look wet immediately after it stalls ?
You'd expect to wind the air screws out to weaken it - more air = leaner mix, but I read an equally plausible description of the 400's Keihin idle circuit as posted by Hondaman on the US site that makes some sense and suggests winding the mixture screw out will actually richen the mixture as it's the air bleed that draws the fuel into the idle jet, and the greater flow or air would draw more fuel. Regardless of the theory, it's an easy experiment to do, so it would be worth trying an adjustment in small steps in either direction to see how the bike reacts. - and then let us know how you get on !
It's also worth thinking about plugs - have a look at Julie's recent 400 idle issues thread that appear to have been improved by a change in plugs.
Andy
--- End quote ---
Hi Andy
thanks a lot for the feedback.
I've been playing with the airscrews and first went from 2,5 to 2. Now I'm at 2,25 turn out, because I also thought I needed some more air to prevent the stalling.
Also tried to give the carb some more idle by giving the base throttle position a bit more, but that only make the return to idle worse, and finally still the bike stalls.
The idle certainly does not go up before it dies. It runs nicely around the 1200 rpm mark first and then slowly goes to 1000, 900 and below 800 rpm it won't run anymore obviously.
My plugs remain black carbon (so seems rich). I have 4 new D8 plugs ready for install.
I'm actually considering lowering the float level another 1 mm, because I feel the bike runs slightly rich all over the revs, but this has not bee scientifically proven.
I'll look for the other thread, I remember replying in there too.
Erwin83:
Erwin83:
Erwin83:
Movie with sound:
https://youtu.be/ztPY2APeSJI
Erwin83:
It's been a while since my last update.
After losing 2 cylinders (capacitor blew up) during the last few km's of the Distinguished Gentleman's Ride in 2018, I added one more mod to the CB350 (with 400 engine): Electronic ignition unit.
Ever since, the bike has been running great, though starting to leak more and more oil from valve cover seals and head gasket (O-rings). Up to the point that it wasn't just a drop anymore, and my left shoe got wet.
So, I decided to make the CB my winter project again for season 19-20. Last winter I restored and customized a 1978 Guzzi V35 to a Scrambler, so was in need of new work anyways.
Coming up:
- New cylinder base gasket, new head gasket, new valvecover gasket, etc..
- And whilst everything needs to be taken apart anyways: I ordered a 466 big bore kit from Australia 8). I've been wanting to do such a job for a while and took the chance now.
- Also (already done): new stem bearings and new wheel bearings are installed.
- New throttle cables have been ordered (I was riding with just a pull-cable for the last decade or so)
- New instrument cables have been order. Shorter ones to match better with my set-up: 60cm rpm (of a Honda CB360 G5) and 80cm speedo (of a Honda CB50-J)
I'm just about ready to start pulling the engine apart and will post update every so often.
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