SOHC.co.uk Forums > CB350/400
Progress - She runs at last! (75 CB400F)
ManicGTI:
So, big progress for me. After 20 odd years since it's last road tax, I have got her ('75 CB400F) started for the first time since my top end rebuild! Thanks to all that have reponded previously.
IT STARTS!
Literally on the button, first attempt, with Choke open or closed. Very happy about this! However I'm far from out of the woods.
- Appears to be running very rich (all plugs immediately / consistently blackened)
- Revs increase dramatically when I try to open the choke.
What's changed since my last attempt:
- Carbs stripped and rebuilt (again), bodies simmered in a pan for an hour or so with a dishwasher tablet, then recleaned with parts cleaner spray and went over all ports blowing and checking (concentrating on idle circuit).
- Re-Bench synced them, this time doing it in the 'closed position' rather than open. Used a 4mm drill bit as it was what I had to hand, maybe I should have gone for 3mm as closer to the 'interweb recommended' 1/8".
- Also rechecked/adjusted Tappet clearances, Points Gaps, and Static timing.
So, any thoughts on what to do next?
- Check timing with timing light now I can run the engine.
- Redo carb Static balance?
- Idle screws?
- Try the OEM Idle jets back in there now the bodies are cleaned.
- Fit Hondaman transitorised ignition box (likely unrelated, but i'll fit it anyway)
Or is this likely to be something more fundamental, ie Rebuild kit jets not correct? Carbs bodies still not clean? REv counter isn't working, so not a clue what
At the very least this has renewed my enthusiasm so i'm keen to keep the momentum up!
Dave
For info, my previous thread: http://www.sohc.co.uk/index.php/topic,9575.0.html
Johnwebley:
glad its running,
when I assembled my carbs and bench synced them ,I used a torch to shine through the carb ,and adjusted then so they all were
almost closed,I figured I could use the main throttle stop screw to open them as needed,
are you sure you have the float heights set correctly? seems very rich ,so maybe levels to high ?
Laverda Dave:
I've got exactly the same problem! I started mine today after the rebuild. I had the carbs ultrasonically cleaned, new jets, needles and float valves. I set the carb floats using a 26mm gauge as recommended by Mr Haynes in his book and used a 3mm drill to set the slides.
When I turned the fuel on everything was fine for 5 minutes and carb no.4 flooded closely followed a couple of minutes later by no.1! When I connected the Morgan gauges only carb no.3 registered any reading, no matter how much I tried to adjust the settings on the screws and lockouts using a Honda tool nothing happened! The carbs are back on the bench and I'm scratching my head, I followed the carb rebuild instructions to the letter!
mike the bike:
If I remember correctly, the float heights are 21mm.
Chris400F:
I agree, 26mm certainly doesn't sound right. This thread on setting float heights may help (people have been here before!).
http://www.sohc.co.uk/index.php/topic,7882.0.html
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