Honda-SOHC

Thought i'd add that I ended up basic ally doing the above.  I simmered the carb bodies in a Dishwasher Tablet Stock for an hour or so (Missus loved that), then did the bagpipe routine through all the holes to work out what went where.

It seems to have done the job, I was about to send the carbs in for US but I'm inclined not too for the time being, bike now starts and runs.

Oops, should have checked the subsequent posts.  Yup, 21mm.

I'm wondering if starting it in the garage doesn't help, always going to sound more 'dramatic'.

My plugs were like this:
https://goo.gl/photos/dF5kWjGSGkeJ6j3e6

Is there anything else I should be checking on top of the following?
- Bench Syncing (possibly have them too far open)
- Float levels
- Idle Jets?
- Idle screw adjustment?

I'm sticking with the idle at the mo, not touching the throttle really!

Dave

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

I think I will just stick with using the dishwasher or if there really bad boiling them on the hob with a dishwasher tab as its not failed yet.

Mick

May have to try this!

   Apologies, Tom, yes I do still have them!

Thanks for that link, interesting site!

So it's the internal drilling that I am concerned about.  The net seems to have mixed opinions of self-US cleaning, and I'm not keen on spending much on a cleaner for one project, esp if it's not an appropriate cleaner!

I have previously stripped, cleaned (by hand) and rebuilt all four.  They are now sitting with replacement Jets, Needle Valves, O-Rings etc (after a few rebuild attempts eliminating various leaks!).

History: http://www.sohc.co.uk/index.php/topic,9575.0.html

Hey all, i've been away for quite a while as my 400 has been laid up in storage following a housemove.  I've just managed to get it back so onwards I can go again...

Does anyone have any recommendations for Carb cleaning services?  (Ultrasonic) I'm not sure it's the direction i'll be going in yet, but i'm fed up with rebuilding them, and I don't think I'm getting fuel through.  I'm worried that my 'hand' clean wasn't enough and the internal pathways are still blocked.

Thanks,

Dave

I have the Coils feeding 1/4 and 2/3

I can't get it out of my head that I don't think fuel is getting through, is there anyway of simply bench testing them off the bike to check fuel is getting through the idle system?

Maybe an Air leak between carbs and block, or blocked Idle channels in the carbs?  Seems strange that all four carbs would have the same issue though.