Honda-SOHC

I do remember reading that float needle valves in some of the aftermarket carb kits have a slightly different overall height than the originals. That would certainly affect float level. For that reason, I used the original needle valves - which had next to no wear - with my new carb kits.

Regards,

That is very useful information.

I tested something:
I closed the fuel tap and let the bike run (hot), hence slowly lowering the fuel level in the bowls.
It actually seemed to idle better after a short while.

So i think it's worthwile to try and set the carbs slightly different.
Let's see what happens.

By the way, i get a dry fauled plug so it would read rich.
Carbs are rebuild, in sync, standard settings.
Floatbowl level too high? So increase float level to 24? (Sits at 21-22mm now)

I just see you are running open pipes, this can affect the running as no back pressure, you may need to increase the size of the pilot jets to compensate, the information for the air screws is correct and turning them in will increase the fuel at low engine speeds but may not be enough.

Thanks Kevski! Quite helpful.
I think i have the screws all leaned out now at 2,5 out.
So let me first try to make idle somewhat richer by turning everything in again. After syncing, i have not played with the air screws at all.

With regards to the lack of back pressure, isn't that something that especially plays a role at higher revs?
I'm actually quite happy with how she runs higher up.

Hi mark,

Yes carb settings are all standard, carbs newly built with new jets and needles, etc.. I'm also running a standard filter and airbox. Only thing different from a standard cb400f is the exhaust (open 4-2, see pics).
A cb350/400 does not have an acceleration pump btw.

After synchronising, i haven't played around with the airscrews at all. They be a bit far out.
Is a bad pick-up from idle "typical" for a lean idle?
If so, which way is leaner, which way is richer (clockwise, anti-clockwise)?
I would say, clockwise is close, so less air, so richer. But i can't really find this info.

Thanks for the advice.

Erwin

Nice spring day in holland today, so went out for some fun.







Thanks for the compliments all! Much appreciated.

The sound is... LOUD. Less of a screamer compared to a 4-1.
I would say pretty similar in tone compared to my old (inside) rotten 4-4, but without the rattle of rot ;-)
Pretty deep tone down low and really winds up higher up in the revs.

It's pared 1-2 / 3-4 indeed, with custom made Y pieces on each side of the frame.
It's similar to the 4 in 4 of the 350. Those are connected too, albeit a bit further back in the silencer.
After the Y pieces come a standard connection pipe with a 30-ish degree angle. Then comes the silencer.
Headers are original (chopped) of the 4in4.


It runs OK in the higher revs, but it won't idle comfortable yet. Also from idle away it needs feeding in order not to stall.
However I still need to make real work of the carb settings. Fiddling with that every ride now.


With regards to the seat: the upholsterer also did a renewal of the foam, but this being a original giuliari seat, means the bump is actually metal. There's a little storage space back there too.

Update on my three-fiddy:

Changed the silencers for shorter ones, because the red-tips just came in too long to my taste:
I went for the peashooter style "hooligan" cans (little did I know this name reverts to the sound):






Especially the 3/4 from the front is much better in shape, where the old red cans just stuck out way too far.
See:

My choice for a classic looking tyre, has been a set of Heidenau's.
A set of K36 to be precise.

https://goo.gl/photos/haxu5KNF9wR9Yi937