Honda-SOHC

So I also forgot to mention. My compression tester is a rubbish one. It doesn’t have a valve on the spark plug side  but on the gauge side. Meaning my compression reading should be a way higher with a proper tool.

Now I’ve done other engine rebuilds with this tool. And I always had a low reading with it. I never bothered changing my tester as the engines were running strong all the time after my rebuild.

About the pods. As I said previously, the previous owner discarded the airbox, bracket included so I didn’t have the choice really. I’m running K&N pods with oil on them. I run K&N filter on my africa twin and it’s spotless. I agree that velocity stack will knacker any engines. But pods are not supposed to if they are from a good brand

I've ordered a repair kit for the CB350F carburettors. I rode it today and their is still a bit of smoke when hot so I guess I have to reduce some jet size somewhere!

It will arrive next week. Hopefully that will do the job. I'll keep you updated

Hello everyone,

After countless carbs disassembly and reassembly. I start to see the light at the end of the tunnel.

I'll try to get through the process briefly :

1) I first went for pilot #42, main #98, 3rd clip position
2) Soot and smoke was building up, idle was hanging when up in the revs
3) Changed the spark plugs for DR8EA but it wasn't firing properly and flooding so back to the D7EA
3) Went for new O-ring (thanks Nurse Julie and Fogrider) for the mains and put back OEM needles and emulsion tubes
4) Very little difference but slight improvement in the riding qualty though still soot and black smoke and hanging idle
5) I measured how much petrol were in the bowl, between 50ml and 60ml (is that too much?)
6) I went for pilot #38, main #110 (I don't have any #105), 3rd clip position
7) Somehow some carbs started to leak petrol from the overflow massively and flood the pods (and so the engine)... taken them out to fix this...
7) NO MORE SMOKE! NO MORE HANGING IDLE! 

It really starts to run well BUT it's struggle to take off when hot and sometimes stalls, I really have to rev it to take off. Once rolling it's fine. Basically low revs are bogging. It's idling fine though. If I wait at a red light and try to go it's really boggy like it's building up. I tried to play with the mixing screw but very little difference on this problem. I struggle to put it in Neutral so I guess carburetion is not quite there, yet!

Now here are my different thoughts :
1) Some carbs are still leaking very slightly from the overflow (like a drop or so but only when riding) and I kind of find a bit of petrol under some pods, if the level is too high in the bowl, could it flood the carbs? I don't have any smoke though but I tested late this evening maybe I didn't see it.
2) Clip position is too high so it's running too rich when accelerating
3) I need to go for #40 pilot jet
4) Get the DR8EA back on to see if it helps to fix this

Let me know what your thoughts are on this one,
Thanks

Tom

Hey guys,

So good news, no more smoke and no more hanging idle! Now the midrange were weak so I lifted the needle to 3rd position from top. This fixed the problem quite well.

Low revs are struggling to pick up so I believe I’ll need to play with the mixing screw (current idle jet at 40 and I’m still 1.5 turn out). But will do this tomorrow evening if I have the time.

Also from 3/4 to full throttle its really not picking up. I suppose I’ll need to change the main jet to 100 to try maybe 105 but I don’t want to cut corners.

It’s the first time I started to get some sensations on the bike and felt like it’s actually running! I could almost take it out like this. But I’ll take the time to have it running a bit better before I go for an actual ride.

Thanks a lot for your help @k2-k6 and @fogrider! Keep you updated

Thanks for taking the time to explain this @K2-K6

I think restarting to square  one is probably a good thing. Now I’d really like to buy an OEM needle as the aftermarket ones at troublesome apparently.

My current jetting is :
Main 110
Idle 42
Clip on the 3rd position from top

I still have the original ones so I can do this.

I’ve got D7 grades plugs so that should be ok on that side.

One last question, I didn’t apply any oil on the K&N pods. I believe applying so K&N pod oil might increase the resistance so I’ll probably do this too.

@bryanj here are the electronic ignition that I’m running (not a Dyna S) https://www.davidsilverspares.co.uk/CB550K3/part_192275/
I still have the points somewhere so I might give it a go.

I probably have some O rings kicking around so I can change those

I can’t try anything until this week end but yes definitely a hanging idle and black smoke is a mixed message. Now I’ve read somewhere that you can solve this by dropping the needles so can be worth the try.

Also I know it’s a complication but I can’t put the air box back as the previous owner discarded the air box

I forgot to mention, I tried to run it with a standard idle jet and the needle a bit higher but none of this helped, it actually was worst. Also the symptoms were quite the same.

What is hard to understand for me is how I have such a soot which means running rich while my idle is hanging which mean lean?