Starting trouble!

[walleye]

Hey folks!
Not posted for ages, hope everyone is ok?
Recently rebuilt the top end put on a short mega with pods. Trying to suss the jetting. Tried the following:
42.5 jets, already up to 6 turns out on the air screw, throttle stop in contact but not tensioned. Bike won't start on either choke or no choke. Will start and run with a pinch of throttle. 45 jets, up to same amount of turns. Similar results.
Change starter jet size?
Try next size pilots?
Needle clip height?
I've still not got my head around carb alchemy.
Any suggestions welcome!!!!!!

 

[NewHavenMike]

Everything is stock? When you choke, do you prime the engine? Ill sometimes give a kick or two before turning the ignition on to start. Just to get more fuel in the cylinders... Its getting colder here in the morning so thats why.

I had a similar problem when I got mine going, it would only start when I was giving it gas. The timing was too far retarded, but if you can idle thats probably not your problem.

have you taken the carbs down to clean them up?

 

[walleye]

Hi Mike.
It only idles if I hold on a bit of throttle. Not stock. 1980 SE 4G5, pod filters(cheap) and 2 into one baffled short megaphone.
I cleaned all circuits with carb cleaner and compressed air. Floats are free and set at the right height.
I'm getting close but don't think it should need so many turns out on the air screws.
Maybe another clean and blow out wouldn't hurt with the air screws removed?

 

[Rides520]

Some sage wisdom from others on the forum informed me that 4 turns is basically max, end of story. If you need additional fuel due to lean plugs at 6 turns, a larger volume of fuel is required which could be an incorrect jet, or a cracked carb boot sucking air. From what i understand, your plug color is based off idle which is the pilot circuit. The pilot only effects 0 to 25% throttle. If the bike is unable to run up to and at 45 mph+ smoothly i would refrain from focusing on fuel and turn your attention to spark. The bike needs to run to jet, not running, no jetting. Otherwise you will forever chase your tail thinking its a magical jet combination. I would either put stock jets in or whatever you took out back in since for example, I'm at 2500 ft elevation, and my bike will run 2-3 different combinations of pilot and main jets relatively okay as long as the timing is spot on. To make it harder, without detailed notation while driving i could very well convince myself that all 9 combinations feel the same, this makes jetting one of the last steps on the list and one of the more difficult things to pick up.

The holy 3. Fuel, Air, Spark. I think it should be called fuel, air and ignition cause in my mind spark makes me think spark plugs and wires and not so much the idea of accurate spark = timing. If you have points i would double check gap and timing, might as well check inlet and exhaust valve clearances if you haven't in 2000+ miles. fuel regulation screws are what there called on the mikuni 34s, which is something to take into consideration, lefty loosy is more gas = richer. righty tighty is less gas = leaner.

 

[walleye]

Thanks Rides520!
I shall revisit the timing and gaps as first port of call. Having adjustment problems. I set the left correctly and can't seem to get the right side correct. Inlet/outlets already checked. Regulation screw. Gotcha.
No more than 4.
Thanks for your indepth reply!

 

[NewHavenMike]

The pod filters could be a problem if they are blocking passages on the carb body.. What is your jetting? Put the idle screws back to 2.5 turns. If youre just idling, the mods shouldn't be a HUGE problem, unless the pods are blocking the air holes in the carb. This would make you very rich and youre turning the screw out and making it more rich.. Does the exhaust stink like gas? lol like a pungent gas smell. Youre rich!

Ive upgraded from the points ignition, But i think the side you want to adjust is the left side. So, Set the timing to the right cylinder and then find out where you need to move the left point to even out the timing.

Points can make it difficult to get accurate tuning. Its possible and Ive worked with it for a while, but I just got sick of setting gaps and having unreliable spark.