is it the carbs

[Davidgale]

just recently finished restoring a 350 sport . the bike starts first kick every time without choke carbs have been ultrasonicly cleaned all new filters seals needles an seats an cables fitted. but cant get it to tickover below 1800 revs . i have just fitted another set of carbs of another 350 sport i have and same problem wont start on choke but kick starts first time an tickover at 1800 revs .any advice would be mutch appreciated cheers. dave gale

[morini_tom]

Are you sure you haven’t fitted the slides back to front?

The number of times I’ve seen this is beyond count. It’s easily done as nothing stops the slide or cap being put on the wrong way round.

Throttle cable should enter on the engine side of the carb and the cable run from adjuster to slide should be straight down

[George 350]

Hi David,

High idle speed could be due to slides hanging on the cables, (not sitting on throttle stop screws), float level too high - (adjustment or leaky float), or over advanced ignition. Running rich won't help either.
Unlikely to be an air leak as starts without choke, but 'never say never', so worth checking.
For the first one, easy check to do is unhook cables at the twistgrip and see if the speed drops.
For the float level, check the dry height as per the manual/handbook, but ideally do it 'wet' - you will need special mainjet holders with a tube added to do this though. I made mine as I've never seen any for sale anywhere.
Finally, for the ignition timing, add some masking tape to the flywheel and mark up ANT1, PMS1 and PMS2. Measure distance from ANT1 to PMS1, then make an ANT2 mark the same distance from PMS2. Then with a strobe check each cylinder is advancing the same, both at the 6000pm check point and at idle.
Report back on what you find.
Regards,
George

[Davidgale]

slides are definitely in the right way bike is very responsive to the throttle . there's 2 ml play in cables .i thought putting another set of carbs on bike would of made a difference but exactly the ame its also running very rich

[3potjohn]

At least you haven’t got a flat spot!
You have something like
Main jet 112
Pilot jet 50 or lower say 45
Atomisers 260 BD or K
Choke plungers OK - with the float bowls off you can attach some tubing to the choke jet and try blowing through. I once removed the choke jets and blanked off with appropriate small screws when chasing a fault.
No effect with throttle stop screws backed right out?
Tacho reading correct -ish?
Standard ign?
Ign timing?
Cam belt a tooth out?
Standard air filter?
Carb balance tubing connected ( if present)
John

[Davidgale]

after putting another pair of refurbished carbs on bike yesterday with standard jetting an same problem going to look at timing to night it has standard ignition an a new cambelt fitted