1st Overbore & Running Lean

You said it takes more tickling than normal, that can be an indicator of low float height.

Fast Eddie said:

You said it takes more tickling than normal, that can be an indicator of low float height.

Click to expand...

For clarity, its not that it takes a longer tickle to get an overflow, but it might take two overflows, a second after several failed kicks, before it will light up.

I mean this seriously, I’m not just winding you up honest… but it’s beginning to sound like yours is a bike that just prefers a choke ?

Fast Eddie said:

I mean this seriously, I’m not just winding you up honest… but it’s beginning to sound like yours is a bike that just prefers a choke ?

Click to expand...

That big boom you just heard was my head exploding Next someone will say he needs "a little choke"

Tickling again after 2-3 failed kicks is not abnormal. Failed kicks is abnormal assuming you know how to start one (or aren't too weak).

Forgive me, had a steroid shot in my foot-makes me testy.

Do you have the kick start knack if you don't you will have problems.

ashman said:

Do you have the kick start knack if you don't you will have problems.

Click to expand...

Well been successfully starting this, my firdt KS bike, for past four yrs. Why now a change from 9/10 first timers to 8/10 5-8 timers?

Tornado said:

Well been successfully starting this, my firdt KS bike, for past four yrs. Why now a change from 9/10 first timers to 8/10 5-8 timers?

Click to expand...

Most likely your primary circuit is clogged. IMHO, that's what every symptom you've stated says. I'm sure you know, but I'll say it anyway.

The primary circuit starts near the bottom of the float bowl, goes up on of the two tubes built into the float bowl, enters the bottom of the carb body and immediately takes a sharp turn towards the engine, goes most of the way across the bottom of the carb body, make a 90 degree turn towards the center of the carb. If a non-premier, goes though the fixed pilot jet; if premier goes a little further into the pilot jet. People often clean the jet (whether fixed or removable) but not that part across the bottom of the carb which is probably the most likely place for crud to build up! All tickling does is fill the pilot circuit unless you overdo it.

Also, the only thing battling gravity trying to pull the gas back into the bowl is the vacuum from the engine which is minimal and inconsistent at kicking speed. Thankfully, we have a crossover tube to help a little at idle and especially at kicking speed.

Assuming nothing has been changed since it was starting right, the other things like fuel height in the bowls are probably OK. If you have an electronic ignition that doesn't fire on the first opportunity, then you need two full engine revolutions to start which makes the pilot circuit even more touchy.

Good advice. I killed my kill switch .

ashman said:

Do you have the kick start knack if you don't you will have problems.

Click to expand...

Agreed. It's a Zen thing.

My 850 is very consistent starting from cold. The routine is pretty simple.
1. Ignition off, fuel tap on, tickle carbs to overflow, throttle shut, kick once through. 2. Ignition on, throttle closed, kick through and she fires right and wants to idle a few seconds before blipping the throttle. A consistent two-kick start machine.

When warm:
2. Fuel tap on, ignition on; wait a few seconds for carbs to fill, no tickle. Kick through at 1/4 throttle. It usually lights right up. Tickling when warm almost always floods the engine requiring a few WOT kicks to clear it.
(Deleted text) ~998cc

998cc said:

Agreed. It's a Zen thing.

My 850 is very consistent starting from cold. The routine is pretty simple.
1. Ignition off, fuel tap on, tickle carbs to overflow, throttle shut, kick once through. 2. Ignition on, throttle closed, kick through and she fires right and wants to idle a few seconds before blipping the throttle. A consistent two-kick start machine.

When warm:
2. Fuel tap on, ignition on; wait a few seconds for carbs to fill, no tickle. Kick through at 1/4 throttle. It usually lights right up. Tickling when warm almost always floods the engine requiring a few WOT kicks to clear it.
(Deleted text) ~998cc

Click to expand...

Yup, this is essentially what i'm doing. When trying warm starts, I do not tickle unless too many non start kicks have been done.

Tornado said:

For clarity, its not that it takes a longer tickle to get an overflow, but it might take two overflows, a second after several failed kicks, before it will light up.

Click to expand...

Ok, understood. That’s to be expected though as your kicking will have used up some fuel.

Which then raises the possibility that the engine could be flooded after several failed kicks …

If I’m in a position where a bike hasn’t started after several kicks I’ll try it with a WOT, that gets plenty of air in and quite often is enough to fire it up, meaning it had flooded (ie soaked the plugs).

Tornado said:

Yup, this is essentially what i'm doing. When trying warm starts, I do not tickle unless too many non start kicks have been done.

Click to expand...

But are you kicking it right, you can do all the above but if you don't have the right swing on the kicker which is the knack and getting the kicker in the right position for that swing, the first start for the day will always has to be the biggest and best swing on the kicker and after its been started for the day it will or should be a lot easier, well on my Norton anyway, mine is always a first kick start every time whether cold or warm, but then I do have a big juicy spark from the Joe Hunt and the longer RGM folding KS lever which also helps.

Had carbs off lastnight to go through them. Nothing obviously wrong, like main jet unwinding or needle unclipped. Did find one pilot jet o-ring showing a small tear so replaced with a good one. Poked through pilots with fine wire and got good spray out all four peripheral holes. Also good spray out the two tiny holes in carb throat. Used some silicone grease on all pilot, air and slide adjuster o-rings. Rechecked slider movement and max open sync, which were near perfect after using my CarbTune vacuum balancer previously.

Off to test ride.

Update:
No big improvements. Of the 4 or 5 starts I made today, first was typical 4 kicks no throttle and finally fired with a wee bit of throttle on 5th try. Next starts with warmed up bike, a couple of first kicks no throttle, then after a 25 minute cool down, a three kicker that needed a tickle plus some throttle.

I think I'll try swapping back to my older (original?) coils just to see if any changes. They were running well first couple of seasons with the bike and tested with better resistance than the new "Lucas" branded set I got with my EI.

Amal carbs do need a little bit of throttle opening when kicking when cold, not much but a little, mine starts first kick every time even cold but the Joe Hunt helps there, when I had EI it was always on the second kick when cold, just needed that more spin on the crank to get that spark, with the Joe Hunt it fires up before the full swing on the kicker and only 1/2 swing on the kicker every time after the first kick for the day.

Ashley

Tornado said:

Update:
No big improvements. Of the 4 or 5 starts I made today, first was typical 4 kicks no throttle and finally fired with a wee bit of throttle on 5th try. Next starts with warmed up bike, a couple of first kicks no throttle, then after a 25 minute cool down, a three kicker that needed a tickle plus some throttle.

I think I'll try swapping back to my older (original?) coils just to see if any changes. They were running well first couple of seasons with the bike and tested with better resistance than the new "Lucas" branded set I got with my EI.

Click to expand...

I doubt it’s your coils.

More likely to be a requirement to fine tune your pilot air screws to your newly refreshed motors needs.

As I understand it, the recommended ignition advance for petrol is 28 degrees, not 30. When you use petrol, the jetting and ignition advance are critical. Your problem is with the low running jets, the needles only start to meter fuel above 1/4 throttle. When you read a spark plug, the way you know the jetting is right, is there is about a 3mm wide black ring on the porcelain insulator right down inside the plug, just before the porcelain meets the metal. It is only a reliable indicator if you are worried the main jets are to lean - that is not your current problem, The main jets only meter fuel at full throttle.
If you needles are too low, it causes a cough at about 1/4 throttle. That is also not your problem.

If the bike idles smoothly with the throttle closed, it will usually start easily with the throttle closed, unless the motor is cold - then you need the choke.

Within reason , it does not usually matter what ignition advance you use, because you usually jet to suit it. But if it is a bit too far advanced, you might end up needing bigger jets. Or just back it off a bit.

Just back from a 130 mile ride. She's running great.
I seem to have licked this issue. Went through the air screw/mixture setup and found I was quite far way from 1.5 turns out. At 1.5 turns, lots of popping just ticking over. At 1 turn out, no popping, no roll on lagging, but a rougher idle. Now I'm at about 1.25 turns out, plugs looking chocolately brown. And, starts now seem to much more consistent ....last 7 were first kicker, with first start of day having a tickle and throttle cracked open. All next starts were with throttle cracked, no tickle, up to maybe 40 minutes cool down...then it needed two kick no tickle to fire. Checking my Amal carb pamphlet, it does state to hold throttle open slightly while kicking, even for warm starts without choke.

Only trouble I had today, was on run home, my 9 litre HiRider tank must have sloshed its remaining volume over the reserve side and/or forward away from the main petcock, as she sputtered then died. After pulling off road, could see air in the clear fuel filters to each carb. Switched to reserve and saw the fuel fill those two filters immediately. Started up and nursed it to next fuel station (about 10 km away). She topped out at 7.12 Litres to fill, so had nearly 2 Litres still in there. Reckon I'm making about 47-49 Mpg with it.

JFWIW, .020" of over bore will have ZERO effect on tuning. The issues were unrelated to the insignificant 9cc of displacement.
So many things get touched/neglected during a tear down & rebuild, it's logical to diagnose by symptom.