New hard starting problem.

[tarzan]

I was having a hard starting problem a couple months ago,some of you may remember.Well I pulled my carbs and found a twisted float and floats were at just under 23mm.I straightened and reset floats to just over 23mm.Then I put on some cheap pod filters I had ,just in case I had to pull the carbs again,to make removal easier.The bike started right up and ran well.I rode it from then till today and all seemed well.And it started easy all the time.
I wanted to go meet some of the guys for the rally this weekend so I thought I would do light maintainance on it and change from the pods back to the air box.So I install the airbox and resync the carbs and adjust the pilot screws.It seems to run great.However now it is back to starting hard again.Like it is flooded at start-up.This seems backwards from what I have read of cheap filters.
Anyone have any suggestions?Thanks in advance. Rick

[prometheus578]

"Well, not really..."

This seems backwards from what I have read of cheap filters.

Now, it's not, on some bikes, gonna make a lot of difference, but here goes.
Not to question you.. you state it's "like it's flooded on start up".
Carburation is a delicate combination of a few things: Vacuum and a restriction to flow that sort of causes another vacuum.
Sort of.
The fuel mixture the gets to the cylinder comes from several sources, in a way.
To make things easy... vacuum caused by the pistons moving downward sucks air through the filter, and the same vacuum sucks the fuel up from the bowl.
There is a balance here...between what percentage gets sucked through the air filter, and what percentage is left to suck fuel up from the bowl.
Air filters are restrictive... they resist letting air through them, to a degree.
Anyway....
So now... you put in a less restrictive filter system, the pods. It's now easier to suck air through the filters, so more air comes into the carb. This also means that since it was easier for the air to flow in, there's less vacuum left to suck up fuel.
Pods, because they're more "free flowing", means you'll be burning a leaner mixture(less fuel involved.)
Now... I don't know about your jetting settings, etc, but suppose your bike likes to run with the mixture it gets from pod filters.
Now.. if you put the stock airfilter and box back in... you've put in a more restrictive filter again. More restrictive... more vacuum to act upon the fuel jets, and you're suddenly running a rich mixture again.
A good gauge would be to read your spark plugs. If they're white/gray/tan.. you're probably where you want to be. If they're black and sooty, your getting too much fuel.
Based upon what you state... you could either adjust your carb jetting, or decide which air filter system you want to run.

[tarzan]

Thanks Prom,
Well I pulled the plugs last night just to see if it is flooded and the plugs aredry and white-light gray.So I reinstalled the plugs and tried to start it .Still not starting, so I pull out choke,not happening,so I twist throttle with choke on and it starts .It runs fine then.Though I'm sure I'll have the same problem on startup.
So it looks like I was wrong about running rich.It is acually lean.I have stock 110 jets in all carbs with stock everything including exhaust.I do have a k&n in the stock air box.One thing that I noticed when I pulled the pods off to install the airbox is that the air jets on all the carbs had a little red oil from the filter spray on them.Also these pods do restrict the airjet some.So that would indicate that the pilot circuit has a problem right?Since it starts ok with the pods but not the box? My carbs are so clean they look like they are boiled.But if I have to I will go back in.

[prometheus578]

"The ol' Pod/Airjet issue."

Has been cited many times, here.
Some makes of pod filters do indeed partially block the airjet holes.
Not good.
I've not encountered this, but I believe one of the fixes is to cut away at the pod lip to clear the area by the air jets.
Also... that filter oil is rather thick. If too much was applied to the filter elements and some got sucked into the carb channels, I suppose there is the possability that those circuits are plugged. You may want to pull the carbs and blast everything clean with carb spray.
There's a lot going on here.. and there may be several issues.
Yeah, you're lean. Now, you're lean enough where it can't get fuel to start or you're lean due to plugged circuits.
Either way... having to give the bike throttle just to start means than no fuel is flowing through the idle(or enrichener/choke) circuit.
Another possability is that the idle is set too low. With the idle set too low, the throttle plates aren't open enough to allow proper passage of air to draw up the fuel. This may explain why you have to give it throttle at start up. Usually, giving throttle at start up results in too much air flow, not enough fuel... bike has a hard time starting.
So... we have several things here that could be the culprit. Which one is the main instigator.. hard to say.
You've had the carbs off. (which can screw up the synch)
You've made changes to the float setting.
You've changed filter systems.
Etc.
Somewhere along the line, things got goofy.

Also, make sure that that little jet in the float bowl is clear, too. That's for the choke system. A lot of people forget about that one.

[tarzan]

That all makes sense.BTW I sync'ed the carbs yeterday so I know thats good and I adjusted the pilot screws too.I turned them in until the idle started to get rough then back out till it smoothed back out.Then I turned them out about 1/8 turn further.
Thats how I usually do em on cars so I figured that should work on bikes too.
Also about the idle.It was at 950,so I just went out and adjusted it to 1100.I never really considered that too low of an idle could do this.That must be why we ask the GURUS! It starts fine now ,but it always does right after I shut it down.It doesnt get hard to start till it sits a while.
So I'll check it out in a while and see if that worked.

[tarzan]

I rode the thing all the way to Sandpoint,Idaho(about 75 miles one way) today ,Ijust got back and the hard starting is still there.It also was rattling pretty good this afternoon.Probably detonation.Above 3k rpm.Granted,it was over 100 deg..The heat could have something to do with that.
Maybe tomorrow I will pull the carbs and check the pilot circuits like Prom suggested.

[TopCatGr58]

Hey Tarzan,

Hard starting is not so much the Pilot jet circuit as the Starting jet, which is down in the bottom of the Float Bowl, it's pressed in, and due to crud collecting in the bottom of the bowl, is easily clogged. Sometimes it takes a fine wire stuck into it to help dislodge the crud. You should be able to see carb cleaner spraying THRU it when you squirt it into the tunnel in the edge of the float bowl.

Secondly, like Prom stated, most of the time cranking the throttle open will usually hinder the starting, because it drops the vacuum going to the starter circuit, so it doesn't suck as much fuel up from the bowl. Some folks reported easier starting once they stopped cranking the throttle open. However, yours started easier when you cranked it open, so either it's still starving for fuel, and opening the throttle allowed it to suck fuel thru the main jets.....or it's actually too rich, and it allowed more air in????

When the engine is cold, it needs a richer mix to get it going. Once it warms up, it needs much less, and it's been running, the pilot circuit is active, and so it lites easily when warmed up!

My bet is on clogged Float Bowl jets.

Detonation is NOT GOOD! Have you checked your timing? What grade fuel? Most folks report being able to use Regular just fine, but if you're getting too much advance, you can get Detonation/pinging.

T.C.

[prometheus578]

Further thoughts, T.C.
I was gonna mention this earlier... but with so many different things going on here, I didn't want to add to the confusion.
Firstly... If the throttle plates are all the way closed..., most bikes won't start. You'll note when looking at "good running" carbs, the plates are open a little.
So... this makes perfect sense now that his bike will only start when a little throttle is applied.
Secondly.. him stating that the idle is only at 950rpm further leads me to believe that the plates were closed.. or not open enough.
And, seeing how these tachometers aren't too accurate anyway... his idle could have been considerably lower.

Want a good test?
Take a bike that runs well and back off the idle speed setting screw till it no longer touches the throttle actuation lever. Now try to start the bike. You'll be really lucky if it starts.