carb question

[Bob2010]

please forgive me if any of this sounds completely

I noticed that when my 09 sits for a while with just regular gas in it, it acts quirky once it fires up.
It will run and idle just fine. I can even turn the choke all the way up , getting it to 6k rpm, no problem.
Once you crack the throttle, it immediately bogs, cuts out, dies, or does all 3.

My 2010 which has stage 3 jet kit, does this less often , if at all, and usually recovers after 5 minutes of running.
The 09 suffers this more presumably because its still stock.

Now over the weekend, I started the bikes for the first time in like 5-6 months. Both fired right up, idled fine, but again, the 09 took almost 20 minutes of idling and even a few trips around the cul de sac before it pulled hard when you cracked the throttle. Using Stabil in the gas tank helped the initial start-up but not so much the warm-up as I described.
Is this normal?
What allows the bike to run at idle, allows the choke to bring up RPMs nice and steady and holds around 6k, but one crack at the throttle it cuts out and dies?

edit I just want understand better how this works so maybe I can figure out a solution to the issue. Maybe its not an issue at all and completely normal for carb'd bikes that sit for a bit.
I just dont want to open these up for a cleaning when there is no need to Thanks in advance!!

[Kscreations08]

Originally Posted by Bob2010

It will run and idle just fine. I can even turn the choke all the way up , getting it to 6k rpm, no problem.

Hey Bob. I don't know much about these but this was a red flag to me. Fully choked, my bike doesn't even get to 4k on idle... Don't know which one of us has the problem. Lets wait for the professionals lol

[cuong-nutz]

Have no fear, Motofool is here!

[Kscreations08]

Lol I love how you didn't even use the mention feature because we all know he will fly in, cape and all. #loveMotofool

[cuong-nutz]

My assumption is that the stock jets are more restrictive which makes them more prone to gumming up.

The idle air screws and pilots control the idle to half throttle and mains take over from half to WOT.

[csmith12]

The first start of the season can be well... full of stumbles and fumbles, it's pretty common and normal. Last season when I pushed my 250 out of storage, it took me just shy of a hour to get everything in order for worry free rides last season. Let's just say they have to "clear their throat" a bit to get back to normal. My best guess is condensation/debris somewhere in the system and just takes a bit of running to work itself out.

Don't be hasty and pull the carbs without just yet, check the simple stuff first; fuel quality/filter, air box/filter, snorkle clean/clear, pop open the gas cap and check vents. Draining the carbs as part of your storage plan goes a long way when you turn the key for the first ride of the season.

[subxero]

Like normal Csmith is spot on

Definitely check your air box, it is not uncommon for mice to make cute little nests in air boxes which restricts air and obviously makes the bike run like crap.

Definitely drain the bowls, why not? its quick easy and you can see if there is any moisture in there, which there probably is especially if bikes are stored in a area that does not have temperature regulation which exposes the bike to warm up and cold down cycles which will condensate moisture out of the air and it ends up collecting in places like the carb and bowls


If the bike ends up running good after a long warm up then there is a chance it just takes longer to warm up to get to a good operating temp for the jetting settings.

Has anything been done to the bikes jetting at all? shims?

The bike is getting flooded with fuel that it can not burn when you use throttle. The choke works because it is a very small steady stream of fuel and the bike is able to burn all of it or at least 95% of it and spin up with out getting overwhelmed with to much fuel. When you turn the throttle you introduce way to much fuel way to fast. If you try giving the tiniest bit of throttle and very slowly roll it on you will probably find out the bike will not get flooded and bog, It will spin up just fine.

It is just the way carbed bikes work, your 2010 probably warms up quick and is closer to ideal jetting than the 09 which is probably a fair amount off in the rich condition. Other mods you have done to your bike might also have an effect. If the bike is rich condition it will take longer to warm up, more fuel and more un burnt fuel at that will slow the warming up process as the fuel helps aid in cooling the engine, and partially why to lean of jetting is bad, not enough fuel = to much heat = seize

stale fuel can have an effect but if both bikes have been treated the same you can rule that out as your issue and assume it has minimal effects.

One last thing to check is vacuum lines and make sure the carbs are synced.

[DaBlue1]

Originally Posted by Bob2010

......My 2010 which has stage 3 jet kit, does this less often , if at all, and usually recovers after 5 minutes of running.
The 09 suffers this more presumably because its still stock.

Your carbs are set up differently. The one with the jet kit is going to run a tad bit richer, more efficient and stronger. Warm up, idle and overall performance will be better than the stock 09. Even though you stabilized your gas and the bikes run, After a while gas will still lose some of is energy. Adding fresh gas is always better (especially with the RFG some northern states have). Keep in mind it's still cold up North so patience is key.

See The Truth About Winter Gas and Fuel Economy Impact Analysis RFG

Originally Posted by Kscreations08

.....Fully choked, my bike doesn't even get to 4k on idle...

This is OK on a cold bike in cool temps. You don't want the idle that high anyway. If it gets up to 3-4k with full choke on when it's fully warm that's fine too. Actually Kawasaki recommends keeping the rpms under 2500 rpms during the warm up.

2000-3000 rpms is a common idle speed range for when the choke is on. They key is reducing the amount of choke (small increments) during the warm up until the bike can maintain a steady set idle speed on it's own. It is also acceptable to ride off with the choke on a short distance until the bike is warmed.

Never let your cold engine idle too high with no load and for long periods of time.

Originally Posted by csmith12

The first start of the season can be well... full of stumbles and fumbles, it's pretty common and normal. Last season when I pushed my 250 out of storage, it took me just shy of a hour to get everything in order for worry free rides last season. Let's just say they have to "clear their throat" a bit to get back to normal. My best guess is condensation/debris somewhere in the system and just takes a bit of running to work itself out.

Don't be hasty and pull the carbs out just yet, check the simple stuff first; fuel quality/filter, air box/filter, snorkle clean/clear, pop open the gas cap and check vents. Draining the carbs as part of your storage plan goes a long way when you turn the key for the first ride of the season.

This is the best piece of advise for those starting their bikes for the first time of the riding season.



Some good carb info that may help you understand carbs a little better.

Motorcycle Carburetor Theory 101
http://www.motorcyclecarbs.com/carbs101.pdf

[Bob2010]

Guys +1 for all the great help! I didn't expect such a large and informative response from everyone
Thank you

[Motofool]

Originally Posted by cuong-nutz

Have no fear, Motofool is here!

Originally Posted by Kscreations08

Lol I love how you didn't even use the mention feature because we all know he will fly in, cape and all. #loveMotofool

Abundant in Ninjette.org is good opportune help.