Carb cleaning QUESTION

[ortizj2289]

Whats up everyone,

So I just got done removing the carbs off my '08 250 for the first time and I gotta say i feel pretty damn good, mostly because i've been putting it off for nearly a year and its finally done. My bike was all sorts of sluggish the last time i rode it. After messing with the fuel treatments, changing spark plugs and air filters, i came to the conclusion that something was wrong with the carbs. Long story short, I expected the carbs to be very dirty but when i opened the float bowls, everything was CLEAN. No gunk, no residue, just a lot of fuel. I figured I might as well clean what i can on the carbs while they're removed. They have been pre-soaked and scrubbed in a pine-sol solution. Everything looks great so I'm not going to follow through with a carb cleaner since it looks unnecessary and i don't want to disassemble any further to remove any plastic parts.

MY QUESTION IS, after I rinse off the pine-sol solution, is it good to air dry and reinstall or is letting water dry on the carbs a bad idea? How do i go from pre-soak to reinstalling back on the bike???

[Ghostt]

Have you remove the both main and pilot jets? Main jet holders? Did you remove the slides? Idle needle screws?

To answer you original question, you need to blow out the carburetors, and all the fuel circuits, as well.

[alex.s]

i always just blow it out then flush it out with gas

[MrAtom]

Yeah mine looked clean but i sprayed the fuel passages and it ran after that. There was crap in it. I just couldnt see it.

[Ghostt]

Another thing to check is the OEM fuel filter located just inside the fuel inlet elbow, might be clogged.

Also are there any modifications to the bike at all?

When you say sluggish, at what point or points?

[ortizj2289]

Originally Posted by Ghostt

Have you remove the both main and pilot jets? Main jet holders? Did you remove the slides? Idle needle screws?

To answer you original question, you need to blow out the carburetors, and all the fuel circuits, as well.

I have removed the main and pilot jets, main jet holders, the slides and the idle mix screws. The reason I ask is because I rinsed it with water and noticed corrosion forming almost immediately after drying. Can't be good.

[Ghostt]

Hit them again with carburetor cleaner, and then blow them out, and all the circuits as well.

[ortizj2289]

Originally Posted by Ghostt

Another thing to check is the OEM fuel filter located just inside the fuel inlet elbow, might be clogged.

Also are there any modifications to the bike at all?

When you say sluggish, at what point or points?

Just checked the fuel filter,very clean, nothing clogging it up. there are no modifications besides a K&N air filter if that counts. Laggy I think is a better word now, not sluggish. Anytime I accelarated, it felt like it took the bike a second to realize that I turned on the throttle, making it go. Maybe 1-2 second delay. Just a poor response.

[ortizj2289]

Originally Posted by Ghostt

Hit them again with carburetor cleaner, and then blow them out, and all the circuits as well.

Awesome! I'll give that a try. Thanks.

[Ghostt]

That's the idle mixture screws need adjustment, here is my how-to write-up

Your initial setting should be 3 full turns out from the bottom, remember just slightly tighten them, don't go all Conan on them.



Then warm it up, slowly turn 1 side pilot screw in until the rpms drop, then back out till RPM's peak (and no further)* Twist throttle...see how it reacts...tweak to taste.
Repeat on other side... test ride. You're looking for best throttle response and transition from just cracked to 1/4 throttle opening or so.*

Thats a quickie, 10 cent tutorial on setting pilot screws.**

Also while your reassembling be sure to check the float height, this is very critical, if they are out of spec, then you can't properly tune anything after that.

Also here's another how-to on syncing carburetors the proper way.

You can get a reasonable sync with the carbs in hand. Back the idle adjustment off to close that carb then match the second carb to it with the sync screw. You can then turn the idle adjustment up while using a thin feeler gauge (maybe .002") between the throttle plate and the throttle bore, adjust to just fit, and then check the second one and adjust to match. If you have good feel for this it will run fine once installed.*

It would do folks well to take a minute to review and understand what a sync tool does, how it works. And take another minute to look at the carb linkage and sync adjustments available to fix irregularities that might occur. It can help take some of the mystery out of this as well as stop unnecessary carb sync screwups.*

Meaning, that the carbs were right once, the butterflies were matched and it performed well, but then changed. Undecided And the problem somehow occurred in the butterfly direct shafts, or the sync screw turned or wore that pad that it rests on, or the carburetor pairing/ bridging brackets twisted in relation to each other, and enough so that the butterflies no longer operated in sync, such that performance noticeably suffered. And a fix will be accomplished by changing the butterfly position, the only thing the sync adjustment does. Hmmm. Really? Undecided*

Meanwhile, the tool measures vacuum at each individual runner. That's all it does, how it works. And vacuum is effected by a huge list of things, butterfly position being only one of them, and the only one addressed with that tool while turning those sync screws. The rest of that list includes, valve adjustment, jetting, float level, compression differences between cylinders caused by wear as well as factory CC differences in the head, intake runner, as well as flow by port variations, etc. Variations in cams, wear or factory tolerance. Then there's the potential big one, pilot jets and pilot screw mixture settings. All of those effect the vacuum and will be read by the sync tool, accurately identifyng the difference that exists, and with the only adjustment being used to "correct" the problem, move the butterfly relationship, one to the next.*

It's that clear understanding that has me of the opinion and long time practice to not touch the sync screws on a set of carbs that were right once and were never dismantled from the rack. And jet cleaning as well as float needle changing doesn't require that they be dismantled. And further, if I DID dismantle a set of carbs, I just matched the butterflies on the bench at assembly, using a feeler gauge, and then never touched them again, never gave them another thought.*

That method, properly executed, will have THAT portion of the complete equation, balanced flow to each cylinder in a multi-cylinder/ carb application due to butterfly position, satisfied entirely adequately. And in fact, it has worked for me every time I've done it on every bike (as well as individual runner/ butterfly V-8 intakes, all eight) that I've ever owned or any that I've fixed for others. And the times I fixed for others was usually after an attempt by others to sync the carbs, chasing a problem, or sometimes not even chasing a problem, but one they created wth a sync tool, chasing a problem from that list, that was never a butterfly position change problem. Those linkages are so direct and simple that they don't know how to screw themselves up. Not enough to care about.*

I'm sure this will start a lot of controversy so I won't argue it, just offering it for those who understand the whole picture that I outlined and might make good use of it. It is what I've done, on every engine I ever worked on, including blue printed racing engines as well as regular old, high mileage street stuff. I've had at least four, four cylinder bikes with over 100,000 miles that ran quite well, the whole time, and never had a carb sync performed. When they did finally get a total disassembly, this is how I set them up, on the bench. Over the years I've straightened out at least a half dozen messed up ones, probably more, and on the bench, after fixing the original problem which was fouled pilot jets.*

I only posted this because it seems like its coming up fairly often, especially with problems from a sync gone bad. One I would suggest was never a sync problem to begin with. A big or sudden change in performance is NEVER a sync problem. NEVER. Remember that. Cool If there is a problem, and you connect the gauges? YES, there will definitely be an imbalance indicated. But because that hole has a problem that is from the rest of the list. A bad plug, a plugged pilot jet, a screwed up float, a bad valve or setting, etc. Every one of them effecting the vacuum in the intake but NOT from a sudden move of a butterfly position, a sync adjustment.

****

Also I've attached pictures that shows which part of the carburetor is doing what.

It's also important to keep in mind, to get it running smoothly, before doing any shimming, jet changes, etc..... Let's first get a solid baseline to start with.

Hope this helps, any questions, just ask.

[Ghostt]

Also if you parts, etc... Send @ducatiman a PM, he's from the EX-500.COM but he also lurks he as well.

He offers carburetor services and I personally vouch for him.

[ducatiman]

thanks, ghostt. a before/after teaser example of my work

[Ghostt]

Np @ducatiman, glad you could make it.

Would you be so kind to explain how you got them soo clean?

[ducatiman]

pro sodablast equipment

[crazymadbastard]

I was gonna guess jewler steam blaster.

[Racer x]

I'm a little late to this but I almost always replace pilot jets. The tiny hole gets blocked because of corrosion. You need a proper jet reamer to open it up to the proper size not just open.

[ducatiman]

guitar string .011", .012", .013" or larger (depending on jet size) works perfect

[Ghostt]

I picked these up, for $7 USD i couldn't pass it up, and they work.

Carburetor Carbon Dirt Jet Remove Cleaning Needle + Brush Tool Kit.
http://www.ebay.com/itm/331287738438