Carb Mixture (pilot) screws?

[barryware]

My kids 2004 Kat600 has sat for a couple of years (on and off). Last season, it was only ridden once.

We were not aware of the bowl drains so you all know what has happened.

It idles like crap, pops on deceleration, hard to keep lit when you first start it.

So.. I decide to take off the carbs and give them a good cleaning. The first thing I checked was the position of the idle mixture screws..

The screw plugs were already removed by the bike shop when it went in for its 600 mile service.

The position(s) are all over the place. From left to right (when sitting on the bike), 1 is 3 1/4, 2 is 4 1/4, 3 is 2 3/4, and 4 is 3 3/4.

Should I put them back where they were or should I open them all the same when I put it back together? I have read a bunch of posts stating where to set them but they are all set the same.

I'm not a bike mechanic but I am pretty handy at this stuff. In the old days of multi-barrel automobile carburetors, you would adjust the idle mixture screws to get maximum RPM. Once you had them set, if you open one a bit more, the RPM would drop and if you closed it a bit from max RPM it would drop also.

Same with a scoot? Advise? Any one near Chicago that wants to clean the carbs and sync em after I get it back together?

[steves]

Those settings don't sound right. I would think start at two turns out and see how that goes.

With a jet kit, you usually start at 2.5 turns out.

I think my pre was 2.25 turns out when we drilled the caps out.

[barryware]

Would they adjust the same as I explained on a multi barrel automobile carburetor?

Also... As long as I got your attention, the idle RPM adjustment is bottomed out and the scoot idles at a bit over 600 r's. It has been this way since it was new.

Now that I have the carbs out, I can see that the do-hicky that engages the idle adjustment (the throttle cables also attach to this), has a tiny allen set screw.

Can I reposition this by loosening the set screw and get the idle adjustment closer to the middle of its travel? I am trying to get the internals of the carbs clean and it reassembled without having to touch the sync screws.

I gotta tell you guys... We screwed the bike up by letting it sit without draining the fuel out of the carbs. Once in a while it got started and then it would sit again which just made matters worse.

The boy, moved to Arizona and no longer wants the bike. He claims that the life expectancy for a bike rider is about 3 days out there.

I just want to get the carbs cleaned so it runs right. It has 2200 miles on it which I know I put on 1K just playing around with it. Need to get it sold once I correct the self inflicted problem with the dirty carbs.

I can't find a carb stix to rent and I really don't want to spend 100 bucks for a one time use. Don't really want to take it to a shop because I don't trust any of them and then there is the issue of getting it there (to the shop) once it is put back together.

Anybody know who may rent the stix or know where to purchase an inexpensive set that is functional? I don't want to buy junk but I don't need the best either.

[KatanaJim]

Make your own carb vac gauge. There is a thread on here about it. Cost me $6 in parts and works pretty good!

[steves]

Would they adjust the same as I explained on a multi barrel automobile carburetor?

Also... As long as I got your attention, the idle RPM adjustment is bottomed out and the scoot idles at a bit over 600 r's. It has been this way since it was new.

Now that I have the carbs out, I can see that the do-hicky that engages the idle adjustment (the throttle cables also attach to this), has a tiny allen set screw.

Can I reposition this by loosening the set screw and get the idle adjustment closer to the middle of its travel? I am trying to get the internals of the carbs clean and it reassembled without having to touch the sync screws.

I gotta tell you guys... We screwed the bike up by letting it sit without draining the fuel out of the carbs. Once in a while it got started and then it would sit again which just made matters worse.

The boy, moved to Arizona and no longer wants the bike. He claims that the life expectancy for a bike rider is about 3 days out there.

I just want to get the carbs cleaned so it runs right. It has 2200 miles on it which I know I put on 1K just playing around with it. Need to get it sold once I correct the self inflicted problem with the dirty carbs.

I can't find a carb stix to rent and I really don't want to spend 100 bucks for a one time use. Don't really want to take it to a shop because I don't trust any of them and then there is the issue of getting it there (to the shop) once it is put back together.

Anybody know who may rent the stix or know where to purchase an inexpensive set that is functional? I don't want to buy junk but I don't need the best either.

You can bench synch the carbs using the adjustment screw. It should be on the top of the spring, between the two carb banks. I think it's just a flat head screw. http://www.motorcycleanchor.com/katana/trinc/sync.htm

You can adjust the idle screw just by turning it up or down a little bit. I think the bike should idle around 1000 RPM.

Here's a thread on cleaning and rebuilding the carbs...

http://www.katriders.com/forums/viewtopic.php?t=23982&highlight=carb+synch

Here's another with pictures:

http://www.katriders.com/forums/viewtopic.php?t=19942

[barryware]

You can bench synch the carbs using the adjustment screw. It should be on the top of the spring, between the two carb banks. I think it's just a flat head screw. http://www.motorcycleanchor.com/katana/trinc/sync.htm

You can adjust the idle screw just by turning it up or down a little bit. I think the bike should idle around 1000 RPM.

Here's a thread on cleaning and rebuilding the carbs...

http://www.katriders.com/forums/viewtopic.php?t=23982&highlight=carb+synch

Here's another with pictures:
http://www.katriders.com/forums/viewtopic.php?t=19942[/quote]

I have read through most of the posts before I embarrassed myself asking questions.

The current setting of the mixture screws have me boggled. I paid extra at the first service to have the caps removed and the mixture screws opened a bit. On the invoice the dealer called it "fuel Screws" and charged the kid (I actually ended up paying for the service) an extra 50 bucks. After close inspection, I think they screwed up (no pun intended) one of them. You can see the drill mark in the screw and I can't get this one all the way out. Locks up, won't come out any farther. They are no longer there or I would bring them the carbs to fix the one mixture screw.

Can't see the pics in the one thread... Just red x's

The idle speed adjustment... It is screwed all the way in. Some how, I have to reposition the relationship between the the do-hicky that it engages with which also connects to the throttle cables. I see a little allen set screw. I was wondering if I can reposition this do-dad to get the idle speed adjustment closer to the center of travel.

[KatanaJim]

Drilling into the screw head and stripping it, is a pretty common occurence. There is a brass plug covering them from the factory which requires removal before adjusting. You have to drill it then thread a screw in and pull it out.

[md86]

Ok , since the pilots were all over , you can assume one of 2 things .... either someone DID do an idle drop , or they worked themselves loose . Personally , I'd set them back where they were and see what it does once cleaned . If it don't feel right , or plugs get black , I'd go with the 2.5 turns instead and start over .

[barryware]

Thanks for all the advise.

Lets say that I don't want to trust anything and I want to adjust the idle mix screws from scratch.

Would the procedure be the same as in a multi-barrel automobile carburetor?

That is, adjust the mixture screws for maximum RPM. Once adjusted, if the screw is turned either in or out, you should see a drop in RPM?

I still want to get the idle speed adjustment closer to it's center of travel. Right now, it is screwed in all the way and there is no more unless I trim the spring a bit. I can see an allen screw on the piece that is on the carb. Unless somebody knows about this, I don't want to mess with it. Is the allen screw what holds it on to the shaft? Is it pressed on? Would a Pic help?

If I can rotate this piece lets say 10 degrees or so, it would put the idle speed adjuster more in the center of its travel. Like I said, right now, there is no more to go.

[barryware]

Just an update in regards to bringing up the idle speed.

The do-dad that attaches to the carb throttle shaft has a roll pin, not an allen set screw so there is on way to reposition the "stops".

My options are:

Remove the spring from the idle speed adjustment to allow more "clockwise" adjustment. This may cause it to change by itself from the vibration when the engine is running.

Use a thinner washer under the spring - however I may only get an additional turn out of it.

Shorten the spring - grind it, cut it.

Put a little "fug" on it and "fug it"

I think I am going to buy a set of sync gages from JC Whitney. I know they are not top quality but they are 56 bucks and I only need them once.

If anybody wants them once I am done, lemme know or I can just sell them with the bike.

[Teh_K]

From what I've read from a few others on KR, yes - the idle-drop method of adjusting carbs will work... and probably has the benefit of being fine-tuned for each carb specifically. If I had the tool (or wasn't too frugal to buy it), I would try it. Otherwise, I think the stock setting for a 600 is 2-and-5/8th turns out.

[The CyberPoet]

Stock USA setting for a 04 Kat 600 are:

Warm idle: 1200 +/- 100 RPM (1300 +/- 100 if it's a Calfornia model with the pollution control)

Needles are identical to Canada's, which should put it at 2-5/8ths turns out, as Teh_K said.

If it holds idle at 600 RPM and the idle adjustment wheel is turned all the way counter-clockwise, then you've got something else going wrong (pilot jet passages still clogged or rubber o-rings under the pilot mix screws bad).

Suggest you might want to try to track down another set of carbs on eBay (98 - 06 Kat 600 are identical).

Good Luck!
=-= The CyberPoet

[barryware]

Goos to hear from you again Cyber.

Since the bike was new, the idle speed adjustment was all the way in. Now that I have the carbs out, I see how it works.

Basically, if you turn the idle adjuster out just a couple of turns, the throttle plates are touching the carb body. I would think that there should be plenty of adjustment.

I don't have anything back together yet. I was going to try to clean the carbs without separating them but after looking everything over, I don't believe I will consider that an option. As long as I am doing it, I might as well do it right.

I didn't want to have to buy a sync gage(s) but too late.

I took a little off of the idle speed adjuster spring. Now I can get about 3 - 4 more turns on it and that should do it.

A quick question...

How does the "Jet Needle Stopper" come out of the diaphragm? Just pull it or give it a twist? The pictorial in the manual doesn't show it or explain how to remove it. It just says to remove it.

I don't want to remove it incorrectly and break it.

[The CyberPoet]

Reference Image (04 Kat 600 Carb blow-away diagram)

If you're talking about items #7 thru 13 in the above pic, and how to pull them out #14, just pull (I use a pair of bottlenose or needlenose pliers to grab item 7). Twisting won't hurt, but it won't make a difference to getting in/out (at least that I've ever noticed).

Cheers,
=-= The CyberPoet

[barryware]

Those settings don't sound right. I would think start at two turns out and see how that goes.

With a jet kit, you usually start at 2.5 turns out.

I think my pre was 2.25 turns out when we drilled the caps out.

Just an update.... I cleaned and put the carbs back on. I opened the mixture screws 3 turns....

It won't idle @ 3 turns. I opened all the pilot screws to 4 turns. Now it idles but not so good. I thought I had a way of adjusting the mixture screws (home brew tool) but it didn't work out so well so I ordered a tool from Pro-Motion. Once the engine gets hot, it is not so easy to get something in to the mixture screws.

It is close... One big difference, when the choke is on (I know it is not really a choke - it's an enricher) it idles at about 5K. So.... even though I disassembled the carbs and cleaned them, there may still be a piece of s#it somewhere in one of the low speed circuits. This tells me that it is starving for fuel at low speeds.

For now.... The carbs are synced. One effects the other so we will see where this goes. (If you open a mixture screw, the vacuum drops)

I did not want to use the B-12 stuff I bought. Smells strong and I am concerned about the plastic floats. So I got some Sea Foam.

My plan is to fill the carbs with S/F and let it sit till my adjustment tool arrives. The engine will run on S/F so maybe I will start it everyday and replenish the S/F in the fuel line to make sure the stuff works its way into all the little passages.

What is the best RPM to sync the carbs? At 1500 RPM the carbs show completely synced, but at 3K, they are a little off.

Gracia's..