Finally got it started, having trouble with high idle

[Asmodeous]

So I finished rebuilding the carbs and got the bike to fire. The jets were clogged. A little tip I picked up from an old school guy at a bike junkyard which worked great for cleaning jets and small areas is to use a steel guitar string (the smallest E you can get) to clean out the jets. This worked GREAT for me.

My problem is that the bike starts and runs with no choke at about 1000 rpm and then after a few seconds of running it will jump to 4000 and some times fluctuate between 3000 and 4000 or just stay there around 4000 rpm. Can my AF screws change idle RPM ?

I'm also having issues with the choke sticking but I know thats due to residual varnish/gum that is being dislodged by the gas I'm running through the system. If I remove the carbs and clean it out after they stuck there is always varnish in there. Is there any lubricant that I should put in the choke piston area ?

I'm have no vacuum leaks and I've plugged any hoses I'm not using. I'm running off a fuel bottle I made, not the tank. I've got the air box disconnected for quick removal of the carbs for cleaning or AF adjusting.

After I got the bike running initially, I killed it and bolted the air box together and connected the other hoses. Bike wouldn't start. Figured it was fuel. Pulled the carbs again and took them apart from the top and bottom. There was varnish/gum all over the parts which were freshly cleaned even after these carbs sat in a parts cleaner bath for days. Cleaned them by hand again and unclogged the jets which had gotten reclogged. I've done this twice, the second time nothing was clogged but there was varnish on 3 of the 4 needles. The second time the inside of the carbs was fairly clean.

Then I put the carbs back on the bike and it fired right up. After it idled ok. I had thought I had the set the AF wrong for carbs 2 and 3 so I pulled the carbs off and changed them. I have a jet kit (installed before I got the bike) and the AF screws were set out to about 2.5 turns when I got it. Thinking back on it I can't remember if I set all the carbs to 2 turns on the AF screens when I adjusted carbs 2 and 3 or if I pulled them off again and did it later.

I am thinking I should set the AF screws back to 2.5. I'm going to do that this coming weekend and see what happens.

[Kreylyn]

Start at 2.5... factory setting is now considered a bit lean due to the fuel mixtures being sold today.

If you blip the throttle and it hangs for a bit then slowly drops down to a very low idle or won't stay running at all... generally means your looking at a lean condition for the pilot circuit. A/F settings, float settings, vacuum leaks, or dirty pilot circuits would be the things to look at. The staying at high rpms is the engines attempt to use fuel from the main jet circuit since the pilot jets aren't providing enough fuel for idle.

BTW... it's generally not considered a good idea to use steel on the brass jets... you can dmg them very very easily. Plastic or organic "straws" are generally safer to use if you have to poke something in them, as they are softer than the brass and will not deform the holes.

Be patient, and remember... if they are badly dirty... it generally does take many cleanings to finally get them right.

Krey

[Asmodeous]

Should I set the #3 carb to a 1/4 turn less then the others like the factory shop manual suggests or just set them all to 2.5 turns ?

Also, I'm getting a lot of white smoke out of the tail pipes which would indicate a rich mixture right ?

[Kreylyn]

Should I set the #3 carb to a 1/4 turn less then the others like the factory shop manual suggests or just set them all to 2.5 turns ?

Also, I'm getting a lot of white smoke out of the tail pipes which would indicate a rich mixture right ?

The 2.5 setting is a starting point, not the final setting. Idealy, you should set them there, start the bike... and adjust to fine tune.

As for the "smoke"... that depends...

Is it smoke or steam, and are you sure?

Steam generally would just be condensation burning off and eventually will stop.
White smoke = Oil burning normally.
Black smoke = Rich fuel settings.

Krey

[Asmodeous]

My dad called me and let me know that he pulled the carbs and set the carbs to 2.5 turns and the bike now runs much better. When its cold it holds idle around 1200 but when it warms up, it climbs and now runs around 3000 rpm at normal temperature. Also, the white smoke has stopped.

Should the #3 carb's AF be set to a 1/4 turn less then the others like in the shop manual or one the carb has been rejetted should they all be the same ?

[nealy212]

man i might be wrong but it sounds like you have a leak somwhere? atleast that was the trouble that i had. it would be fine cold bout as the motor got warmer it would idle up like that..even if you adjusted the idler it would go down but then give it a min it would go right back up,, ended up just haveing some bad o-rings in the intake boots

[Asmodeous]

Are you talking about the o-rings that go between the intake manifold and the carb boots ? I haven't taken those off at all and they could be bad. I read on another site at those can go bad and cause major problems. I'll have my dad spray the boots with carb cleaner while the bike is running to see if thats a problem, RPM should shoot up if there is a leek there. I can only work on the bike on weekends. The bike is in Simi Valley and I'm in Santa Barbara during the week.

[Kreylyn]

As a generalization, the warmer an engine, the better it will run with lean settings. The colder the engine, the better it will run with richer settings. keeping this in mind the following can apply.

Cold engine runs poorly but rpms go up or runs better as it gets warmer = lean conditions.
Cold engine runs fine but gets worse as it warms up = Rich conditions.

The question here is what is causing the condition that applys to your situation. A/F settings, float heights, clean/dirty jets, vacuum leaks, aftermarket air filters, poor condition/no airbox, etc... all of these could cause lean conditions.

As for the 1/4 turn, I didn't give you a yes/no answer because there isn't one. Start all at 2.5 turns, start the motor... and then fine tune the A/F screws to where the engine needs them by adjusting them as it's running. If you have a flow sensor it makes it easy... if not, you can get it close by doing the following...

With motor running, pic one carb body and very slowly reduce the setting (turning in towards seating the needle) until that cylinder starts to stumble. As soon as you hit that point, turn it back out 1/4 turn and leave it. Do the remaining 3 carbs. This should put you very close to the proper A/F mixture for each carb. No, they will not all end up exactly the same.

Krey

[Asmodeous]

The bike came with a K&N filter and the carbs had a jet kit installed. Exhaust is stock.

I've been running the bike with the air box off. It didn't seem to make a difference in how the bike ran when I put the air box on so I've been leaving it off for easy access to the carbs. I figured once I got it reasonably close I would put the air box on and do more adjustments from there.

[nealy212]

yeah i agree with krey there deff could be a few things. i would start with the cleaning of the carbs, set your floats. i think it would be a good idea since you already have it all down go ahead and replace the orings in the boots. there about 10 bucks at the dealer. check the boots for cracks, better to do it now than keep tearing everything back down. i had to put my a/f screws to 3 turns,, well to get it really close put the stock filter back on each time,, it could really mess with it not haveing it on.

[jamesm113]

take out the K&n air filter & put in the stock filter. The K&N filter will lean out the mixture causing your high ide

EDIT: i just noticed your from sb, too. I've been having the same problem with my 2000 kat

[Kreylyn]

Jetted bikes may need higher A/F settings... 2.5 to start is for stock setup. 3-4.5 turns may be needed depending on the jetkit installed and how it was installed. Some dynojet kits for the Kats called for the pilot air jet to be dirlled (not saying yours did/was... I don't know, you will want to check). If it was drilled, your looking at closer to 4 turns on the A/F for it to idle right. Determin what jetkit went in, and double check their instal instructions if if calls for drilling.

No airbox is about the same as with the K&N filters. Make sure you have the airbox properly installed, bottom drain plug crimped off or plugged as it should be, and the boots fit properly on. Also make sure the crank case hose is connected. It SHOULD make a difference in running with/without the airbox or there is a major issue still in the settings.

Krey

[nealy212]

krey,, my bike is stock and there still at 3 turns? maybe theres an issue?

[Kreylyn]

krey,, my bike is stock and there still at 3 turns? maybe theres an issue?

Stock air filter, no jetting on the carbs, and no air/vacuum leaks? It could be that the floats are a little lean. This would cause the need for higher A/F setting.

Krey

[Asmodeous]

Ok, I've replaced the intake manifold gaskets and the bike runs a LOT better. I was actually able to take it out for a ride.

When it was cold I had it idling sweet at 1200 and then I took it out for a ride. By the time I got back my idle was around 3000 again. The throttle is a lot more consistent now and the bike seems much happier but I still end up with a high idle.

I've also started to try and use the choke and I'm having issues when I do use it. If I use the choke I don't get full return when I try and turn the choke off. I've taken the pistons out and cleaned them up as well as the cylinders then lubed everything with WD40 as I've see suggested here on the forums. They seemed to work well but when I put the choke rail back on I have to manually push the pistons back in the last 15% to get the choke all the way off.

I'm going to get the bike started and spray some more carb cleaner around the boots and air box to make sure I don't have any vaccume leaks. If I do I'll work on getting those fixed.

Also, I want to make sure I understand carb tuning properly. If I lower the c-clip which raises the needle that will make the mixture richer right ? If I turn the A/F screw in clockwise that makes it richer and when I turn it out counter-clockwise it makes the mixture leaner right ?