Help me cyber poet

[macgyver]

hello i have a idle problem on my bike and knowing how knowledgable cyberpoet is about engine troubles i was hoping him or anyone else with engine insight could give me some ideas about whats going on here. sorry this is a little long but i want to give you as much info as i can about what may be going on. i have an 1988 katana 600 not sure if the carbs were ever synced or valves were adjusted and ever since i got it on occasions when sitting at a light just idling i notice the idle goes from in between 1-2 grand down to the one and sometimes below. it stays below for a few seconds a slight pop from the engine is heard (misfire?) and the idle shoots back up to between 1-2 grand. i also sometimes notice it sounds like the bike is backfiring slightly at some points. now i have been trying to figure out what makes this happen because it is an itermittent problem and it doest happen all the time. the only conclusions i have are that when i am out riding (not stopping at light to light) that when i do stop it appears to idle fine. when i am stuck in traffic it seems to do it more often. normally before starting the bike i pull the choke and let it run for a minute or two with the choke on and than take off the choke and let the bike run for awhile to warm up. it seems like also when i do this the problem does not occur. these are not deffinite causes though because sometimes i let the bike warm up normally and i am out riding and it is idling fine and then it just starts up again randomly. by the way it has a 4-1 vance and hines pipe on it...do you think this may be a call for a jet kit? the pipe is black inside within buildup... do you think this may be a fuel running to rich conditon?? also when it is idling erractily below 1,000 rpms when i pull the choke out slightly it increases the rpms back up but when letting it run for a while with the choke like that it will slow the engine back down. i dont know the history of engine, work ect of the bike but it atleast appears as if the top end was off at one time or another as there is a newer gasket visible sticking out. it did this occasionally when i first got the bike and now a month and a half later appears to be doing it more often. could this just be a simple spark plug problem? thank you for the help

[macgyver]

i will probably end up sitting down when i get home with a 1/2 gallon of captain morgans and pulling the plugs out all the while cussing and throwing stuff. thats normally how i work best. just gotta remember not to get too drunk to remember either A. what the hell am i doing inthe first place or B. where did this little screw come from.

[Yellow2002Kat]

I really have no mechanical advice for you (sorry), but I do have a little tip. Whenever I try to work on something I'm unfamiliar with I always take pictures of it together and while I'm taking it apart with my digital camera. This way I don't wind up with the old "where the heck did this screw come from" problem. It's helped me a couple of times and only takes a second to do. Good luck!

[Junior]

Whenever I try to work on something I'm unfamiliar with I always take pictures of it together and while I'm taking it apart with my digital camera.

I'd rather see pics of him cussing and throwing stuff!


I'm no mechanic either. My motto: If it's broke buy a new one.

[Anonymous]

I'm no mechanic either. My motto: If it's broke buy a slow one.

[Junior]

I'm no mechanic either. My motto: If it's broke buy a slow one.

You have WAAAAAAY too much control around here.

[macgyver]

Well thanks for the advice. i never had the fairings off before but i'm sure i can figure it out. i have some mechanical experience. as for taking pics with the digital camera to rememember what went where thats not a bad idea. well you will know how things went by tommorow if you see pics of me drunk throwing shiat. i'll probably just sit by the bike and drink a couple shots and stare at it and see if that fixes it first

[steves]

Pulling the plugs is a first good step.

If you aren't sure when the last time the valves were adjusted and the carbs synched, that seems like another good plan.

While you're at it, you should probably examine the carbs to see how junked up they are. Could be a clogged jet or something causing the idle to drop.

[slayergsxf1]

Yeah get a tune up..by the looks of the bike its in really nice shape....How many miles on it?Change the plugs and maybe if it doesnt have one already a K&N Air filter.Mine used to idle a little funky but after the K&N its been pretty much on the money. Do the simple first,plugs,OIL,airfilter,pop the bowl covers off the carbs and see if theres and pancake syrup in there.Only one shot of the Captain before touching the carbs OK! Good luck dude...Also make sure each cylinder is firing....

[WildKat]

Do you ever notice the idle spiking up after you've been riding for awhile at all? Not normally when its cool, but after the engine is nice and hot. That's a good sign that your carbs are due be cleaned out and possible dirty air filter.

[letsride]

i dont think its the plugs but make sure there the correct one. also check the plug wires. make sure there not cracked or leaking spark. also remove the rite side cover and check the ignition gear for cracks splits and worn out while it is off clean it. do not sand or grind any part in there like they use to do on lawn mowers. now im not saying this is your problem. the poping is a build up of unburnt fuel from lack of spark then spark so you get the pop. so go trew the elec more so the spark and ignition. then fuel.

[BraadaJim]

Clogged idle jet?

[macgyver]

thanks for all the replys i pulled the bike apart yesterday and discovered the bike has a k&n filter on it. it doesnt look terribly dirty but while i have it out i might as well get a filter kit and clean the filter out. went to take the plugs out and realised that i don't have the right spark plug socket. does anyone know what size spark plug socket and spark plugs are to be used. i will probably get a socket from advanced auto tonight and get the plugs out. i am not very good when it comes to carbs and i could easily see myself pulling them off and messing something up so if the plugs and filter doesnt fix it i will have to take it to a mechanic and have him sync/clean the carbs. supposedly the owner before me cleaned the carbs at one time but not sure how long ago so they may be due for a good cleaning. the bike has 12,000 miles on it and i was very suprised how clean everything was under the fairings the spark plug wires appear to be in good condition and i dont believe that would be the problem. as for wildkats question well on saturday the bike ran fine all till i left and headed back to dallastown and then it started acting funny again. yesterday on route 30 on the way home it actually stalled itself at a light because the idles got so low. i always thought the longer i rode and the less stop and go i did that it would run fine but that is not the case now and it seems to be doing it more often then before. thanks again for all the help i appreciate it and i will keep you posted with whats going on.

[The CyberPoet]

Re: Help me cyber poet

1988 katana 600
not sure if the carbs were ever synced or valves were adjusted and ever since i got it on occasions when sitting at a light just idling i notice the idle goes from in between 1-2 grand down to the one and sometimes below. it stays below for a few seconds a slight pop from the engine is heard (misfire?) and the idle shoots back up to between 1-2 grand. i also sometimes notice it sounds like the bike is backfiring slightly at some points.
4-1 vance and hines pipe on it
when i pull the choke out slightly it increases the rpms back up but when letting it run for a while with the choke like that it will slow the engine back down.

Clogged idle jet?

My call would be an intermittent clogged idle jet... probably debris in the float bowls... which makes me think tank rust at the lower end of the tank. Might also be fuel starvation from a bad vacuum line or borderline failing petcock issue (easy to test: when the bike drops idle like that, switch the petcock to prime; if the problem resolves within 30 seconds and doesn't reappear while in prime, it's the petcock).

What I think should be done for the other issue:
(A) Strip the fairings
(B) Put a spare bit of fuel line on the petcock and get a glass container (spaghetti jar). Set the petcock to prime and fill the container (you can cap it off if you need to in order to prevent fumes), then set it down on a shelf for 10 - 15 minutes. Now look at the bottom of the container -- any debris collected there? If so, it's time to deal with gas tank rust.
(C) Remove the tank, the airbox.
(D) Remove the carbs. Do not rotate them yet. Get another glass container as wide as the carbs (pyrex cassarole dish comes to mind) and rotate the carbs forward so the fuel runs out into the cassarole dish. Let sit for the same 10 - 15 minutes, then look for debris in it as well.
(E) While you are waiting for the carb fuel to settle, flip the carbs over and locate the four screws at the bottom of each carb fuel bowl (this is still the simple part -- don't get intimidated). Get each screw started by grabbing the outside of the screw with a pair of very small vice-grips (or bottle-nose/needle-nose vice-grips). Once you have them turned 1/4 of a turn, you can back them out the rest of the way using whatever normal tool they would match to -- phillipshead screwdriver or allen key, depending on whether the stock screws have been replaced. Remove the lids to the float bowls and look inside. If you have a digital camera, snap pics at this point. An orange or red paste will mean tank rust. Large rust-colored chunks will also mean tank rust. Black specs will be dirt; white is sand.
(F) Grab some paper towels and physically wipe the bowl and see if you get any build-up on the paper towel. Go back and examine what came out of the carbs when you flipped them over. Then spray out the float bowls with carb cleaner. Spray each jet passage as well.

If you haven't found any visible debris at this point, and given how you feel about carb work, reassemble everything on the carbs, put it back on the bike, and reassemble the bike, then take it to a shop with a dyno. Or simply bite the bullet and decide you are willing to do the work yourself (in which case there's a half dozen to a dozen people here to help walk you through it, as well as some reasonably decent pics on various webpages, such as Doug771's carb pages to help guide you).

Cheers,
=-= The CyberPoet

[paradoxmd]

went to take the plugs out and realised that i don't have the right spark plug socket. does anyone know what size spark plug socket and spark plugs are to be used.

i think it's an 18mm socket you need.