A video of my 83 kat carb problems

[linexrandy]

I've finaly got my newest project, a 1983 katana 1100 basketcase, up and running. It came with a set of Keihen CR Specials and I cannot get them dialed in. I have it running on all 4 cylinders as the pipes are all equally hot a minute or two after startup, but when you start to rev it the first and third pipes (cylinders) are alot hotter than the other two (using the spit sizzling test). It has a rough idle and takes forever to come back down to idle after reving it. The throttle cable is not binding and the carbs are closed so its like its getting too much fuel. Main jet is a 125 and secondary (I think) is a 55. Clip on needle is in 5th postition from bottom (taper). All of the slides are aligned (synched??). I attached a video for reference Thanks, Randy.

[ame]http://s249.photobucket.com/albums/gg238/linexrandy/?action=view&current=1100.flv[/ame]

[linexrandy]

Nobody?? Well I took it out on the road today and it ran like crap until I could get it up above 3 or 4k rpm, then it ran great. Anyone have any general carb knowledge before I post this in mechanics 101?

[scottynoface]

Sounds like a vacuum leak is causing the idle to hang. As per the not running well, how clean are the carbs?

[64dumptruck]

How do the spark plugs look?

[Astro4x4]

Have ya dialed in the air fuel mixture?

[pontiacstogo]

Hanging idle on Keihin CR's is classic misadjustment of the air screws. Start be seating them all (lightly) then backing them all out 1 full turn. From there, adjust them all the same amount and only in 1/4 turn increments until you can blip the throttle and the engine drops to a steady idle. On CR's you turn the screws out to richen the idle circuit. Air screw pictured here;



You might have to **** around with these abit until you get a good idle but they will be the cause of your hanging idle assuming the throttle is not binding and there are no vacuum leaks. Here's my CR33's on a GS1000SZ Katana as a comparison;

[ame=http://s29.photobucket.com/albums/c272/pontiacstogo/Silver%20GS1000SZ/?action=view&current=Startup002.flv] CR33's[/ame]

[linexrandy]

Thanks for all the replys guys. I have the air screws all turned out 1 full turn and havnt adjusted them other than that. I'm fixing to go back to work but will mess with them tonight. A guy up at work says it sounds as if they are not synched as cylinder 1 and 3 run hotter than 2 and 4. I have no clue how to sync these carbs!! The slides all look the same height.

Also where would I look for a vacuum leak? The boots are all good and tight also. The carbs are spotless as I had to clean them twice. The plugs look like crap, wet and black, but I cant pick a new set up until tomorrow (15 miles from town).

[steves]

Do a visual synch on the rack of carbs, then hook up the gauges to see where you are at.

[pontiacstogo]

You can't vacuum synch CR's.....

Synch them on the bench. Remove the top covers and set the idle speed screw high enough for a small diameter copper wire (O.D. of .025" to .050") to slide under the engine side of one of the carbs, then set the other carbs to match that one. It can take some time but the goal is to make sure all the of slides are set so the copper wire just "drags" under all of the slides.

I'm still willing to bet you'll find your high/hanging idle is caused by the adjustment of the air screws .

[linexrandy]

Well I went out and tinkered with it this afternoon. I've tried the air screw settings anywhere from 1/4 turn all the way to 2 1/2 turns with no decent idle and still the hanging idle. Thing is, I found out it will run really well with the choke out (obviously won't idle, but revs great on all 4 cylinders and sounds awesome). The slides look like they are already in sync but I need to pull them off and check them. This bike came from N. Carolina and I'm in Texas. I'm wondering if its a jetting issue or the clip position on the needle would change anything? It gets enough fuel with the choke on, but too little air to idle, and with the choke off, it sounds like its only running on 2 cylinders and still won't idle. I'm about ready to take it to a shop, but not ready for the fee's they charge.

[pontiacstogo]

Well I went out and tinkered with it this afternoon. I've tried the air screw settings anywhere from 1/4 turn all the way to 2 1/2 turns with no decent idle and still the hanging idle. Thing is, I found out it will run really well with the choke out (obviously won't idle, but revs great on all 4 cylinders and sounds awesome). The slides look like they are already in sync but I need to pull them off and check them. This bike came from N. Carolina and I'm in Texas. I'm wondering if its a jetting issue or the clip position on the needle would change anything? It gets enough fuel with the choke on, but too little air to idle, and with the choke off, it sounds like its only running on 2 cylinders and still won't idle. I'm about ready to take it to a shop, but not ready for the fee's they charge.

CR's don't have a traditional choke per se - the lever on the side is an enrichment lever. On all of my CR equipped bikes, you can stall them with the enrichment lever - it only needs to be used in all but the coldest weather and even then, only for a couple of seconds.

Have the carbs been tinkered or messed with? If you PM me your email I will email you a PDF document that shows what areas of throttle operation is affected by what jets/setting. Idle is air screws and slow jet.

It might be time to make a note of all of your jet sizes and needle and place a call to Sudco...

[suzukiray]

Randy, you need to make sure the FLOAT LEVELS are all correct first. Next, 55 pilots are TOO big. Try 45s or keep going smaller till the mixture screws are happy at 1/2 to 1 turn out. Run it one more time with the screws turned all the way in & then 1/8 turn open. The needles should be on the middle clip position or 1 step richer & the mains need to be around 130. Let me know how it goes with trying the mixyure screws almost CLOSED. Ray.

[linexrandy]

Ok thanks guys. Ray, did you get the pics I emailed you? They were kind of crappy and probly not very helpful. Is sudco where I should order jets through? Sorry for the newb questions but this is my first street bike attempt and its got me flustered!