Motorcycle Repair: 1993 Suzuki Katana / Idle / Surge / Starting / Bogging Problems, suzuki katana 600, 1993 suzuki katana 600

Question
I have a 1993 Suzuki Katana 600 with about 13,000 miles. It has a K&N filter, Yoshimira (sp?) slip on pipe, and it has been jetted (though, i do not know details about the jetting as it was done well before i bought the bike).

the bike has always bogged through the midrange, from about 7,000 to 10,000 rpm. this is annoying, but something i can live with. i assume it is a problem with the jetting.

last year though, i took the bike to shop to have them try to work out the bogging issue. however, instead of fixing the bogg, all the shop did was adjust the idle screw (? or is it called a fuel adjustment screw?) and they created a horrible surge. now, the bike has this terrible surge, it revs from 2,000 rpm to about 6,000 rpm all by itself! if you set the choke too low, it will stall out on the bottom of the surge. set the choke too high and the bike will scream up to 10,000 rpm on the up surge. it is not really ride-able in this state. though i can certainly get it to a shop.

also, the bike needs A LOT of attention to get it started . . . prime, crank, choke, repeat, crank, crank, crank, etc. usually takes at least 5 - 10 minutes of continuous cranking to get it to start.

obviously, this hog has seen better days :) i only paid a few thousand dollars several years ago for this bike. all i ever wanted was a couple wheels and a seat to tool around on . . . and that is what i have had up to this point. i just want the darn thing to start, idle within proper range, and drive. i don't expect it to be perfect.

i can do minor repair stuff myself and have alread tried lowing the needles in the jet kit: no difference. i'd LOVE to just pay someone to fix the bike, but i'm a bit weary after my last experience. it seems like most shops just have no interest in tinkering with my ratty 93 kat.

well, i guess i've said enough. my personal thought was to go to a local shop and tell them to change the plugs and adjust the idle, and see if that fixes anything. obviously, i don't want to go spending $1,000 + to fix a bike that is probably worth around $1,500 or so.

by the way, the carbs were cleaned two years ago and the oil is changed at regular intervals.

thanks!

Answer
Hi G,

The carburetor synchronizing screws are out of sync causing the idling and starting problem. There may be some gasoline varnishing (gumming) also contributing to the non-starting behaviors.

Describe the appearance of the spark plugs.

Include your email addy as requested. I reply with repair info files.

Respectfully,
Mark Shively