TOPIC:

i just bought a 1992 suzuki 250r quadracer, and someone put a '75 KZ400 engine in it. i FINALLY got it to start, but it would only run with the choke on. so i did some looking around this website and found my problem may be becuase i didn't have any air filters on it. so i put the air filters back on it that came with it (uni filters), and got it to start. i fluttered the throttle for a while and got it to stay running with the choke off. BUT, it runs decent idling, but when i put it in gear and take off, it spits and sputters. if i hold the throttle wide open, and dump the clutch i can get it to go, and pick up speed. but it only goes like 15mph. i know it should be alot faster than that. also it seems that the left side cylinder head isn't as hot as the right side, i checked with my hand, ouch. i found the idle screw, but i can't find any adjusting screws. also thesethings probably need to be cleaned or rebuilt or something i assume. not a job for me. i work on classic cars, i don't know anything about motorcycles. anyone that can offer me some help or advice please do so. maybe something i can try to see if it will run a little better. then i need to find someone to fix these carbs. i am located in upstate NY. thanks!!!

What is it like with the RPMs, what does it do at certain rpms?

i do not have a tach on it so i don't know the rpms, but i can tell its not revving like its supposed to. with the choke on i can rev it like crazy in neutral. with the choke off, it will idle pretty good, but when i open the throttle it spits and sputters. if i can get it to rev high it acts alright. BUT, then when i put it in gear, it acts like the choke is on all the time, even if it is not. it just won't rev highi don't think its revving over 3000, maybe 4000 at most. if i pull the clutch in, it will rev up. it seems to be a problem when its under load. i just got it yesterday and it would only run with the choke on, but i had the air cleaners off too. so today i put them on, and it will run with the choke off, but it acted up. i rode it what little bit i could, stahled it and started it a few times, and it acts a little better. like it will idle with the choke off. is my problem the cabrs aren't sync'd? or maybe they are dirty? or is it an ignition problem. the battery is crappy too. maybe the battery doesn't have enough juice and its affecting the ignition and spark to the plugs? also it has champion plugs in it, and i have never had luck with them.... what plugs do you other riders use? thanks, jeremy

Sounds like your carbs are full of junk. Take them off the quad of death, remove the bowls and clean them. Check the main and idle jets to make sure they are clear or, better yet, buy new jets. Screw the air/fuel screwa in until they LIGHTLY seat. Don't treat them like a lag bolt. Then back them out 1.5-2 turns. Stick some fresh NGK B7ES plugs in the engine, add some fresh unleaded and light the fuse.
Or, sell the 440 engine and buy a 250 2 stroke out of a late model RM and go just as fast with half the headache.

First thing I'd suggest is get rid of those Champions and get NGK..B8ES I think and check that you are getting a spark. If it's only running on one cylinder then It's not going anywhere fast. Your problem could be a number of things or a combination. Place to start is with the ignition and make sure you have good spark. After that look to timing, valves and leave the carbs to last.

Good Luck

thanks for the reply's so far. i'm going to change the plugs and see if i can get some new wires too. these ones don't look the greatest to start with. after that how do i check the timing and valve clearances? i know nothing about bikes. i don't wanna just dive in and mess it all up without knowing what i am doing. thanks

junkyarddog82 wrote:

i don't wanna just dive in and mess it all up without knowing what i am doing. thanks

Jeez, that's what all the rest of us do. You saying there's a better way?

Nevco's right. Besides, what's the worst that could happen? You could remove a part and have your balls fall off? No. Before my bike ran like crap, now it runs more like poo-poo. People here have talked me through a lot more than I thought I could handle prior.

Keep good notes of what you do, scour archives here on the site, get a manual and get your hands dirty.

Some say "stupid is as stupid does." I think I speak for others here when I retort "stupid is what stupid's not done." It may make more sense to take it in to a shop, but there is much less to be learned that way. Try something stupid, bite off more than you think you can chew. I know I'll help with what I can.

junkyarddog82 wrote:

i just bought a 1992 suzuki 250r quadracer, and someone put a '75 KZ400 engine in it.... i don't know anything about motorcycles....

Did you poke around this site and figure out how to access and search the "not model specific" thread of the KZ information filebase? On my 'pooter, once the info page loads, I have to scroll way down near the bottom to get to the "not model specific" thread.
That is where a lot of good info lies waiting for you to study.

while checking some stuff i noticed the plug wires were kind messed up. i managed to break one off (not on purpose). i now need a coil and wires. do the wires come out of the coils, or do you need to just buy the whole setup? tommorrow i will be getting plugs. whats the easiest way to check for spark, right at the end of the spark plug wire where it goes onto the spark plug? also after i change the above parts, if that doesn't help, what should i check next? when the bike was running, the cylinder that wasn't firing started to get warm, and i thought it might have been firing, but the exhaust was still cold, and when i pulled the plug wire it didn't change the sound of the bike. so i am assuming this is an ignition proble, not a fuel problem. more help please!!! thanks

If there is a collar around the wire where it enters the coil - like in the pic below - then you can unscrew the collar and pull out the wire. If no collar then you might be able to find a splice thingy in an auto parts shop which will allow you to join up a new wire.

You should probably replace the plug caps while you are at it.

To check for spark make sure everything is hooked up right - wire in the coil, plug cap on the wire, new plug in the plug cap - and with the metal part / screw thread part of the plug just resting against the engine fins hit the starter button. You should see spark across the tip of the spark plug. Dont do it in bright sunlight. Makes it hard to see spark.

To check if a cylinder is firing sprinkle or spray water on the exhaust pipe and it should sizzle right off.... saves on burnt finger tips and is more accurate test method.

Have fun

junkyarddog82 wrote:

while checking some stuff i noticed the plug wires were kind messed up. i managed to break one off (not on purpose). i now need a coil and wires. do the wires come out of the coils, or do you need to just buy the whole setup? tommorrow i will be getting plugs. whats the easiest way to check for spark, right at the end of the spark plug wire where it goes onto the spark plug? also after i change the above parts, if that doesn't help, what should i check next? when the bike was running, the cylinder that wasn't firing started to get warm, and i thought it might have been firing, but the exhaust was still cold, and when i pulled the plug wire it didn't change the sound of the bike. so i am assuming this is an ignition proble, not a fuel problem. more help please!!! thanks

Dude, if you are not jerking us around, then you don't need to be fooling around with this stuff. If you are in sort of a suburban area, then you can find a good mechanic in your neighborhood to work on your scoot for you. In fact, this site is so widely viewed, that you may get a PM from someone who is willing to come over to your house to help out.
Hell, I will be glad to do that. I am afraid I won't do it for you, but I will show and tell everything I know to help you do it. The stuff you are discussing has nothing to do with your bike. This is stuff you need to understand to make __ANY__ engine run.
Are you any where near north Georgia? do you own a trailer? Have bike,,,will travel! !!_YES_!!