KZ1000 Engine vibration

a clutch basket with collapsed springs could mimic his problum.

kzz1p wrote:

Do you know if the motor has ever been taken apart?

It doesnt appear so. The bike only has 5k miles on it. But I cant say for sure. Anything is possible.

a clutch basket with collapsed springs could mimic his problum.

i dont know exactly how a motorcycle clutch is put together yet so I dont really understand this.
I do have this problem that I cant seem to get rid of either. When I pull in the clutch and put her into gear I usualy get a pretty loud clunk as it goes into gear. Sounds like something is going to break. No amount of adjusting can make this go away. Could this be related.

Only 5000 miles.

If not already done:

Spray water mist over exhaust header pipes to assure engine is running on all four cylinders.
With engine running, spray should sizzle and instantly evaporate.

Would check torque on handlebar clamp bolts. Tighten front bolts first, then the rear bolts.

Assure correct drive chain slack. Lube and check for any kinks.
Assure correct rear wheel alignment and chain alignment between sprockets.

Check wheel balance, especially front wheel. And assure tire isn't out-of-round, damaged, or cupped. And assure correct psi in tires.

Consult FSM to assure all engine mounting bolts and all engine mounting bracket bolts are tight.

If adjustments to the pilot air screw at idle rpm fail to influence the rpm, something is probably wrong with the pilot circuit inside that particular carb.

Do spark plug readings after steady riding for a few miles in the vibration band of operation. This being after a throttle chop with simultaneous ignition kill and clutch disengagement, and coasting/braking to a stop. This will indicate what is happening inside the combustion chambers during the vibration experience.

If all else fails, consider a bar snake, lead weights, or similar internal handlebar dampening (unless fitted with internal handlebar wiring), or even foam handlebar grips.

The clunk when first shifting into low gear (especially after a cold start) is normal. The clutch plates are freeing themselves.

Good Luck!

It is running on 4 cylinders.
Havent checked handlebar torque but the vibration is more in the seat than the handlebars (i will check anyway)
Chain and wheel alignment are done.
I havent checked the balance of the front tire but everything else is ok with the tires. It isnt speed related. It is definitely rpm related.
The FSM is my second bible. All engine mounting torques are spot on.
I think I may go through the carbs again but i am not sure how much the pilot circuit affects the rpms that high up. It does seem to idle just fine an all but I havent tried everything until I have tried everything twice.
The plug chop after driving at that rpm is a good idea. I am not sure if I could stand it though.

Thank you for your input guys. I have a few things to check into.

Remember to carry in the tool kit a short length of rubber hose or tubing that fits snugly onto the sparkplugs to assist removing them while hot and without burning fingers while doing the plug reading on the hot engine after the plug chop.

It is probable and most likely that there is a rotating part in the engine out of balance. This could be anything from your crank to a gear cluster or the rotor on the alternator. If the vibration goes away past that RPM than it is a harmonic vibration and it could be impossible to find without tearing the engine apart. Most engines have one of these at a given RPM range, particular only to each engine. I would check your cam-chain tensioner, it might be bad and the vibration might be the rotation of the cam chain. Also you may try to go to a higher octane fuel, see what that does.

like i said before regear the bike so that you can ether drive thru the vibe or that you don't even hit it at all if its buzzing at 4-5000 gear it so that you are at 3750 at crusing speed if i remember correctly they come stock with a 41 or 42 rear and i think a 15 front try going up a tooth on the front it will move the vibe away from the crusing spot it is just buzzing not shaking the bike apart then you can try putting handle bar ends they will take a lot of extra vibration away as well make the bike work for you not the other way around. up on the front down on the rear will drop engine rpm at a given speed.

88, All things motorcycle vibrate some. Am quessing you feel this is extrordinay or you wouldn't be concerned, era 4's buzzed a little, the bigger the less. cam chain and clutch issues are prevelant in un-loaded & low rpm situations. something to check and hopefully put out of mind is a twisted crank. a hydro-locked cyl with the assist from elect. starter is enough to do the trick. a degree wheel and TDC guage may eliminate this from search. luck G

if it had a twisted crank it would vibrate all the time not just in certain rpm bands believe me if it was twisted you know the second you fired it up.

it definitely goes away at higher rpms. maybe not completely but it is way better. the only reason i am chasing demons here is that my 750 was so much smoother. i am a little disappointed with how not smooth this one is.

My KZ650 had a noticable vibration between 4,300 to 4,800 RPM. Finally realized it was a vibration in the exhaust system. The baffels were rusting away. You could feel the vibration through the handlebars, and hear the vibration in the mufflers. On the centerstand, it sounded like a thrashing machine at about 4,400 RPM.

Changed the exhaust system and realized that the engine was completely smooth at the previous RPMs. Now has a very slight harmonic at two other spots, but just barely enough to feel, and not enough to blurr the mirrors. Normal, I believe.

Might be worth a check.

I have the same type os vibration in my 1000, still ahvent figured out what is causing it, I have added the anti vibe bar ends, foam grips, and I have mirrors off a oem honda that I bought new, they have been the best for a clear vision at speeds yet.
I really noticed mine when I changed gear ratio, I am sure it was there before, just didnt ride at that rpm.
I wish I could figure it out, but for now, just compensate for it