Bad clutch or dogs?

My bike keeps lurching hard and going out of gear for a second. It has only done it in second gear it may have done it in third one time but it has been a while i cant remember for sure. It bucks and it will rev up hard like its in neutral, and then it goes right back into gear on its own. This normally happens when i give it 1/4 throttle or more. If i give it just a little throttle about 1/4 throttle and just let the rpms come up right around 4500 rpm it will buck or go out of gear happens almost every time. I also think it just doesnt sound right around 4-5000 rpm range especially when its light throttle and in 1st 2nd and 3rd gear. And a couple times i got in it a bit maybe half throttle and i am pretty sure i saw the rpms slowing on the tac like they were coming up then slowed down the rate of increase for a sec, dont know if thats anything but it was around 4500 to 5000rpm. I have fresh kawasaki 10w40 with about a quarter bottle of zddp plus. My motorcycle class instructor actually pulled my clutch lever in one time and he was like yeah your clutch is fried. I dont know how you could tell just by squeezing it, i have had a couple people say it sounds like the clutch but i would hate to replace it if i need to be saving my money for something else.

you may have three seperate faults here.

The elecronic tachos can bounce a bit, this is usually the tacho pulse wire taken from one of the coil -ve. These coil feed wires get hot under the tank and the terminals can deteriorate over the years.

I would not use any additives in your oil. Clutch slip and modern oils is a known problem here.

Finally, slipping out of 2nd could a gearbox fault - maybe check your gear lever adjustment and for wear in the linkages, sometimes moving it touch on the spline helps. Hopefully someone else will chip in here, but I think 2nd gear is the one that goes first and I may have this on one of mine.

The clutch is the first and easiest to check. Check the adjustment at the cover and grease it. If that doesn't work and the cable is good, time to inspect the clutch plates. If they smell burned or are worn out, replace them. If still popping out of gear, open the clutch cover, remove the sprocket and take off the shifter cover. Might be a broken spring or springs.


If not, time to split the cases. 2 ND gear is the first to go. I back cut mine but it didn't last. There are two gears in play here. One on the counter shaft and the other on the primary shaft where the clutch basket is. If bought used, it's best to back cut them. They are worn and if not done, they will only last the expected life, no more and you're back to where you started from. Yeah you can just change the two gears, but the bearings and other gears will be just as old.
JMO
Steve

thanks a lot guys that was very helpful. I have never even inspected a clutch but i will figure it out. I thought zddp plus was safe to use and neccesary for flat tappet cams because mordern oil contains no zinc.

You just explained the most common transmission fault exactly. Your second gear engagement dogs are worn. Easy to spot when you take the trans out or you can drop the pan and look up into the gears. So so common. Most Kz's are in some form of wearing the second gear dogs the minute after they are new. Not a lot of good unworn ones out there unless they have been redone. Ive disassembled maybe 50-75 different 900/1000 motors and I would say 60% had worn second gears I wouldn't use.

That's the power gear. I got mine from a low mileage KZ 900. I back cut it myself. The other dogs were fine in both transmissions.

Is it possible to reface the dogs, rather than a race backcut?

This is maybe a problem on my750R1, I'm thinking of going for a 6 speed 550 transmission convesion, or replacing it with a spare zx750 motor complete or just transmission parts.

This 2nd gear thing doesn't seem a big problem on the 550's, but is well known on the bigger kz .

I guess power= tourque x rotation. Putting a 550 mill alongside an 1100 ... the double power is just about a couple of inches difference.

edit doh! wanted to post a pic of a 550 and 1100 motor split cranckases alongside each other ...it amazed me the differenece in power compared to the size of each.

I guess they can be refaced but at what cost? When I back cut I don't let the metal turn blue, I use oil. I try not to go too deep. I believe they're case hardened. Like I said, I tried to save my old ones but they were too far gone. The bearings were just as old also. I pick up things like this for if I need them later.
Steve

what bike are we talking about kev?

leon

Tyrell I've had my ZX750A1 motor apart and the factory gear's
are cast with a slight back cut.
My tran's only has 10,000 mile's on it and show no wear on the dog's
their as cast.

It has been a while i have not been able to look at it unti today. i got in a motorcycle accident on another bike, but luckily it could have been much worse and i had a helmet.

Leon its a 77 kz1000 ltd that i have worked on more than i have rode.

So i found out tonight that the three plates farthest in were all broken into pieces. Not sure that this is causing my problem but i have a new set on the way. I am just afraid of the second gear being bad because if it was the clutch wouldnt it do it in every gear? And second is the first to go....well i can hope and pray that the new clutch plates fix it :laugh:

Down shifting without a clutch can do it too. I hope for your sake second gear isn't shot. Big job.
Steve