Bike Starting Issue

Hey everyone!

Im a bit new to working on bikes so please try and understand.

I recently bought a 1981 KZ750 and it had a slight starting issue. The starter would turn the engine SOMETIMES and others it would sound like the starter is spinning but not turning the engine. Usually if I just play with it for a sec it would catch and start the bike right up. Once running and hot I could shut the bike off and start it again with out ever having a problem, its just that initial cold start.

I took the starter off and checked it and it seems to be spinning just fine. I put a little pressure on the gear to make sure that it would spin even if something is holding it and it still spun.

Someone told me that it may be the starter clutch but I really just wanted to double check that...

The gear the starter connects to in the engine if I spin it to the left (towards the front of the bike) it spins freely. If spun the other direction (towards the back of the bike) it can not be turned by hand.

Can anyone help me figure out what this issue is so I can get it fixed and hopefully get a couple more rides before it gets too cold.

It sounds like the starter clutch is slipping sometimes. When it does engine does not turn, and sounds like marbles inside.

The gear movement is the way is supposed to be, as the starting clutch only cranks on one direction, and free wheels on the the other one.

Most people only change the rollers and the springs on the starting clutch, but the race on the hub also wears, and mostly is not visible.

Mine was slipping once, and I replaced the whole thing. It takes a lot of disassemble to get to it. Exhaust, Clutch, oil pan, and Secondary Shaft behind the crank, have to come out.

So what is the quickest cheapest way to get the bike back on the road?

I half way wish that the thing had a kick start then I would just say forget the starter

The quickest cheapest way to get it back on the road is to do nothing, and push start it. The more expensive, and longer way to get it back on the road is to fix the starter clutch. As Hugo said it does require a fair amount of work, but since your bike does not have a kickstart it is the only way to solve the issue.

There are several specialty tools that you will need. Some of which will be easier to aquire than others.

Re-assembly requires the proper torques for each bolt, and specific checks required to ensure proper operation.

Everything required and step by step instructions are in the SERVICE MANUAL.

Good luck.

Hi Tracker, It could be someone put a special additive or oil in your bike. I use regular oil from Wal-mart and sometimes the full synthetic or combination of both. I haven't had any issues with the bike in over three years and 8000 miles. I would change the oil and go from there. It might be as simple as that. You may still have to change the starter clutch, but can still start it pushing it. Good luck. I change my oil every two thousand miles and the filter at four thousand. Bob

So your saying its possible an oil change will allow me to start it again?

The oil has little to do with the Starting Clutch. Even with the slipperiest of all oils, it should catch, everytime. I lived with this problem for about a year, until I got fed up, bit the bullet, and changed it. Never looked back. But to me fixing as much as I can by myself is part of the fun of owning a old bike.

Tracker, replacing the starter clutch is involved, not because is difficult to change it, but because all the things have to be disassembled to get to it. The most involved is transmission clutch because it has many parts and a big nut torqued at a gorilla strengh of 90 ft-lb. Right here you need a impact wrench.

So even if you do it yourself takes some money, and time. You need a factory manual, study, plan for it, and get the right tools. The easiest way is taking to a motorcycle mechanics, but of course, it may be expensive because of the labor.

I have done this fix twice. The first time I just replaced the rollers and springs. That fix lasted a few thousand miles. The second time I did it right and replaced the entire assembly. The job is an all-day job, even if you have the parts sitting right there on your workbench ready to go. You will be tired when you are done. Get the entire assembly and do it right the first time.

Is this what I need to buy?

cgi.ebay.com/ebaymotors/KAWASAKI-KZ400-K...&hash=item27b527334a

Tracker wrote:

Is this what I need to buy?

cgi.ebay.com/ebaymotors/KAWASAKI-KZ400-K...&hash=item27b527334a

That's for the 750 twin. Your's is a 4cyl..correct?

Listen to what Hugo is telling you. He's right on the money Buy or download a service manual and read it. It's no a 5 minute job. Not overly complicated either but you need to be mechanically inclined.

failed to read that... Yes mine is the 4

I did find a used starter clutch off a 81 kz750 H [What is the difference I am a novice to the kz's]

cgi.ebay.com/ebaymotors/1981-Kawasaki-KZ...&hash=item3a5f9a3a59

It seems to be the entire setup.