My friend bought an old (1977) kawasaki KE125 bike for $100. It's in pretty decent shape but it wasn't running when he bought it but with a little work today we got it to atleast start. However, I dont really know a lot about bikes and neither does he. I used all that applies to cars to figure out that it didn't really seem like we were getting fuel. Now even when it will actually start it will idle for a minute or less before shutting off on its own. If you baby it you can rev it barely and what I think is odd is that it wont start if the exhaust is on? So if anyone on here could give me some tips I'd appreciate it.

KE125?
I'm guessing it's a two stroke. Which means that it requires some sort of lubrication in addition to the gas. (Sometimes this happened automatically. Sometimes it had to be pre-mixed.)
If it's been sitting for a while, there is every possibility that the carb is all gummed up. I know that with two strokes, exhaust tuning makes a much bigger deal than with four strokes. If the carb is gummed up, I could see the presence or absence of an exhaust system making enough of a difference to let it run or not.
Also... If it's supposed to have oil mixed, and it doesn't, it could be shutting down because of the lack of lubrication.

Edit - It is a two stroke. But it has a separate oil tank under the side cover. That being the case, I'm thinking the bike mixes the oil/fuel for you. That's assuming there's oil in the tank.

[This message has been edited by Raydar (edited 03-27-2011).]

It is a 2 stroke, and it has an oil case with a line to what looks like a throttle body for the oil. It has a line that accuates with the throttle, a line where the oil comes from a case and a line that goes across to the carb. What I wasn't sure of was if the line going to the carb was a vaccum line or if it was supposed run gas through it. At first I thought gas just because of how the line is bolted on but gas does not come out of it when you kick over the bike with the choke on or giving it throttle.

I had one of those, except mine was two years older. It has a rotary valve two stroke engine. There is a separate tank for the premix oil. Like said above, it probably needs to have the carb cleaned out and the air/fuel mixture screws adjusted. If I remember correctly, the engine was rated around 13 HP and the bike had a top speed of 77 MPH.

quote Originally posted by avengador1: I had one of those, except mine was two years older. It has a rotary valve two stroke engine. There is a separate tank for the premix oil. Like said above, it probably needs to have the carb cleaned out and the air/fuel mixture screws adjusted. If I remember correctly, the engine was rated around 13 HP and the bike had a top speed of 77 MPH.

We'll have to take a look at the carb, it was supposedly cleaned out but I don't know if it was done correctly. I can't imagine hitting almost 80 on that!

..The carb is easy to pull off,,Im positive it is gummed up
check the float needle to see if it has a rubber/neoprin tip if so do not soak it
remove the jets they just screw out .soak them for a few hours you can see if they are clean,, the pilot jet is real small clean it good
often you can just use a can of carb spray cleaner to clean out the passage ways & jets
the float needle & the cone it fits in should be clean.air pressure & Q tips are used to clean out the carb .
the float probably just fits into a recess in the needle
once u have it running check timing on the flywheel
gap the spark plug at .025 use NGK plug
hope fully it is getting oil & the rings will free up & reseat
what will screw every thing up is if the crank bearings are worn or loose
this was a peppy bike for a 125 cc,
the exhaust on a 2 stroke will clogg up ,you have to soak it to remove carbon..sometimes the exhaust port cloggs up you can remove pipe and you will see a carbon build up just forward of piston
people often stop riding or sale 2 stroke motorcycles because performance drops & it is the pipe needing cleaning,, the muffler baffle may be removable on this bike.
check out rotary valve make sure it is not broken or chipped,you can eyeball it thru the carb mount

the idle jet is always 1 1/2 turn this may be on the side, on top, or in the carb bore I use to be a scooter mech but my memory sucks

[This message has been edited by uhlanstan (edited 03-28-2011).]

Mine was a KS 125. I found a price and spec sheet from the 1976 Cycle buyer's guide.

Here is a picture of mine from back in the day.

The bike was fairly easy to work on and I rebuilt the engine and clutch once, all by myself, with no shop manual. I sold it back in 1984 and the kid who bought it blew it up because he didn't add two stroke oil to the reservoir.

[This message has been edited by avengador1 (edited 03-28-2011).]

i had a 1979 xr 250 given to me..its a been a fun bike to tinker with..runs with all new goodies on it..probably do a piston and rings this spring ..then shes done!! these old bikes are cool..tim

Definitely sounds like a carb problem. Disassemble & give it a thorough cleaning. Be sure all of the jet passages are open. It doesn't take much to clog them.
The floats being off sounds like the issue. I also suggest installing an inline fuel filter between the tank & carb. There is bound to be debris in a tank that old.

------------------
86 GT
87 coupe restoration project.

[This message has been edited by nmw75 (edited 03-28-2011).]

Thanks for all the info and advice. The bike will now start most of the time and idle somewhat but if you put any strain on it, it dies. Someone had put a fuel filter on it but I think you guys are right with the carb needing to be rebuilt and the exhaust needing to be cleaned out. We will probably take another look at it wednesday and Ill let you guys know what happens with it.

Update! So we did get it running enough to figure out some things and try to ride it. For one the exhaust had a huge mouse house in it which blew right out once we took out the end baffles. Now it will run with the exhaust on it, but riding it is a whole nother story.
One of our friends who rides bikes took a quick look at it and realized something is up with the gears. Its actually only clicking into one gear down and one up and will not go into neutral. Today we looked further into it and found something odd after taking off the clutch cover.
The clutch cable pulls a piston that is "supposed" to actuate a rod that goes into the case of the bike and operate the clutch. When I was poking around looking at the clutch i realized the rod that goes into the case can just come right out and there is no resistance on it when you push it all the way to the back. There is a single ball bearing that was behind the rod after it was completely removed from the bike.
So that to me explains why it is not rideable and why it will not shift gears but I dont know how to go about fixing that. Anyone know?

If I remember correctly it sounds like you are missing a retaining/adjustment bolt and maybe a spring. These adjust how the clucth disengages when you pull the lever. Another problem my bike had was that the shift fork could break and then it only downshift. I had mine welded back together when it broke. If you can find a service manual that would be a plus.
A quick search turn these links up.
http://www.fixya.com/motorc...kawasaki_ke_125_1976
http://www.themotorbookstore.com/kawrotval801.html
http://freemotorcyclemanual...-motrocycle-manuals/
http://www.cyclechaos.com/wiki/Kawasaki_KE125
http://garagecompany.com/bkawman.html

[This message has been edited by avengador1 (edited 04-30-2011).]

A new spark plug,fuel filter, and air filter wouldnt hurt.

Thanks again guys, those diagrams should be pretty useful once we can get the clutch popped off. As far as how it runs, I'm more worried about it actually being able to move and **** while its running first then having it run great. If we cant get it to move at all first making it idle well would just make it cool to look at lol.

You also should check the fuel filter screen in the petcock. They tend to get clogged with rust and old gas and will keep the engine from running properly.

You might have to buy a clutch puller,I once had a Kawasaki dirt bike,but I've never changed a clutch.