1986 Kawasaki KH125 from United Kingdom


Very fun


Hi, I have just been given a KH125 by a friend.

It broke down a few months ago. The problem is that there is no spark. The HT lead seems fine and I have tried a new spark plug, but still no luck. Any suggestion would be appreciated, thanks.

General Comments:

I had a go on this bike when it was running, and it felt a bit different to my KTM, but I fell in love with it. This is a very fun bike to ride around town on, and this is the first problem with the bike in 3 years.

Would you buy another motorcycle from this manufacturer? Don't Know

Review Date: 27th March, 2007

28th Mar 2007, 22:22

You just need a new battery.

30th Mar 2007, 13:51


2nd Apr 2007, 12:21

Thanks for the suggestion, but still no luck. Any other ideas? I can't wait to get it back on the road and have some fun.

3rd Apr 2007, 17:06

Hello. I had a KH125 many years ago as my first bike and wish I had kept it (reg: G499KMS). I miss it so much.

Anyway, regarding your no spark, forget a new battery, the bike will start even with a flat battery because the ignition runs off the generator.

If yours has points ignition (my one did), renew the points as they do get pitted, and as a worthwhile measure, renew the condenser. Prior to this, check all connections, especially at the ignition switch, ignition coil and generator. After this, the bike should start and run fine. Good luck.

23rd Apr 2007, 15:57

Kroninbergs KH125:

Have you got compression?

7th Sep 2014, 14:37


There is a leakage coming from my exhaust every time I try to kick start the KH125 K6 rotary valve engine. When I stop kicking, the leakage eventually stops.

I cleaned the carburetor and fitted a new spark plug, and the leakage isn't happening due to those components.

I am wondering if it could be the exhaust valve or perhaps something else?

If it is the exhaust valve, how would I go about fixing it?


1989 Kawasaki KH125 from United Kingdom


An excellent small commuter machine from Kawasaki


When I bought the motorcycle, it clearly had not been cleaned for years.

Engine cut out constantly in the wet.

Remedy was to spray WD40 all over the coil and HT lead. End of problem.

When this occurred for the first time, due to inexperience at the age of seventeen, I took the bike back to the dealer where I bought it. I later learned, I was charged for nothing. Don`t let them rip you off!

Gearbox often use to jump out of gear. The fault was either a defective selector claw or stopper lever.

Gearbox used to leak oil via the selector shaft. Renewed the oil seal to no success. Suspect a worn shaft. The shaft was never replaced.

Exhaust started blowing. Renewed the seal at the down pipe to muffler connection. Cost nothing.

Oil change revealed petrol contamination of the oil. This was due to blown "O" ring on the disc valve induction. This affected the top end speed, thus reducing it to 55mph.

Renewed the pads at 17000 miles. Cost £10.

Renewed the rear tyre at 18000 miles. Cost £30 and fitted by an associate free of charge.

Started running erratically. A service revealed a pilot circuit in the carb was blocked, clogged exhaust and bad ignition timing. Remedy was to overhaul and clean the carb, adjust the ignition points, and decoke the muffler. The machine was noticeably faster and easily pulled wheelies. Sounded throaty.

Loss of compression at 21000 miles due to a broken top piston ring. At this stage, I sold the bike to a person of interest, who later informed me that a new piston kit was all that was needed and no rebore.

General Comments:

Robust disc valve two-stroke engine.

The engine is economical and is reliable when in good condition.

My one, although worn, started with the first kick.

The exhaust note is distinctive at low RPM and is music to my ears (a deep burble). After about 6000 RPM, the machine really takes off and sounds loud.

The build quality is excellent and the finish is pleasing.

The engine covers are polished aluminium and look impressive.

The 13.5 litre fuel tank gives good range.

The speedo and tachometer reveals important information at a glance.

The suspension is well damped to give a smooth ride.

The models fitted with six volt electrics would benefit with a twelve volt system.

The point system would be better replaced with CDI ignition, in order to reduce maintenance further more.

At the age of seventeen, this bike was pure freedom and joy. However, I did long for a bigger and better machine (the stupidity of youth).

In hindsight, I wish I had kept this motorcycle. It was fun to ride and looked the part, although not as flash as many sports 125s.

Would you buy another motorcycle from this manufacturer? Yes

Review Date: 16th June, 2005

2nd Mar 2006, 19:18

I think that what we could learn from this review, is that when you bought the KH125, it had been neglected and needed a thorough clean and overhaul.

I've just bought a 1990 KH125 that has been standing in a friend's garage for seven years, it won't go anywhere near the tarmac until I've checked the crank case seals, replaced all of the fuel and brake lines, changed brake pads, brake oil, probably fork oil and seals etc...

This really is common sense, make a point of checking seals etc on any used bike you buy and I would replace brake lines, pads and tyres as a matter of course. If you wait for things to go wrong before you think to check them, then you're going to spend more time in the garage than on the road riding.

My bike has to be reliable before I take it to Oxford (where I am at university) as my workshop facilities are in Birmingham, so anything more serious than adjusting the chain or an oil change is going to be a problem whilst I'm here.