Buyer Guide
With Warnings

L1 side panels should have EX on them - but these can be sourced second hand and crop up online frequently - if everything else is correct but a panel or badge is missing, fine, but DO NOT BUY if just the badges are there but everything else is wrong. The panels are the easiest thing in the world to swap and the laziest scam is just to put EX badges/panels on the side of a K-series bike - I've seen a few being offered as 'rare EX's' for stupid money and they are nothing of the sort. Just because the badge says 'EX' it doesn't mean it is - in fact, from what I've seen lately, presume the bike is a 'wrong un' from the start and go through everything to prove otherwise.

The following information (except about the spoked wheels) also applies to an L1-Ex.

Other K-Series Models

Again, check the frame and engine numbers on the V5 against the engine and frame numbers on the bike. Are they right for the stated model number against the list at the bottom of this page? Has the engine been replaced? This might not be an issue for you but it's a bargaining point for price.

Is there more documentation with the bike? Old MOT's, tax discs, owner manuals or even an original warranty/service booklet with model details inside? Does everything add up? Is the mileage right? Scuffed and faded engine case labels but low mileage clocks may mean some thing's not right.

Check for a solid front mud-guard and bracket as they can be a pain to get hold of and check for rot under the rear mud-guard where it meets the plastic insert (rear guards are easier to source). Also check for rot around the battery box and on the swing arm. If possible take the seat off and check that the regulator/rectifier is in place and that the seat is in good condition (seats and covers are available though).

The 6v systems are pretty weak but they should still work and the 12v systems are better for lights etc (12v from K7 onward - everything before should be 6v). There are indicator, neutral and high beam warning lights on the instrument panel and the ignition can be turned all the way to the left past lock to switch on a parking light (it's visible in the headlight, don't switch on and leave by accident!). The clocks should be lit when the lights are on too.

Check for pitting on the forks and be suspicious of forks covered by non standard gaiters. Don't worry too much about the shocks, the plain black shocks (or the non-standard chrome topped ones) can be sourced new and cheaply with a bit of hunting around.

Do the keys fit the ignition, tank lock and helmet lock? (The helmet lock is located on the right side between the side panel and shock - this lock is used the least and should be pretty original). Many tank locks have worn over the years and can be opened with almost anything; new barrels for everything on the bike may be a problem so you might end up with two keys if you have to replace ignition or tank locks, which is a pain.

A common problem is the snapped kick-start shaft - make sure the kick-start lever hasn't been welded or bodged onto a broken shaft. A new shaft is both hard to source and involves splitting the engine to replace. The exhaust needs to be right too, it should have KH125 stamped into it, as long as it's solid it can be re-chromed but they are difficult to find in good condition if the one you're buying is rotten.

Check for tank leaks and the general condition of the paint and bright work. The side panels are often cracked around the screw holes and the inside upper bracket lugs broken (panels can be found second-hand); the grab rail is often removed for some reason and can go walk-about; wheels can have broken spokes and are prone to rust; the head light rim is thin metal and can suffer rust; indicators & stems should be chrome (rear stems black), look out for evidence of the bike being dropped by scuffed, bent or replacement indicators; finally, the chain guard - check it's the right type, the K1, K2 & K3 had fully enclosed guards, later models just a chrome upper section. 

A ropey paint job or chrome on a 1987 Sunbeam Red or Ebony K4 can easily be made to look great by getting bits from a mid-1990's K9 because,  apart from the electrics, they're the same bike with the same colour scheme. If you want to go the whole hog, paint and decals can be sourced or re-done by specialists but it won't be cheap, so too re-chroming of parts. Maybe it'll be worth it in a few years.

As for engine and gear box, there should be some blue smoke coming from the exhaust when revved and there shouldn't be any horrible noises from the top end. Check that the 2-stroke oil bottle is there (view hole in right panel) and that two cables run from a silver cable splitter with one cable entering it; the choke is a thumb switch on the left handle bar and should be connected. The choke and accelerator cables run into a black 'boot' above the right-hand engine casing held in place with a metal spring-like band. This 'boot' covers the carb and should have a little rubber adjuster screw in it - the whole thing should be airtight. However, the 'boot' often shows signs of tampering where owners have tried in vain to adjust the idle. Look for missing adjusters, split 'boots', missing metal spring-bands and general shoddy tampering - all of which will tell you that the carb needs a clean or a rebuild (parts available).

The engine oil level is checked by a screw next to the kick-start - the oil should be up to the hole. Needless to say, it should go through the gears Ok and that the green neutral light should work on the instrument panel. 

Don't worry about things like shocks, tyres, chains, sprockets, batteries, bulbs, cables, air filter, hoses, brake pads and indicator lenses etc, they can still be sourced new. A brake disc will be fairly expensive if you can find one. While I like my bike original, I did buy an engine bolt set that replaced all the engine case bolts and screws with a stainless allen head set - much nicer and easier. A future project is to replace the rubber front brake hose with one that looks similar but is fully braided. 

Guide To Identification

The frame numbers for each model comes from two sources, the rear of the official workshop manual that lists the frame numbers for K1 to K7 and the Kawasaki microfiche that were used by dealerships to identify models and order parts etc. As the workshop manual doesn't list engine numbers, the only engine number information I have is from the Kawasaki microfiche. 

Frame Number Summary

K1 & K2 - from KH125K-000001

K3 - from KH125K-001601

L1 EX - from KH125L-000001 (note the 'L')

K4 - from KH125K-003001

K5 - from KH125K-004030

K6 - from KH125K-008901

K7 - from KH125K-013501

K9 - from KH125K-015001

K10 - from KH125K-017001

Engine Number Summary

K1, K2, K3 & L1 - from KH125DE-007501

K4 - from KH125DE-011501

K5, K6, K7, K9 & K10 - from KH125DE-014293