Kawasaki KZ250C - a few fixings

I have been looking at a Kawasaki KZ250C single with some electrical problems recently and thought I'd just write down what I did in case I forget and in case its useful to someone else. I could find very little on the web about this model so this might help others.

The KZ250C looks like this:

It had been bought recently for AUD$2000 and had obviously had some restoration work done to it by the previous owner(s) - mostly appearance related though.

Some details about this bike:
1. The seat had been remodelled to extend towards the rear and cover where there might usually be a carrier. This made it a bit harder to identify because there were 3 different models of this bike available in Australia each with different seats and the seat that this one had wasn't like any of them.
2. Its a 1980 model (made October 1980) with VIN #: KZ250C-003349 and Engine #: ODE 022539.
3. Chain and sprockets need replacing - front 15t, rear 37t and a 100 link chain of size 520H.
4. Battery needed replacing - YB10L-A2 12v 11Ah. The battery dimensions are 133x85x145 high - multimeter test showed only about 10.5V.
5. Paper air cleaner and air box - all original and clean and fitted ok. The paper filter was dirty and I would have ordinarily replaced this as a matter of course but was unable to buy a genuine new one, so just cleaned the old one. Kawasaki part number 110105022. I got a lot of advice and support from BikeBiz Kawasaki Granville - they couldn't get many parts but pointed me toward where I might (eBay mostly). I was able to get the battery, front sprocket and oil filter from BikeBiz.
6. Screws/bolts throughout the bike were all the original Phillips head style made of 1980 cheese. As a result, they had all pretty much had their heads stripped and needed replacing. I replaced quite a few of these as I went along - excellent and cheap service from Nepean Boltmaster.
7. The inlet rubber manifold connecting the carby to the cylinder was a bit perished and probably needs replacement but I was unable to buy a new one. Kawasaki part number 160651028.
8. The petrol hose was perished and as a result, the fuel filter was full of rubber dust and pieces. Lucky it had a filter at all because its not a standard fitment. Fitted new 4.8mm petrol hose and fuel filter - both from SupaCheap Auto Accessories.
9. The engine contained 3 litres of engine oil (very black) I found upon draining - it is only supposed to have 1.4 litres max. Oil change 25621km with 1.4 litres of Castrol Activ 4T and Kawasaki oil filter part #: 16099-004. Once I got it going, I changed it again (1.1 litres - no oil filter change) at 25719km - the oil was already very black.
10. The most significant point however about the bike was that it had broken down on the ride home after purchase with some serious heat being felt through the ignition key (enough to cause a finger blister). There was no spark and the starter motor did not work at all ie. there was no power to the starter.

Typical of the state of most of the Phillips head screws on the bike.

RHS switchblock with starter button and destroyed screws - I had to use the impact driver to get them out and, as a temporary solution, hacksawed a slot for a blade screwdriver to be used.

New petrol hose and fuel filter installed

Low mileage

Investigation showed that there had been quite a bit of non-factory electrical work added to the bike including:
- driving lights mounted on the crash bars - 2 x 35W
- an ammeter mounted on the handlebars
- an immobiliser switch mounted under the left hand side cover - this had been wired to bypass the main 20A fuse (interestingly) and there was much melted wire nearby in the battery box.
- the extra wire used to wire in all these bits was 20A cable which is much thicker than the factory wiring used predominantly on the bike.

To fix:

The usual tool suspects were needed including:
- multimeter
- a test circuit (I just made this from a 9V battery, bulb and wires - this is to check where wires are coming from and going to)
- various bits of the right sized wire and male/female connectors
- impact driver - removes any of the shredded Phillips Head screws - as the photo above shows, even the ones in the RHS switch block were destroyed.

What I did:
Overall the approach was:
1. Remove all the non-standard wiring and accessories
2. Start at the battery and work out along the wiring loom to the ignition coil and starter motor to make sure that power is getting to where it should go.

Process:

1. Remove accessory driving lights and associated wiring.
2. Remove the ammeter (it's internals were melted anyway) and associated wiring
3. Remove the immobiliser switch and associated wiring
4. Remove the non-standard ignition coil and replace it with the original - this had been replaced as a first attempt to cure the no-start problem
5. Replace the battery - the original showed 2 cells half full and 10.5V. I filled cells with distilled water, charged for required time, and it showed 12.76V but was back to 10.5V 30 minutes later. Discarded battery and got a new one from BikeBiz Granville - YB10L-A2 12v 11Ah.
6. Test the voltage across the terminals of the starter solenoid after the new battery was installed - should have been about 12.7V but was zero - ordered a new one on eBay from Brooks Barn Parts for about AUD$38 delivered from the UK. It took about 10 days to arrive.
7. Install solenoid - being non-genuine, it doesn't quite fit - have to cut the rubber holder it came with in order to make it fit the existing steel casing under the left side cover.
8. The 2 central wires of the solenoid are also a different colour to the genuine item and, because there had been so much non-genuine wiring that had to be removed, it took a while to work out how to connect it up properly. I had also bought a Genuine Service Manual for the KZ from ebay for USD$28 which had a colour wiring diagram which helped enormously in working out which wires go where. Basically, the Green/Blue wire from the solenoid joins to the Black wire from the large wiring loom returning from the RHS handlebar switch block. Interestingly, the returning Black wire has a female connector as does the Green/Blue wire from the solenoid so I changed the solenoid one to a male plug. Also, the Yellow/Red wire from the solenoid joins to the Yellow/Red wire from the loom which goes to the Voltage rectifier under the RHS side cover.
9. Still no go - so I removed, disassembled, cleaned and reinstalled the ignition switch (especially the dirt off the points contacts), the RHS switch block (kill switch, starter button, headlight on/off) and the battery earth contact. Still nothing.
10. Due to the changed wiring - especially the non-genuine wiring bypassing the main 20A fuse - it was hard to work out how the White/Red wires of the fuse were to be wired back in again. It took a bit of work and some on-going deciphering of the wiring diagram in the Service Manual but it turned out that the White/Red wires from the Voltage Regulator and the fuse were now presenting as separate wires with male and female ends instead of, as the wiring diagram shows, the 2 wires coming together in a double female joining to a single male plug wire coming from the positive side (ie. the battery side) of the solenoid. I had to remake the female double plug connection and create a new short wire from the +ve terminal of the solenoid with a male plug to join it to and hey presto - everything works!

See the photo and diagram below to illustrate points 8-10 above:

Showing the completed wiring under the LHS side cover

An extract from the Service Manual Wiring Diagram showing the relevant bits that needed changing - compare to the real photo of the wiring above.

Bits acquired for the KZ:

- Service Manuals - I bought 2 hardcopies of these on eBay (1 from the US and 1 from NZ) - they were slightly different at around $55 each = $110. These were essential to working with the bike. They are really indispensable when working with old bikes. Unfortunately I couldn't find a PDF version of the service manuals for the KZ250C (ie. the single cylinder version). There is one for download for the twin cylinder version but it is a very different motor obviously.
- Starter solenoid - from the UK via eBay - $38
- Oil filter - $11.00 - from BikeBiz Kawasaki Granville
- Castrol Activ 4T oil - 4 litres - $39.95 - from SuperCheap Auto Accessories
- Battery - $50.00 - from BikeBiz Kawasaki Granville
- Front sprocket - 15T - $16.00 - from BikeBiz Kawasaki Granville
- Needs a new 37T rear sprocket and 100 link 520H chain - yet to source these - the chain will be no problem but the rear sprocket might have to be made - probably from The ChainGang as I have bought stuff from them before and they are excellent.
- Electrical tape - $11.69
- Fuel hose - 4.8mm - $15.70 - I could only buy a minimum of a metre even though I only needed about 20cm
- Fuel filter - $8.45
- Split pins - $5.99 - to replace rear axle nut split pin (pkt of 8)
- Circlip pins - $5.99 - to replace brake cable end pins (pkt of 8).

End product and back on the road - great fun: