The ongoing story of my Z650 project, where I aim to get the thing roadworthy and rideable. Cosmetic stuff will mostly come later ! This post is still a bit of a catch-up on jobs I've already done.
Paperwork Stuff
One of the big incentives for getting this machine back on the road instead of buying a new bike is because under UK law, it is old enough to qualify as an "historic vehicle".
That means I won't have to pay the annual Road Tax, and it is exempt from needing an MOT certificate (the annual test of roadworthiness needed by any vehicle over 4 years old here in the UK). I guess the logic is that vehicles this old are owned by enthusiasts who want to look after them and know how to do so.
Being an old bike, insurance is also cheap. However, the insurance company does still want me to have an MOT. But at least I can solve the various problems and test ride it before paying for the MOT without worrying about being stopped by the police !
Carburettors
After 10 years of being laid up, the carburettors were in a terrible state. Although they were okay to get the bike to start, they needed a good clean.
So I stripped them down and gave all the parts a good clean in my ultrasonic cleaner. That took a good amount of time, the cleaner is only a small one so it took about three loads for each of the four carburettors. I used carburettor cleaner from bestultrasonic.co.uk -https://www.bestultrasonic.co.uk/carburettor--engine-cleaner-ultrasonic-fluid-1-litre-104-p.asp - they haven't sponsored me or anything, I just found it to be a really great cleaner :)
Choke Plunger Problems
Something I gave special attention to were the choke plungers, which were really gummed up. I forgot to take a "before" photo, but here is how they looked once I had polished them up.
With the carbs reassembled, I found the choke didn't work. I spent days trying to work out what had gone wrong. Were the plungers too worn to be used ? Was the control rod bent ? Was the spring-loading on the bolt holding it in too strong ?
Then I realised I had done a really, really dumb thing. On Mikuni VM24SS carburettors like this, there are four lifters which screw onto the control rod to operate the plungers. I had put them back upside down. As Homer Simpson would say... D'oh !
The lifters have to be set up so that the plungers ride on the back of them, not get hooked up by them. Once they were the right way around, the choke worked perfectly. The photo below shows the correct way up for the lifters (circled).
Fuel Level Setting
With the carburettors back on the bike, the next task was to set the fuel level height in the float bowls. The specification is that the fuel level should be 2.5mm to 4.5mm below the edge of the carburettor body.
There is a drain screw on the float bowl which allows you to screw in an alternative screw with a clear pipe that can be used to measure the height.
But with 4 carbs to do, I chose to find a way to do two at a time. I took a spare float bowl, cut a panel out of each side and glued in some clear plastic (which admittedly fogged up almost immediately, but I could still see the fuel level. This meant I could do two carburettors at a time, which sped the process up nicely.
Below is a photo of the "official" special tool, next to the modified float bowl.
The Joy of Electrics
With the carburettors reassembled (with an approximate bench synchronisation using the 1mm wire method) and back on the bike, it was time to get it running long enough to get up to normal operating temperature. Then I could do a proper synchronisation as the first step to getting the carbs fully set up.
It went perfectly, yes ? No. No, it didn't. That is an untruth.
I started the bike up, and flashing fault lights appeared on the instrument console. The brake lights had decided to go faulty.
It turned out that the wiring loom had all kinds of age-related corrosion and bad connections due to the time the bike was stored and off the road, as well as 40 years of history of modifications, repairs and additions. The first set of repairs will be the subject of the next post.
