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Bike Review - Posted 20th June 2013
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Suzuki GS1000 Winter Project - Part 4

Duncan Cooper returns his classic GS to the road after it spent seven years in storage. This time it needs a new brake master cylinder, and all may not be well with in the electronic ignition dept...

All the messing about with the carburettors (in Part 3) had given the final coat of clear lacquer on the petrol tank time to cure sufficiently for a flatting-off with fine grade wet-and-dry paper. I think I used 1200 grade but 1000 grade would probably do, all followed by a polish-up to a high gloss with T-Cut.

Before, after, and the other one... With fresh fuel the bike ran, so Duncan needed to finish off the fuel tank paint - starting by flatting-off the lacquer with fine wet-and-dry and then polishing it back up with T-cut until a mirror shine with nice clear reflections appeared

I fitted a filter between the fuel tap and the carburettors to protect their spotless interiors, half slotted the tank into place, struggled to get the fuel pipe onto the tap because there's no room around it due to that damned airbox(!), finished fitting the tank, sloshed some fuel into the tank (oops. Luckily that petrol 'resistant' lacquer is actually quite good), put in a new battery and hit the road!

Sorry, I meant 'rode up and down the drive!' as I hadn't got an MoT at that point…

The bike felt good, powerful and indomitable - inspiring the feeling that I could roar off across Europe on it if I wanted to. But on inspecting the GS after this brief test run I found tiny spots of liquid dissolving the new paint on the front-right of the fuel tank. It soon clicked that the seal in the front brake master cylinder was seeping fluid and this was being blown back onto the tank.

I quickly washed the spots off the tank and began a slow, long and fruitless search for the correct master cylinder refurbishment kit. I could find the wrong refurbishment kits. Cheerful young Suzuki parts managers would assure me that it must be my bike that was wrong. I'd show them the master cylinder, with the Suzuki symbol cast into it, and say 'Well, just give me the kit for that then,' but they'd just look perplexed (while still being cheerful) and explain that they couldn't identify parts themselves, oh no. They just put the bike's frame number in the computer and it tells them what part number they should get. And if that part number doesn't correspond to a part that fits, well, you're buggered.

Miserable old parts manager not shown... With the bike back together and running Duncan soon found a reason to take it apart again - a seeping master cylinder

What I wanted was a miserable old parts manager, like the one they used to have a Slingers Suzuki in Preston, one who would simply look sourly at whatever I plonked down in front of him, shuffle off to the shadowy shelves and then eventually come back with the parts I wanted without needing a frame number or computer. But all the miserable old parts managers who actually knew what the parts were seem to have faded away. I fear we shall not see their like again.

So, it was left to me alone to find a solution. I tried a bit of thinking - lateral thinking even. The design of the Suzuki is GS1000 is reputed to be heavily inspired by (or copied from) the 1970's Kawasaki Z1. This is sometimes used to cast the Suzuki in a poor light but maybe this could work to my advantage. If Suzuki used the same specification for their master cylinder as Kawasaki then maybe I could use one of the pattern parts now being made to restore all the old Z1s (which have become valuable due to being an iconic bike of the 70s, or because they have a cool name).

This did turn out to be the case and after a false start with a pattern Brembo type, I found one with the correct bore that looked almost identical to my original. The fiddly Suzuki brake switch wouldn't fit, but I fitted a pressure switch instead, even though it's not required for the MoT. The brand new Chinese copy made the front brake work better than ever, so it was off to the MoT station and then onwards to about 500 miles of riding to be sure that the bike was truly back up to strength. Done over several weekends, you understand. Not on the same day as the MoT. That would have been very tiring.

Now much earlier I mentioned that I was re-commissioning this bike so it could be sold. I didn't intend to ride about enjoying it. So with the Suzuki having proved its fitness I sent an advert off to that paragon of motorcycle publishing, RealClassic magazine, and then sat back and waited for the offers of cash to come rolling in.

Notice the digital grass. Amazing what they can do these days... Using a pattern master cylinder intended for a Kawasaki had the GS back on the road and serious testing began

After a while I got bored and decided to go for a ride. All went well, but just before getting home I noticed what might have been a drop in power, but I was so near home I couldn't really tell for sure before arriving back. Offers for the bike continued not to roll in and I even considered advertising elsewhere but decided to go for another ride first. The thoughts I'd had about poor running had been shoved to the back of my mind but they now elbowed their way to the front and loomed at me. I started up the bike, finding it was undeniably down on power and just wouldn't run properly.

'Oh dear' I said. Or something like that.

I wasn't really in the best of moods for clear thinking but decided to act upon my first thoughts about what the problem might be. In retrospect, this might not have been the best thing to have done. I decided that as the carburettors had been stripped and cleaned the problem had to be with the ignition. It's either the fuel or the sparks, after all.

Can't see the point, etc.... Things went fine for about 500 miles but then a glitch had Duncan searching for possible causes. He blamed the aftermarket electronic ignition and replaced this optical sensor on the end of the crank with the original points system

Now this Suzuki came to me with an aftermarket electronic ignition fitted. It always worked fine but the bike mechanic at my MoT station always looked at it suspiciously and often was heard a disparaging word. As it had always worked I'd left it well alone, but now something was wrong and the seed of suspicion that had been planted grew into a certainty that the non-Suzuki ignition - the 'outsider' - must be the cause of the ills.

I decided to revert to points ignition but this wasn't as easy as I'd hoped because the original points plate and associated cam had been removed by whoever fitted the electronic ignition. I found a small handful of points plates offered on the internet but there was no 'point' (ahem) in getting them as they didn't come with the cam that fitted to the advance / retard bob weights. Further eBay scrutiny revealed an enlightened breaker in Iowa, USA (K&M Cycles & More) who had kept the set of parts - points plate, cam and indeed bob weights - together, so I bought those for a very reasonable price.

Newer isn't always better. A lesson for us all there... The points plate and cam which Duncan found were, of course, secondhand. However the condensers were new. But newer isn't always better
Cool Classics on

I also bought new points and condensers but when the points plate arrived from the USA it came complete with all the old parts still in place and, truth to tell, I only got round to swapping the old condensers for the new ones, leaving the points be. Re-fitting the original ignition components was completed very late in the evening so I decided to leave starting the bike until the next day.

I slept soundly, sure in the knowledge that the traitorous electronic ignition system had been expelled and the bike would now run without trouble.

The bike wouldn't run. It was exactly the same as before…

Next time: just fix it!


When he's not rebuilding his Suzuki, Duncan runs Bikeheart European Motorcycle Tours. His aim is to guide you on your own trusted motorcycle on a motoring adventure of a lifetime. Bikeheart carefully select their routes to reward those looking for a riding and cultural experience, in regions where the weather should be better than at home. See

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