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Our bikes – Suzuki GSX-R750F freshen-up

Suzuki GSX-r750F

(by Guy ‘Guido’ Allen, ride pic by Stuart Grant, December 2020)

Suzuki GSX-r750F

Little surprises

With age creeping up on it, our GSX-R needed a little TLC

You gotta love the ability of old motorcycles to spring little surprises on you. All too often you’ll unpack the latest idiotic purchase, only to be rewarded with it instantly marking its spot with large quantities of some essential fluid. I had a puppy that did that once – it was so pleased to see its new owner it immediately wet the carpet. Fortunately I don’t have that effect on everyone…

Our 1985-model GSX-R750F (it was originally a Japan delivery, hence the paint), was doing pretty much the same thing. Lined up for a photo shoot with the modern equivalent, it started the day grumbling at low revs and ended it by running like crap. By the end of the week, it was unrideable, while much of the fuel had mysteriously disappeared.

Its previous owner had warned me that it had a bit of a tendency to leak petrol if you forgot to switch off the tap, which a healthy one shouldn’t do. The tap, by the way, is a bugger to get to – hidden in a spot where you need smaller hands than mine to get to it and stronger hands than my daughter’s to turn it.

Suzuki GSX-r750F

Anyway, it was becoming obvious there was an issue with the carbs, mostly likely with the float needles and seats. While the bike had relatively modest miles on board (about 50,000km), sheer age can wear out these items. The flat-slide 29mm CV carburettors were a special thing in their day, but they’re simple enough to work on.

Suzuki GSX-r750F

Seats and needles still mystify me to some extent, as a visual inspection doesn’t always reveal whether they leak. Sure enough, ours had a tell-tale ridge in the needles, where they’d worn. And were dumping fuel at a prodigious rate – some of it ended up in the crankcases, necessitating an oil change. However I’ve seen sets from other bikes with similar wear, which have kept on sealing. Go figure…

Suzuki GSX-R750F

If you need to replace them, do it as a full set of seats and needles. Anything less is just asking for trouble.

Suzuki GSX-r750F

As it turned out, the rubbers connecting the airbox to the carbs were looking tired and cracked, so we shouted it a new set. The rubbers just did not want to co-operate, and needed to be individually warmed up and softened with a heat gun before being coaxed into place.

Something else that had got my attention was the mysterious appearance of a spot or two of hydraulic fluid around the handlebar area. This is not a good sign. A quick look revealed no issue with the brake line, so I cheerfully ignored it until the bike was up on a work bench.

Suzuki GSX-r750F

Just to add to the thrills, the clutch line was on the way out and was only a flex or two from complete failure. Naturally we replaced everything, including all the brake lines – it was a timely reminder that it really is worth checking the hydraulics on these old machines, which I confess I hadn’t.

We replaced the rubber lines with braided steel running black covers, from Goodridge. You get sharper lever feel and a near-enough to original look. A great result.

So far we had given it a full service, new tyres, rebuilt the carbs and replaced the hydraulic lines. All up, we’re probably looking at a cost getting up around Au$2000 at normal workshop rates.

Suzuki GSX-r750F

To me, it seems a pretty typical sorting bill for a recent acquisition. I usually count on at least several hundred for a decent-sized multi-cylinder bike, by the time you get it up to full health. Even with the best of intentions, owners who are thinking of selling have a tendency to let things go, most commonly servicing, drivelines and tyres. If it’s been sitting for a while, you can start to add things like fork seals to the list.

That’s fine if you’re expecting it, but potentially a nasty shock.

As for the Suzi, it was now a much happier camper and a delight to ride. Even now, it feels light, sharp and, once you wind up that powerplant, surprisingly punchy. Claiming a little over 100 horses for 186kg dry weight, it should.

See our GSX-R750 model profile here.

See more 'Our Bikes' stories here.

Suzuki GSX-r750F




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