Tuesday 31 July 2018

Suzuki GS750


A while ago I bought a Suzuki GS750, the second update with twin discs and cast wheels. It was cheap and low mileage, but there was a catch. It had been damaged by fire. How or why I never found out because the seller was one of several people who had owned the bike without finishing the rebuild. It wasn’t a runner but didn’t seem far from it on initial inspection.

The engine was fitted into the repainted frame but none of the electrics were connected up and the carbs were but a molten blob, although there were some replacements (the originals were so far gone that they couldn't be compared). Overall it was not a pretty sight.

Certainly, if it had something with a self destruct engine like a Honda twin cam four (cue for outraged CB owners to write in - Ed), I wouldn't have even considered buying it. There was no way I could tell what horrors might be lurking inside those shiny casings. Full of optimism and positive thinking (I must have been full of something) I took the plunge and bought it. Well, it was the beginning of summer and I had nothing else to ride...


Generally, buying bikes that just need finishing is a big mistake. Multiply the expected cost by ten and that'll be nearer the mark. Just because all the major parts are present and correct, dont believe that a few hours work will finish it. Take my word for it, finding the right nuts and bolts to fix on all the fiddly bits will keep you and your wallet occupied for a long time.
 

Once I'd finally bodged everything into what I naively imagined would be a functioning state the real problems started. The engine was fully wired and plumbed and turned over on the starter without emitting any ominous noises from its insides. The ignition timing was spot on, new petrol was in the tank. There was plenty of compression and the plugs were getting wet. So why didn’t it start?
 

I removed the cam covers of the rebuilt motor and had a look. Some idiot had assembled the engine - with a nice new gasket - but somehow forgotten to fit the jockey wheel between the cams. Although he'd taken the trouble to time the cams correctly, missing out the wheel meant that the inlet was effectively lagging in phase. Thankfully, it wasn't far enough out to bend any valves but finding a jockey wheel wasn't very easy.
 

With that fixed, it started and ran well, so it was time for a test ride. I only did about 50 miles before it became apparent that something was very wrong with the transmission. By now I wouldn't have been surprised if someone had missed out a gearbox bearing, but actually the real culprit was the chain. From a distance it looked fine, on closer inspection, however, it didn’t. The fire had melted the O-rings which had coated the rollers with black gunge. As I'd never even pushed the bike around I hadn't noticed anything wrong before. More expense.
 

Success comes to those who persevere and patience is eventually rewarded (I usually keep a huge hammer nearby - Ed), In the end I had a reasonable Suzuki GS750... I just try to forget that it probably cost twice as much as one I could have bought from the local rip-off emporium!
 

The good news is that the bike lived up to its reputation for being reliable, fast and good handling. At first I scared a lot of pedestrians when it kept back-firing on the over-run. The cure was simple - refit the vacuum pipe for the fuel tap (I'd been using it on prime). Seeing as how I could make it back fire at will, and very loudly, I really missed this audible warning of my approach, but I was a bit worried that it might damage something or, worse still, catch fire.
 

The valve clearances altered quite a lot while they settled in but they are easy to adjust - even a screwdriver can be used as a special tool to depress the seat in order to remove the shim. After a few 1000 miles the rear wheel bearings suddenly collapsed, without warning; luckily when I was only doing about 10mph. I'm glad it didn’t happen two minutes earlier when the speedo reading was a lot higher. The remainder of the journey was completed at walking pace with much wobbling and accompanied by terminal noises from below. Once again the cause was a missing part - in this case a bearing spacer. It was amazing that it didn’t happen sooner because without a spacer all you do when you tighten the spindle bolt is push the inner races of the bearings together. 

Tyres vaporized at a predictably ridiculous rate, and I remember the handling seemed better on some cheapo Jap Dunlops than other supposedly superior stuff. Strange but true. Petrol consumption figures were a bit disappointing, never more than the low forties mpg and it did bum a bit of oil.
 

In terms of flat out performance, a GS750 is well down on its GSXR modern equivalent, but in the real world it wouldn't be that far behind. A good spread of torque meant that a five speed box was adequate without needing to tap dance on the gear pedal to keep things moving.
 

To me, and, I suspect, most other bikers, the GS fours provided a balance of practicality and power that late eighties race-replica models can’t match. A roller bearing crank undoubtedly costs more to make but it certainly lasts longer in unsympathetic hands. Simple twin shock suspension works well enough and is easy to fix if it goes wrong. Likewise, two valves per cylinder engines satisfy most most needs for speed and reduce complication.
 

So that’s it, a solid, sensible motorcycle that is cheap to buy and run, but doesn’t reduce you to the mind numbing boredom of something like an MZ.
 

R Ker