Q: I own a 1978 Suzuki GS750 and was hoping you guys can help me with an issue, or two? It is old, I know, and in quite rough condition, but it seems to run OK after many hours of messing around with the carbs – predictably.

I did fit some aftermarket rear shocks, from China I’d imagine, which seem to help with the rear end handling, but not so with the front end. I have cleaned out the forks and filled with thicker oil (heavy grade), but with no adjustment in those days they’re just way too soft. I’ve asked around for heavier springs but people just laugh. So do you perhaps know where I could source such items?

Also the stock points and condensers are rubbish and constantly need to be adjusted – very annoying to say the least. So, do you have any advice on that issue also?

Looking forward to your reply…

Dane

A: First the forks. Don’t bother searching for new springs; you won’t really generate much benefit. However, get someone to make up one-inch spacers that sit on top of the spring, which used to be a cheap race modification for Production Racing in the 70s/80s, it’ll add pre-load, and that will help ten-fold.

As for the ignition assembly, throw it away and convert to an electronic system. It’s easy to install, then set with a strobe light for each pick-up and you’ll never have any problems again, it’ll also run much smoother.

Dynatek Dyna S systems are one of the best, so try Club House Kawasaki (011 618 4646), who imports these electronic ignition systems in SA; they’ll be able to assist.

Q: Hi guys, I understand Bill seems to be good regarding information on old classic bikes, so I was hoping for some of his ‘expert’ advice?

I’ve just acquired a Kawasaki z1000, which I believe to be a 1978 model. It’s in a very rough condition with many missing parts, but seeing as I’m now retired I thought it would make a superb restoration project.

It does run, but badly, so I’ve taken off the carbs to be rebuilt and ordered a new electronic ignition system. However the problem, and the question I’m asking, comes from draining the old oil. When I emptied the oil out of the pan I noticed many small pieces of ‘brass’, which seems to be rather strange seeing as I can’t seem to find where they could be from. If you could shed any light on these brass pieces, and where they’re from, and why they’re in the oil, I will be grateful?

Keep up the good work with your informative site, too.

Mike Collinworth.

A: The Kawasaki z1000 has a roller-bearing crankshaft, meaning the big ends have needle roller bearings instead of common plain shells found it all of today’s bikes. Plain shells generally sit inside a con-rod that can be split open into two pieces so they can be replaced.

A roller bearing big-end is found inside a one-piece con-rod and the only way to replace them it pull the crankshaft apart, because these types of crankshafts are pressed together and not made from one solid piece.

Your problem stems from the ‘brass’ side-thrust washers that sit each side of the big-end bearings. When they start to ‘shed’ pieces it’s the first sign of big-end failure, I’m afraid. It is a serious issue, and seeing as you’re restoring the bike, you might as well take out the crankshaft and send it to a reputable engineer, otherwise it’ll only get worse and eventually it will cause irreparable damage to the engine.

We can recommend www.bikeworx.co.za for all crankshaft repairs.  

Q: I’ve just been given an old (1980 I think), Suzuki GS 850 – the one with the hefty shaft-drive. It’s been standing for a long time, so after a good clean I tired to get the engine running with some degree of success.

However, the biggest problem was the old exhaust, which isn’t the original system. I’m not sure what it is, but it’s black with a rotten silencer. I managed to fit a silencer to it (4-1 system) and now the bike looks better, at least.

I had to take off the carbs to clean them and they have ‘pod like’ filters on them, again I’ve replaced them with new ones because they were trashed. I noticed the main jets are 105s, which I believe to be the standard size.

So my question is – seeing as the bike has a 4-into1 system, and ‘pod’ filters, what jet size would you recommend seeing as you seem to be quite good with classic bike questions? It would be great to get them right the first time so I don’t have to take off the carbs and stuff around them again. Looking forward to your response.

Chris Cummins.

A: Yes Chris we’ve spent many hours ‘fiddling’ around with these types of jet settings. We’re not sure if you’re at sea level, or Jo’burg altitude though?

We’d recommend starting off with 125s, as they seem to be a good base setting for these types of modifications. If you’re living at altitude you could try 122.5s, or maybe a 120 main jet. It might be difficult to find them though so you might have to search around local ‘old’ dealers and the like.

Hope this helps with your new/old bike…

Replied: April 23rd, 2024

Q: My uncle has given me an old Suzuki GS850, the one with the shaft drive. I managed to get it running and went out for a ride, but suddenly the bike came to an abrupt stop and I could smell something ‘odd’ coming from behind the air box.

When I removed the side panel I realized it was coming from the battery, one of those yellow one’s, and when I took it out it was swollen and cracked down one side.

So I was wondering if you’d have any ideas on what could cause this, because I’ve never seen anything like it before?

Regards.

Piet Stock.

A: There have always been issues with early big Suzuki’s and the charging systems. I’d predict there’s a short inside the stator behind the left side engine cover. Over time the copper windings become brittle and especially the three wires coming from it to the voltage regulator/rectifier units, which control the correct voltage and current.

See if you can get/borrow a battery and check the voltage with a meter onto the battery terminals, and make sure it isn’t more than 13.6 volts +/- above 3,000rpm. But if the readings are ‘strange’ you’ll have to replace the stator I’m afraid, which can be very expensive, but you can install it at home with very little tools. Maybe replace the regulator/rectifier as well for a new complete charging system to be sure?

This is what we’d recommend, replacing the whole system, and a new battery of course.