Death rattle in my GSX

[Rhubarb]

My mid 80's GSX750ES has an engine rattle. It has always had a slight rattle that goes away when I pull in the clutch. Quite common for an older GSX I am told and nothing to really worry about.

However, last weekend I gave it a filter and oil change that was a couple of thousand k's overdue. The next time I went for a ride it developed an engine rattle when I throttle off. It doesn't rattle under load.

My guess is it's the timing chain. Perhaps the old thick oil was hiding the chain rattle.

Any thoughts ???

[kiwi cowboy]

My mid 80's GSX750ES has an engine rattle. It has always had a slight rattle that goes away when I pull in the clutch. Quite common for an older GSX I am told and nothing to really worry about.

However, last weekend I gave it a filter and oil change that was a couple of thousand k's overdue. The next time I went for a ride it developed an engine rattle when I throttle off. It doesn't rattle under load.

My guess is it's the timing chain. Perhaps the old thick oil was hiding the chain rattle.

Any thoughts ???

Bugger!!.
is it like the clutch rattle only worse? mabe something like the new oil doin somthing in the clutch

[Squiggles]

How many k's has the old beast done?

[Rhubarb]

It's done 75,000km. Yeh, it's quite like a clutch rattle but it sounds more internal.

[wickle]

Dont agnore it! find it I did and now have a connecting rod sticking out front of bottom cases on my 1980 GSX750

[Rhubarb]

Dont agnore it! find it I did and now have a connecting rod sticking out front of bottom cases on my 1980 GSX750
Yeh, even though its a great sunny day today and I have seen dozens of bikes riding down Dunedin's peninsula road, I have decided to leave the 'Old Girl' in the garage until I can get it looked at.

[Dadpole]

Did You refill with synthetic oil? The old aircooled motors seem to prefer the mineral based stuff. There are a lot of references (EG Oldskoolsuzuki etc) to increased noise after changing to synthetic. I have stayed with the mineral oil on mine - big brother to yours

[Rhubarb]

Did You refill with synthetic oil? The old aircooled motors seem to prefer the mineral based stuff. There are a lot of references (EG Oldskoolsuzuki etc) to increased noise after changing to synthetic. I have stayed with the mineral oil on mine - big brother to yours

I used Castrol Magnatec 10W40. I see on the Castrol website that this oil "combines Intelligent Molecules with synthetic technology". So I assume it is synthetic.
What mineral oil did you use in your bike?

[Dadpole]

Motul Was the Brand. Don't remember any details and have ditched the container. :blink:

Rumour has it that the synthetic oil does too good a job of cleaning out old gunge resulting in more play in components. (Or it could all be in the mind of the owner) I will leave the final word on that to the experts.

I gather that the synthetic or semi-synthetic does the job better than mineral oil, but will wait until I pull down the motor and give it an overhaul before I look at changing oil types.

[FROSTY]

sounds to me like the cam chain might have hit last legs status.

[MSTRS]

I used Castrol Magnatec 10W40. I see on the Castrol website that this oil "combines Intelligent Molecules with synthetic technology". So I assume it is synthetic.
What mineral oil did you use in your bike?

New oil wouldn't normally make a rattle worse...your old oil would be thinner because of age etc. But using Magnatec in a bike? No way. It is an engine oil formulated for cars. Never use in a bike gearbox/engine combo if your bike has a wet clutch. You need to use bike-specific oils or make sure that the oil you want does not contain 'friction modifiers' - it will say on the pack if they are present. Perhaps this is the source of your rattle?
But I'd still be picking it is the cam chain, and has been all along. Fix it or weep.

[McDuck]

Bugger for all involved ;)

[hayd3n]

hymm yea could just be the oil
ring mciver n viech they might be able to help you out over the phone

[Rhubarb]

hymm yea could just be the oil
ring mciver n viech they might be able to help you out over the phone
I rang Veitches and they suggested a synthetic oil.
Tonight I changed the oil again but this time I used a Mineral Oil as suggested by another KB'er. Took it for a ride down the peninsula and it is now a lot quieter !!!
Might check out the cam chain anyway.

[hayd3n]

I rang Veitches and they suggested a synthetic oil.
Tonight I changed the oil again but this time I used a Mineral Oil as suggested by another KB'er. Took it for a ride down the peninsula and it is now a lot quieter !!!
Might check out the cam chain anyway.

awsome!!!!! bak on 2 wheels wahoo

[Dadpole]

Nice To hear that you are mobile again. The suggestion to check out the cam chain is a good one. What was causing the rattle is still there, just not so audible now.
Have you checked your cam chain tensioner? They have been known to stick as they get older. If you have a manual, it will show you how. It may even be worth pulling it out (which can be a pig of a job) to give it the full treatment.

[MSTRS]

I rang Veitches and they suggested a synthetic oil.
Tonight I changed the oil again but this time I used a Mineral Oil as suggested by another KB'er. Took it for a ride down the peninsula and it is now a lot quieter !!!
Might check out the cam chain anyway.

Bad advice!! Semi-synthetic might be ok in a bike the age of yours, but not a full synthetic. In fact, I doubt anything older than even 2000 should run full. The thing about full synthetic is that this type of oil is thinner than mineral oils when cold, but basically retains that state of viscosity under use and does not need to be changed as often. As engines and oils have continued to develop, you need to use an oil suitable for yours...ie, one that suited yours when it was new. In saying that, semi-synthetic may be ok but it must be bike specific (that wet clutch thing). Car oils in the 80s were fine in bikes because they did not have those 'friction modifiers' then. Some bikers use diesel oil and report excellent results.
Check the cam chain. It is most likely the cause of the rattle and it's a cheap fix to replace or adjust, compared to ignoring it. Wickle told you what to expect...