Help identifying oil

[Beelzeboss]

Hi,

I will shortly be buying a written off GS500 to use the engine in my off-road buggy. I have read about not being able to use mineral oils after an engine has had synthetic in it. Is there any truth to this?
How could I (inexpensively) test the oil in it to see if it is synthetic? Unfortunately the bikes don't come with any service history, and since it is being sold by the insurance companies you can't talk to the previous owner about it. So, is there a way?

[fred]

I've never heard that before. Just put whatever oil in it and as long as it is the right weight and doesn't have friction modifiers, everything should be fine.

[ohgood]

I've never heard that before. Just put whatever oil in it and as long as it is the right weight and doesn't have friction modifiers, everything should be fine.

+1

Usually you'll see newbie folks saying 'OMGZ NO DONT USE DYNO OIL AFTER SYN DUDE!' on forums. They'll say something about seals, and gaskets. Then they'll say that while they were tearing down the bottom end "for maintenance issues" they found the dyno-oil caused their crank to assplode all over the bearings.

Use whatever oil you like, but cheaper, and non-friction modifying is best.

[GeeP]

Shouldn't be a problem.  Put some new oil in it.  Rotella-T 15W40 is cheap and plentiful around most of the world.  Just avoid "energy conserving" oil with friction modifiers.

Running a synthetic after many hours of operation on "regular" oil used to be a problem.  Early synthetic oils were rather powerful solvents.  In a high-time engine that was previously run on "regular" oil, adding a synthetic would dissolve all the sludge built up in the engine.  On the plus side, the synthetic oil would enter the rubber seals and cause them to swell, stopping leaks.  However, synthetic oils available today have largely solved the seal swelling and sludge dissolving issues from what I've read. 

Still, a synthetic oil isn't going to extend the service life of your GS engine at all.  The GS engine needs new valve seats after about 80,000 to 90,000 miles.  The engine top and bottom ends will still be fine at that point, regardless of the oil you run in it.  When removing the engine to replace the head or make new valve seals you might as well overhaul it in my book. 

Don't get hung up on oil.  How often you change it and how you maintain the overall machine is far more important.   

[loudog]

I agree.

I'd drain the old oil out for a good half hour and put anything in there you want. No worries.

[bobthebiker]

Don't get hung up on oil.  How often you change it and how you maintain the overall machine is far more important.   

Thats the truth fo sho.  long as you've got decent oil in it and its changed regularly, with regular valve adjustments, I think you're set.

[beRto]

Wow! Consensus in a thread about engine oil! That's unheard of! 

[Xyloft]

I agree.

I'd drain the old oil out for a good half hour and put anything in there you want. No worries.

I have no idea how old the oil was in my bike when i got it and i didnt think the original owner had changed it.   the bike only had 2500 miles on it, but i changed it, put 2-300 miles on it and changed it again. 

[jp]

When synthetics first came out, there were a few types around that used a base fluid that was incompatible with regular motor oil. That is no longer the case, and hasn't been for at least 20 years. Use whatever kind of oil you like and it'll be fine.

[Beelzeboss]

Alright, thanks very much for the info. I read in the service manual to change the oil every 4000km (2500 miles). Is this adequate? I know in my car the recommended interval is 10,000km and I change it every 5000km, should I do a similar thing in the bike? (Bear in mind this engine will be under quite a lot of stress, but not reving over 9,250 rpm or so)

[shiznizbiz]

There was a young kid at the local shop that sells the oil filter needed for the gs (only place in the 16th largest city in america that sells that particular one...wtf)  and he said the same thing to me about not using conventional after synth.  I laughed very loudly and walked away...he yelled, Im serious!! I shook my head.   Damn kids, ignorance is a powerful thing.

[GeeP]

Alright, thanks very much for the info. I read in the service manual to change the oil every 4000km (2500 miles). Is this adequate? I know in my car the recommended interval is 10,000km and I change it every 5000km, should I do a similar thing in the bike? (Bear in mind this engine will be under quite a lot of stress, but not reving over 9,250 rpm or so)

3,000 miles in the GS is fine.

You can generally tell when the oil is ready for changout by shifting feel.  As the oil accumulates hours, shifting becomes more "notchy".

[shiznizbiz]

Alright, thanks very much for the info. I read in the service manual to change the oil every 4000km (2500 miles). Is this adequate? I know in my car the recommended interval is 10,000km and I change it every 5000km, should I do a similar thing in the bike? (Bear in mind this engine will be under quite a lot of stress, but not reving over 9,250 rpm or so)

3,000 miles in the GS is fine.

You can generally tell when the oil is ready for changout by shifting feel.  As the oil accumulates hours, shifting becomes more "notchy".

Indeed.   

[Jackstand Johnny]

You gotta do a write up on that buggy! I wanna see pics and a how to.

[shiznizbiz]

Alright, thanks very much for the info. I read in the service manual to change the oil every 4000km (2500 miles). Is this adequate? I know in my car the recommended interval is 10,000km and I change it every 5000km, should I do a similar thing in the bike? (Bear in mind this engine will be under quite a lot of stress, but not reving over 9,250 rpm or so)

3,000 miles in the GS is fine.

You can generally tell when the oil is ready for changout by shifting feel.  As the oil accumulates hours, shifting becomes more "notchy".

oh yessir!! you can tell for sure.  Reaaal nothcy like, clunky chunky tink tink notchy. instead of smooth muffled metalic clickity clickty