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Gear oil
Posted: Sun Feb 14, 2010 7:42 pm
by skids
Last year the gear oil I put in was too light (silkolene 75w-80w, the bike shop recommended it which should have clued me in right there), once the bike got hot it was a real pain to get into neutral.
I'm replacing it with motomaster 80w-90w from Crappy Tire that they sell for trucks and farm equipment. Hopefully that will work out a bit better when I'm in stop and go traffic.
If I ever find some Belray gear saver, I'll swap that in.
Posted: Sun Feb 14, 2010 9:16 pm
by Suzsmokeyallan
Sorry i dont like that Motomaster branded stuff Cambodian tyre sells, id prefer to stick in some 20-50W Castrol GTX first.
Posted: Mon Feb 15, 2010 12:14 am
by Buffalo-guy
I think the 80/90 would be OK, as long as it has the GL5 rating, which makes it compatable with wet clutch. I use full synthetic 75/90 in my buffalos, and it works a treat. Cheers.
Fred
Posted: Tue Feb 16, 2010 2:36 pm
by oldjapanesebikes
Most CTC oil (the more expensive lines) is made by Esso or by Shell. Basically - if a product meets the specifications, then it should be fine. The rest of what you pay for is just 'brand magic'.
Posted: Tue Feb 16, 2010 8:37 pm
by tz375
I use Silkolene gear oil in a couple of our race bikes and it works fine. A race bike gets worked hard and we have tested Honda CR oil, zero weight aircraft gearbox oil, Silkolene, Motul etc and to be honest thay all seem to work fine.
Trans oil rarely gets hot enough to make much of a viscosity difference, so something doesn't sound right there. If your trans gets hard to shift when it warms up, it could be a dragging clutch or something not right with teh shift mechanism.
Way back in the day, Suzuki recommended motor oil, so I guess whatever works for you is all good by comparison. So if thicker oil works, you may manage to avoid a tear down for another couple of seasons.
Posted: Wed Feb 17, 2010 12:09 am
by oldjapanesebikes
Posted: Wed Feb 17, 2010 2:37 am
by pjmcburney
I'm happy using 15W40 or 20W50 engine oil (same as I use in my Kat engine, which circulates around a clutch and gears) in my GT's gearbox for a couple of reasons:
1. It's significantly cheaper than 'specialist' two-stroke gearbox oils (better than half the price - you cannot convince me the gear oil is twice as good),
2. It doesn't make me physically ill when I get a whiff of it
...
Cheers
Paul
Posted: Thu Feb 18, 2010 3:24 pm
by skids
Thanks for the advice and the viscosity chart.
The oil I bought is GL5, I'll throw that in and see if I like it. I'll also take the advice and check and readjust the clutch. I do have it set pretty light.
Posted: Mon Feb 22, 2010 9:51 am
by rngdng
I use GL5-rated gear lube from any autoparts store. I have used 75/80, and 80/90 weights with no real difference noted. Big, expensive namebrands aren't worth the extra dollars IMO.
Lane
Re: Gear oil
Posted: Mon Nov 22, 2010 8:45 am
by ericsattic
Just curious to hear from T500 owners about the recommended gearbox oil (20W40) versus 20W50. As we know 20W40 is the original factory recommendation; it is hard but not impossible to find it these days. Most times I am inclined to go with what the factory says, so I was just wondering if anyone out there thought there would be any "harm" in using 20W50 in the gearbox. As we know there's an Achilles Heal on the T500's regarding gearbox oil level / volume, and the two T500 bikes I own ('68 and '70) do not have the oil level modifications (they only hold 1200cc of oil). I use 20W50 because its a bit more viscous than 20W40 so I am hoping I am on the right track (or in the right gear!). Thoughts on this?
Re: Gear oil
Posted: Mon Nov 22, 2010 9:19 am
by tz375
Eric,
I wouldn't get to hung up on the factory recommendations. They made those in 1969 when oil choices were very limited. Almost any oil available today is better than the stuff back in the day. I prefer a two stroke specific gear oil as posted above, but use any of teh oils recommended by these guys and you should be golden.
Re: Gear oil
Posted: Wed Dec 22, 2010 9:49 am
by tz375
PEDRO wrote:I find it unlikely that too light a oil will make your clutch drag, we as richard does use silkolene in the gearbox of our race bikes and road bikes, customers too, but no one seems to have mentioned that the gearbox also feeds the centre main which does a lot of work, so dont go too light on a road bike.
The other cause for clutch drag is previous owner may have removed the triangular oil catch plate from behind the clutch this then allows the clutch case to over fill...... that makes your clutch drag!!!!
Found that on lots of engines plank removes it does not understand what its for does not replace!!!! you would be stunned at the amount of "race prepped" engines I get in like that, saves weight apparently
Of course PEDRO is talking about the 500s with the oil feed to the center main bearing, but the comments still apply. If the gear change gets stiff when hot, it's unusual to be the oil, but there's no harm in trying something different to see if that works for you.
Re: Gear oil
Posted: Thu Sep 19, 2013 5:08 am
by GT750Battleship
I'd be interested to know people's thoughts on gearbox oil change intervals,(mileage/kilometres) on the GT750,seeing that the centre crank bearing is lubricated with gear oil ? I've always changed mine around the 5,000km mark,I also "measure in" & "measure out" & don't wait for the "dribble" to come out the oil level screw hole
Cheers,
GT750Battleship.
Cheers,
Re: Gear oil
Posted: Sat Sep 21, 2013 3:53 am
by joethebike
I have owned my 1972 T350J since new and it has done about 95,000 miles now including 2 Castrol 6 Hour production bike road races back in 1972 and 1973.
While the bike is on its third crankshaft (2 rebuilt between races and one that wore out a crankpin) and third set of barrels, the gearbox is still original and that's with using ordinary old 20-40 SG mineral engine oil from many brands.
The gearbox is still working well with no bad noises or shifting problems so I would save money and just use the specified oils changed at 5000 mile intervals.
Re: Gear oil
Posted: Sat Sep 21, 2013 5:36 am
by GT750Battleship
First of all Joe thank you for keeping me entertained at the 6 hour races...!
Those were the days....was only speaking to Blair Harley a few weeks ago about the "horn incident" I think the "win" at the time by your bike was described as "giant killing" in reference to your bikes capacity !!
I was a member of the Willoughby Bike Club,the 6 hour Races were certainly a good idea at the time,but from memory it caused a lot of headaches for the committee!!
Cheers,
GT750......
