At the moment we are using some Putoline light gear oil, but I am beginning to think that maybe this is causing a problem with our transmission. When the bike is cold it shifts fine through the gears and really smoothly, but once the bike heats up we have trouble shifting past second gear unless you drop the revs slightly. Do you think that since our bike is pretty old now (1995) that it doesn't like these high grade specially formulated transmission oils and would probably run better with 10w40 motor oil?
The bike more or less fine before switching to this oil so it has got me thinking a bit.
New plates and springs, smoothing out any notches in the basket, verifying the integrity of the shifting mechanism, etc... will probably allow you to use any oil you want without many clutch issues.
When plates get glazed, and springs sack out, and the basket gets notched, the clutch is much more apt to act slightly different with various lubricants.
New clutches tend to act similarly with a vast array of fluids.
I did start to think that the clutch may be at fault but most bikes shift without a clutch, so that threw me off that idea. I must admit, the clutch basket did have a few notches in it but how does this affect the clutch mechanicsm? Basically, how does the clutch basket work?
At the moment we are using some Putoline light gear oil, but I am beginning to think that maybe this is causing a problem with our transmission. When the bike is cold it shifts fine through the gears and really smoothly, but once the bike heats up we have trouble shifting past second gear unless you drop the revs slightly. Do you think that since our bike is pretty old now (1995) that it doesn't like these high grade specially formulated transmission oils and would probably run better with 10w40 motor oil?
The bike more or less fine before switching to this oil so it has got me thinking a bit.
Try ATF Type F in your gear box. My kx500 had notchy shifting and the ATF has made it butter smooth. I have had same issues with my 05 yz250 about not getting into the 1st gear without slowing engine speed. Drain your gear box refill with ATF ride bike for a few minutes then drain gear box then refill, this will help flush the other oils you have used.
Well the bike is slightly better with the 10w 30 oil but it still doesn't feel right. We changed the shift forks last week so it can't be that, and everything else seemed with the tolerance limits. I will try ATF fluid if you really think it will help. Cheers!
even though you might not think so I agree with jaybird. It sounds like the clutch. And when you shift without the clutch atleast with my bike I have to ease off the throttle a bit. But anyways check your clutch. look for notches in the basket as well.