Changing tranny fluid on 78 sr650

Ok, I'm stumped. There has to be tranny fluid in this thing but I can find no info and I see no signs in looking at the bike. Pls help a noob.

Most motorcycles have a unitized engine design where the crankshaft and transmission share a common enclosure. Therefore, the same oil and filter that feeds the crankshaft, camshafts, etc, also lubricates the transmission and clutch plates.

Later, Doug

StreetfighterKz wrote: Most motorcycles have a unitized engine design where the crankshaft and transmission share a common enclosure. Therefore, the same oil and filter that feeds the crankshaft, camshafts, etc, also lubricates the transmission and clutch plates.

Later, Doug

Diplomatically handled...well done.

Ditto.
Steve

As stated, the engine oil circulates through the tranny and also the clutch. This is why it is very important to use the correct oil for the bike. Here's some info that should be helpful in selecting oil. If nothing else, just remember to use oil with JASO-MA marked on the container.

The ingredients in oils have changed over the years. For example, today's Castrol GTX oil (and pretty much all other AUTOMOBILE oil) is not the same as it was in the 1980's. Back then it worked great in KZ bikes. But, things have changed. Early AUTOMOBILE oils contained zinc phosphorus compounds (ZDDP) to protect engine components from metal to metal contact. This was good for engines, but it was found to be destructive to catalytic converters. Consequently, in AUTOMOBILE oils ZDDP was virtually eliminated and replaced with different chemistry generically referred to as "Friction Modifiers." These work fine and offer good protection for normal AUTOMOBILE engines. However, today's AUTOMOBILE oil "Friction Modifiers" are destructive to wet clutches, and all KZ models (and many other brands) have wet clutches. As a result of these oil chemistry changes a distinction needed to be made between those oils which are suitable for wet clutches and those which are not. That distinction was documented by the Japanese Engine Oil Standards Implementation Panel (JASO). JASO developed a number of different oil specifications for different applications. The specifications that apply to 4 stroke motorcycles fall under the "4T Specifications." Within the 4T specifications the JASO MA class oils are specifically formulated for 4 stroke motorcycles with wet clutches.

There are synthetic, semi-synthetic, and non-synthetic oils that meet the JASO-MA standard and any of them will work ok. However, using oils that are not designated as meeting the JASO-MA standard is destructive to KZ clutches.

Good luck with your bike. Ed

650ed wrote: Early AUTOMOBILE oils contained zinc phosphorus compounds (ZDDP) to protect engine components from metal to metal contact. This was good for engines, but it was found to be destructive to catalytic converters. Consequently, in AUTOMOBILE oils ZDDP was virtually eliminated and replaced with different chemistry generically referred to as "Friction Modifiers."

Auto oil does contain ZDDP, the quantity is just reduced compared to olden days. Typical modern auto oil has about 800 ppm zinc and phosphorus, whereas motorcycle oil is 0-20% higher.

Standard auto oil won't hurt your clutch, it's the stuff denoted as "energy saving" that you need to stay away from. These oils are typically low viscosity, like 5w-30, so I'm not sure there is a great amount of risk with 10W-40 (but you best check the label before purchase).

Diesel engine oil like Rotella has about 1100-1300 ppm zinc and phosphorus. It's also certified for use in wet clutches. I wouldn't be afraid of using other brands of diesel oil either, even if it's not MA certified. Most diesel oil makers don't want to spend the money to certify since the motorcycle market is small.

The newer formula of Castrol GTX 10W40 killed the clutch in my KZ650. I suspect when they reduced the ZDDP they put in some other friction modifier (maybe moly?) to compensate. Since replacing my clutch I have used no oil that is not JASO-MA certified. Certainly any oil labeled "Energy Saving" will have additives that are harmful to wet clutches, but I believe the problem was pretty wide-spread otherwise I doubt JASO would have come up with a new standard for wet clutches. Replacing clutches is a pain in the butt and fairly expensive, so since there are plenty of JASO-MA compliant oils available in every price range it seems an unnecessary risk to use oils that do not meet that standard, but that's just the way my mind works. Ed

Thx guys. I changed the oil and filter as per spec so I'm good to go.

Nessism wrote:

650ed wrote: Early AUTOMOBILE oils contained zinc phosphorus compounds (ZDDP) to protect engine components from metal to metal contact. This was good for engines, but it was found to be destructive to catalytic converters. Consequently, in AUTOMOBILE oils ZDDP was virtually eliminated and replaced with different chemistry generically referred to as "Friction Modifiers."

Auto oil does contain ZDDP, the quantity is just reduced compared to olden days. Typical modern auto oil has about 800 ppm zinc and phosphorus, whereas motorcycle oil is 0-20% higher..

I don't think SN class oil has 800 PPM, all I know for sure is it has to have less than that limit so it might or it might have zero. Oil makers don't say anything about what's in the product and I don't believe anything they say anymore anyway.

650ed wrote: The newer formula of Castrol GTX 10W40 killed the clutch in my KZ650. I suspect when they reduced the ZDDP they put in some other friction modifier (maybe moly?) to compensate.

Could be. The thing about "energy conserving" label is that it probably has friction reducers (like moly) but it also has the lower cold grade like 5W-30. I don't think 10-40 or 20-50 would ever get the "energy conserve" badge even if they did have moly. I think with new oil, the only safe move is to look for the MA cert.

bountyhunter wrote: I don't think SN class oil has 800 PPM, all I know for sure is it has to have less than that limit so it might or it might have zero. Oil makers don't say anything about what's in the product and I don't believe anything they say anymore anyway.

Check some oil analysis results at Bob is the Oil Guy... www.bobistheoilguy.com/forums/ubbthreads.php?ubb=cfrm