oil in chaincase has a burnt smell

[pat the rat]

my bro recently changed the track on his rx1,everything was fine for 200 miles until today when he started smelling burnt chaincase oil,he pulled the dipstick and it smelled bad and the oil is very dark in color,would a bad bearing do that,its the first time we encounter this,anyone ever experience this

 

[apltx08]

Can I ask you a stupid question...are you sure the OIL didn't drain out caused a bad or pinched gasket on cover or drain plug wasn't tighten and fell off...cuz I've seen this happen to 1 of my bud's and FRIED his after a few 100 miles

I'd take the cover off and check things out...sounds like a missed placed shim maybe, it could be a bearing its hard to tell till you check them all 1 by 1, how about the reverse forks are they lined up properly when you put the cover back on they can be a pain in the @@$ or his chain tensioner could it be to tight and causing overheating, does the CHAINCASE get very HOT to touch, something got be wrong, what type of oil is he using, my Bud uses QUAKER STATE 75W-140 full SYN and it STINKS!!! some OILS tend to smell more than others when they get hot, any spare parts left after re-assembling.LOL it happened last time we changed my Bud's drive shaft last year, we were all down and when we pulled the oil drain pan we had a @#$% shim hidden under it...so we took it apart and got it right!

 

[pat the rat]

he did mention that the cover was hot after his ride,he has no leaks that he can see but there is oil in the case cuz its black,i know what you mean about the reverse fork,it is a pain,will take cover off tomorrow to inspect

 

[apltx08]

Does he change his oil regularly...cuz I've seen some get pretty CAKED up with sludge and when you take them apart you kind of disolve the stuff and some is left in then when you fill it with fresh OIL it mixes with the new oil and makes your new oil dark...the case will get warm to hot after a WOT run of a few miles and like I mentioned earlier some oils tend to SMELL awhful after a long runs...smells like that old DIFF oil they use to use in the '70!

My oil recipe is 200ml of SWEPCO 212 Gear oil 75W-140 with 50ml of Lucas oil Conditioner, no smell, runs MUCH cooler, I change mine every 1600kms or so.

 

[APEX 06]

I was just about to ask how mach oil you put if you over fill it could do that to. Or I have seen chains go bad get hot from not moving the way it should.

 

[grader]

my guess is the chain was adjusted too tight. i switched from gear oil to 5-30 synthetic motor oil after much reading on the subject. first its not a gear box its a chaincase. second 75-90 or 75-140 anything is too thick for winter temps. third motor oil does just fine in the transmissions of every japanese bike on the planet where it also lubes the motor, and you never get that rotten egg sulfer smell if it does get hot.

 

[pat the rat]

we added oil until it showed the proper level on the dipstick,he is using gear oil,mobil synthetic if i'm not mistaken,myself,i always get what yamaha recommends with no issues,the chain was hand thightened so i dont think it was too tight

 

[grader]

hand tight can be too tight, back it off aprox. one third turn for some slack.

 

[Len Todd]

If the oil is leaking, it will get low. If it gets low, the oil will get hot. If the oil gets hot, the oil will burn. If the oil burns, the chain-case components will be damaged. If the oil was low and burned, the seals (if they have not already) will eventually fail and you will most-likely cook all the components, eventually.

I suggest that you totally disassemble the chain case. Inspect all the components. Replace the Drive Shaft bearing and seal. replace the jack-shaft bearing and seal, including the o-ring, at a minimum. Also replace the Cover gasket. Once it has been cooked it is no longer reliable. It will crack and leak.

The reason I provide this recommendation is my personal experience has taught me that once it starts leaking, 25 miles and you have ruined about $500s worth of parts. And this is if you are lucky enough to save the chain case. $50s now for sure or probably $500 later. The choice is yours.

 

[apltx08]

Here's a good article on Motor and Gear oil...

Gear Oil and Motor Oil Are Not the Same
Gear oil differs from motor oil. Most people assume that SAE 90 gear oil is much thicker than SAE 40 or 50 grade motor oil. However, they are the same viscosity. The difference is they are calculated by different classifications, SAE gear lube and SAE engine oil. Another main difference is the additives used to produce them.

Motor oil has to combat byproduct chemicals from gasoline or diesel ignition and should contain additives such as detergents and dispersants. Since an internal combustion engine has an oil pump and lubricates the bearings with a hydrodynamic film, the need for extreme pressure additives such as those used in gear oils does not exist in engines.

Additional Differences
Because many of the components found in the drivetrain consist of ferrous material, the lubricant is required to prevent rust and possible corrosion to other materials. Rust and corrosion problems are not nearly as prevalent in engines.

The many small and intricate components that make up gear sets found in the drivetrain can be quite noisy and may be subjected to shock loading. The viscosity and extreme pressure formulation of gear oil quiets gears and dissipates shock loading.

The rotating motion of the gear sets also tends to churn the lubricant, resulting in foaming. If a gear lube foams, the load carrying capacity is significantly reduced because the air suspended within the oil is compressible. For example, when the gear teeth come into contact with each other any trapped air bubbles will compress, therefore reducing the thickness of the separating oil film. In turn, this reduction could lead to direct metal-to-metal contact between gear teeth and result in accelerated wear. The gear oil must have the ability to dissipate this entrapped air, insuring a sufficient lubricating film exists to protect the gears from contact wear.

Typical Drivetrain Fluid Additives
Much like engine oil, the chemical compounds, or additives, added to drivetrain base stocks either enhance existing properties or impart new ones. Some of the additives that may be found in a drivetrain fluid include the following:
• Extreme pressure and/or antiwear agents - These additives are used to minimize component wear in boundary lubrication situations.
• Pour point depressants - This type of additive is used to improve low temperature performance.
• Rust and corrosion inhibitors - These are used to protect internal components.
• Oxidation inhibitors - These additives are used to reduce the deteriorating effects of heat on the lubricant, increasing the lubricant’s service life.
• Viscosity index improvers - These allow a lubricant to operate over a broader temperature range.
• Anti-foam agents - These are used to suppress the foaming tendency and dissipate entrapped air.
• Friction modifiers - The required degree of friction reduction can vary significantly between differing pieces of equipment in drivetrain applications. In some cases, friction modifiers may be required to obtain the desired results.

 

[apltx08]

we added oil until it showed the proper level on the dipstick,

Take a measuring cup and pour in 250ml MAX...with or without reverse, the DIPSTICK is out of wack, w/reverse its usually @ "STD" mark or close, I always measure mine.

 

[Len Todd]

I too use the STD side of the stick. It's full mark is really close to what the spec calls for.

 

[pat the rat]

thanks guys for the good info,will take it apart and inspect

 

[Len Todd]

Good thing to do. The oil had to go someplace. And the oil going someplace is never a good thing. At the very least, I would replace the Drive Shaft oil seal and O-ring.

 

[pat the rat]

well,we opened it up and inspected everything,the oil was dark and smelled bad but he didnt ride it long when it started to smell,the chain was defenatly too tight so that might of been the problem,he cleaned everything and put it back together with 250ml of yammi oil,then went out for a 70 mile trip,everything seems fine now,he'll be keeping a close eye on the level and colour of the oil