How about this oil in my 92 750 Nighthawk?

[BusyLittleShop]

Moly is what kills wet clutches.

Negative... Moly will not defeat a wet clutch in good working order...

Mileage not Moly is the objective truth why our wet clutch begin to loose their grip...

Under scrutiny you'll find that clutch slip was due to normal glazing and contaminates...

To remove the effects of high mileage the savoy rider will employ good old sweat equity...

Start with inspecting and measuring the friction plates to make sure you have plenty
of material to work with... your shop manual should state minimal clutch thickness
in thousands of an inch or mm...

Next remove oily contaminants with Acetone... Bust the glaze with a sheet of
600 grit black dry emery paper resting on a hard surface... rotate the clutch plate in a
circle motion... go easy... you're just busting the surface glaze... don't get carried away
remove too much material... You should end up with a friction plate looks dull like a
new one as opposed to a shinny glazed one... recheck thickness...

Finally check the steel plates for bluing caused by localized heat... check for warpage... consult the manual for ranger of thickness... flush away the contaminants with Acetone and wire wheel the surface to erase the blue marks and also to generally scuff up the surface... all in all aim for a dull surface free of Blue marks...

 

[Nessism1]

In addition to what Larry L said, sometimes the friction material ages and petrifies with time and usage. Also, clutch springs sag. I've never sanded friction plates before, but I have fixed several slipping clutches with new OEM springs.

 

[RaymondP]

Now you've got me thinking. Have a 2013 Triumph Thruxton air cooled inline twin with a wet clutch. Have been using Mobil 1 15W50 FS from day one and no clutch slip yet after 30K. Being in Michigan (can reach late 80s/90s in summer), I only ride about half the year, hence the relatively low mileage. Engine generates a lot of heat. Very evident when standing at a light during summer, thus the 15W50.

Never considered it but I use Rotella T6 15W40 on my boat. Would this be a viable alternative, or should I stay the course with the Mobil 1 15W50? Have had the top cover off to reset the tappets with new shims at around 26K miles and the engine, or at least the parts I can see are as clean as a whistle.

Manual states 10W40 or 15W50 semi or full syn. that meets API SH (or higher) and JASO MA such as Castrol Power 1 Racing 4T or RS Racing 4T.

 

[Nessism1]

Now you've got me thinking. Have a 2013 Triumph Thruxton air cooled inline twin with a wet clutch. Have been using Mobil 1 15W50 FS from day one and no clutch slip yet after 30K. Being in Michigan (can reach late 80s/90s in summer), I only ride about half the year, hence the relatively low mileage. Engine generates a lot of heat. Very evident when standing at a light during summer, thus the 15W50.

Never considered it but I use Rotella T6 15W40 on my boat. Would this be a viable alternative, or should I stay the course with the Mobil 1 15W50? Have had the top cover off to reset the tappets with new shims at around 26K miles and the engine, or at least the parts I can see are as clean as a whistle.

Manual states 10W40 or 15W50 semi or full syn. that meets API SH (or higher) and JASO MA such as Castrol Power 1 Racing 4T or RS Racing 4T.

I'd stay with the Mobil 1 15W-50. It's got a good shot of ZDDP, and it's proven as a great motorcycle oil.

 

[Pete in PA]

Negative... Moly will not defeat a wet clutch in good working order...

Mileage not Moly is the objective truth why our wet clutch begin to loose their grip...

Under scrutiny you'll find that clutch slip was due to normal glazing and contaminates...

To remove the effects of high mileage the savoy rider will employ good old sweat equity...

Start with inspecting and measuring the friction plates to make sure you have plenty
of material to work with... your shop manual should state minimal clutch thickness
in thousands of an inch or mm...

Next remove oily contaminants with Acetone... Bust the glaze with a sheet of
600 grit black dry emery paper resting on a hard surface... rotate the clutch plate in a
circle motion... go easy... you're just busting the surface glaze... don't get carried away
remove too much material... You should end up with a friction plate looks dull like a
new one as opposed to a shinny glazed one... recheck thickness...

Finally check the steel plates for bluing caused by localized heat... check for warpage... consult the manual for ranger of thickness... flush away the contaminants with Acetone and wire wheel the surface to erase the blue marks and also to generally scuff up the surface... all in all aim for a dull surface free of Blue marks...

I just did the clutch a year ago in my 92. I kept the steels, lightly sanded them with 220 to get rid of the glaze. New Honda springs and frictions. The frictions are an entirely different type of material. Not sure what. Looked good to combat slipping.

 

[CleanSump]

I have a buddy who will only use conventional in his Suzuki thing because he read synthetic will make his clutch slip due to the extraordinarily high torque and horsepower of his engine. He was offended and defensive when I suggested he stop riding the clutch.
I should note his owner's manual says synthetic oil is fine, but of course, he says his is special.

 

[02SE]

I have a buddy who won't use conventional in his Suzuki thing because he read synthetic will make his clutch slip due to the extraordinarily high torque and horsepower of his engine. He was offended and defensive when I suggested he stop riding the clutch.
I should note his owner's manual says synthetic oil is fine, but of course, he says his is special.

He won't use conventional, and won't use Synthetic. What is he using in this 'high-powered' Suzuki, and which model is it?

 

[CleanSump]

He won't use conventional, and won't use Synthetic. What is he using in this 'high-powered' Suzuki, and which model is it?

I edited. He will only use conventional. I think it's a 400cc dual sport. He put knobby dirt tires on, rides it on the street, and says it's a Motard bike or something. It's isn't a big horsepower/torque engine.

 

[cci]

Negative... Moly will not defeat a wet clutch in good working order...

Mileage not Moly is the objective truth why our wet clutch begin to loose their grip...

Under scrutiny you'll find that clutch slip was due to normal glazing and contaminates...

To remove the effects of high mileage the savoy rider will employ good old sweat equity...

Start with inspecting and measuring the friction plates to make sure you have plenty
of material to work with... your shop manual should state minimal clutch thickness
in thousands of an inch or mm...

Next remove oily contaminants with Acetone... Bust the glaze with a sheet of
600 grit black dry emery paper resting on a hard surface... rotate the clutch plate in a
circle motion... go easy... you're just busting the surface glaze... don't get carried away
remove too much material... You should end up with a friction plate looks dull like a
new one as opposed to a shinny glazed one... recheck thickness...

Finally check the steel plates for bluing caused by localized heat... check for warpage... consult the manual for ranger of thickness... flush away the contaminants with Acetone and wire wheel the surface to erase the blue marks and also to generally scuff up the surface... all in all aim for a dull surface free of Blue marks...

Lots of good guidance here for anyone having clutch problems. I never thought to use acetone, I will try that.

Mileage for sure, and rider habits/service application. I know a motor cop who only gets about 15K miles out of a clutch.

Anytime anyone ever tells me they are having clutch problems I start as described here, and by measuring the clutch spring pressure (homemade jig that uses the drill press to compress the spring to a set distance and a bathroom scale to measure the force.) It's somewhat unusual to find bad springs and almost routine to find damaged plates.

All I would add is to the part about checking the steel plates for wear; the easiest and most reliable way I've found is I keep a piece of plate glass in the shop, if you set a clean, dry steel plate on the glass and tap the edge of the steel clutch plate at the circumference in a few places gently with your finger, and flip the plate over and do it again, if the plate is warped or dished it will tip up on one side or the other depending upon how it is dished.

A small amount of warpage is difficult to measure otherwise, and in a multi-plate clutch if several of the steel plates are warped it adds up quick.

 

[Pete in PA]

Read through the latest motorcycle oil change thread. Lot of reading!
Found at least 4 people using this exact oil.
Also the amount of frankenbrews used. If you don't like a certain quality of the oil, what oil are you going to blame???

 

[Pete in PA]

Wanted to update. I went with the PCMO Mobil 1 15w-50. Big mistake. VERY bad shifting immediately!
Not even going to try the 10w-40 Mobil 1.

 

[KrisZ]

A 92? It likely had weak clutch springs. And if you didn’t change the springs, the new clutch plates will wear prematurely as well. Nothing to do with oil.

 

[Bonz]

Have you seen his other Nighthawk 750 thread? It's right below this thread in the subsection of the forum. I'm reading he's not having trouble as it relates to the clutch, the feel isn't what he likes with his left foot going through the gears.

 

[Legs4Arms]

Before JASO was a thing, I used car oil in my bikes. LOTS of different car oils. Never a clutch problem.
I don't like spending more $$ for a "motorcycle" oil that maybe is a worse oil than this.
$27 gets me 5 qts, available close for me.
This oil is NOT energy or resource conserving which just like in the past it wont hurt the clutch.
I already have a new clutch in my bike maybe caused by Rotella.
I'm NOT using any diesel oil again.

View attachment 323868

If only I could get it here for less than a King's Randsom

 

[FZ1]

Wanted to update. I went with the PCMO Mobil 1 15w-50. Big mistake. VERY bad shifting immediately!
Not even going to try the 10w-40 Mobil 1.

Try Amsoil 20w-50 MC oil. Shifts nice in my bike.

 

[Bonz]

In the other Nighthawk 750 thread, it was said the 15w50 also caused slower cranking on 45° days, and could feel the bike was slower with the heavier grade oil. I give a thumbs up to Amsoil MC 20w50 as well as Mobil 1 VTwin 20w50, Redline 20w50 and Mobil 1 4T 10w40.

With that said, I won't go synthetic in an '80s technology UJM. Oil change intervals are more frequent and the benefit of synthetic would be lost in my opinion as oil gets dirty from the byproducts of combustion and blow by with the old air cooled engine tolerances whether it's synthetic or conventional oil in the sump. The 1982 Seca 750 I've posted about elsewhere on this forum is going to see a steady diet of 20w-50 conventional.

 

[thetricky]

Says it meets the requirements...Not certified.
Diesel oils are branching away from being a good motorcycle oil due to changing regs for pollutants. What's their first priority...Diesel engines.
JASO came out in 98. Before that it was car oil all the way. Some bought "motorcycle oil" How good is it really for what you pay??? Id rather pay less for a better oil.
Mobil 1 is the best oil out there available anywhere.

Exactly…so run an MA oil. We’re only talking a couple quarts here, you aren’t filling a cat d10 with oil. If you can afford the bikes yet want to skimp on a couple bucks for oil then perhaps you are in the wrong hobby?

 

[ZeeOSix]

Under scrutiny you'll find that clutch slip was due to normal glazing and contaminates...

Clutch plate glazing is caused by excessive clutch slippage. It's not something that happens normally unless the clutch is slipping way too much for whatever reasons.

 

[Pete in PA]

A 92? It likely had weak clutch springs. And if you didn’t change the springs, the new clutch plates will wear prematurely as well. Nothing to do with oil.

I would never do a clutch without doing clutch springs. Did all Honda parts. Works great, no slipping.