Black oil, Slipping clutch

[free99]

Hey guys,
I'm having trouble tracing this down: My engine runs superbly when I first start her up, and for a little while once I remove the choke. But once I get off the highway I notice it's a lot harder and noisier to shift than it was before my last maintenance binge.

Here's the thing I fixed: My clutch would previously slip in 3rd, occasionally in 5th. I bought new springs (much needed), scuffed the fiber plates and the metal plates before reassembly. No slipping, everything seemed fine, like I gained 10hp.

Now, approx 2 weeks on, I notice my oil (10w40 non-syn with no friction modifiers, replaced 700mi ago) is becoming black, clutch has started slipping again, and I'm having a hell of a time shifting to neutral without blipping the throttle a bit. There's a strange ticking sound when I use engine braking in 2nd and 1st gear. The clutch pin adjust has been backed out by 1/4 turn per the manual... I don't know what I'm missing here. The fiber plates still have thickness to them (so it'd seem).

Aside from measuring the thickness of the plates, can you think of anything else it might be? Could reduced valve clearance heat the oil up like this?

 

[timebombprod]

I'm not sure what to do but im curious, is the ticking inconsistent and sounds like the engine skips a beat or so?

 

[Redman]

......

Aside from measuring the thickness of the plates, .....
.....

My expereince is that if clutch friction plates are old, they may measure within service limit but likley are hard and not gripping like they should.
Especailly since you say is still slipping with new springs.

I say replace the friction plates and you will find it was slipping lot more than you knew. Will be so different that have to learn to operate the clutch all over again.

 

[Gorminrider]

The first thing is IME, the gearbox at low speed is clunky on these after the first 1000km on new cheap oil anyways...1st->2nd and back again at low speed just won't work that well especially when the 10w-40 is hot. Roll the bike backnforth at stop helps.. Whether it's because the first owners made it worse by trying to force it, I don't know, but because it works better with new oil, I think it's just a feature of that particular gearbox with cheap oil. I'm used to it on my GSX400 s... At high rpms it's fine though...
That's not to say you don't have a gearbox problem. Just that, because of their nature, it could have been made worse by someone forcing it..bent control mechanism etc...

The second thing- related- is that it's tempting to try to adjust the clutch to fix this. It won't. Per your description, my thought is to adjust the clutch per the book, including that bit of slack at the handlever that means the clutch is fully engaged. You've maybe already done this, but...maybe not and if not, your clutch is not fully engaged causing the slipping.
Whatever, if the clutch plates were abused by previous use,(you needed to change the springs) you could certainly try new ones. The clutch was very common across many bikes and they should not be expensive. Lots of second-hand ones should work too. For Myself, they seem to last a very long time and I've only bought one set as a whim because they were hyper fancy expensive ones I got cheap.

As to black oil, after 700 miles, of course oil shouldn't be black so soon....not on the dipstick anyways. I suppose in a jar, it'll be brownish but have lots of life left in it.
The simplest reason would be that it wasn't changed early before ,including the filter, so it's still flushing that old black oil.

As to valves, if you think they are possibly too tight, ADJUST THEM. The damage possible is far worse than black oil, which I doubt is the cause of that anyways.

 

[Nessism]

Sounds like your sump is full of sludge which is contaminating your clean oil and making it dirty fast. You might want to drop the oil pan and clean it out. Realize first though that the exhaust needs to come off and if the bolts on the head haven't been taken off in a long time they may be seized and cranking them out often results in breaking them off. There are tons of threads here issuing caution to NOT force the header bolts out. Use a small 1/4" ratchet handle and use mild torque so the bolts won't break off.

Regarding the clutch, it sounds like the fiber plates are petrified and need to be replaced. I'd replace the steel plates at the same time since they like to warp. A fresh clutch, along with new cable, is truly a thing of beauty.

 

[free99]

Alright, Redman, gonna just order a new set of friction and driven plates.

Gorminrider, slipping clutch could certainly explain seemingly overheated oil (my understanding on a key cause for it blackening). I don't want to turn this into YANOT (yet another oil thread), but I guess this shouldn't happen if I go back to T-4 Rotella?

Ed, I don't think sludge could have formed in 700 miles; I had previously dropped the pan etc when I had to disassemble the entire engine, I made sure the pan was sparkling.. But, what is your opinion?

 

[Nessism]

It's normal for the oil to look somewhat dark after 700 miles. Blow by gases and clutch friction material will mix with the oil. I wouldn't worry too much about that. Be sure to use diesel oil like Rotella or motorcycle oil.

 

[Gorminrider]

Gorminrider, slipping clutch could certainly explain seemingly overheated oil (my understanding on a key cause for it blackening). I don't want to turn this into YANOT (yet another oil thread), but I guess this shouldn't happen if I go back to T-4 Rotella?

Well, I did say,

Whatever, if the clutch plates were abused by previous use,(you needed to change the springs) you could certainly try new ones

as Redman is saying too. But blackening the oil in 700 miles due to a slipping clutch is new to me. I'd wonder how the bike would be rideable slipping so bad as to "blacken" oil but without creating smoke and fire...so that's a curiousity to me.

As to oil, the one or two that have agreed with me per the gearbox, have found their solution in fancy Amsoils and the like. I am not myself impressed with oil for diesel pickups whatever brand- it soon gets "chopped up" but is probably safe enough around the pistons and valves...

 

[Guest]

Sounds like your sump is full of sludge which is contaminating your clean oil and making it dirty fast. You might want to drop the oil pan and clean it out. Realize first though that the exhaust needs to come off and if the bolts on the head haven't been taken off in a long time they may be seized and cranking them out often results in breaking them off. There are tons of threads here issuing caution to NOT force the header bolts out. Use a small 1/4" ratchet handle and use mild torque so the bolts won't break off.

Regarding the clutch, it sounds like the fiber plates are petrified and need to be replaced. I'd replace the steel plates at the same time since they like to warp. A fresh clutch, along with new cable, is truly a thing of beauty.

I may be wrong - happened before - but I don't recall having to drop the exhaust on a twin to drop the pan. So it's easy to do, BUT, you must use a new gasket because these motors run way more oil pressure than the roller bearing ones and the center holes of the pan are pressurized to 40 plus psi.

I'm suspecting that the clutch actuating spiral - made out of genuine plastic that must have cracked by now - may be in dubious shape. I think the GS500 ones 'may' fit but haven't tested that theory yet myself. They're all metal w/ ball bearings and a way better idea.

The clicking is probably the chain loose and the upper run slapping on the swing arm pivot when the bike pitches forward, or a loose countershaft sprocket. Or something expensive.

I back my header bolts out every other year and give them a fresh coat of anti seize. Not much work compared to not doing it and having to deal with a busted off bolt. Just four on a twin.

 

[free99]

So I did a bit more investigating while I wait for the replacement drive/driven plates to arrive.

The countershaft sprocket is tight, rear wheel is straight, chain is a little loose but I can't get it to touch the pivot if I try with my hands, and.. Well it's actually become this moderately frightening quiet roar when I accelerate. I am inclined to suspect the rear bearings, but I don't know for sure.

My ears are telling me the sound is coming from my left-hand rear. I've rechecked the clutch actuator a few times, chain tension...hmm, what else. The roar only seems to appear when accelerating, roar intensity is proportionate to accel intensity. Decel doesn't seem to make much noise.

What in the hell? I've removed the chain guard, made sure there's no contact between frame and wheel, rear drum brake is a little loose for the sake of elimination. I can't get the wheel to wobble while on the centerstand. What could be happening?

 

[LAB3]

So I did a bit more investigating while I wait for the replacement drive/driven plates to arrive.

The countershaft sprocket is tight, rear wheel is straight, chain is a little loose but I can't get it to touch the pivot if I try with my hands, and.. Well it's actually become this moderately frightening quiet roar when I accelerate. I am inclined to suspect the rear bearings, but I don't know for sure.

My ears are telling me the sound is coming from my left-hand rear. I've rechecked the clutch actuator a few times, chain tension...hmm, what else. The roar only seems to appear when accelerating, roar intensity is proportionate to accel intensity. Decel doesn't seem to make much noise.

What in the hell? I've removed the chain guard, made sure there's no contact between frame and wheel, rear drum brake is a little loose for the sake of elimination. I can't get the wheel to wobble while on the centerstand. What could be happening?

It isn't too big a job to pull off the rear wheel to check the bearings and grease them plus it's a regular maintenance task as well. On my 450t there was a rather loud noise on acceleration and it turned out the nut on the drive sprocket was loose which I didn't notice until I swapped the sprocket out while installing a new chain. You have already had that nut off while working on the clutch so you might want to check that.

 

[Maddevill]

I use Rotella T6 in all my bikes. Replace those friction plates. Check the rear wheel bearings and have a look at the output shaft bearing. Take the chain off and rotate the shaft. See if it feels smooth. Good luck

Mad

 

[free99]

D'oh!

D'oh!

Rumors of my rear bearing's demise have been greatly exaggerated.

Does this work? :facepalm:
No? Well, how about this: :stupid:

Turns out after:

• adjusting tension with the bike on its sidestand
• Taking the wheel off and seeing that all 3 bearings look/feel fine
• Trying (and failing) to locate the swingarm lube point

That the noise was apparently due to my x-ring chain not having enough lubricant. :stupid:
I saw a bit of rust on the chain (which I replaced 4000 miles ago), and gave it a quick clean with some #2 diesel on a whim. Suddenly the roar is gone when I accelerate almost as fast as I can.

So: Turns out that while x-chains need less care than a regular non- or o-ring chain, they still need a bit here and there.

Sorry to have wasted everyone's time on this one.