Topic: Is my gearbox living on borrowed time?

[Jonesy]

I did the standard oil change drill yesterday and was alarmed with what I saw. In the bottom of the oil filter housing there was a small quantity of little metal chunks. I'm worried the tranny is on it's way out.  When I shift gears (mainly from first to second) it makes a loud "whack" noise (always done it since I got the bike a year ago) and sometimes you really have to lift hard on the gear chang pedal to make sure it's in second. It's never popped out of gear, but should I be looking at tearing it apart this winter? Maybe sooner?

[Lumbee]

...you didn't say what kind of bike you had.  Any any rate these mills are pretty durable, and even more so with the bottom end.  You could try dropping the oil pan/screen and check for debris...

[Jonesy]

Oops.. Sorry. CB750 K3.

[Luke]

Mine does all of those things to, so if yours is on its way out, so is mine.  Im personally not going to worry about it, I think its fairly common, and if mine gives up, I will address it then.

[MRieck]

Were the chunks aluminum or steel. Check with a magnet.

[nomadwarmachine]

I'm not saying that your gearbox is not hurting, but 750K2 has been whacking into first gear since 17000 miles, and I willl turn over 40000 this weekend.  I find that setting the idle a little low (around 1000) makes shifting into first a lot easier -- takes longer to warm up, but the bike seems happier.  As far as the metal bits are concerned, if they are aluminium from the pistons (non-magnetic), start worrying -- if they are small fine steel from the tranny, I would not sweat it unless there are very many of them.  You can always drop the oil pan and look, but I would leave it until the winter (of 2008).   

[Matt at PSB]

If you are running modern automotive oil then yes your gearbox IS on borrowed time. Run any brand of oil you wish synthetic or not as long as it actually has this written out in the fine print on the oil container: "API rating of SG" and /or a "JASO rating of MA". API ratings of SJ, SI, & SH will do in your gearbox sooner or later. The phrase: "meets or exceeds all earlier API ratings" on a container of SI, SJ, or SH is not going to save your gearbox in this application. Post 1996 American automotive oils (SI, SJ, SH) have been stripped of their extreme pressure zinc & phosphorus base additive to make then more compatible with automotive catalytic converters. The gear faces in your bike's transmission need these zinc & phosphorus based additives to survive.

This topic always starts a long thread of responses called an "Oil War". Sure you have run you bike on Castrol GTX for thirty years now without troubles. Go out to the trash heap & find a 1995 container that held GTX. Compare the fine print to what is on a modern container of GTX. You may not have changed, but the EPA has changed your favorite oil. Knowledge is power: always read the fine print

Matt at PSB 

[Jonesy]

I was running plain-jane Pennzoil 10W-40, but had switched to Honda Motorcycle oil ($4 a quart- ouch) I stay away from synthetics since they turn engines into leakers. I suppose I should drop the pan... wouldn't hurt to clean the oil pickup while I'm in there...

Matt- are you saying since I've run auto oil in my bike it's now permanently damaged?  I think that's a bit extreme.....

[TwoTired]

I was running plain-jane Pennzoil 10W-40, but had switched to Honda Motorcycle oil ($4 a quart- ouch) I stay away from synthetics since they turn engines into leakers. I suppose I should drop the pan... wouldn't hurt to clean the oil pickup while I'm in there...

Matt- are you saying since I've run auto oil in my bike it's now permanently damaged?  I think that's a bit extreme.....

My $.02...

If you were running "modern" Auto oil in there, you can expect accelerated wear in the transmission.  At some point, accelerated wear leads to worn out.  Somewhere along this progression lies "permanently damaged".

Maybe the evidence is in your oil pan?  Loss of metal seams like "permanently damaged", to me.  Worn out and needs replacing, is another matter. 
I hope, for your sake, it's not.   

[Jonesy]

OK... I meant my last post to mean is it reasonable to expect stuff to just start disintegrating after only one oil change interval that used the wrong stuff? I'm the umpteenth owner of this bike and had no control over what's been done to it (or put into it) during the first 25,000 miles of its life before I got it and added my own thousand miles. As soon as you put a mechanical device into service, it starts wearing and nothing short of an overhaul will put the metal back where it wore off from- that's a given. What's done is done. I only brought up this topic because I was looking for ideas as to what the issue may potentially be and how concerned I should be about it. I'm doing everything I can at my level of knowledge to preserve what I have. Obviously my next step is to drop the pan and see what's in there.

[Matt at PSB]

I was running plain-jane Pennzoil 10W-40, but had switched to Honda Motorcycle oil ($4 a quart- ouch) I stay away from synthetics since they turn engines into leakers. I suppose I should drop the pan... wouldn't hurt to clean the oil pickup while I'm in there...

Matt- are you saying since I've run auto oil in my bike it's now permanently damaged?  I think that's a bit extreme.....

No, I'm saying stop running automotive oil. Some metal debre is normal in the filter: That is what it is there for.

This is good reading on this topic: http://cb1100f.net/modules.php?name=Forums&file=viewtopic&t=13116

Matt at PSB