Oil gunk

[liambucket]

Hey all, I'm just wondering if its usual for a CB/XL125s engine that when it comes time to drop the oil is it usual to find little fragments of what I can only assume are gearbox bits (as they will stick to a magnet) And then after I had removed the side cover to clean the centrifugal filter I found a back/brown film of shit with some more tiny metal fragments sitting in the bottom of the case (I assume the black/brown sludge is clutch residue?) Or is the motor toast? Its a 1978-85 era CB125 frame with a unknown XL125s Engine (still running points)

Cheers for any help

[FJRider]

Yep ...............

Not toast ... I've seen worse.

Might go for a few years yet. (or not)

[RGVforme]

Hey all, I'm just wondering if its usual for a CB/XL125s engine that when it comes time to drop the oil is it usual to find little fragments of what I can only assume are gearbox bits (as they will stick to a magnet) And then after I had removed the side cover to clean the centrifugal filter I found a back/brown film of shit with some more tiny metal fragments sitting in the bottom of the case (I assume the black/brown sludge is clutch residue?) Or is the motor toast? Its a 1978-85 era CB125 frame with a unknown XL125s Engine (still running points)

Cheers for any help

A lot of short trips cause the brown sludge.....Metal "Swarfing"...On a sump plug and in oil is normal bikes and cars.

Worry when it starts making funny noises.

[liambucket]

Yeah its only had a few short trips around the block in.... 10 years? Bike got pulled out of storage, got a new barrell then I bought it, All ive done is whisk it up and down the road to make sure it went and stopped then thought Id treat it to oil (dont know if the bloke who fitted the barrel did oil I would think he did) But there isnt alot of the sludge or metal bits. But enough to have me a little bit worried haha, I hope the engine lasts a little while longer, its in a old bucket racer and I want to try get at least a season or two out of it before it needs a re-fresh

[AllanB]

Anyone ever run a oil flush through a motorcycle engine? Common on cars - done a few myself after purchasing a older used vehicle - engine oil flush and fresh stuff in there.


You can always run a few oil changes through it over a short period of time to effectively flush out the unknown oils. Filter too obviously.

It's a Honda - clean oil, plugs and unless it is making evil noises it will go and go and go

If the clutch is toast it usually smells burnt.

[liambucket]

Anyone ever run a oil flush through a motorcycle engine? Common on cars - done a few myself after purchasing a older used vehicle - engine oil flush and fresh stuff in there.


You can always run a few oil changes through it over a short period of time to effectively flush out the unknown oils. Filter too obviously.

It's a Honda - clean oil, plugs and unless it is making evil noises it will go and go and go

If the clutch is toast it usually smells burnt.

Yeah once I've refitted the oil filter (the screws holding it on are questionable) Its getting flushed with a few changes of oil before I put in my apparently gold plated oil in, stuff retails for $160 for four litres of it, got it down to $77 So Im pretty happy with that considering Ill get around 4 changes with it.

[Grumph]

Yeah once I've refitted the oil filter (the screws holding it on are questionable) Its getting flushed with a few changes of oil before I put in my apparently gold plated oil in, stuff retails for $160 for four litres of it, got it down to $77 So Im pretty happy with that considering Ill get around 4 changes with it.

DO NOT put modern full synthetic oil in the old shitter. Full synthetics don't do well in roller bearing cranks plus some pattern gaskets - which we can assume that thing's got - will dammnear dissolve on synthetic.
spectro 20/50 mineral at around $50 for 4 liters is more than good enough IMO.

The crud you're seeing may just be the residue of previous owner's lack of maintenance or a past blowup where it hasn't been properly cleaned out.
Clean the centrifugal filter - it's worth making or buying the right socket to get it off the crank - and keep an eye on it at every oil change.

[malcy25]

My CB100 had multiple piston failures due to the hammering it used to get everywhere and the poor quality after market pistons we used. It never created a problem elsewhere in the engine. I eventually sold it to a mate and we stripped the centrifugal filter and it was full of shit.

Clean it, refit it. As Grumph says, don't get flash on oil, change it regularly and just ride it.

[liambucket]

DO NOT put modern full synthetic oil in the old shitter. Full synthetics don't do well in roller bearing cranks plus some pattern gaskets - which we can assume that thing's got - will dammnear dissolve on synthetic.
spectro 20/50 mineral at around $50 for 4 liters is more than good enough IMO.

The crud you're seeing may just be the residue of previous owner's lack of maintenance or a past blowup where it hasn't been properly cleaned out.
Clean the centrifugal filter - it's worth making or buying the right socket to get it off the crank - and keep an eye on it at every oil change.

Grumph, I did ring Penrite to see what there listing for oils were for a 1979 CB125, and they said if I was going racing with it to use it, It is a full synthetic, with Ester and Zinc.. I was just going off what the supplier lists for the bike.

[liambucket]

And the filter, I just took the three countersunk screws off and popped that little cover off to find a whole heap of gunk, Is there more to clean than just in there?

[Grumph]

Grumph, I did ring Penrite to see what there listing for oils were for a 1979 CB125, and they said if I was going racing with it to use it, It is a full synthetic, with Ester and Zinc.. I was just going off what the supplier lists for the bike.

Way overboard for a CB125. I stand by what i said before. I've got several customer roller bearing posties racing on Spectro 20/50 mineral - very satisfactorily too.
Find a manual. Inside that cover is a piece on the end of the crank which is the centrifugal oil filter. It should be pulled off and cleaned thoroughly.
This requires a special 4 pronged socket. They are available aftermarket - see trademe - or can be made by cutting away a standard socket.

[AllanB]

I'm a big full synthetic fan, however I'm with the above on this one - a 79 CB125 with unknown history and a load of crud in the filter. Mineral or semi synthetic are absolutely fine - just change them frequently.

I've been interested in semi-synthetics for a while out of curiosity as they have become a default in many workshops. What I am trying to determine and relatively unsuccessfully so for is a percentage of the 'synthetic' element - some are stated as 'synthetic technology'. They are good old Dino oils with strains of synthetic additives to improve the base oil.

Nothing wrong with that but I do wonder how many are just shy of cheaper standard oils ........ and really offer limited improvement if such.

[liambucket]

Did I mention that its a mid 80's XL engine fitted, anyway. I've already bought the oil and used some so theres no taking it back now. I had thought the XL/CB engines had white metal and ball bearings? Either way. The synthetic is in there now. Penrite stand by their products too, So if it does need a mineral oil I'll get it through them. Though whats this about it dissolving gaskets?

[husaberg]

Did I mention that its a mid 80's XL engine fitted, anyway. I've already bought the oil and used some so theres no taking it back now. I had thought the XL/CB engines had white metal and ball bearings? Either way. The synthetic is in there now. Penrite stand by their products too, So if it does need a mineral oil I'll get it through them. Though whats this about it dissolving gaskets?

No white metal bearing in a old Honda single, Roller and ball bearings and direct in the alloy head (for the cam).
The head from a Gl145 has a roller cam set up (but with points) As well as bigger valves than even the XR200/XL125S Head (this can be changed to a CDI set up)
Any oil will be fine, just change it regularly. Watch for a wobbly cam in the head as this upsets the ignition timing, Plus through in a new camchain.
Make sure you don't displace the oil restrictor rubber blob in the head, make sure the o-ring is good in the cylinder stud as this is the oil feed for the top end.
The CB100 has the best and closest gear ratios (5 speed)
The XR185/XL185/XR200 crank fits all the S model cases and gives a 57.8mm stroke. This can be made to fit the early cases with a bit of machining on the crank inner bearing surfaces.

Vincent Crabtree did a nice little overview of all the Xr200 and similar stuff.
Google "on the problem of the XR200"

[Grumph]

Though whats this about it dissolving gaskets?

I have had the experience of a full synthetic oil dissolving aftermarket gaskets.
Another reason why I stay away from putting synthetics in a motor with unknown history.

Your story is the reverse of a customer of mine some years back...He got a full oil sponsorship - from a brand I approved of too - then I found he was putting it in his bloody van. I told him to put it in his van AFTER it had been in the race motor...