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1983 Honda CM250 Oil Question

Discussion in 'Maintenance and Servicing' started by Choofalong, Jan 31, 2012.

  1. So: I finally got my Haynes Service manual and am getting set to do an Oil change. Couple Questions:

    1: I was expecting to have to do an Oil Filter change, as well as just the Oil: but there is no mention, whatsoever, of an oil Filter that I can find in the Oil changing Section. What am I missing?

    2: I recently heard that Motul 5100 10W30 Engine oil is/was designed for Honda Engines, at least they go into most newer models when put into Servicing at a Honda Dealer or when new: Would this be an acceptable Oil for my Older Bike? If it is not, what would be a recommended one? I am currently using Motul 3000 SAE 20W50, as it was given to me from the Previous Owner: i was orginally just going to get the same, as there is not enough for a full Oil Change left in the Bottle.. which also looks prety old, so not sure if using it would be a good idea anyway.

    Thanks for your time!
  2. what does your manual say regarding the oil you should use for your bike?
    Do you have an oil filter changing tool?
  3. Manual says for Genral/Allpurpose: SAE 10W40

    Would the minor difference be really a big thing? I mean; if Honda ended up swapping to this other Motul one later; wouldn't that mean they realised it's better?

    Or would it be more of a thing where it's a different process for the Engine Build?

    I have it on good authority that the CM250 I have is basically a CB250 motor in a Pre-rebel Frame: the CB250 is one of the Motors that the 5100 oil is recomended for... at least the newer models.

    I really have no I dea what the numbers in the Oil mean or anything else: what I have written here is pretty much the extent of my knowledge, and a lot is pretty mucch heresay, atm, so go ahead and talk to me like the Newbie I am :D

    EDIT: My Brother says he has an Oil Filter Changer Tool... thingy that works on cages: not sure if the same will work on a Bike?
  4. Not sure about the CM but the CB250 does not have a filter. Once a year or so you take a cover off the engine ( may require a new gasket on replacement) and in the bottom of the sump is an oil strainer - basically a wire, mesh screen that traps the bigger particles but probably not as well as a normal filter. That said, the engines seem to go on forever so I guess it works.

    30 oil sounds a bit lightweight and if the manual says 10W40 I would go to the higher weight, especially in summer.

    Bike oil filters are usually much much smaller in diameter than car oil filters so the car took may be too big. But if you have a cannister filter and the car tool fits then it will be fine to use.
  5. ... Reading up; it's looking like I might be in for a bigger job then I was expecting...

    It's some sort of Oil Filter Screen thing that I have to take the Oil Pump out to do. One thing I have noticed: the manual keeps refering to just "Engine" oil: Does this mean ANY 10w40 Engine Oil will do? I assume this would mean the only thing that is important is the actual numbers: but, there are Motorcycle-specific oils out there too! Gah, it's getting all quite confusing trying to figure out what the "best" thing, for my Bike would be! I suppose, if I looked, there would be Oils out there specifically for Older 4 Stroke Engines too!

    -sigh- I was thinking about buying a new Air Filter, but I am just gonna try a Cleaning, like manual says :(

    One other thing that has come up though: Sparkplugs. I am thinking about just buying new ones and replacing, as who knows how old the ones in there are, but in the manual, I am only getting US or UK recomendations on Sparkplugs: any Idea which one I should be following/asking for?

    LMAO: I was getting a little depressed with the 3 day "%100" chance of rain coming up here in Newcastle... this little project is getting me looking forward to it though!

    I am also looking forward to getting my Chain and Sprockets replaced... The Chain Lube I put on it made a remarkable difference: can only assume getting a new set would be an even better improvement, if only a slight one
  6. On an older Honda I would be using 10W40. The 10 denotes that the oil is "thinner" on a cold start than, say, a 15W40 or 20W50. Given that the lower viscosity oil will provide pressurised lubrication to your camshaft significantly sooner after a cold start and given that what commonly kills older Japanese engines is camshaft wear. this is a Good Thing.

    I've seen too many 70s/80s Jap engines go to an early grave due to skimping on their lube needs to treat such things lightly.

    As well as the oil screen, there may be a centrifugal "filter" in there somewhere. Check your manual again. If there is one, you'll need to dig out the hard metallic crud that will have built up in it.

    It's all a little more involved than changing a modern cartridge filter but your engine will thank you for it.

    Have a hunt around online for a conversion table. NGK are international and so if you can find the NGK number you'll be able to match it at an Australian bike shop. Places like Supercrap are cheaper but often don't carry the plug grades/sizes common on bikes.
  7. Thanks all for the info: I will be going for the 10w40 as stated in the Manual: I am kinda partial to the Caltex Magnatec: I like the idea of "higher technology", but I've not been able to find one specific to 4 Stroke Motorbikes: Only "Engine Oil"

    Would using that be ok, or should I stick to the Specific 4 Stroke Motorbike Oil? and what happens when the Oil says (motorbike specific one) "For use on any Model later then 1990"? SHould I stay away from that, and try to find one that states is for older, 80's Engines?
  8. Pretty much any oil you can now buy will be better in most respects than the best available in 1983. As far as your engine is concerned, don't worry too much about the blurbs on the cans.

    However, many modern car oils contain additives which can cause slipping problems for motorcycle clutches which share the engine oil. Or, OTOH, might not. It's something of a lottery. On something like a CM250 which doesn't have a vast amount of torque and so gives its clutch a relatively easy time you might get away with it. If you didn't, a set of clutch plates for a CM is neither cripplingly expensive nor hard to fit so the gamble might be worth it.

    Others here know more than I do about this, though. I currently use diesel engine oil in all my bikes and have had no problems but that's my particular oil choice in my particular bikes with my particular usage patterns so I can't speak for other applications.
  9. I too have heard this theory about using Diesel Engine Oil for Bikes... I can't recall where (probably here, tbh) but it was recomended for Bikes with Wet Clutches, and especially older bikes. This was a question I was going to bring up, so I am glad you did!

    I am curious about the Highlighted section... care to elaborate? I basically try and get 100km a Night/day done, at least: but am looking to get into the longer rides, building up some stamina when it comes to riding: would this higher usage have any bad effects if using said Diesel Oil?

    Even just an opinion of the advantages of this type of Oil, over others, might help me decide

    EDIT: Crap: I just realised I haven't asked another important Question: Should I be going a Synthetic Oil? It's supposed to be better using a full Synthetic on Older Bikes, over a Blend, right?
  10. No, regular usage won't have a detrimental effect, whatever decent oil you use. I'm just covering my arse really. The stuff I'm using (Valvoline Super Diesel) is rated for use in petrol engines. The key here is to look for something like CF/SJ in the small print. C stands for Compression ignition, ie diesel and S stands for Spark ignition, ie petrol. If it's got both a C and an S rating, calling it "Diesel" oil is a marketing description, not an engineering one. Indeed, based on something I read on Castrol's website, many "Diesel" oils don't have an S rating because they contain additives that will knacker the catalytic converter on a petrol engine. That's not a consideration for the (current) majority of bikes. The lube properties should still be OK.

    But I digress. My main concern is that the Valvoline I use is a 15W40. I can live with that because my bike's manual says I can use 15W oils, I ride in Perth so temperatures never get that low and I make sure my engine sees nothing more than idle revs until I'm certain that my cam is seeing pressurised oil. I don't worry about clutch issues because I haven't had any and if I did, swapping out the clutch plates won't kill me. Whether my lack of problems is down to a lack of friction modifiers in my choice of oil, my tendency to not sit for long periods with the clutch pulled in, the particular material that Suzuki made the DR650 clutch out of or simply sheer blind luck, I have no idea and so can't offer reliable advice.

    The main advantage of Valvoline that I use is that I can buy it in 20l drums for ~$100, use it in all my fleet of vehicles apart from MrsB's Ural and so can use a single delivery pump for filling sumps so there's less mess.

    OTOH, for an old tech Honda, particularly one ridden in cooler climes, I'd be reluctant to go for a thicker W rating than the manufacturer recommends. Their top ends need all the help they can get. I'm not sure if there are any 10W diesel oils out there, hence my reluctance to actually recommend the diesel route in this case. If you can find one, by all means go for it.

    Don't bother with synthetic. The main advantage of synthetics is extended life between oil changes. On your particular engine, given its lack of proper oil filtration and fragile top end (compared to modern motors), you should be changing your oil at 2000 km intervals or less, regardless of what your manual says. Using a synthetic is pointless with intervals like that. Just use a good mineral oil. Good, in this context, meaning from a recognisable brand rather than Aldi's cheapest.
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  11. Thanks very much for the in-depth reply: will definatly have a look out, for sure: For now, I am gonna stick with the recommended 10w40 Oil, that states is good for 4 Stroke Engines.

    Guess it's almost time to get down and dirty!
  12. 10W-40, motorcycle specific, forget about the full synthetic.

    You don't have to get the very cheapest around, but there's no need to go anywhere near the sometimes absurdly expensive synthetics designed for racers with lights.

    A relatively cheaper one that meets or exceeds the spec in the manual (and they will this many years on) changed maybe every 5-6000km or six months will be about the best and cheapest insurance you can have.
  13. Agree with Wayned apart from this bit,

    Fine on a modern with a proper oil filter but the CM has what is, effectively, a 1960s engine design (direct descendant of the CD175 I believe) and so needs 1960s oil change intervals. The sump only holds a couple of teaspoonfuls so keeping it fresh will be a lot cheaper than wearing out the cam bearings.

    Yeah, I know I keep banging on about it, but running old (1970s and very early 80s) bikes on a budget so tight that it squeaked has left me permanently marked :D.
  14. Last time I pulled th CB250 apart the strainer just sat in a pair of slots in the sump. wasn't connected to a pump as I recall, although to make any sense I assume the pump was next to it and pumping through it.

    Out of curiosity Pat, what do you use in the Ural?
  15. Plain old 20W50 car oil in both engine and gearbox, as specified in the manual. Dry clutch so friction modifiers don't matter a damn. Currently using Valvoline XLD but anything with a brand name and a cheap price tag will go in.

    Oil change every 2500 km. Manual says to do the filter every other change but I got a bargain bulk bag of 'em from the US and swap them every time.

    I put a deep sump on it a couple of years ago that ups the oil capacity by ~40%. Physics says that it won't actually run any cooler but each individual oil molecule will get heat cycled through the heads 40% less frequently which can only be good.

    TBH I'm still not entirely convinced about the engine oil in the gearbox. I might try a dose of EP90 at some stage. GL4 though, rather than GL5 'cos ISTR that GL5 eats brasses and bronzes, which is a problem when that's what most of your plain bearings are made of in a 1940s design.

  16. Fair point - I was thinking that motor had a decent oil capacity, but was more familiar with the CB250T (aka Hawk, with the counter balancers).

    The oils have improved a lot too though, but that could have been better qualified with suggesting that, depending on it's oil capacity and recommended oil change intervals, change it somewhat sooner, if not at half the interval in the manual. If it only holds a couple of litres, that's only $20-25 and a few minutes.

    Thinking a bit more about it's age too, I'd personally lean towards heavier oil to guard against having metal bits come together.
  17. Pat,

    I use 15W50 in my beast and EP90 in the gearbox, diff and shaft.

    After reading the Delo thread I use that in the Yamaha but the BMW always feels hot (maybe I just have sensitive feet?) and I figured oil suited to a higher temp range might be better suited.
  18. The Ural gets EP90 in the final drive but the manual is very specific about the 20W50 in the gearbox. However, I do have some reservations about a number of aspects of the manual so I'm inclined to experiment.

    As a general rule, air cooled engines will subject their oil to greater extremes of temperature than water cooled ones. However, as air cooled engines become rarer, so do oils specifically intended for them so it's necessary to rely on the general improvements of all oils over time and to use a little nous and some mechanical sympathy when selecting them. It's one of the reasons why Harley branded oil isn't entirely a wank. It's being specifically sold for big air-cooled engines with dubious heat management and so has its uses elsewhere too.