what oil?

I just bought a 1989 Yamaha YX600 Radian and it needs an oil change. What weight oil should I put in it? Or could someone point me in the right direction as to where to look to find out.

Congrats on your purchase! The Radian is a great bike!


I don't know the weight oil recommended for it, but if you don't already have one, I STRONGLY suggest getting a manual for your bike. You'll be glad you have it sooner or later.

i had a question why did u pick that bike?

I agree with Saturn. Buy a service manual for the bike. It will help you with all the little specifics of your bike. Whatever oil you choose, stick with motorcycle specific oil. The new high mileage, high detergent car oils don't have the correct formulation to protect your engine and trans.

thanks for the input guys. i just bought a manual online, it should be here in a few days.
i bought the radian because i had wanted a bike for a while and it came up for sale on the road i drive on every day to work. i stopped to look at it and i liked it so a few days later i took it for a test drive and loved it. i made an offer and he accepted.

another question: how many miles is a lot for a street bike like mine? it has 19k on it now.

I agree with Saturn. Buy a service manual for the bike. It will help you with all the little specifics of your bike. Whatever oil you choose, stick with motorcycle specific oil. The new high mileage, high detergent car oils don't have the correct formulation to protect your engine and trans.

Shell Rotella 15W-40 is made for diesel fleet service, but works well with wet clutches, and is a good grade for motorcycle service. And it comes in gallon jugs real cheap at WalMart...me and several others have been using it for years in bikes, with good results...

:screwy:
can anyone else confirm that ^

nuther q:
recently the bike has developed a very annoying vibration in the trans (i think) when the engine is between 3500 and 5000 rpms. it sounds like it is on the right side, but it is hard to tell. i'm thinking it is coming from the clutch area. it does it both when the bike is in gear and in nuetral. could broken down oil cause this? the oil is completely black in the eyeglass thingy. i'm not driving it anymore 'til i change the oil.

You said vibration, but then you said sound.

Do you feel it (vibe) or hear it (sound)?

The exhaust runs down that side, yes? Check the hangers, header flanges, and clamps would be my first guess, put your foot on the pipe (with the motor cold, or you'll melt your shoe) and brace it, see if the sound disappears when you rev it...clutch basket noises usually occur at idle. Nothing moving in the tranny when the bike is still, so doubt it's that. Could be primary chain noise or something. Or camchain, etc...motorcycles have so many chains, jackshafts, and gear drives internally, trying to guess what a noise is without hearing it is pretty dicey.

Check that the engine is solidly bolted to the frame also...I had a Vulcan 750 that developed an annoying vibe in a certain rpm range, turned out it had a mount backing off...

i can't feel the vibration, i can hear it. i'm pretty sure it is somthing inside, but i'll check those other things you listed.

btw, i lol'ed at your sig.

it was the muffler. it cracked at the joint between the header and the muffler. anyone know where i can get straight pipes for it?

You wouldn't want to straight pipe it...you'll loose power off the bottom and it'll blubber and sound like crap, may be hard to start cold also. You have to re-jet the carb and open the intake to make use of straight pipe.

i just want it for the sound. i think the side without the muffler on it sounds awesome. what does it take to re-jet the carb and open the intake?

Whatever oil you choose, stick with motorcycle specific oil. The new high mileage, high detergent car oils don't have the correct formulation to protect your engine and trans.


Complete and utter rubbish put out by motorcycle DEALERS so that they can make a dime off of you. If you want to know the truth, do some research instead of being spoonfed every little tiny scrap of bullshit that the stealerships dish out.

Steel, you're wrong. Many motorcycles use the same oil for both the engine and transmission. These new car oils have so many additives that they don't have the shear strength to withstand the added abuse in the trans. If you want to use a SJ or higher rated oil in your scoot, by all means do so. I hope you have fun replacing the trans side bearings and clutch parts.

Steel, you're wrong. Many motorcycles use the same oil for both the engine and transmission. These new car oils have so many additives that they don't have the shear strength to withstand the added abuse in the trans. If you want to use a SJ or higher rated oil in your scoot, by all means do so. I hope you have fun replacing the trans side bearings and clutch parts.

Prove it. Ive never ever met anyone who has claimed to have problems with their bike from running car oil, yet i hear it all the time. I wont be changing anything in my engine for quite some time, have fun overpaying for oil :)

here we go again......


my reason is that the cost of decent bike oil (repsol, motul) is nothing compared to car oil of comparable quality.

but also, name a car that runs a wet clutch.....

Like I said in the last one of these, Shell Rotella is made for OTR diesel trucks, but lacks the friction modifiers that don't play nice with wet clutches, comes in several grades (I use 15W40) is ecellent at suspending particulates (like diesel carbon or wet clutch wear debris)and is pretty damn cheap by the gallon at Walmart and others...myself and many other cyclists have found it to be a very good alternative to MC specific oil...

i just want it for the sound. i think the side without the muffler on it sounds awesome. what does it take to re-jet the carb and open the intake?

Sorry, I lost my bead on this thread somehow...

Doing exhaust "just for sound" is not really adviseable on a bike (or a carb'd car for that matter) there are two issues...backpressure (the amount of restriction at low flow) increases scavenging (an effect which helps fill cylinders with air faster for better torque and throttle response in the low rpm ranges)...and the additional flow out the back end creates an imbalance in relation to the amount of flow the stock airbox can deliver...the imbalance screws with the venturi effect of the carbs, making the mixture wrong. An engine with wide open exhaust and a restrictive stock airbox and carb tune will run lean, and cook the pipes and make exhaust valves run hot and possibly burn...

To remedy, you need to improve airflow into the airbox, usually done with addition of a K+N type filter and possibly a less restrictive box design, along with a re-jet of the carbs, which includes larger main jet orifices and new needles which can be adjusted up or down to fine tune the amount of fuel the jets meter through the range of throttle opening...it's time consuming work if you have multiple carbs because everything must be resynchronized and correct needle positions can be trial and error...that's why fuel injection is so nice, all you need is an interface and some fuel maps to try until it works fine, no messing with mechanical settings...

Stock engines anymore are already tuned way lean for EPA appeasement...doing anything to make it worse is asking for trouble..do it right if you're gonna do it.

Like I said in the last one of these, Shell Rotella is made for OTR diesel trucks, but lacks the friction modifiers that don't play nice with wet clutches, comes in several grades (I use 15W40) is ecellent at suspending particulates (like diesel carbon or wet clutch wear debris)and is pretty damn cheap by the gallon at Walmart and others...myself and many other cyclists have found it to be a very good alternative to MC specific oil...

The reason that oil works in bikes is because it doesn't have the friction modifiers.

...that's why fuel injection is so nice, all you need is an interface and some fuel maps to try until it works fine, no messing with mechanical settings...




fuel injection on bikes is a bit more primitive to cars. they don't have the capacity to vary the fuel according to the oxygen sensor enough when aftermarket pipes are fitted.

i was told that the ECU can only change very small amounts (if at all) which would be more inline with atmospheric conditions rather than larger changes.

the new gixer range is supposed to have a better tolerance than the others.

oh and power commanders are fricken expensive to buy and set compared to new jets


back to the oil debate......

$50aus for my oil. $10aus for cheap shit supermarket grade "motor" oil
thats $40 per 6 months or 21 cents a day. why could you be bothered complaining.

relative side note. i had an old tradesman ask me why i change my oil in my car every six months when he's been driving over 100,000 k's on the same oil in his F100. he thought he was saving money by not changing the oil. the truck was so slow and hard to drive. one day i paid for new oil and changed it for him. suddenly it had some torque. and he wasn't wasting money on as much fuel either........:screwy:

That's why I said you need an interface (power commander or similar) to modify it's map. But compared to the labor cost of having someone remove multiple carbs, disassemble, replace stock needles and jets, re-install, road/dyno test, R+R as many times as it takes to get it right, carb synch, etc...the cost of a power commander still wins, I think. And the user gets to mess with it and tune it to his satisfaction, not some wrench who doesn't know how it feels when YOU ride it...

I was just up at the chain auto parts store, and noticed they carry Castrol MC spec motor oil 10w40 and 20w50 for $3.59/qt....pretty reasonable as MC spec oils go. About the same as the factory branded oils at most metric bike dealers, a little less...SG/SH rated but no friction modifiers.