Before you begin, kneel way down and look under the engine between the left footpeg and the kickstand, just above the bottom frame tube there should be a rubber splash guard (may be missing on some bikes) you should be able to locate the oil drain bolt which is facing the left (not straight down as on cars and some bikes) once you have located this bolt you are ready to begin...
you will need the following items ...
* 2 quarts oil (see below for discussion and links on oil type)
* socket wrench with 10" or longer extension and 17mm socket
* paint pan for catching the dirty oil (and usually the darn drain bolt)
* funnel and jug for storing/disposing of dirty oil
some things to keep in mind ...
* it is recommmended you go for a SHORT 5 minute ride to warm the oil slightly so it flows better - but not so long a ride as to make the mufflers dangerously hot (many people burn themselves the first few times until they get the hang of it - i suggest leather work gloves for safety)
* let the oil drain for 15-30 mins to allow time for it to all settle out and also for the mufflers and dirty oil to cool off
* if you totally remove the drain bolt all at once, the dirty oil usually gushes out and can get all over your frame and mufflers and other stuff down there - back it out until it starts trickling - then slowly back it out some more untill it is almost all the way out - and let the oil pressure fall a little before totally removing it ... the bolt usually falls into the drain pan - later when you are cleaning up be sure to pour the oil out of the pan and into the funnel slowly and carefully and stop when the oil gets low enough for you to fish the bolt out - then resume pouring ... the bolt hole is not perfectly perpendular (it's slightly angled with bike lean) so you might need to reach under and start the bolt by hand when replacing it
* when tightening the drain bolt back after the oil change - DO NOT over tighten you risk stripping out the threads - it should be gently snugged not muscled down - there is also usually a brass crush washer for teh bolt too - this needs to be replaced after every couple of oil changes - it is brass or another softer metal meant to crush 'slightly' to help prevent drips
* i use a dedicated funnel JUST for the dirty oil - i avoid using the same funnel to fill clean oil as the dirty funnel might have metal particals or other dirty oil contaminats that i do not want to put back into the engine - i have another funnel i use just for clean oil filling
* you will need a place that you dispose of the dirty oil when your oil jug container is full - DO NOT throw in trash or pour on ground or down sewer drains - it is classified as hazardous waste material - take it to your local automotive service center or pep boys or wal-mart or whatever - they will take your dirty oil (in some/most cases there is a slight disposal fee)... i use 1 gal plastic jugs (old clorox bleach jug in pics above) and this holds two oil changes quite nicely - you can also use milk jugs or detergent jugs - just so long as it has a broad base to prevent tipping over and will hold at least 2 quarts - the rebel 250 takes 1.6 quarts in the manual - but i have found that 1.75 quarts is a better measure - and after the next ride or two following the oil change remember to check your oil level to see if it needs topping off a little - and also check under the bike to see if there are any leaks
will post more if anything occurs to me or if there are any specific questions ...
One of the posters on the honda rebel forum created a video of the procedure :
IMHO synthenic oil is better than natural dino oil - but is also more expensive - the warning about synth is in regards to ADDITIVES like stuff to make it slicker - stuff to make the filter better - stuff to do magic tricks ... remeber that the rebel has a wet clutch, which means that the engine oil is also the clutch fluid - and super slick additives and stuff can do a number on the clutch plates ... in fact the first thing to do when you have shifting difficulties is an oil change - this usually clears up a majority of the complaints - and some people even know when the oil is getting dirty by subtle changes in how thier bike shifts ... also remeber that the rebel 250 does not have a oil filter - it has an internal mesh screen that is a pain to open up the engine to take out and clean (8,000 mile intervals recommended) - super filter additives means that the screen gunks up faster and might even totally block up - regular frequent oil changes helps reduce the issues with the screen - the manual says to change the oil every 4,000 miles but many change it every 1-2,000 miles and some even say they do it every 600 miles - i do it every 1,000 miles or so (or about once every month or two)... personally i feel synth is better than dino as it resists breaking down under hard riding high heat conditions and has fewer contaminats to produce carbon deposits ... BUT ... it is also more expensive and if using cheaper dino oil helps make you more inclined to do regular frequent changes then by all means do use dino - just go with a dependable name brand no lighter than 10w40 ... i like 5w50 in cooler weather and 15/20w50 in summer (the first number in front of the w is cold viscosity and the second number after the w is hot visciousity - the lower the number the thinner the oil - the higher the number the thicker the oil)
below are some links to sites about engine oil and motorcyles and such ....