Buying a motocross bike is always a dodgy buisness. Buying a bike off of someone you have never met before, not knowing what torture he has inflicted on the bike is always daunting. So I will try and help as much as possible. I myself have had dealings off of dodgy dealers until last year I was fed up with buying bikes off of complete strangers. To be honest if you want a mx bike your far better (paying more money than on ebay) going to a motocross dealer and forking out for a second hand bike, it's then at least had a look over by a trained mechanic and had a service. If you don't have a dealer near you or don't want to spend an extra £500 or more at a dealer than buying online is best. Ebay do as much as possible to provide a online service without dodgy dealers...but that doesn't stop them. You can normally tell a bike is dodgy by looking at the photos or how the sellers ad is layed out. If the advertisment has had no organization or layout to make it look attractive then it could suggest the guy selling it couldn't give a fu**, this is not always the case but always think to yourself 'if I'm making 2k from this bike sale, shouldn't I at least make it look appealing. If the photos of the bike are very dark and showing hardly any areas of the bike, don't buy, 9/10 times the seller is trying to hide something. If the bike has just been washed and all the floor space in the photo is wet, you cannot tell if there are any leaks, this is a big problem and is most common, so beware... If however the add is good, pictures of the bike look amazing and your now counting how much you have in your piggy bank then always go and view the bike first !! Important areas to check : engine, swing arm, subframe, airbox, plastics, wheels, tires, chain, sprockets. Remember !! when going to view the bike ask as many questions as possible, this may piss the seller off but at least you will know what punishment has gone on with the bike. As stated above, when viewing, if the bike is sat waiting for you just been washed and the floor around the bike completely soaked then move it, onto a dry spot so you can have a look to see if there are any oil spills. Oil Leaks are a big sting in the arse, you don't want one, so avoid it !!
Engine - run the bike !! kick it over, and pull back the throttle gently then let go...if the noise decreases gently to tick over then its fine, any grinding means a buggered piston and barrel. I will also point out at this point that if there is an excessive amount of oil comming out the back of the exhaust be careful !! this is usually down to two things. 1.oil seals in bottem end (crank casing(gearbox)) have perished and oil is leaking from gearbox into the top end (piston and barrell(this could lead to new piston needed)) and 2. The seller has but a ludacris amount of oil in. this could purely just be poor maintainence skills but it could be that the crafty sod knows theres an engine/gearbox problem and has topped the oil up so you cannot hear the grinding.
Gearing - once on tickover select each and every gear, slowly release the clutch to allow the bike to move slowly foreward...if all gears engage smoothly and the bike pulls smoothly with the clutch then everything is fine, however if there is again any grinding the gears are shot or if the bike stalls the clutch could have perished. If the bike has been sitting for a while though (and I mean 1/2 months) the clutch plates could have seased together. Dont' worry all that is needed is new gearbox oil and a good 30mins run, it'll free itself and work...hopefully. As stated above though please ask the seller as many questions as possible, he could be using the 'oh its sat here for months not doing anything' which is utter bollocks. If the bike was sat there for that long without him selling it, there's something wrong with it. The best indicator for a bike actually standing there for so long is the petrol in the gas tank, petrol will decompose and you can easilly tell fresh from old. simple... :D
Bearings - Check all bearings !! Bearings can be a pain in the ass to replace so save the hassle. The simplest way to check is rock it back and foreward. This counts for the wheels, swingarm and other various places. If there is ALOT of play the bearings are goosed. If there is ALITTLE play, this is normal. You get play in almost every part of a dirt bikes chassis, it's just usuall, but if it's a numpty seller tell him the bearings are buggered and tell him you want £200 off the sale price, it works...sometimes. :D
Seals - Front fork seals and wheel seals are pains in the arse also. check the rubber hasn't split or perished, if so...fork rebuild needed. But to be honest if your buying a used bike you will want to get these parts replaced anyway, unless the owner/seller can prove the forks have just had a new seal job. But remember, no reciepts, no belief.
Thats the main areas covered in detail, to sum up what I have said: If possible buy second hand off of a dealer, if not check all vital areas are fully functioning, that its on dry ground, in clear daylight and in the owners house/garden/bathroom whatever ! if not either walk away or haggle for a cheaper price. Don't be afraid, tell the seller straight that the bike he's selling is dodgy and needs work, the worst he's gonna do is tell you to f*** off, not that bad...7/10 though the you can agree a fair price with the seller and be on your merry way with a nice shiny (or dirty...and rusty) motocross bike.
Thank you for reading my used motocross guide. If you need any more information please don't hesitae to ask, details are on my homepage. If this guide has helped you I would like to know, please rate it as I want to see what your thoughts are.
ashkirkmotocross[dot]webs[dot]com - ashkirkmx[at]live[dot]co[dot]uk - Best Borders motocross track. Headshaw Farm, Ashkirk.