late 90's YZ250 (maybe 2000's)

[michigan_soler]

ok, so my dad came home with an early 90s yz 125 and i got that running by just a shot of carb cleaner and a new plug. but we also have one thats either late 90s or early 2000's that will not start, we had it goin alil bit by doing a "push start" with a rope and suburban. so it ran for a while, then we turned it off... put it in the garage and now we can't get it to start for ANYTHING. can someone point out what could be wrong with it (i took off the carb and sprayed it all out with carb cleaner, new plug and all that good stuff)

also, how do i tell exactly what year this thing is?

[crdude]

sounds like your top end might be shot, im not sure on the yammys but on my honda, on front of my frame there's a plate rivitted(sp?) to my frame that has the year and what not on it.

[wamxp1mp]

Well they looked really similar from 96 thru 2001 I know that the 2000-01's had the white plastic air boxes anything older is going to be black in color if the plastic's haven't changed (usually the tank doesn't get changed) the 96 & 97's had the darker blue color 98 on has the newer lighter blue color. I also think it was in 2000 they got aluminum subframes with like square tubing I think one of the edges of the tubing was actually rounded (yes they was painted blue!) oh ya! and in 2000 the radiators where no longer painted black. I almost forgot also in 2000 they got high speed adjuster added to the shock it was a red anodized nut.

YZ's don't have those plates on them like honda's telling ya the year it's coded into the serial number. I thought threw yamaha's website you could search for parts by the vin # that might help ya out.

[michigan_soler]

well, its got a black radiator (well 2 kinda) im new to bikes in general. and the air box is black...

i will pull off the vin number and try to find that crap... but can someone help me on getting it going, i would MUCH rather have a working bike then know what the hell i have...

[mad_biker]

First I would take the plug out and see if it is getting spark (it should be a bright blue spark) If the spark looks weak and redish try a different plug.If it still isn't giving a blue spark pull the flywheel cover off and make sure that stator plate mark is alined with the mark on the crankcase.And if the plug looks realy black and sooty then it could be that it is running so rich it fouled the plug ( that would also explain why you had to pull it with a suburban to get it start) So if it is getting good spark with a new plug and the old one is black and sooty, get some smaller main jets (probly the next 3 sizes smaller than what it has now) Just start with the next size smaller and see if it will start with out using the suburban . Hope this helps.

[mad_biker]

Oh yeah, and if you cant get it to run with out pushing it or pulling it pull the flywheel off and make sure the key hasn't sheered off.

[michigan_soler]

well, the reason we think we had to start it with the suburban was cuz they sat for like 6 months to a year... but the plug has been tested with 3 plugs... and they all look fine, i tested it on the block and shocked myself, but it barely hurt, so would that be somehting with like a coil (again, im very new at this all)

[iceman]

could be your mix. if its too rich it wont run unless youve got a race bike. im leaning towards your jetting though. get that all worked out and make sure the air filter is clean too.

[Blue 250]

Does the bike have good compression? If not than it needs a new top end. I would do it anyways just so you know its good.

[bikepilot]

A quick compression test will verify the condition of the top end. Compression testers can be bought for ~$30 and are well worth having around. Post a pic of the bike and I can at least give you a ball park figure as to what year it is and probably nail it down exactly.

good luck

[SirFallsALot243]

Yep, if you can only get it running by push starting it, Ill lay money saying it needs a top end. You need a MINIMUM of 100 to run. If it only bump starts, youre at 80 psi or less. Do a compression test, and work from there.

[michigan_soler]

well, i have a compression tester at home. so i will try that tonight, it DID start from a push start, but now wont... so the top end was probably going bad and now IS bad. should be getting a digi cam to my house soon for car pictures, i will for sure take some of the bike while im at it.

by the way, thanks alot for your guys help!!