Can any of you motorcyclists or mechanics help me out?

IMAROBIT · #1 04-26-2009, 12:25 AM

So my band mates have an old street legal dirt bike in their garage. It belonged to a guy who lived in their garage who is currently in jail, and Im trying to get ahold of his family members to see if I could buy it or how to get ahold of him.

Its a yamaha enduro 250, looks like a 73 or 70's, not sure about any more model information. Im sure its street legal, its got tail lights and license plate and everything

Im trying to find something online about it, any paper work or manuals to get a basic understanding about how its motor would work or how its put together. I have a basic understanding of how cars work(ive been a mechanics assistant for alomst a year), but Im trying to figure this thing out.

It doesnt start or run, and I wanna learn and figure out whats up. None of the lights or anything electrical works, some Im thinking a battery would be needed.

would you guys know any good websites or forums that would help me? I like figuring mechanical things out, and no one cares if i mess with it to see whats going on.

thanks

MCBTunes · #2 04-26-2009, 01:24 AM

Bikes are pretty simple. You tell me it is an enduro - so I would assume it is a 4 stroke. Do the plugs give you any spark? Battery is an obvious place to start. If all the plugs spark and the battery has charge it is likely a more significant issue and probably not worth it for such an old bike.

IMAROBIT · #3 04-26-2009, 01:42 AM

man, i dont even know. I could even get it to turn over. Im not even sure how the bike works at all

Craigmartini · #4 04-26-2009, 03:49 AM

You will easily get it to run. What might not be so easy is getting ahold of the title so you can own it before you spend one red cent on fixing it. Take it from me I made that mistake before. I had a Yamaha 650 special, givin to me by someone who didn't have the title for it.

The guy who did have the title was in jail and had no idea where he put it... I thought well, I will see if I can get it to run before I bother dealing with the legal stuff.
Well it ran great after I put a new battery in it took the carbs off, tore them apart and cleaned them, and bought new spark plugs and wires.

Needless to say the bike was totally useless because I could never get a title for it. The guy in jail didn't really care to help me get a title for his old bike that he gave to the guy who gave it to me....... So I gave it to someone I met who had the same bike and wanted some parts. I was happy to get rid of it by then.

I hope you can get the title for it because that sounds like a cool bike and would be a great project. As far as online stuff goes, "The roadstar riders "forum has a lot of guys on it who know alot about Yamaha bikes. If they don't know they will know who to send you to for info for sure.

Best of luck,

Craig

Jools4001 · #5 04-26-2009, 04:28 AM

If it's a 1970's Yamaha Enduro it's most likely to be a DT250 which is a two stoke. That will make it even simpler to work on because it won't have any valvegear to worry about.

I never had one (Ossa's for me) so I never worked on one but a few mates had them

It won't have a battery, it'll have a kick start and all of the electrics will be powered by the magneto attached to the crankshaft (I think it's magneto from my memory of 40 years ago). The ignition will be very simple 'points' based timing and it may just about have some sort of Capacitance Disharge ignition by that era or may just have a coil.

Being a two stroke, all the engine internals will be lubricated by two stroke oil that is carried in the fuel either by mixing it into the tank yourself using the correct proportions (pre-mix)or, alternatively, Yamaha were one of the first companies to have a separate metering system to automatically squirt the right amount of lube into the fuel.

The thing about two strokes is that because the lube is carried in the fuel the engine will not have been lubricated since it was last running so the barrel could be corroded and the crankshaft will also be dry (or at best gummed up with oil residue that will have almost solidified by now. The carb will almost certainly be completely gummed up
so before you attempt to start it, it really needs a complete strip and inspection.

Even if the cylinder barrel and crank are corroded you can still get the barrel nickasil plated which will also mean that you will be able to run the tolerances tighter and the amount of oil in the fuel leaner

Two smokes as they're often called due to the bluish haze of burnt oil that the fuel contains are very, very simple engines to work on, make more power for a given engine size, but becoming increasingly rare because of the emmisions issues

T-Bird · #6 04-26-2009, 04:34 AM

Hi.

+1 for title first, then drop some money/time into it.

Early 70's Yamaha enduro sounds 2-stroke to me, but the balance between 2 and 4 stroke bikes differs quite a bit from place to place. Either way, it's probably a quite easy task to get it running.

To get the electrics (charging if any, lights) working can require some ingenuity as the originals are often shot. Some work without battery, directly from the light coils, some have more dedicated electrical systems.

While I was searching info for the -85 KTM GS600 I bought a few weeks back I stumbled across quite a few off road / enduro enthusiast sites, but can't remember any right now. I'm SURE that a Google search will prove itself fruitful.

Pics would help quite a bit.

Regards
Sam

cardboardJoe · #7 04-26-2009, 05:40 AM

You're welcome to ask any specific questions, If you know the model and the serial number I can look up the specs you need.

IMAROBIT · #8 04-26-2009, 01:06 PM

thanks guys, it all helps a bunch.

it is an orange color. I googled "70's yamaha enduro 250" and a picture of a 73 orange one showed up and it looked identical

Card bord joe, next time Im at my band mates house i will try to get some more info for you.

thanks

iamlowsound · #9 04-26-2009, 01:22 PM

Sounds like a fun bike. Old bikes are the best, simple and pure. Just got back from riding my 1975 honda.

lowsound

IMAROBIT · #10 04-26-2009, 07:19 PM

yeah man, its in pretty good cosmetic shap and looks like a lot of fun to drive.

Ive always wanted a street legal dirt bike, even one like 30 years old.

I would really like it to be my first mechanical project...either that or im gunna rebuild my dads cj5 jeeps, then he would probably kill me