threeputt

I have a 1975 DT250B Enduro and when I got it there was no foam left on the air filter cage. It was quite easy to find a K&N replacement. It doesn't use the foam cage, it replaces it. Have to grease both ends to form a seal between the rubber ends and the filter box but works wonderfully. I think it was around $45. Yambits in England has a lot of hard to find stuff, if you don't have luck more locally. I also got a new seat cover from someplace up in Canada (via eBay). I can dig later and find out who it was but if you search you can find them - they manufacture the things. It wasn't new old stock but looks it, right down to the YAMAHA white lettering on the back. They might be able to point you in a good direction for a seat pan/foam etc. Jeff

UPDATE: It is not the carburetor. Had a friend far more knowledgeable than I take a look today. Fuel delivery is fine, no plugged main jet, no plugged anything. No vacuum lock either. We're leaning toward the problem being an electrical gremlin now. Frustrating is the word. Jeff

Hadn't thought of the cap on the tank. Shouldn't be an issue though- didn't do anything to the cap and it was running fine before. Jeff

I'll try that. In the meantime, I removed both the pilot screw and idle screw and blew some carb cleaner in the holes. It didn't help... Jeff

Thanks for the reply. I rebuilt the petcock while I had the tank off - all new gaskets, etc. Both petcock screens are clean and unobstructed. Jeff

My '75 DT250B sat for a month or so while I re-did the tank, redkote, etc. Put it all back together and now it bogs down at anything more than half-throttle or so. Starts, idles, and putters around fine, but when I give it a twist, it bogs down and the engine nearly stops. When I let off the throttle, it behaves normally again. I'm hoping I don't need to try and get inside the carburetor (I'm scared I'll screw something up), so before I go that route, I'm hoping for other suggestions. It's fresh fuel, new fuel line, new in-line fuel filter and as far as I know, fuel is flowing from the tank without any obstruction. I'm thinking it's in the carb, but that's why I'm asking. Thank you for any help. Jeff

would be nice to have that oil light on my '75 DT250! Jeff

Cool video, looks like you have fun on them. I found a little more info, the Yamaha paint code for Portuguese Orange was 00N7 (zero zero N 7), and it is/was a ColorRite paint. Haven't contacted ColorRite yet, but the paint guy I know says he can match it anyway. I appreciate the help as always! Jeff

Portugeuse Orange is the name of this paint, that's all the information I can dig up from Yamaha. Does anyone have any more information on this color? Who manufactured the paint, any color codes, other names, etc? I need to try to get some of it to re-spray the bottom of my tank. Acetoned the bad RedKote job out of the tank to redo it and it took a little paint with it where the petcock goes. I have a guy trying to eyeball a match, but more information on this color would be helpful! Any other forums where I might posit this question would be good to know as well. Thank you, Jeff

Good points about the pump. Best oil? I don't know, I just buy the Yamalube 2S. I'm open to suggestions for a better 2 stroke oil... Jeff

THANKS for the replies! I will keep looking for a cable. I even went to a local Yamaha dealer here - their parts lady is very good - and she found 4 cables at various North American dealers. Well, at least according to they computer inventory. Alas, none were had. I found one on eBay about a week ago, NOS, but the fella knew what he had and wanted $140(US)! If I have to, I'll bite the bullet and pony up I suppose. Motion Pro, a company here in the US, says they can fab a new one if I send them the old one, so that's always an option. One more related question... A friend of mine, small engine guru, 2-stroke whiz, and he had a Hodaka dealership back in the 70's, says the oil induction system introduces more oil than is needed today due to forty years on improvements in oils. He suggests that the alignment marks should be lightened a bit. I use Yamalube 2S. Any thoughts would be appreciated. Jeff

The oil induction/injection still works on this bike but I'm having a hard time adjusting the oil pump mixture rate to get the marks to line up per the manual. The cable is old and stretched and there simply isn't any adjustment room left. Trying to find a replacement has been tough. I thought to better control things I may just go to pre-mixing my fuel and 2-stroke oil. What do I need to do to make this change? Is it as simple as - stop filling the oil tank and fill up the gas tank with pre-mix - or is there something I need to plug off or close up with the oil tank/line/pump etc? Thanks! Jeff

Thanks for the compliment but there is still lots to be done. I wish I were more familiar with this sort of thing. Speaking of which, I purchased a .pdf version of the 1975 DT250/400 service manual and the quality is horrible. Bought it from a fella on the e'bay but it wouldn't be proper to say from whom. The standard text is fuzzy at best and the smaller text on the pictures is useless. Does anyone know or can you recommend another venue to secure a legible copy? It sure would help! I scored some repro turn signals from the Vintage Spoke in Kansas. They look perfect, and were way cheaper than old trashy originals. Haven't put them on yet, but that will happen soon. The wiring is still there it seems, at least three of them are. Have yet to locate the fourth. Also waiting on a complete engine seal kit from Yambits in England. I haven't popped for fork seals just yet but that's on the list along with a rebuild kit for the oil induction pump. Brake shoes coming as well, the front are nearly gone and the back aren't too far behind. The seat is fine. No rust that I can detect, at least not on the underside. Don't know if water has trickled in the holes and affected the inside. Fella I got it from said it was covered in decades worth of junk in the back of a garage. I'm watching for a seat cover, but not a high priority. As for now, I only plan to ride it on nice days. I wouldn't trust the electrics in the rain LOL. I need to pop the wheels and have them trued and balanced. It's gets a little interesting above 50 MPH! It has taken a few spills over the years it would seem. The frame is true as far as I can tell, but the handlebar is canted slightly to the right. Not sure if I can loosen something and straighten that or not. Might be the forks are bent, but I can't tell by eyeballing it. I need to have it checked out at a local bike shop here. As to the jetting, it is rich enough I think! Going down the highway at 50 or so, there is a very faint trail of smoke behind me. Nothing billowing, but at the end of a ride, a drop or two of oil will fall from my license plate! It's not fouling plugs, so I suppose it's better to err on the side of rich rather than lean... Oh yes, 3400 and change on the odometer, but I'm not 100% convinced it's the original instrument cluster. The ignition key won't fit the steering lock so that's a head scratcher. I didn't think to check that when I went to see the bike originally. I would assume it would be the same key…? Jeff

This is the tube sock job LOL It has a K&N there now and runs just fine. Sent from my iPhone using Tapatalk

That's a sweet looking 400. I'd love to add one of those to the stable. Jeff

Couple pics, hope it works. First time using tapatalk on my phone.. Sent from my iPhone using Tapatalk

While waiting for more paperwork to get it plated, I've been poking around a bit. Something popped up that scares me - the oil filter support screen looks to be wrapped with a section of white athletic tube sock! It's oiled, mind you, and well greased on the ends to seal, but still LOL. Opinions on the K&N replacement filter YA-4074? http://www.knfilters.com/search/product.aspx?prod=YA-4074 I could get a bag of socks for cheap LOL Thanks, Jeff

blackhat250 thanks for the tip. I'll keep an eye out for that. It's a 1975 DT250B. Not sure of the exact date of manufacture. Jeff

BOUGHT IT! Man the smell and sound takes me back. I'll try and get a few photos up as soon as the weather improves and I can get it cleaned up a bit to snap a couple. It seems to be in really good shape, but the turn signals are gone. As soon as I can score a set, I'm planning on plating it and cruising around our small town. I hope there aren't any issues that aren't readily apparent. A friend of mine here used to run a Hodaka dealership back in the 70's and he's very familiar with old 2-strokes. I'm going to let him give it a good once-over and see what it needs. Jeff

NICE! Thanks for the replies fellas. I found a 250 that I'm strongly considering. I'll post if I pull the trigger... Jeff

Old story I suppose, I had a 1975 Yamaha Enduro (DT) 125 when I was a teenager. Loved that bike. I've been keeping my eyes open for another - not a museum queen, rather a nice solid example that I plan to plate and ride. 125, 175, 250, either would suit my purpose, but what I'm hoping to learn is some of the pitfalls to watch out for. Even back when I owned one as a kid, I was never very knowledgeable on these things. My dad kept an eye on us and the bike was very reliable. Aside from the obvious, I'm looking for some key points to consider when shopping around. Any advice would be much appreciated. Thanks in advance! Jeff (newb)

Nice place you have here. I just joined, and am primarily interested in older 2-strokes. Seems to be a knowledgeable bunch around here. Jeff