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1974 Yamaha DT250 Fork Seal Brand?

Maraakate

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Jun 7, 2022
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Lancaster, PA, USA
Normally I would buy OEM, but Yamaha wants $40 for a single seal. I think that's kind of ridiculous for an oil seal. With that said the measurements (at least according to a few vendors) of a new seal is 34mm X 46mm X 10.5mm. Who is a reputable brand? I might just get the Bikemaster ones, I've gotten brake pads from them a few times and they've heled up OK. Apparently the reviews are hit or miss for All Balls. If there's better brands out there that have these seals that are good quality, but not $40 I'm interested!
 
I'm surprised to find that the DT250 had 34mm fork tubes, I'd have expected 35mm since so many fork tube diameters seem somewhat universal. I'm not sure there are any Hondas out there with 34mm tubes so that might ruin a possible cross-reference effort.

In addition to CMSNL having them in stock at about $30 each plus their shipping, I found these

https://www.athena.eu/en-us/fork-oil-seal-kit-34x46x10-5-mm-P22153.htm

and these though they're out of stock right now

https://www.ebay.com/itm/284517054157
 
Ouch at the $25 shipping from EU. Are Athena seals reliable? I know their gasket kits leave a bit to be desired. "Close but no cigar".

Yamaha parts tend to be a pain. Not as many specialty sites like Honda and their OEM prices tend to be double what Honda's would be. The only site I really know of is Mike's XS, but his parts are hit and miss and no DT250 parts.
 
Looks like you can get a set of K&L's from eBay, maybe even locally. Those seem to be trusted a bit more than pyramid. Never heard of pyramid until you linked it. ADV forums have some complaints about that particular brand.

I think I'll roll the dice on the K&L, cheap enough if they're awful im only out a pack of smokes :lol:. Theyre already peaking on both sides, so it wont change either way. If still no good guess ill have to go OEM, unless someone knows of supply houses to get quality seals in those sizes. I don't.
 
...unless someone knows of supply houses to get quality seals in those sizes. I don't.

Jim may know of a seal seller who might be able to cross-reference by the dimensions. You could probably get away with the height measurement being a little bit shorter, maybe even taller depending on available space to the circlip and washer. Honda forks often have almost enough room for double seals (though the stiction would be ridiculous).
 
Update to this: ordered the K&L ones. Seem to fit fine, didn't take it for a ride yet.

Good thing I did it. Besides them leaking pretty terribly, one of them the rubber was disintegrating and the other the spring fell out of the seal! Both were completely rock hard.
 
Took it for a 30 mile ride today, they work great. Now on to the rest of the fun... new tires, tubes, chain, sprockets and brake pads. :lol:
 
A 30 mile ride on a 250 2 stroke single... that would take me back to high school! They were cool bikes, I was envious of my friends who had them while I was riding the heavier 4 strokes back then.
 
A 30 mile ride on a 250 2 stroke single... that would take me back to high school! They were cool bikes, I was envious of my friends who had them while I was riding the heavier 4 strokes back then.

It's a fun bike. Top speed is about 60-65mph so can't really take it out on the highway.

If you got gloves and boots on 30 mile rides aren't too bad :lol:. It does have a bit of the vibrations from being a single, but it's not that bad. Nowhere near as bad as my buddys 80 XS650. That thing walks backward on the centerstand if you rev it!
 
I remember a few twins back in the day that would do that trick. Typically any 360° twin of fair size vibes pretty good, some more than others.

OT, but that thing is pretty ridiculous. Lost a muffler already and the screws inside the speedo and tach have vibrated loose. Had to loctite it, but who knows if it will hold?

And yes, carb sync, etc. is good. It's just that ridiculous.
 
OT, but that thing is pretty ridiculous. Lost a muffler already and the screws inside the speedo and tach have vibrated loose. Had to loctite it, but who knows if it will hold?

And yes, carb sync, etc. is good. It's just that ridiculous.

Yeah, that was one of the things I didn't care for about them, sadly the only 4 stroke in their lineup during the early era of the 650. I just never thought Yamaha was very good at 4 strokes for a while there
 
Well apparently it was made by Hosk as a 500cc twin then 650cc and eventually Yamaha bought that company out.

It puts out some fun levels of power, but the vibration makes it silly. I couldn't imagine touring on it.

If my friend is serious about keeping that thing I think the mufflers should get cotter pins on the mounting bolts. I'd hate to go digital, but he might have to for the instrument cluster if the screws on the face keep vibrating out.
 
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