'89 YZ250 questions

[duffysp]

I just picked up an '89 YZ250 that I plan on using mostly for 'fun' riding (too old for serious MX). I have not ridden in about 20 years, so I need a little technical 'update'. What is the correct gear oil for this bike. My manual says '10w30 or 10w40 transmission oil'. I have never heard of such a thing. Is this 10wXX motor oil? A friend suggested type F tranny fluid. My local dealer seems only interested in selling the latest high priced 'oil of the week'. Also, can the crank seals be changed without splitting the case? Thanks!!!

[KTM250rm393]

Don't know about the crank seals, but if you use type F tranny fluid, be sure to change it regularly. I use Bel-Ray Gear Saver 80 wt for 2 strokes in all my bikes.

A friend of mine uses Quaker State 10w-30 moto oil in his 00 YZ125 and the clutch is holding fine. Just don't use an oil that has a API of Energy Saving as this has friction reducers added and isn't too favorable to your clutch. Another good oil is Mobil-1 15w-40 synthetic with the RED cap. The other Mobil-1 oils have friction reducers added.

[Dell30rb]

I run atf type F. Its super cheap and works well.

[Woody_393]

BTW, the mobil 1 red cap is 15w50, not 40, just so you aren't confused. I love the stuff personally, and run it in the tranny side of my CRF.

[nevada6]

you can just use some car oil , like texaco havoline3 10w40,, but dont ever use use 10w30 or 5w30 with the "energy saving" feature, to much friction properties in those. and change your oil about every 3 rides. i also use pennzoil tcw3 premix for about 7 bux a gallon. been using it for 3 years and cylinder looks great. i have an 89 yz 125.

[ossagp]

Yes you can change the seals without splitting the center cases. Few of the 10-40 wt oils have the EC designation. I have used products with the EC rating without a problem in Cr's and XR's from 125, 250cc 500cc 2 strokes and 500 and 600 4 strokes. Also in my 21 year old sabre which has it's original clutch some 25,000 miles later. Maybe if your clutch is weak it would make it more noticeable though. I have used both Dexron type and Ford type ATF with good results.

Your vintage Yamaha had only one glaring flaw in my estimation enginewise. The center reed stop extends into the boost port area. If you change to boyesen reeds you eliminate the stops altogether. Or you can trim the end of your old stop off just enough to clear the port area. Your midrange will improve noticeably if you do.

[Jonny]

no, you can not replace the crank seals with out splitting the case's. As far as the oil goes, you need to run a motorcycle gear oil, an automotive oil is only designed for gears and lubercation in an engine, motorcycle oil is formulated different because it also provides lubercation for the clutch as well. A good oil to use is BelRay 80wt. gear oil, it is about 5 bucks a quart and you only need less than one to do the job.

Note: Just for kicks I raced that bike in the 1997 world vet championships at Glen Helen, smoked the hole shot and led the pack of wolfs only to have a guy land on me off of a jump on lap 5 while giving me his best Doug Henry impression....but it was always a fast bike.

[Jonny]

correction, I meant yes you can replace the seals with out splitting the case's. Sorry, long day

[CoalPilot]

Right out of the Factory service manual.....

SAE 10W-30 or 10W-40 Motorcycle Transmission Oil for the gear section....Yamalube "R" racing oil or Castrol R30 for the engine.

[Woody_393]

hey Coalpilot, welcome to ATM.

[CoalPilot]

Thanks woody, I just found this place today. I usually hang out on TT. But I need to find more on 2 smokes, as I have one now.

[Woody_393]

Right on. I hang over there on occasion as well. Can't beat the technical info on there. but yeah, 2 smoke stuff would be a bit sparce.

[CoalPilot]

CRF...there is one for sale about 35min north of me, don't know what he wants for it but it has been parked out in the front lawn for 2 months now. It's not even chained up!!! Now it's all covered with snow and ice. The town only has one cop and he's always in the diner. I'm really surprised 1. that no one stole it yet 2. that no one bought it yet. It looked almost new a few weeks ago..I guess he's going for that aged weathered look.

Anyway I am in the processs of restoring an 89 YZ250.

[Woody_393]

right on, he's crazy.

[duffysp]

Hey CoalPilot, Welcome and thanks for your response. Glad to see I'm not the only one working on an older YZ250. I think I'm going to 'bite the bullet' and go through the bottom end. Crank bearings seem a little loose. Good luck with your project. Duffysp

[CoalPilot]

PLEASE whatever you do, DO NOT use car motor oil!!!

[CoalPilot]

DuffySP,

What carb are you using? Flat slide, round slide? Mik., Bing?

I need to get one. Besides the '89 250, I found out that '90-'93 125's are the same and the '93 250.

[MotoMan]

'89 was a good year for yz 250s! I had a 88 and absolutly loved that bike, the 89 was about the same except for upside down forks.

Have fun and watch that 3rd gear hit.

[CoalPilot]

Motoman,

Do you remember what gearing you ran? I'm running 13/52 ...mostly trails and occ. track.

[MotoMan]

Oh my...It's been a LONG time dude... If I remember right I ran a 50 on the back, but man, that was over 10 years ago! :