'74 WR250 Low Compression?

Toni put the gaskets on dry no permatex.I hope you have the torque specs for the engine.You will be fine.You took it apart you can put it back together.If i was closer i would come down and watch you put it together.There's nothing i like better than to watch somebody else work if i can sit there and drink a few beers while they work Good luck!!!
Tom

It went better than I imagined. Rings lined up to pegs, everything slid right together, head torqued to spec. I'll install the pipe and tank tomorrow The gaskets got oily on the process, hope that is ok, I really oiled the piston and rings up good with 2 stroke oil, it got a bit messy. Also I figured it would be good to change the oil in the gearbox, the manual call for SAE 20 oil, I'm guessing this just means regular non synthetic motor oil, right? It all seems to have a range, not just "20" I'll check around, seems to be available online if I can't find any locally.

Hey Tom, I'll be having a few beers too after I get it running again, then maybe a few more to celebrate when I get my plate!

lots of posts on here about oil to run, jaso-ma is the spec which means ok for a wet clutch. has nothing to do with synthetic or not.

Wow. I just read about 2 dozen posts, everyone recommending something different for oil. I thought I'd get a simple answer. I don't want to open that oily can of worms.

So basically, I need JASO-MA to keep my clutch from slipping, same sort of stuff I use in my modern 4 stroke engines? any reason the old Husky manual calls for "20" weight? 10W40 would be ok?

Use ATF type F

yes any of the jaso ma engine oils or atf type f will work fine.
i will say i notice the least amount of shavings running the rotella 5w-40 t6 diesel oil which is fairly cheap, full synthetic, and jaso-ma. atf type does work well and shifts very nice.
atf type f is a bit thicker than other trans oils, i believe its pretty close to an actual 20w. but any of the 10w30 or 10w40 oils will works well. pick a brand and use it.
if you already have a good quality oil you keep for the newer bike that makes the choice easier! i would just recommend sticking with what you choose for the most part.

I need to get this project back underway. In all my other bikes I use exactly what the manual calls for, but in this case SAE20 motor oil apparently isn't what it was in the '70s and would not be a good choice. Since everyone has their own opinion on what to replace it with, it seems there are many things that work well, and I could waste the whole riding season debating this, I just went down to my local bike shop to get something. I asked the guy there (who also has an older 2 stroke) what he uses in his bike. I ended up with BelRay 80W-85 transmission oil. So this is what I'm going to use unless I start to have any problems.

They were wondering how the whole piston install went... quite well I thought, besides being oily and messy. I mentioned getting oil on the gaskets, and was told this was not good, they need to go on dry... it will maybe be ok... they said but better to take it all apart again and wipe the gaskets and surfaces dry, not really what I wanted to hear. I did get oil all over everything, nice clean 2 stroke oil, but I was handling all the gaskets and they were oily. I figured they would get oily anyway, this is an engine after all.

So, do I really need to take it all apart and dry off those gaskets?

Thanks again for all your help Cafe Husky people. Sorry to be such a pain but I need some help. I really appreciate it.

I don't think so , some guys actually put grease on the gaskets instead of sealant. So what would be the difference. I would try it just like you have it , whats the worst it can do leak??? just double check all the bolts for tightness and afterwords also. good luck.

i grease the sidecovers and centercases so they come apart easily, have never greased or oiled the base gasket, reed gaskets or anything. i would imagine they would be fine. on sidecases i bond the gasket to the sidecase, then grease the other side. now that i have andys cast ignition covers i do the same there as well..

I think you will find gear oil will make the clutch drag.

I wouldn't worry about the oil on the gaskets your going to retorque everything after you run it for awhile anyway.I'm not so sure on the tranny oil you got.I use a 20wt nondetergent motor oil in my bikes w/no problems.I'm going to try atf in my next project bike everyone seems to think thats a good choice so i will give it a try.Good luck and get it done and post your pics cause i'm gonna drink a couple of beers to your project
Tom

yeah..everyone has their brands but it seems everyone agrees on an oil that ranges between 20-40 in weight....atf type f being around 20w and the various motor oils just a bit thicker. if that oil really is a a 80-90w that is way thicker than what husky spec'd. not saying its going to hurt anything, but it may drag as mentioned.

It is the equivalent of 20W40, they use a different scale for gear oil for some reason. I had to ask about that too. Anyway I have tomorrow free and will continue to put it together and then cross my fingers and start it up.

Idled 15 min. so far so good. I'll give it another 15 min. run again after its cooled down, then maybe I'll take it for a gentle ride around the yard. How will I know if I have an air leak? I just ride and hope it doesn't seize? I don't have the equipment for the pressure test.

USE YOUR EARS ANY PINGING/ KNOCKING SURGING UNEVEN IDLE OR HANGING THROTTLE A SPRITZ OF CARB CLEANER AROUND THE INTAKE SIDE OF THINGS WILL FIND AIR LEAKS

If your gonna just sit and idle put a fan on it , I personally would just put around the yard and move the throttle up and down a bit nothing to crazy tho.

There was some clutch drag to begin with, still there, dealing with this is likely going to be my next project on the bike. Not too hard to adjust right?

Had fun riding it all over yard, didn't want to stop, what a great little bike! I sprayed carb cleaner around all the gaskets and seals, no effect on idle speed, so I'm thinking it is good.

NOT SURE ON THAT VINTAGE BUT IF ITS LIKE THE LATER ONES ITS EZ

A victory lap around the yard. It runs great with the new piston and exhaust, AND passed the inspection for a plate. Thanks everyone!
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looks to fit you very well! what was the trick to get it quieted down? or just a different inspection guy?