xt350 smokin like mosquito fogger

I have a 94 xt350, been pretty great to me. But in the fall I had removed the air box cover (had put in a new uni filter) seemed to run a bit better. I was riding it pretty hard in the fall, and after stopping for a couple groceries near the end of my commute home, realized that after start up and arriving at the first set of lights a huge cloud of smoke from what I thought was some 'inconsiderate automobile' then saw it was my exhaust blasting out that smoke. Soooo, being fairly close to home, I puffed home a kilometer and parked her. I was thinking rings, and that now would be as good a time as any to teach myself to redoe the top end. A few days ago, I said what the heck and got it going, ran it around the block....no smoke! looked again last night....the big idiot i am, realized after the fact....no oil visible in the sight glass, added a liter, thinking 'oh, maybe no smoke due to no/low oil', started again, and around the block like a dime, with no smoke again.....whats the deal? (engine sounds great still!)

side note, not sure if totally related, but i believe around the time I removed the air box cover (in the fall) when accelerating at highway speed, it seemed to cough and sputter here and there (looked in 'trouble shooting' in the xt manual and seems as though that problem would stem from carb issues....

thanks in advance for your thoughts conclusions and/or suggestions!

Likely rings.

Unless you rejetted when you pulled the air box door, you were running very lean/hot and likely toasted the rings.

Once it warms up it will likely start smoking again.

Or the valve seals, which were probably done anyway by now. It is almost 20 years old, and can legally drink in most states.

Valve seals would have smoked on startup. You're right though. They should be changed. It would suck to have them start leaking a week after a rebuild and they come with most gasket sets.

ok thanks guys! I appreciate it....

i'll take it a bit farther than just around the block to confirm this....

So the next thing is then.....how hard is it really, to re-ring?..and i guess re-do the valves???? (think she'd benefit from cleaning up the intake/exh ports/bowls?....not a port and polish, but just a good cleanup?)

Bike has an iron liner. Have it checked for wear, might get by with a light hone, new piston, writst pin, clips and rings. Be sure to install a new cam chain tensioner. Very easy job. Check the cam timing four times before you put the spark plug back in it.

I would not waste the time on the ports.

Ok awesome, you think it would be say less than 10 hours wrk for a novice/intermediate??? (pretty mech inclined, wrked on cars and engines in genereral quite a bit, but haven't performed any rebuilds as of yet)

First time...

Should be able to do it in 10 hrs. You'll want to take your time and triple check everything. That doesn't include any valve work.

It is a pretty easy job on that bike.

As stated earlier, have the cylinder checked for wear and see if you need to bore to the next oversize before you buy the piston and rings. Any good machine shop should be able to do this check for you for a couple of loonies.

Make sure that you replace all of the top end gaskets. They are 17 years old, and even if you don't tear them during disassembly, you probably won't get good seals with them when putting it all back together.

I would replace the piston, rings, wrist pin and cam chain tensioner. Check the cam and valves for wear. Check the valves to ensure they seal properly. If you have to do a valve job on the head, make sure you replace the valves and springs and valve stem seals as part of the project.

Go with OEM parts and you won't have an issue. After all, it has lasted 17 years with the old OEM parts, you should be able to get another 10-15 out of it when all done.

Ok great! thanks so much for your help guys! Ya, I kind of like the idea of grabbin a bigger piston, bike has pep, but clearly would be more enjoyable with more, lol.

you guys think the clymer manual should be sufficient? (anywhere/thing I can find with all the 'tips and tricks' so i can potentially avoid any fatal first timer mistakes? (ex: not ensuring that the ring gaps are opposite eachother etc)

i would port match the exh to the gaskets as they are quite a bit smaller. the intake boots are the restriction on the intake. mine are matched to the intake now but i did a lot more work and just finally figured out my jetting with the help of an o2 sensor. now it rips.

and a yes it shoud only take you about 10hrs if you have all the parts other than machine work on the jug. do not remove the cam gear bolts and put new guides and a new tensioner with a new chain as yours will be streched.

thanks for the tips and suggestions guys! next time i'll be posting to ask how to fix what evert i mess up while attempting this rebuilt lol

thanks again!

Jack up the kickstand and run a new WRR under it if that happens.

Jack up the kickstand and run a new WRR under it if that happens.


Seems like a common cure for XT350 issues.

I haven't actually had any problems with mine for a while, but the old girl is getting tired so she's going into retirement.

It is similar in overall power, although the power band is different. The suspension is a lot better, and so is the technology. I've owned both, and while the XT was a great bike, the WRR is a lot better. It should be at the cost and dates of design. But while my XT took me everywhere I asked it to, the WRR can do it better. What the WRR needs is to be about forty pounds lighter. I also have a DT400E, and I find that it too is similar to the other two, but with drastically better power delivery off the bottom. What the DT has against it is fuel consumption and dated suspension. The flexy forks on the XT are still better than the DT, and of course, even though no race legs, the forks and rear suspension on the WRR are far and away better. I have the DT apart for an engine freshening, and considered fitting more modern suspension as an update. But then I'd have to deal with the back end, which I'm reluctant to do. Maybe I'll just find it a new home.

If you're a real happy with the XT, find a TT version and steal the forks, swing arm, shock and any other goodies you can swap. I knew someone years ago that did this and he had a superior bike. I'm sure there are other bikes of that vintage that could also donate the suspension parts, such as the IT and YZ series.

If I thought I could legally get away with it, I'd slip a YZ250 liquid cooled engine into my WRR frame, then I'd have a real update of one of my favorite old bikes: a '73 DT3. That thing hauled me places I doubt I'd go today.

yes! I totally pondered a WR motor/2-stroke upgrade, but after seeeing the prices and thinking of potential complications in a swap, decided that for me, a rebuild (piston 40 over?) would be great for now... Maybe a DRZ (SM?) in the future...

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