The XT350 thread

Discussion in 'Thumpers' started by Burtonridr, Sep 26, 2007.

  1. SkidMarx

    SkidMarx Long timer

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    I can see there you would get 1.7.
    "Total Amount" is very misleading.
    Thanks for the link BTW. I lost that manual 20 years ago.:lol3

    I looked through some of you're earlier posts. Going by the condition/milage of that bike. I would be VERY surprised if you had any real issues.

    The fact that it starts easily, and has new boots tells me that the PO (or mechanic) likely already adjusted the Pilot screw and generally knew what they were doing.

    In response to your post regarding the noise from the top end, it's likely normal valve clatter. Mine had a lot of top end noise when it was new. I wouldn't worry about that either.
    It doesn't have enough miles to have a stretched timing chain, and the Auto cam chain tensioner should also be fine for the same reason.
  2. Jaunty

    Jaunty Adventurer

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    Hello and thanks for having me.

    This thread is huge! :D

    Just acquired an 89 xt350. It did not run, but after a carb cleaning she fired right up and is LOUD! The cylinder starting smoking, so im wondering if its getting too hot. I used a infrared temp sensor on the outside and noticed it got up to 350'ish. Does anyone know if thats too hot? Im worried about riding it, but im also hoping its just dirt or oil built up on the outside thats burning off.

    i ordered some intake boots because mine were obviously torn. is it possible that a leak at these boots could cause overheating like this or is there likely another issue (oil pump?)

    Should i be worried about the cam chain tensioner at this time?
    The cylinder area is quite noisy. rattling and such. It does not smoke at all out the tailpipe though.

    Is it difficult to remove the valve cover and check the valve clearance? i noticed some gasket material there as if it were done recently.

    advice appreciated.
  3. SkidMarx

    SkidMarx Long timer

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    Yes. Absolutely. do not run the bike with bad boots.
    Not likely. I few people have had issues but it's still pretty rare. If the chain is loose, it's more likely that the chain guides are so warn out that the tensioner has run out of adjustment.
    Pull the valve cover and check the chain tension. It should be very tight. if it is, you're good.

    This is normal to an extent. They have a noisy top ends. Lots of valve clatter at idle. it should go away once you rev it up a bit.
    Good
    Not really. The gasket is rubber and is reusable.
    Checking is pretty easy. adjusting them...not so much.

    How many miles are on the bike?
  4. Jaunty

    Jaunty Adventurer

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    thanks for the response...

    it has 7900 miles.. i havent ridden it so i dont know for sure if that works. the tach does not work, but im assuming the odo is still functional.

    I have the clymer manual so i will be going through all the basics. Stoked! :D
  5. oceansfiftyseven

    oceansfiftyseven Adventurer

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    Congratulations Jaunty! Torn intake boots will cause it to run lean and hot if it will run at all. Yes you should worry about the tensioner and the chain itself. The chains stretch and the tensioner maxes out and the chain will rattle badly and eventually skip teeth. I had to replace mine at 7000 miles.
  6. SkidMarx

    SkidMarx Long timer

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    Wow, that sucks. Never heard of anyone having one go that early before. That would have been warranty work on my bike(a long time ago).

    I have close to 30k miles with no issues with the chain or adjuster. I have replaced the guides though.
  7. gearheadE30

    gearheadE30 Long timer

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    If you look around a little more, there are a ton of people who have had faulty tensioners that caused excessive chain stretch in 10k miles or less. Mine was one of them. I rebuilt all of the timing bits, and I've since gone to a manual tensioner and in 2k miles it hasn't needed to be adjusted.


    Also, for all of you who are measuring out your oil amounts, it's better to just get the bike vertical (balanced on its two wheels) and fill it until it is in the middle of the sight glass. Start it, run it for a few minutes to fill the oil filter, stop, wait for the oil to drain back, check again, and then you're good. You'll never get all the oil out of the engine, so always go by the sight glass.
  8. Jaunty

    Jaunty Adventurer

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    my oil looks clean and its in the middle of the sight glass.

    i believe the previous owner lost the rubber valve cover gasket and used some type of form a gasket as its oozing out (unless that was the actual head gasket area, i'll have to look again).

    thanks for the info guys
  9. SkidMarx

    SkidMarx Long timer

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    If you look around a little more and pay attention, there are very few people who have actually had the ACCT fail on the XT350. There are some, and they are very vocal, and there seems to be a general distrust of the things which I suspect is bleed-over from the DRz400 crowd where there was a real issue.
    Many people have switched them out because they suspected something was wrong, but in most cases it wasn't the problem.

    I'm not saying that they don't fail, but because of the way they are made, they either work or they don't. They use a flat coil spring (like in a watch) those springs don't generally wear out over time. If they get fatigued, they simply break. Depending on where they break, they can also be fixed. Look here.

    BTW, The cam chain tensioner can not cause your cam chain to stretch out.
    In order for that to happen the spring would suddenly have to be more powerful, the chain guides would have to be made of something that doesn't wear out, and the chain would have to be built like the one in a XR200.
    The Cam chains in these bikes are not weak. It's a proper multi-plate design, and won't stretch easily.

    What a bad ACCT can do if it fails is cause the chain to jump which can be catastrophic. This is the reason that the people who have had them fail are so vocal. To them, the ACCT is the devil. Can't say that I blame them.

    Some people choose to use a MCCT because they are worried about this possibility. I'm fine with that, to each their own.
  10. SkidMarx

    SkidMarx Long timer

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    A lot of people put a bunch of silicon gasket sealer on the gasket and it makes a mess. It also ends up in the oil screen which sucks. The rubber gasket includes the 2 half circle plugs you can see on the left side of the head so it isn't likely missing. It fit's in a slot in the cover and I'm pretty sure it doesn't actually require any sealant. You will want to look that up though. It is reusable.
  11. sjc56

    sjc56 Long timer

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    Put in 1300 cc oil, did about 10 miles, still smoking, bike runs good though. I'll do a compression and a leak down, just need to borrow some gages.
  12. backroadbob.com

    backroadbob.com Roads Scholar

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    These guys are giving you a lot of very good advice. These engines are pretty bulletproof. I put 35,000 miles on my first one (38,000 miles total) before I checked the valves and they were still spot-on. The entire valve train still looked like new. I ran Castrol 10w40 and changed it as soon as it appeared dirty which was often as the engine had only a metal screen for an oil filter. Definitely invest in new intake boots. These are the weak point of this engine.
  13. oceansfiftyseven

    oceansfiftyseven Adventurer

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    Hey sjc56, I would also suspect the muffler for the smoking. Before I replaced mine on my XT and repaired the top end, mine would smoke when warmed up. Sometimes badly. Carbon and unburnt fuel from my at the time crappy running XT, had built up in the exhaust. Saturating the packing. The harder I ran it the hotter it got and the worse it smoked. If it smokes at start up when cold, nevermind.
  14. SkidMarx

    SkidMarx Long timer

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    This was going to be my next suggestion.
    Is it just a little smoke, or are you fogging the countryside?
    To be honest, if it's just a little, keep an eye on the oil level and ride it. The thing is 25 years old. I'ts allowed to smoke and leak a little.
    The compression and leak down will be good to know regardless.

    If it is smoking at start up, and then quits, you have leaky valve seals. Not a big deal to fix if you're handy.
  15. sjc56

    sjc56 Long timer

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    It's smoking when it's cold it's smoking when it's hot, birds are falling out of trees, the EPA has banned be from starting it, my town wants me to do mosquito fogging. Yup it smokes. I'll ride through the fall for short trips,and keep an eye on the oil, it seemed to have burned a quart in 50 miles. I'll just pretend it's a 2 stroke.:1drink
  16. webmonstro

    webmonstro A Aventura Continua....

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    rings

    you need rings

    been there done that - it was the piston rigns
  17. Lenz1

    Lenz1 Been here awhile

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    I'm using a manual cam chain adjuster on my TT350 (same engine as the XT350). The cam chain does not need to be bar tight for correct and safe operation.

    Just remove the cam assembly cover and look down into the cam chain space on the right side. Insert a rod / screwdriver / scriber between the cam chain and the tensioner guide approx midway along this section of the chain - don't mark the guide surface. If the chain will move 5mm - 6mm off the tensioner guide with a light effort then it's fine but no more than this. I've run similar sized racing engines up to 14,000 rpm with this approach for years without failure or premature wear.

    The std auto tensioner provides a one shot tension adjustment of the cam chain and is then locked off. It doesn't take much for this initial setting to be well out of acceptable tolerances. A visual check of cam chain clearance / slack is very useful.
  18. gearheadE30

    gearheadE30 Long timer

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    Yeah, I suppose you're right about them being vocal. I've had 2 of them fail - the first one had a broken spring, and the second one worked for a little while and then jammed rather than continuing to apply tension, so over time it developed a really bad case of slap.

    My theory for the accelerated wear when it broke was that since there wasn't any tension, the chain was snapping back and forth rather than being under relatively constant tension. That snapping motion greatly increased the transient loads on the chain. There are marks on the inside of the jug that seem to back this up. I have no idea how it didn't jump time. This is how it was when I got it, with the broken clock spring in the tensioner.

    Rings and a quick hit with a cylinder hone only takes an afternoon or 2 depending on your mechanical proficiency. Mine smoked the same way, and rings fixed it. Just make sure you check the bore diameter before buying rings to see if it's been bored over before.
  19. SkidMarx

    SkidMarx Long timer

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    I expect that would do the trick.
    I don't blame you for hating the things. They cost you a bunch of time and money.
    I'm the same way with the intake boots. Leaky boots caused my head to actually melt between the valve seats which cost me a bunch of money at a time that I didn't have any. If sjc56 hadn't already said they were new, I would have told him to replace them before doing anything else.
  20. sjc56

    sjc56 Long timer

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    I want to check my compression so how do I disconnect the compression release, can I just disconnect the cable?