• 4 Stroke Husqvarna Motorcycles Made In Italy - About 1989 to 2014
     TE = 4st Enduro & TC = 4st Cross

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Crank Case Breather / Dirty Engine Issue

cgkoch

cgkoch

Husqvarna
C Class
I'm wondering if someone might be able to offer some advice? Here's the deal:

I was riding my TC450 last weekend. Stopped for a break, and noticed that my Crank Case Vent Hose had popped off the airbox.
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I know for a fact it was off for not more than 20 minutes, but the bike was probably sucking dust the entire time. Turned the bike off, and walked it back to the truck. Went home and tore it apart. There was a small amount of dust in the airbox (not visible, but could feel a little). Same for the intake boot. Carb was very clean. Now what do I do?

Obviously I'll drain and flush the oil a few times. Do I need to tear the head off and clean out the cylinder / valves? New piston and valves? Or has the dust already gone into the cylinder, out the exhaust, and done it's damage. I've only got about 40 hours on the bike, so would like to avoid piston / head job.

Any thoughts would be greatly appreciated!

Oh, and first time posting. Thank you all for countless posts and tons of information!!!
 
If it was my bike, I wouldn't be tearing it down, I'd clean up what I could and ride it. The breather is mostly an outflow from the engine, since the engine takes in massive amounts of air from the intake side, the breather just makes sure when the piston travels up and down that the system is vented to the atmosphere, and never gets into a situation with too much or too little air pressure..
 
This isn't really a big deal. Just change the oil and filter. Clean the screens.

I doubt anything stuck in the top end. While the engine is running there is a lot of oil being splashed around under the cam cover. The oil will have washed any dirt down to the sump and it will have been picked up by the screens and filter.
 
The issue CGKOCH is concerned about is not how much unfiltered air was drawn into the crankcase through the breather but how much unfiltered air was sucked through the opening in the airbox that was NOT connected to the vent hose and went into the intake/head/cylynder. Certainly a valid concern.

I'd say you caught it pretty quick- and although it most likely did suck some unfiltered air and dust which you already verified- for the most part what's done is done. I'd clean the carb and intake boot and what you can, change the oil and filter (next oil change a little sooner than normal as well), and put a proper snail clamp on that breather tube.

It would seem a bit premature to do a total rebuild at this point. The added wear may be equivalent to having done some bad mainenence for a period of time. It may shorten the life but it may be immeasurable.

Just glad you caught it when you did, :thumbsup:
 
Thank you for your input here, it's nice to get some feedback! I will do as HuskynXJnWI suggested and clean the intake track, carb, plus dump the oil a few times.
 
I missed that opening for sure! I looked at mine and it way up there, mostly fine dust got sucked in, I doubt any big stuff came in. Here's another take on this issue, that cgkoch got from a guy on TT:

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Today, 12:15 PM
36MotoMarc
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Quote:
Originally Posted by cgkoch
Or has the dust already gone into the cylinder, out the exhaust, and done it's damage. .

Yep, this. Check valve clearance immediatly. Write it down. Then check every 5 hours or so (it's so easy to check!). Your 1st indication that the dust, indeed, caused damage will be tightening of your valve clearance. Probably intakes but if any of them tighten up rapidly, you will need to pull the head. The silica can imbed in the valveseat, ruining the coating on the valve. The seats need to be cut to remove particles/refinish, then new valves, prob piston and camchain while you are in there.

There's also a chance that your motor will brush this off and not care.
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Good luck!
 
Mark gave some solid info on what could happen but didn't seem too displeasured to give bad news / or NOT. I spose its cause these kinds of questions are hard to answer because at the end of the day 'who knows?' short doing some measureing and making educated calculated guesses or better yet without fully tearing down - and at that point who cares- might as well put some new parts in... Been there with questions like this- "uh oh! is it toast?" its a hard place to be.

Question of how much money, time, denial and hope you have. You could check the valve clearence- but: do you exactly know what the clearance was before this happend?
if you don't, all you can do is adjust your valves.
If you do, now you know why- and you can adjust your valves- and hope they don't keep moving on you...

You seem like a guy that checks his valve clearences so I'd just watch their movement and write down the measurements to gauge wear and to ensure they don't start wearing quicker than expected- and address it if it becomes an issue. Just as you would normally. You could also do a leakdown test- for some confidence...

"Stuff Happens" but it was 20 minutes I have enough hope and denial to give ya to say your not too much worse off than you were before / short of spending the time and money to rebuild on a whim- just watch for wear a bit closer.
 
These engines are alot harder than most give them credit for ... I'd call it a non-event till something happened to signal your engine has a problem ... Just watch a little more closely at the engine ...

But, how much air is sucked in that small hole anyway? Did you hold your finger over it and check? Where to you ride at now to get dusty?

What you might wanna do is remove the hose from the airbox, then plug the airbox hole, and add some sort of filter on the end of the hose ...
 
Again, thanks for your responses. I re-shimmed the valves when I tore the intake apart looking for dust, so I will take Marc's / Huskynxjnwi's advice and check them more regularly to see if anything moves.

Ray-Ray, I have plugged the airbox hole and ordered a Uni-Filter to reroute the Crankcase Breather Hose. When I get it running again I will pull the plug and check to see how much air comes through the hole. Since it's the path of least resistance, I would speculate that a fair amount of air (and dust) comes in...

Finally, what's the protocol on posting the same thread in different forums? Is it cool or frowned upon????
 
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