Help! 400ex Smoking

[gery350]

So, I shouldn't waste my time/money testing compression? Should I just go ahead and start the tear down? Gery, why do you think I will need both rings and valve seals? Are valve seals something worth replacing anytime your in an engine? Let me know what you all think.

due to the amount of smoke your getting. if you do it yourself its relatively cheap. more then likely your burning oil thru the rings. once you take it apart it would be foolish not to replace the seals. im sure they're only a couple of bucks. in other words you need rings and might as well replace the seals while your at it.

[gery350]

oh 5:00. gotta go to job#2.
we'll talk later. good luck.

[hondarider95]

The smoke really looks white to me. If white means water, is there any chance that maybe my fuel has water in it? I doubt it cause it runs fine, but the smoke does look white to me, unless it is very light blue.

[Ida_Mann]

What else commonly needs to be replaced on a bike of this age? Valves, valve springs, cam chain?

So forget the compression test?

I'd say forget the compression test.

take care of them rings and other than that,,,,shouldn't be a problem.

Id@

[hondarider95]

Ok, the tear down begins. Hopefully I can get the drain the oil and get the engine out tonight, I got some other stuff to do later, but I should have an hour or two to work on it now. I will keep you all posted.

[xr100racer]

Hold up on pulling that motor buddy, you should be able to service the top end while the motor is still in the bike. And you will need a valve compressor tool to replace the seals.

White smoke is burning water, I would drain all the gas out of the tank and fill it up with some fresh fuel. If your confident the smoke is white then I would try that first before tearing the motor apart. There could be water in your tank

[hondarider95]

But would it run with water in the tank? I have already started the tear down, but I can dump the gas out of the tank and hook a few things back up to test it with fresh gas. I guess, I'll try that tomorrow. I am gonna pull the engine anyway, so I can paint the frame. So I figure I can knock out two things at once, and it will be nice to be able to sit a table with the engine to rebuild it. I think I am gonna replace the cam chain while I am in there. I'll test the gas thing tomorrow, I dont think that it will fix the problem, cause it runs to good to have contaminated fuel, but it would be nice if that was the case.

[xr100racer]

Sounds good. I would just test the gas thing for peace of mind, to know that your defiantly fixing the right thing. Working with the engine on a table rather than standing over the bike is nice. If your going to paint the frame I would suggest powdercoat. Lets us know how it goes

[hondarider95]

I will definitely let you all know how it goes, actually I will probably just start a new post with pictures and stuff about this remodel. I was thinking powder coat too, but it is really expensive. I am now thinking I will use some pj1 paint. I'll remove the old paint, sand it, prime it, paint it, and clear coat it, then I think it should be ok. I have read about a few people that have done this with success.

[gery350]

back from job2.
if you want to test the gas just pour some from your tank into a glass jar. if its contaminated you will see the water at the bottom of the jar.

[xr100racer]

If you do test it like that then shake your tank up before you pour it into the jar. Like gery said, the water will stay at the bottom. So if your bike has been sitting for a little bit and then you pour into a jar, the water will be at the bottom of the tank and you wont get any in the jar.

[hondarider95]

Why didn't I think of that? That is pretty much what I do every time I fly (I am getting my pilots license), we have a special little cup thing that bleeds gas from the bottom of each tank and the carb to see it there is any fuel contamination. Well I'll do that tomorrow, instead of starting it back up with fresh gas. So when I pull the engine tomorrow and open it up what all do I need to test clearances and what not? Just feeler gauges? Also the tool that is need to compress the valves is it something special or just a large c clamp?

[Ida_Mann]

a 400 will run with water in the gas,,,,I can testify to that because I drowned mine and finally got it started,,,,it started spitting water out of the exhaust for about 5 minutes.

Id@

[Mr. Fixit]

It would be a good idea to go to the Honda dealer to get the 400ex service manuel. You'll need it for torque specs,valve clearance etc. Lots of valueble info. I bought one for both of my Hondas. 

[hondarider95]

Ya, I have had serivce manuals for all my bikes. But I just downloaded the pdf for this one, but I think I will buy it also cause I like to have something I can move around and take to the bike. Or just print the pages I need.

[hondarider95]

Do I need to measure anything before I pull the cylinder? Or should I go ahead and pull the cylinder out?

[xr100racer]

Just pull it

[hondarider95]

Got the cylinder and piston out. What do I need to measure? Go to this post for more info and pics:

http://www.atvflorida.com/forum/index.php/topic,21118.0.html