I'm posting this question for the second time since I didn't get an answer . .
If anybody can help me with this one .. Would be great !! [img]i/expressions/face-icon-small-cool.gif[/img]

My foreman is making noise when I cruise to about 40 -> 70 Km/h ..
I think it's the engine, 'cause the sound seem to come from it . .
It's a kind of Valve noise, but it's coming from below the cylinder head, so my guess is that it's
the camshaft or crankshaft, something in this area . ..

I've adjusted the valves about a month from now, and I just did about 5 runs since then, but the sound was
there since I buied it (the quad)! . .

Anybody has experienced this kind of noise, it's hard to describe.. It's like valves needing adjustment, but
loudder . ..

Now, I'm thinking about dismembering the engine to pieces and rebuild it .. .


Thanks !!


[img]i/expressions/face-icon-small-blush.gif[/img][img]i/expressions/face-icon-small-disgusted.gif[/img][img]i/expressions/face-icon-small-happy.gif[/img][img]i/expressions/face-icon-small-disgusted.gif[/img][img]i/expressions/face-icon-small-confused.gif[/img]

 

i had the same problem with mine but it made the noise at all speeds and just idleing, i found out that their was a crack inside the head repalaced the head and it was good as new (honda paied for it)

 

[img]i/expressions/face-icon-small-shocked.gif[/img]

I hope that the Head is not cracked!! .. Where was the problem on yours!? . .
But I don't think that this is my problem since it makes the sound at different RPMs . ..


Did you do the Repair job?! .. I mean, you did install the Head by yourself!? . .
If so, I've created a Topic in the Honda forum, just before this one, (Foreman Engine Question),
I need the torque settings for the cylinder, valve cover etc... Do you have this information !? .. My manual
doesn't give them to me ...

Thanks ! [img]i/expressions/face-icon-small-wink.gif[/img]

 

When did the noise start? After you buried it in mud? Adjusting the valves didnt make anydifference? Does it seem to keep time with the revs? Hows the oil and filter, got enough oil in it? Its hard to dianose noise issues when I cant hear it, but if it increases with revs, and its louder than the valves....maybe exaust pipe is loose or cracked. You may have to take it somewhere and have a tech look at it, and listen to it.

 

Ok, I didn't give much details, here they are :

- Oil level is perfect, I check it each time I ride..
- Oil filter is ok, I do oil changes very often, like after 2 or 3 rides, or every 100 hours
- The noise was present when I buyed the ATV .. I did not noticed it when I "test drive" it .. as the noise seem to
be present when I Rev it near after 1/2 of the throttle or near top speed..
- Valves are adjusted as I said, but I'll recheck them ..
- I cleaned the Carburetor

- I did a repair on my muffler, 'cause there was a part that was loose inside the muffler, due to backfireing .. .
I just removed the loose part... A metal tube ... Is that called a Spark Arrestor?! Or the Spark Arrestor is the
"star-like" metal thing ??

The quad do backfire when I release the throttle, say from 1/2 to 0 .. Maybe your right when you say it's the muffler,
maybe it is loose on the head, I'll check this .. It may explain the backfires also . ..
And since I've remove a piece in the muffler, maybe I need to rejet 'cause there is less restriction now . ..

And a new sound did appear from nowhere the last time I trailed, it's like a metal vibration, it doesn't seem too serious,
I think it's the metal shield on the pipe of the muffler ..


Hmm my dad has a 2002 (2003 ?) fourtrax 350 .. The sound of his engine is soooooo different of mine ...
The sound is like running low on oil .. But I know I'm not low on oil .. .The Oil filter is installed on the right direction ..
The engine does not seem to overheat ...
I have theories, like a worn bearing inside the engine or something like that .. .

I'll check the muffler and tell you if it was that ! 8]

 

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The Statements with the "-" are about the sound of MY Quad (Foreman) not the one of my father .. In case it was not clear !

 

I've just checked the Muffler, it's not loose, clamps are tight, and no problem near the Head . .
I don't think there are leaks also.. But I don't know any methods to seek for Muffler leaks . . ..

 

I wonder if this isnt the reason it was for sale.
If youre still on speaking terms with the last owner, maybe you could ask him whats up with the noise. Maybe he ran it out of oil, and it ruined a bearing, which is now making noise. Your best bet is to take it to a tech and let them give you an idea whats wrong. Its possible, its something hes seen before and could be a cheap fix.
A quick fix for the backfireing on thottle let off....the pilot circuit is too lean, adjust the idle mixture screw, out(richer), at least 1/4 turn.
carb adjust this article will help explain the adjustment.

 

Hmm .. Well, that's what I thought about the sale when I heard the strange noise.. But at the price I
had it .. It is in good shape, except from the noise .. The quad is strong .. And compared to the New 350 of
my Father, it's real strong ... Well, maybe no damage done .. Yet ...

The Saler did show me the maintenance sheet of the ATV, he sent the Atv at the Dealer for maintenance like every month
or so, I don't remember the exact delay between each check..

If the problem is a bearing.. I hope it's not too hard to fix! .. I'm new to mechanic, but I love to learn ..
So it will be fun to play inside the engine, I just need to learn a bit . . .


About the Carburetor, I adjusted the pilot screw about 3 or 4 times, I tried different methods, but none did
remove the backfiring problem .. . . I'll try Rejetting . .. Then, if not fixed, I'll dismember the engine, check everything
valves etc ... Hell, I'm very embarassed when I encounter someone on a trail and the Atv make a backfire, that make you
feel like your driving a crap vehicule . .


Anyways, Thank you for your help !! .. [img]i/expressions/face-icon-small-smile.gif[/img]