[Jaywal450]

Hi, new to the forum. I have a older Honda Foreman and it has developed a ticking noise from what I’d guess is the front of the engine right about where the cam chain is. It goes away at high rpms but is plenty easy to hear at idle or low rpm. I have the valve cover off, and when I pull the pull starter, every time a valve goes down, there’s a click right before it comes back up. The valves were a bit out, as they have never been checked (30,600km, 2,170 hrs on it) but not terribly. There is something leaking, either around the valve cover gasket, or from the exhaust pipe where it attaches to the head. I’m guess it’s a worn out cam chain because of the age and mileage of the thing? Tho the ticking is almost too regularly timed to be a loose chain slapping. I’d like a second opinion before attempting to check it, because getting into the front of the engine looks like a pain. It has apparently been run low or almost out of oil because I drained it and got maybe 1 quart out. I have never had an engine apart, or even adjusted valves before, figured an old Honda is a good place to learn. Ive lived on a farm all my life (25 years) and am good at mechanical trouble shooting tho I have never had an engine apart. Any help would be appreciated!

 

[Orvis25]

Hi, new to the forum. I have a older Honda Foreman and it has developed a ticking noise from what I’d guess is the front of the engine right about where the cam chain is. It goes away at high rpms but is plenty easy to hear at idle or low rpm. I have the valve cover off, and when I pull the pull starter, every time a valve goes down, there’s a click right before it comes back up. The valves were a bit out, as they have never been checked (30,600km, 2,170 hrs on it) but not terribly. There is something leaking, either around the valve cover gasket, or from the exhaust pipe where it attaches to the head. I’m guess it’s a worn out cam chain because of the age and mileage of the thing? Tho the ticking is almost too regularly timed to be a loose chain slapping. I’d like a second opinion before attempting to check it, because getting into the front of the engine looks like a pain. It has apparently been run low or almost out of oil because I drained it and got maybe 1 quart out. I have never had an engine apart, or even adjusted valves before, figured an old Honda is a good place to learn. Ive lived on a farm all my life (25 years) and am good at mechanical trouble shooting tho I have never had an engine apart. Any help would be appreciated!

I do not own that atv model, but I would start with a basic engine tune up and see what happens. My trx200sx had a quiet tick and after adjusting my head spacing it disappeared.

You can find the manual for yours (most likely) in the forum on a sticky for repair manuals.

 

[retro]

I'll take a wild guess and say that the click you are hearing while turning the motor over slowly by hand might be the cam chain tensioner & guide making noise against the chain because of a badly worn out cam chain and tensioner. The automatic compression release mechanism on the end of the camshaft might be contributing/causal to that clicking noise as well. Another likely possibility is that the camshaft lobes and lifter cups might be completely worn out. You won't know much more about it until you take it apart.

Is the motor burning oil? If so, I imagine the valve seals might need replacing by now at a minimum.

Welcome to the forums!

 

[retro]

Also check to see whether the exhaust gasket where the pipe mates to the head might be leaking. Slight exhaust leaks sound just like a mechanical ticking or knocking motor. But can't do that until the motor is running of course.

 

[SamUK]

My 450 ticks on start up until I give it a little throttle, mine is definitely the automatic decompression release. It’s an intermittent issue so I don’t see it as major at the moment!

Edit: It’s probably the easiest place to start your process of elimination fault diagnosis.

 

[Jaywal450]

Also check to see whether the exhaust gasket where the pipe mates to the head might be leaking. Slight exhaust leaks sound just like a mechanical ticking or knocking motor. But can't do that until the motor is running of course.

Can i post pictures somehow? Because there is DEFINITE leak right where the exhaust pipe is attached to the top end, beside the valves. about 1/8" think hard gunk around it that ill have to wirebrush off. pressure washer didnt do it. I never really noticed it because its so well hidden under the tank and the plastic side pieces.

I happen to have a neighbor, very old mechanic, (in his 80s) he came by today and his impression was the lobes on the camshaft or lifters might be worn. So ill probably tear the engine down anyways, even if just to learn something. He said he come by later to inspect it when i have it apart. He cant do any sort of work anymore.

My first guess was a stretched timing chain too, but its a tad to well timed for a slapping chain, especially since so matter how slowly i pull the starter rope it clicks at the exact same time. right when the cam would roll over and let the pushrod back down.

Is it still possible to get parts like a cam shaft and chain for an engine that old?

Thanks for the help!

 

[Jaywal450]

Never mind. wasnt logged in when i tried replying

 

[Jaywal450]

I'll take a wild guess and say that the click you are hearing while turning the motor over slowly by hand might be the cam chain tensioner & guide making noise against the chain because of a badly worn out cam chain and tensioner. The automatic compression release mechanism on the end of the camshaft might be contributing/causal to that clicking noise as well. Another likely possibility is that the camshaft lobes and lifter cups might be completely worn out. You won't know much more about it until you take it apart.

Is the motor burning oil? If so, I imagine the valve seals might need replacing by now at a minimum.

Welcome to the forums!

And yes. it was burning oil. Or loosing it somewhere :wacko:

 

[retro]

It was burning oil and leaking oil... and the exhaust pipe gasket (copper crush ring) was leaking at the head. We are batting .1000 so far.

The exhaust valve seal is bad, I can see the shiny oil/carbon buildup on the valve stem. I imagine the intake valve seal is leaky too. So there is source #1 for the oil burning issue.

The valve cover gasket was leaking quite a bit of oil too.

As for camshaft, lifter cups, cam chain, chain tensioner parts availability, many of us use Partzilla to look up part numbers and look at interchange lists. Some even buy their parts from there, but there are a few better service/price options...

https://www.partzilla.com/catalog/honda/atv/2000/trx450es-a-fourtrax-forman-es

It looks like everything you'll need is still available. Once you get done diagnosing this and have a parts list in hand let us know. We can help you...

 

[Jaywal450]

is this much black crud normal??? i know its been abused before i got my hands on it but dang!

 

[Jaywal450]

ill keep working on it in my spare time. next step is figuring out how to disconnect the front and back driveline so i can get the whole engine out. i cant get at the front well enough like this.

Batting??? im from Canada, eh, speak in hockey terms

 

[retro]

LOL, I live just down the road from the town that claims to be the birthplace of hockey and still don't know a thing about it!

You are getting after it though ain't ya! What you see appears normal to me for its age and kilometers on the clock. It was burning oil because the valve seals gave up due to old age. But from what little I can see of the side of the piston, it looks like the piston, rings and bore (stock bore is 90mm) were probably still holding up good.

Download a copy of the service manual if you haven't yet. Its great reference for specs and you'll need it to measure everything you took apart so far... I'm looking forward to seeing the remainder, thanks for sharing!

 

[Jaywal450]

Thanks for the help! I do have a copy of the manual downloaded.

Has anyone tried repainting the plastics, I’m guessing you’d need special paint to make It stick. Or maybe vinyl wrap?? Since I have the thing completely apart anyways, might as well do it right. I’ll for sure repaint the racks and bumper but I’d like to do something with the faded pink plastics too

 

[retro]

Depending on how badly faded or damaged the fenders are, you might not need to do much more than buff them lightly, cleanup with some solvent and put some cheap Wipe New Recolor on them. Some folks paint them but it is difficult to get paint to stick on those plastics long-term. Another option is careful use of a heat gun, which slightly melts the surfaces of the plastics and smooths & brightens them up. Gotta be careful using that method though. You can also buy a three-part kit like @Goober used on his Green 300FW. Search for his thread if interested in trying that.

 

[Jaywal450]

Aaand after tonight’s 2 hours work I have officially determined that either I have no idea how the auto tension works, or it’s f***ed, OR that is one badly stretched timing chain.....

I have the engine sitting on my table now. Should make things easier.

In order to get the front cover off I had to take off the small electric motor on the front. What is that? I hope it’s not devilishly hard to reassemble correctly...

 

[Jaywal450]

I took both lifters out, absolutely no sign of wear at all. So I put one back in, took the push rod and pushed down hard on it, and turned one of the clutches by hand, as the cam push the rod and my hand up, the chain stayed loose. As soon as the cam rolled over, the other side of the chain had the tension, as it’s basically braking/holding back the cam, and the tension shot the tensioner up against where it should be with a VERY familiar sounding *tick*

So I can safely say. I’ve learned a LOT this week lol

 

[shadetree]

cam chain is a little stretched, and the ele shift transfer gears are very easy to put back in.

 

[retro]

You have some good news concerning the cam and lifters!! Thats great that they are still in good condition. And it looks like you got lucky that the chain hadn't jumped yet. So, what is the score so far?

Those mystery parts are the electric shift motor and reduction gears & housing. You'll be greasing those gears and bearings during reassembly.

 

[Jaywal450]

You have some good news concerning the cam and lifters!! Thats great that they are still in good condition. And it looks like you got lucky that the chain hadn't jumped yet. So, what is the score so far?

Those mystery parts are the electric shift motor and reduction gears & housing. You'll be greasing those gears and bearings during reassembly.

One more question, does this engine have a one way bearing? I’ve read somewhere about it and how the engine braking works. The engine braking seemed to work ok, but when I stop the engine I always hear something spinning for 3-5 seconds, reeeeeeeeeeeeeee, *klunk* then silence. Is that normal, or means the bearing isn’t working like it should? Still trying to find as many things to fix as possible before reassembling lol

Ok, I haven’t checked the manual yet for assembly of that shifter motor. Was just a bit worried since it came of in my hands before I could get a good look at how it was put together.

Parts list So far
the exhaust valve seal is shot. (Intake valve was perfectly clean)
New cam chain
Possibly new one way bearing
What about the copper ring you mentioned on the exhaust that was leaking?

Anything else you guys see that is fritzed? I won’t order anything till I have the cam chain off, probably do that Sunday if I have time. Maybe I’ll find something else wrong. Gotta keep my batting score up ?

 

[_Wilson_]

Depending on how badly faded or damaged the fenders are, you might not need to do much more than buff them lightly, cleanup with some solvent and put some cheap Wipe New Recolor on them. Some folks paint them but it is difficult to get paint to stick on those plastics long-term. Another option is careful use of a heat gun, which slightly melts the surfaces of the plastics and smooths & brightens them up. Gotta be careful using that method though. You can also buy a three-part kit like @Goober used on his Green 300FW. Search for his thread if interested in trying that.

I can't locate that page/thread ether... Here are the chemicals .