Strange thermal expansion/contraction type noises

[oilcanboyd 5]

1995 Foreman 400(TRX400FW)

Hello everyone,

I've been dealing with this for over a year now and could really use some help to shed some light on it. Last August, I encountered a problem with shifting beyond 2nd gear, which I was able to resolve  ( @shadetree, @toodeep, and @AKATV. thanks again) 

After i got the front crankcase all back together, following the service manual of course. She has been shifting flawlessly and has never run better. However, since that time, I've been contending with a  weird noise issue that has left me scratching my head. To describe it, once the ATV reaches a specific temperature, roughly 2-3 minutes after starting, it starts emitting an irregular "Ting/Tong" sound. This isn't a constant knock or tick; it's quite random and not overwhelmingly loud when the vehicle is running, but still quite noticeable. What's alarming is that when I turn off the ATV and let it cool down, I hear one or, at times, two or three rather loud "Tings" as it cools down.

I've attached a recording I made last year when the issue initially arose. This clip was recorded after letting the ATV warm up for a few minutes, followed by a 5-6 minute ride. After parking it, this is the sound I captured.  I understand that ATVs tend to make some thermal expansion/contraction noises when parked, but my concern is that these sounds are occurring even during leisurely riding, and when its cooling down it makes a very loud noise, you will hear what i am talking about in the clip.

My best guess, based on the location of the sound, is that it might be related to the valve lash? but I am probably way wrong. I've been too worried to engage in any serious riding since the repair last September, so any help you can offer in solving this mystery would be greatly appreciated.

PS: if you are able to check out the audio make sure to listen to the entire clip 

 

Honda Audio.mp3

Edited October 22 by oilcanboyd

[shadetree 5,803]

4 hours ago, oilcanboyd said:

1995 Foreman 400(TRX400FW)

Hello everyone,

I've been dealing with this for over a year now and could really use some help to shed some light on it. Last August, I encountered a problem with shifting beyond 2nd gear, which I was able to resolve  ( @shadetree, @toodeep, and @AKATV. thanks again) 

After i got the front crankcase all back together, following the service manual of course. She has been shifting flawlessly and has never run better. However, since that time, I've been contending with a  weird noise issue that has left me scratching my head. To describe it, once the ATV reaches a specific temperature, roughly 2-3 minutes after starting, it starts emitting an irregular "Ting/Tong" sound. This isn't a constant knock or tick; it's quite random and not overwhelmingly loud when the vehicle is running, but still quite noticeable. What's alarming is that when I turn off the ATV and let it cool down, I hear one or, at times, two or three rather loud "Tings" as it cools down.

I've attached a recording I made last year when the issue initially arose. This clip was recorded after letting the ATV warm up for a few minutes, followed by a 5-6 minute ride. After parking it, this is the sound I captured.  I understand that ATVs tend to make some thermal expansion/contraction noises when parked, but my concern is that these sounds are occurring even during leisurely riding, and when its cooling down it makes a very loud noise, you will hear what i am talking about in the clip.

My best guess, based on the location of the sound, is that it might be related to the valve lash? but I am probably way wrong. I've been too worried to engage in any serious riding since the repair last September, so any help you can offer in solving this mystery would be greatly appreciated.

PS: if you are able to check out the audio make sure to listen to the entire clip 

that sound is what i think is the muffler !. the core parts are cooling off, this is my guess from hearing the sound bite you posted. very well can also be the muffler heat shield cooling down as well right near the head exhaust.

Honda Audio.mp3 222.47 kB · 3 downloads

 

[retro 3,984]

My guess is it's coming from the exhaust as well. Exactly where I don't know.... could be a baffle inside the muffler has come loose from the muffler body or it could be the heat shield creeping back and forth against the header pipe due to expansion/contraction. I'd remove the heat shield to see if the sound goes away. If it does not then I'd blame it on a baffle inside the muffler.

[retro 3,984]

@oilcanboyd, you wouldn't by chance be known as Oil Can Boyd the MLB pitcher would you?

[oilcanboyd 5]

1 hour ago, retro said:

@oilcanboyd, you wouldn't by chance be known as Oil Can Boyd the MLB pitcher would you?

Lol no but I have a handful of his cards, I pitched in Junior College but never had the skill of the Great Oil Can Boyd, LOL 

[Fishfiles 20,140]

I had to look: 

 

 " Dennis Ray "Oil Can" Boyd " 

 

His unique and memorable nickname has been reported as coming from his beer-drinking days in his hometown of Meridian, Mississippi, where beer was referred to as "oil".^[

[oilcanboyd 5]

3 hours ago, shadetree said:

 

Ok i will go take a look at the muffler area thanks @shadetree , Ya besides this it is running and shifting perfect since replacing that star gear.....

30 minutes ago, Fishfiles said:

I had to look: 

 

 " Dennis Ray "Oil Can" Boyd " 

 

His unique and memorable nickname has been reported as coming from his beer-drinking days in his hometown of Meridian, Mississippi, where beer was referred to as "oil".^[

I remember this card from when i was a kid, Ya ole' Oil Can was an menace on and off the field.    

 

[toodeep 1,746]

I would put my money on the exhaust as well. Over the years something came loose just enough internally to give some sounds will expanding/contracting. I wouldn't loose any sleep over it and ride it until the exhaust gives issues.