[beaglebriar]

Ok fellas I could use some help on this one. I've rebuilt this motor from the ground up and still this noise continues. I used to think I was a pretty good mechanic but now I have my doubts. Lol
Runs great, great power,does not smoke..

Here's a video of what I'm up against.

 

[alloutdoors]

Hum...I'm unsure of the sound, but confident there will be folks here to assist.

 

[beaglebriar]

Hum...I'm unsure of the sound, but confident there will be folks here to assist.

Thanks.

Sure has me stumped. Put a different valve cover/ rocker arms on it tonight..no change. I'm really grasping here..

 

[alloutdoors]

Hum...I'm unsure of the sound, but confident there will be folks here to assist.

Thanks. Sure has me stumped. Put a different valve cover/ rocker arms on it tonight..no change. I'm really grasping here..

There are passionate and great folks here regarding Honda ATVs and confident you will get some input....

 

[shadetree]

too me, i hear a stretched cam chain.

 

[beaglebriar]

too me, i hear a stretched cam chain.

Cam and cam chain are both new. The tensioner was working properly also.

 

[shadetree]

too me, i hear a stretched cam chain.

Cam and cam chain are both new. The tensioner was working properly also.

i would open the front cover, and have a look at the tensioner, the 450's and 500's were bad about the tensioners going out.

 

[shadetree]

if its not the tensioner ?, have a look at the valve seats in the head. I've known many from the ranchers to work their way out after warming up.

 

[Manny]

yowza. possible valve seat, definitely sounds valve train related to me. how'd the valve springs look? I would tear that head off and give er' another look.

 

[Manny]

possible bent push rod? how did the ends look? what about the buckets?

 

[beaglebriar]

if its not the tensioner ?, have a look at the valve seats in the head. I've known many from the ranchers to work their way out after warming up.

This was a thought that I had as well. It doesn't do it when cold or at low RPM. It will really clatter when you blip the throttle real quick or if the engine is seeing back pressure going down hill.

 

[beaglebriar]

possible bent push rod? how did the ends look? what about the buckets?

The push rods and buckets have been replaced. This quad was a total mess when I got it.

It probably should have been parted out but I get tunnel vision sometimes and feel sorry for neglected machines.

 

[beaglebriar]

too me, i hear a stretched cam chain.

Cam and cam chain are both new. The tensioner was working properly also.

i would open the front cover, and have a look at the tensioner, the 450's and 500's were bad about the tensioners going out.

I'm confident that it's not the tensioner.

 

[shadetree]

if its not the tensioner ?, have a look at the valve seats in the head. I've known many from the ranchers to work their way out after warming up.

This was a thought that I had as well. It doesn't do it when cold or at low RPM. It will really clatter when you blip the throttle real quick or if the engine is seeing back pressure going down hill.

bingo !!!!, it's the valve seats !, i'll bank on this. i had a rancher ( 350 ) that like you, replaced cam, cam chain, tensioner , all of it, it made the same rattle, clink, as yours..AND ONLY WOULD DO THIS ONCED WARMED UP !.

 

[beaglebriar]

if its not the tensioner ?, have a look at the valve seats in the head. I've known many from the ranchers to work their way out after warming up.

This was a thought that I had as well. It doesn't do it when cold or at low RPM. It will really clatter when you blip the throttle real quick or if the engine is seeing back pressure going down hill.

bingo !!!!, it's the valve seats !, i'll bank on this. i had a rancher ( 350 ) that like you, replaced cam, cam chain, tensioner , all of it, it made the same rattle, clink, as yours..AND ONLY WOULD DO THIS ONCED WARMED UP !.

Cool! Thanks for your help. I'll tear it down and report back.


What's the fix for this? Will new guides solve the problem or does the head need replaced? (Just thinking that a new guide would be loose also) Also with new guides do I need a reamer?

 

[beaglebriar]

After looking up the parts I see that the new guides are oversized.

 

[shadetree]

only way to fix it is another head.

 

[beaglebriar]

only way to fix it is another head.

That's good to know. Thanks again.

Sent from my XT1080 using Tapatalk

 

[shadetree]

only way to fix it is another head.

That's good to know. Thanks again.

Sent from my XT1080 using Tapatalk

yw. if it was just the valve guides ?, you could press the old ones out, new ones back in. but the valve seats are pressed into the head from the factory, they can not be serviced, which means, a used head ?, or a new oem from Honda, have a look on ebay for used. i can tell ya right now, a new one from Honda won't be cheap !..lol.

 

[shadetree]

oh, and well done on the rebuild progress so far !, i see talent in the making . i rebuilt a trx500fm not long ago, total rebuild from the ground up,all new everything from Honda, cept a couple small things, seat, small plastics. had it all back together, and first gear gave me problems ( i was warned about 1st gear from jeep69 here ..lol ) had to rip the engine back out..and tear it down, replace the gear set ( thanks again jeep69 for the gear set ! ).