Honda ATV Forum banner

1 - 19 of 19 Posts

·
Registered
Joined
·
185 Posts
Discussion Starter · #1 ·
I'm wondering if any of you have experienced this before... Regarding my 87 trx 350; whether hot or cold I have a random tapping noise coming from the right hand side of the head. It's intermittent which is why I'm scratching ma head. It's a light tapping and sounds as though it's coming from the cam sprocket. I just used red,high temp thread locker when assembling it last time so I can't imagine those bolts backed out(again lol). But even if they did, why on earth would the noise happen and then not happen? It goes in a cycle most of the time. It'll lightly tap for about 15 seconds and then go away for the same length of time.
Really got me puzzled. I'm not keen on taking the valve cover off again but I really don't like any noise that isn't at least consistent.
Any ideas of what it might be guys? Thank you!
 

·
Premium Member
Joined
·
5,956 Posts
Its me again too... gotten sick of my rants yet? Lol

Did you notice much wear on the rocker arms (where they each maintain contact with the cam lobes) when you had the cover off? How about the rocker arm to rocker shaft clearances? Was the camshaft endplay OK?

The rockers must be smooth all the way across their faces where they contact the cam lobes AND have the same convex shape that was machined onto them. If the cam lobes have worn into them (making their faces flatten where they contact the lobes, or concave appearing in extreme wear cases) they can start ticking... and be intermittently ticking during the early stages... and getting worse as the wear increases. Once they get a concave profile worn into them they begin to knock loudly but can still be somewhat intermittent if the rocker is moving back and forth on the shaft due to the high amount of rocker endplay the factory allowed.

The rocker shafts & rockers can also wear enough so that their pivot surfaces are uneven and/or sloppy and will make a ticking noise (intermittently sometimes) if slop in those shafts get excessive. Again, the rockers have a lot of endplay from the factory, so they can move back and forth along the shaft, going from a least worn area to heaviest worn area in just one cycle.

It could make a ticking noise if the cam chain is worn out too. A worn out (or cracked/broken) chain guide could also be a possible cause.

You know how much remains on your chain tensioner travel, so you have a pretty good idea whether the chain is OK or not....

You can check and see if the chain guide is a noise contributor by putting the motor at TDC (on the compression stroke), then take out the plug on the end of the chain tensioner and use a short & narrow screwdriver to adjust the tensioner a bit overtightened, then start the motor and listen. Once that test is over put the motor at TDC again and back off the tensioner adjustment a bit and release it, so that it returns to its natural intended chain tension.

EDIT:
Forgot to mention that camshaft endplay can become a factor for ticking if it gets to be too much. The rubber plug at the end of the cam (you see it on the right side of the head) can get worn out or rotten or whatever... and allow the cam to have too much endplay. The cam can then "walk" back and forth causing the cam lobes to contact the rockers away from the center of their convex shaped contact area (where there is no previous lobe contact, or wear) thus the valve lash will go from loose to tight to loose... as the cam walks in and out.
 

·
Registered
Joined
·
185 Posts
Discussion Starter · #3 ·
No I'm not sick at all! I benefit very, very much from your experience!
That was a lot to digest... I'll have to read a few times and try to remember from when I had it apart.
I do not remember the cam lobes being convex. I know they didn't appear concave for sure, if anything they seemed flat which I thought they were supposed to be. I'll read your suggestions a few times and post back. Does anyone know where I can buy a NEW cam for this machine? I can't see the sense in buying a used one! If indeed I need one!
 

·
Registered
Joined
·
4,691 Posts
Sometimes you can luck up on nos (new old stock) on eBay and this site, I've never contacted them for any new old parts, but...... I did find this link burried WAY back in the forums, partzilla, maybe, I've never delt with them, but our members use that site.

My bad i forgot the link lol

http://www.hondarestoration.com/
 

·
Registered
Joined
·
185 Posts
Discussion Starter · #5 ·
Okay, let me ask you this... can I just run it as is? Ticking be damnned? It's really not that bad of a tick as of yet. My plan was to try to get the summer out of it and rebuild as a winter project. I guess what I'm asking is will I ruin the top of the jug and valve cover if the cam is bouncing around in there? I'm guessing yeah...
I just hate to KEEP taking it apart to fix little things every couple of weeks!
Also I know I will need to replace the cam chain too but it has some life left. I remember you (or someone) saying if I had a 1/4" or less on the tensioner after removing it and checking while at tdc it was worn out, and I had just over 5/16.
Part of me just thinks, "it's a honda, it's good for it".
 

·
Registered
Joined
·
4,691 Posts
I.cant advise on that, a slight tick would make me crazyier, then i already am, uh if you could video the noise and post it , one of our experts could advise better then i can :)
 

·
Premium Member
Joined
·
5,956 Posts
I ranted on enough to get confusing, sorry. The convex shapes I was talking about are on the rockers, not the cam. The cam lobes are uniform across the widths like you said...

I'm thinking that a bit too much camshaft endplay is the most likely cause for your intermittent ticking. You said it comes and goes for seconds at a time rather than a random tick... so that indicates endplay behavior as the more likely cause. If it is you can replace that rubber plug during the next teardown and be done with it.

Your chain tensioner having 5/16" of travel left should be fine for this season in normal wearing conditions, so I'd run it this summer and wait to replace it during the off season, like you hoped. If the ticking gets louder you might change your mind, but for now I wouldn't sweat it.

The only place that I know of that sell new cams for the TRX350 is Webcams.com. They hard-face & regrind your stock cam & rockers actually... its pricey, but probably is a good investment if you really needed one.

So, if you want to recheck the valve adjustment thats probably going to be all you need to do for now. Hondas are good for it, like you said... :)
 

·
Registered
Joined
·
185 Posts
Discussion Starter · #9 ·
Hey guys!
I distinctly remember the rockers being a nice smooth convex shape. There were spots that were shinier than the surrounding areas but I guess that's where contact happens the most.
I think I have evidence that backs up your theory regarding excessive end play. The camshaft journal plug was totally sealed and letting no oil by until this noise started. Even now it's only a fine mist around the circumference but I think that points to a worn plug. Which if I'm following you right causes excessive end play.
I'll be rechecking my valve clearance either this evening or tomorrow. It'll be interesting to see if they need adjustment.
Also I wanted to let you all know I purchased a new seat cover from an eBay Store named joemama1931 (I think) and it's really good quality. I'll use her again! It's got a few wrinkles but that my fault not hers. The top seams line up perfect and it's a good material.
Well thanks again! I'm sure barely a week will go by and I'll have some other question! Lol. Take care everyone!
 

Attachments

·
Premium Member
Joined
·
5,956 Posts
Sounds like your cam & rockers are perfect! The cam plug does wear & lose control of camshaft endplay, hopefully you'll be able to do something about that on the next teardown, but I don't expect that it will be a serious problem at all. I have to solve the same problem on mine and probably won't know how I'll solve it until I look it over real good while its apart. My rocker shafts are worn, but yours probably aren't worn much... I suspect that your valvetrain is in pretty good shape. Mine isn't. :-(

Thanks for the seat cover review and pics! I am planning on buying one of those from the same seller... is much appreciated feedback!!!
 

·
Registered
Joined
·
500 Posts
Looks good. I think I would have to keep working at the seat though. The wrinkles would drive me nuts. After it is on there a few days and if you leave it in the heat, it might be easier to pull it tight and add a few staples.
 

·
Premium Member
Joined
·
38,518 Posts
dumb question, but !!...by any chance your decompression lever is lose, smacking the exhaust valve ?????.
 

·
Registered
Joined
·
185 Posts
Discussion Starter · #13 ·
You had mentioned that in a different post and I meant to write about that. The decompression lever is still unhooked (till later today I hope) but it is and remains fully forward and so doesn't contact anything. I've played with it with the engine idling and I have to lift it up a ways before it will start contacting the exhaust rocker.
And yes, the wrinkles in the seat bug the snots outta me too! I'll be stretching it and stapling it later when I do the other work. As you said, it just took a few days of riding and heat to stretch it out enough for me to be able to fix it.
I really do believe my whole valve train is in really good shape. This wheeler, though old, wasn't ridden all that much before I bought it. And it was never worked. So I think I've got a wheeler worth dumping a bunch of money in to.
Too bad we all live so damn far apart, it would be fun to have an old honda meet or something. I'm in Maine so I'd probably have to travel the farthest. Is there anything like that anywhere?
I'm heading out on a long ride right after I write this. Hope you all have a great day and thanks again so much for all your suggestions and tips. It's really made the difference between me being able to learn and do the work myself vs. having to pay through the nose for someone else to do it for me! And it's loads of fun!!!
 

·
Premium Member
Joined
·
38,518 Posts
You had mentioned that in a different post and I meant to write about that. The decompression lever is still unhooked (till later today I hope) but it is and remains fully forward and so doesn't contact anything. I've played with it with the engine idling and I have to lift it up a ways before it will start contacting the exhaust rocker.
And yes, the wrinkles in the seat bug the snots outta me too! I'll be stretching it and stapling it later when I do the other work. As you said, it just took a few days of riding and heat to stretch it out enough for me to be able to fix it.
I really do believe my whole valve train is in really good shape. This wheeler, though old, wasn't ridden all that much before I bought it. And it was never worked. So I think I've got a wheeler worth dumping a bunch of money in to.
Too bad we all live so damn far apart, it would be fun to have an old honda meet or something. I'm in Maine so I'd probably have to travel the farthest. Is there anything like that anywhere?
I'm heading out on a long ride right after I write this. Hope you all have a great day and thanks again so much for all your suggestions and tips. It's really made the difference between me being able to learn and do the work myself vs. having to pay through the nose for someone else to do it for me! And it's loads of fun!!!
if it's not the decompression lever ?, then it's the cam chain or lose valves ?. yeah, most of us are spread out huh ?..lol.
 

·
Registered
Joined
·
4,691 Posts
Too bad we all live so damn far apart, it would be fun to have an old honda meet or something. I'm in Maine so I'd probably have to travel the farthest. Is there anything like that anywhere?
I'm heading out on a long ride right after I write this. Hope you all have a great day and thanks again so much for all your suggestions and tips
A few of us have talked about getting together.....
 

·
Premium Member
Joined
·
5,956 Posts
There is an ATC organization that meet every year... an old TRX meetup would be a lot of fun!
 

·
Registered
Joined
·
185 Posts
Discussion Starter · #17 ·
Yeah it would be a blast! We'd probably have to settle for an "80s" honda four wheeler event though to make it worthwhile. I'd be down for sure. It'd be a great reason to buy a camper... a fixer upper of course. Lol, then I'd have to join "winnebago dyi forum". Hahaha.
So I checked my valve clearance last night and All of them were .0004. I've noticed that gap tends to grow fairly quickly after adjustment to a thousandth over. So I adjusted them so that the .0003 feeler barely fit. Obviously that wasn't my problem and made no difference to the noise. It's not getting worse so I'm not worried. She still runs like a champ!
I stretched out that seat cover and added some staples too so that looks really good now.
I just now readjusted the wheel cylinders because I think the shoes wore in a little more. I was losing a bit of "pedal" but that's all good now.
So for now I'm all set and good to go! We've finally got some good weather so I've been riding all over creation. I'm super lucky because an old, 80 mile section of railroad was converted into a trail for atvs, snowmobiles, bicycles etc. And logging roads crossing Sunrise Trail (that's what it's called) mean that we can access literally thousands of miles of trails and dozens of ponds, mountains, your name it we've got it!! I unknowingly bought my house about two miles from this trail so I can get there without trailering my bike. Some people have all the luck! Guess I'm one of 'em for once in my life!
Thanks yet again guys for the pointers n tips n stuff. Have a great evening!
 

·
Premium Member
Joined
·
5,956 Posts
You DO got it made...! By the end of summer you'll have some intimidating arm and shoulder muscles too! LOL
 

·
Premium Member
Joined
·
4,704 Posts
There's the Vintage Japanese Motorcycle Club--we could crash one of those events if you're serious they might be OK with it. I'd be up for one a year as long as it's not during the Sturgis Rally Holiday

https://vjmc.org/

Edit oh but they probably won't have any fourwheeling trails nearby. I wouldn't be interested in a show and shine
 
1 - 19 of 19 Posts
Top