Weird random tick in engine, cam chain?

subt3rra

subt3rra

SUBT3RRA
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Hey guys--been following several threads with interest and never needed to really start one of my own, until now. I have a trouble shooting question. 1980 XS400 W/about 18,500 miles on it. I've had it for the last 1500 & it was under a tarp for 4 years and not running when I got it. Had her started in 90 minutes, so I was happy.

Anyway, it is starting to have issues that feel like timing. This one is electronic ignition that has never been messed with (still had the plug in the right cover screw). I drilled it out and had a look only, didn't mess with it, so should be factory. I adjusted valves and they are good now. Cleaned carbs when I got it, but suspect the idle jets may need some love soon. Need air cleaners too. So I have idle screw all the way off and I hold the throttle slightly open to hold at 1200-1500. Anyway, getting by like that and otherwise rides great.

Last night riding home in stop and go traffic I started to hear this random "tick". Weird, cause it isn't continuous, it isn't loud but audible over the bike running and I almost think I can feel it. Tough to say again because it is random. Longer I ran it the more frequent it got but still random. I ride a ferry home and there are other bikers on the boat. One guy who happened to have an XS650 back in the day quickly said "Cam chain tensioner" without hesitation. It happened to him he said. I Googled it, and. checked the forum of course, but everything I read sounds like I should be hearing something more consistent. I checked around for the parts, not easy to get quickly. I'm also not sure if it is adjustable, and maybe that's the issue, and I can take care of this in a day. I haven't dug into the manual yet, but a quick look didn't seem like it was adjustable, and the parts are plastic, so they could simply be wearing out and the cam chain is starting to hit the inside of the engine. In any case needs to be fixed...

So, before I open the top up, can anyone think of anything else this could be? I have this vision of opening it up and either everything is shot and I'm looking at a rebuild (doubt that) or, in some ways worse yet, I open it and everything is fine and I have no idea what it could be... an "OK, now what?" situation that leaves me unable to ride indefintley. This is my only transportation so I kinda need this to run to get to work etc...

Sorry for the long post. I really hope there's someone out there who has an idea what's up. Thanks guys!
 
Well pulled the engine and cam cover. Guide and tensioner and blade are all perfect. Cams and everything inside look great. No loose parts, no signs of wear, good and oily. Nothing wrong that I can see.

That's what I was afraid of. Now I have no idea what it could be.

Popped open the starter cover and the alternator cover too. There's a little chain tensioner on the starting chain too. It looks ok too. The chain does have a good amount of slack. Not sure if that's normal or not, but turning the engine it seems like that would be normal. Clutch moves freely...

I haven't had anyone comment on this post, so I am guessing its not an obvious or common issue...

If I figure it out I'll post, but for now if I don't have any ideas I guess I'll put her back together and pay close attention in hopes of finding the problem, since it otherwise runs fine... thanks
 
Check your exhaust gaskets at the head. Replace and tighten evenly.
Worth a look.....
Terry
 
Check your exhaust gaskets at the head. Replace and tighten evenly.
Worth a look.....
Terry
 
How much slack is in the cam chain can you post a pic?Its normal for there to be an inch or two of slack anything more either the gear is worn or the chain has been stretched.Look for excessive wear on the teeth of that gear.
 
Can chain has acceptable slack, no pic sorry. Its not crazy tight and its not loose. Without the tensioner it is about an inch, with the tensioner its tight but moves easily when turning the engine. The guide and tension blade both look good.

I had to pull the exhaust pipes to get the engine out, so I'll see about replacing the gaskets and tightening up. I noticed a hole in the exhaust pipe close to the head on the right cylinder when I pulled it. Its like there is a sleeve over the pipe--meaning there's the chrome outer pipe, and the there seems to be another pipe inside, where I can't see but there must be a hole. Could that have anything to do with the noise? There is sometimes a little after fire, and I know that sound, but that has been it. This noise sounds like metal, high pitched, and random, single "tick"...Thanks
 
Your tick could be valves out of adjustment. The cam chains in these are self adjusting and don't need any adjustments (nothing like the xs650 ones) The head pipes are double walled and the small hole is for moisture to vent from.
 
Just did the valves before the noise. Wouldn't the noise be consistent, as in every rotation? There are sometimes several minutes between the noise occurring. Can't hurt to readjust. Doesn't make any other valve noise tho... thoughts?
 
When you adjust the valves make sure you rotate the engine only in the forward rotation. DON'T go back at all to catch the TDC marks. This will put slack in the cam chain and throw off the adjustment.
 
Just an idea I just thought of maybe the noise you here is a piston slap.:shrug:This can happen at random times.Sometimes slapping at startup then goes away.
 
OK--XSChris may be on to something. When I adjusted the valves it did want to roll past TDC, and I did roll it back to hold it in position. I'll do it again and be sure it only moves forward.

FYI the exhaust hole us definitively a hole that is not factory. I'll address this too...
 
RE: piston slap, doesn't sound like it, and now that I think about it the noise doesn't start until after its been running for a while... at least the two times I rode before pulling the engine...
 
So, I checked the valves again while it was on the bench--they were dead on. Made sure not to let it roll back. So much easier to adjust valves with the engine out!... not worth the hassle of pulling the engine of course...

Now, I am left with my exhaust pipe hole as the reason for the “tick”, and it is a hole--about 1/2" by 3/4" rusted through on the right cylinder pipe, on the inside of the round over right off the head. I will check the gaskets as well. Engine is back in, and I'm cleaning and painting while it's broke down (didn’t want to get into this project just now, but how often do I pull the engine out? Anyway it’ll look better).

Any other ideas? I’ll let you all know once the pipes are fixed if the tick is gone. Wish me luck…
 
So I went out to take a look at the exhaust pipes tonight. I picked them up and something rattled inside. Gave a shake and what looks like a piece of the inner wall fell out. I look inside and there's plenty more where came from. I checked the other pipe and same story. Im no expert but looks like I need new pipes and silencers. This could be the source of my mystery noise.

Bummer.

I've read threads on here where guys change pipes and silencers for a different look and sound. I just want the bike to run. Im not interested in playing "carb jet roulette". So if anyone knows what combo of aftermarket pipes and silencer/muffler will get me there I would appreciate it. Side note, if they werent the stock trumpet look so much the better, but not that important.

Appreciate the help--thanks!
 

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I have had my eye on this one. http://www.amazon.com/gp/product/B0079J86BK/ref=ox_sc_act_title_3?ie=UTF8&psc=1&smid=A26KJ58IOLD9BM

Scorpio was saying this model was available for less than amazon, but when I looked, it was sold out. normally going for 285 is within 10 bucks.

Its a MAC 2n1 muffler, An advantage over some of the custom made ones I have seen here, is the MAC one leaves enough room to remove the oil filter. My local yamaha dealer has it for the same price, and willing to do a military discount. which makes it more worth while with out shipping. you know what I mean.
 
Thanks Arfstrom. Was thinking of sticking with 2 x 2, but that looks good, I'll consider. Anyone use this yet? Feedback on performance? Hoping no re-jet... also , does xs650 head pipe work on our bikes? I find them available but not as many of ours... thx
 
OK XSChris thanks. Any suggestions on header pipes? Does it make sense to make pipes and use a muffler from Mikes xs or something? Again, trying to make getting this repaired and running simple if I can with available gear...
 

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