Gt

[XSokieSPECIAL]

I have a "80" xs1100s with a problem strange to me. I'm an auto tech and this seems backward to me.
I have one valve that gets noisy only when the engine gets warmed up, when it's cool they sound great. But, the warmer it gets, the louder it gets.
I've checked the adjustment and it seems fine. Anyone else experienced this?
Not sure which valve, I think it's #3 intake.

[Ivan]

Might be a flat spot on the cam and it isn't spinning the shim like they are designed to do. Usually a flat spot on the cam gets worse when warm, in just about any engine.

[XSokieSPECIAL]

Noisy valve

So your saying I need a new cam. Not what I wanted to hear.

[Ivan]

Not necessarily, but worth pulling the valve cover again to see. It was just the first thing that came to mind.

[XSokieSPECIAL]

noisy valves

Ya, I'm waiting for a new gasket as we speak. But, this has been a developing problem since I got this thing running last Dec.
Like I said, I'm not really sure which one it is. Will it be visbly damaged?
Ifv that is the problem, do you know where I can get a new or used one?

[Ivan]

Well, if your an auto tech, I would suspect you may already know what a cam looks like when its going flat.

A member here, andreasweiss, sells parts for less than you can find them on ebay, if that is the trouble.

Another suggestion, have you checked your cam chain tension?

[XSokieSPECIAL]

Ya, I do know what a flat lobe looks like in an automotive engine, but I've been learning that a lot of my automotive knowledge doesn't apply to MC tech so I didn't think it was a stupid question. It seems I would have noticed that kind of damage when I checked the adj. before but as you say it's worth another look.
Yes, I did check cam chain tension when I was in there. It seems good and snug.
What you say about the cam makes sense but I really hope your wrong. The new gasket should be here sometime next week. I'll holler if I need more help.
Thanx Ivan!

[skids]

Maybe one cylinder runs too rich which may be ok on startup but misfires when hot(?) I had a bike with a slightly bent exhaust valve once that ran the way you describe, but the exhaust would make a "puff" sound as it ran and would slightly knock at certain rpms.

[Ivan]

duplicate, get rid of it, it makes me look stupid....

[Ivan]

I am not the worlds greatest wordsmith, so, I didn't want you to think I was implying it to be a stupid question. Sorry if that were the case.

A slightly bent valve also makes sense, as skids said. Especially if its just enough to start tapping the piston when it warms up. I would think there would be a horrible misfire on that as well. I have seen cases, on cars, when a bent valve flexes enough to make a seal for a while, but usually ends up fireslotting the head.

This is definitely an interesting one, and I will keep thinking on it. I just hope it isn't something that is a sound that travels from somewhere else to the top of the engine, that could be a real bear to track down. I hate BSR (Buzz, Squeak, Rattle) problems. Speaking of, do you have a set of electronic ears that you could use to pinpoint the sound? I have a set I think is called "EngineEar" thats just basically an amplified stethescope, that thing has saved my time ratios more than once.

Also Skids "knock" made me think about one other thing. Yamaha had a TSB that said these bikes would knock from about 3-5k rpms. Mine always did it, but it sounds more like a ping to me. Their cure was the infamous "operating normally" but they also released a modified vacuum advance to help the noise. Could that be it?

[XSokieSPECIAL]

No offense taken Ivan, just saying it seems sometimes you have to look a little closer on these bikes for things that would be quite obvious on a sb chevy. So I've gotta ask, if I don't ask I don't know.

The more I listen to it, the more it sounds like an oiling problem. It comes and goes when I'm riding. It starts up at higher rpms, then when it comes back down it stays for a while and then quits again. How do the lifters get oil? I know they're not hydraulic, but that is what it acts like.

Ever run across a top end oiling problem with these?

Got my new gasket today so I'll be elbow deep in XS tomorrow.

By the way Skids, thanx for the input but I'm pretty sure a bent valve isn't the problem. It runs great, it's just the clack, clack, clack.

[petejw]

Hi Greg,
Has the bike been sitting a while not being ridden,
or has this noise just started?
Leaky exhaust flanges can have a similar sound,
changing the oil might help also,
the top end on these engines in general are a little noisy.

[XSokieSPECIAL]

Ya it sat for 2 or 3 years before I got it, but I didn't notice the noise until the weather got hotter and it seems to have gotten progressively louder. I know it's not exhaust, it's coming out of the right side of the valve cover.

I'm pulling off the valve cover tonight to check for worn cam lobes, and correct adjustment AGAIN!

Like I told Ivan, It really sounds like one lifter is occasionally running out of oil.

Greg

[thewiz]

Also could be ...

and if I missed this while reading through the thread sorry but .... a weak valve spring. These springs, along with the clutch cover springs, carb diaphram springs, fuel petcock springs, have been under compression for roughly 30 years. That's a long time to be squoze Takes it's toll.

Being an automotive tech does help ... but there is a lot of different stuff to get the hang of. Same deal here. Takes awhile... good news is that all the idiosycracsies are WELL documented here on this site.

[XSokieSPECIAL]

OK, ya'll! I've got one you need to take note of!!!!!!!

Before I start I want to thank all of you very much for your help.

You're not going to believe what I found when I pulled the valve cover this time. I pulled it off and was meticulusly checking clearances and looking for lobe damage. Well, when I got to #4 intake I noticed that it had more clearance on the side of the lobe than at the bottom. no noticable damage to the lobe though. So, I started to set my tool to check the shim and noticed " THERE WAS A NUT MISSING FROM THE FAR RIGHT BEARING CAP! "

For the last couple of days I had thought I had heard a loud CLACK coming from the engine, but when I stopped to listen it was gone. That was the nut flying around in the valve cover. LUCKY OR WHAT?

My bike has 37000 miles on it, I suggest you all check those cap nuts because I checked all the rest of them and most were VERY loose.

Thanx a lot again
Greg