tick & buzz

I've had my 82 SECA 750 a couple weeks now. It just rolled to 25,000 miles and I've racked up about 400~500 miles since I bought it.

The idle has always been rough, but in general the bike seems to be better since I've ridden it a little, dusted off the cobwebs, etc.

This week I changed the oil. replaced the plugs (properly gaped) and put 1/3 bottle of seafoam in a full tank.

I am noticing a couple issues now. There is a faint tick coming somewhere from the top of the motor (I think) Also I'm getting a buzzing noise, I think that's coming from the same spot. I also have just now noticed another thing. It seems like some smoke is coming from the front of the engine, probably from where one of the pipes connects. I never noticed that before. Just at night when there is a light on it.

Other than that the bike idles rough (like it always has) but it seems to run fine when I'm moving.

What are some possible causes of this tick/buzz?

 

Tick/buzz is 99% chance just valve noise.

Valve noise is NORMAL for these bikes.
If you DON'T hear it, your valves are too tight.

The smoke might be oil from your oil change on your pipes.
Or leaking from a valve cover gasket.

Either way, next step for you is checking valve clearances and most likely a new valve cover gasket and bolt donuts.

 

Newbie here, could you please give me a little more detail on this? Thanks!

 

Under the VALVE COVER on the top of your motor... the valves lie inside the head.


The measurement between the CAM LOBE and the VALVE SHIM BUCKET must be precise - and not tight OR loose. Tight, you will wear out the cam lobes and I don't really know what else, but it's not good.

Loose - you risk 'throwing a shim' which will destroy your motor pretty quick.


They also throw off sync/tune of the engine (carbs)

Go read THIS link, the post your questions in here.
http://www.xjbikes.com/Forums/viewtopic/t=14827.html

BigFitz is the man.

 

PS - the VALVE SHIM is what you swap out to achieve proper clearance.

It sits on top of the valve in the bucket, and is a certain thickness.

First you measure the clearance, then if out of spec you remove the shim, record the number on the back, go to the chart and decide which shim you need for proper clearance.

 

If the bike sat for a while, couldn't the ticking be one of the springs?

 

Valve spring? I don't see those making a ticking noise, and anything like corrosion or what not on the springs wouldn't make much noise, and even that it wouldn't last long.

 

Oh... I was just thinking, and I'm probably wrong, that if the bike sat for a while with one of the springs fully compressed-it wouldn't uncompress anymore, right? So every time that valve came down it would make a clicking noise, wouldn't it?

 

True - if the valve didn't release. But I really don't see that happening, the spring steel should not lose it's memory that bad. Maybe if it sat a very very long time.

But ticking noises are almost always the cam on the bucket shim and they are necessary noises really.

 

Guys, the main point here is that we don't diagnose the condition of a valve train by listening to it.

You've got a bike there that very well could never have had its valve clearances checked or adjusted; you're at the mileage where a totally neglected bike will just begin to start running like crap. Rough idling is an indication that you need to attend to things; valve adjustment BEFORE you start diddling with the carbs.

You need to get a service manual and go through the "maintenance" section step by step and leave nothing out. If you just keep riding it in the condition it's in, you may very well burn a valve or worse.

Before anything; before riding it any more, you need to pull the back brake apart and check for delaminating shoes; this is a very common failure especially if the bike has been sitting. If one separates completely it can suddenly lock the rear wheel with potentially disastrous results.
Take a look here: http://xjbikes.com/Forums/viewtopic/t=15874.html

 

Wild,

I had a somewhat similar post (regarding the noise at least).

Check out this link: Fellow XJers Lend Me Your Ear..

I have 1 audio and 2 video files linked, download and take a listen. Does you engine sound like that? I thought I had a problem too, but others that are much better at this game then I am said it was just standard valve slapping (which could possibly be reduced when I check my clearances and reshim as needed).

The 'whinning' can be a few things - 1) your speedo cable. thats the cable from the back of your tach to your front wheel. Often times it gets gunked up, or rusted up. Especially if the bike sat for a while. Get a good cable lube and lube that puppy up (good idea to do anyways). 2) if the noise you are hearing is when the bike is underload, maybe it's just the sound of the shaft drive, or your front brakes rubbing.

As stated the smoke could just be burnoff or a small oil leak. If you cleaned your engine or anything like that and got something on your pipes, or when you changed your oil if any got on your header or whatnot, that would do it. I started to clean by bike and got some metal polish on the headers - smokes like hell ;-)

Good luck, keep us posted!

(BTW: I agree w/ fitz. Check your clearances and then mess with your carbs, then sync the whole thing up. There are no short cuts - i've tried them all and they don't work ;-P ).

--josh

Just some thoughts to try to help ;-)

 

A buzzing noise i once had in my 750 turned out to be a broken mount where the collector box for the exhaust bolts to the bottom of the motor, and its normal for my bike to have a whistle/whine/ highish pitched sound from about 3 to 4000 revs, a mate used to call it the whistling bike. Its always sounded like that, no better no worse.

 

I may be chiming in a little late, but...
If you are getting a bit of smoke from where the exhaust pipe leaves the head, and If it is an exhaust leak and not spilled or dripping oil, that could account for the ticking noise.
exhaust leaks at the head can sound like a bad valve.

cheers
k

 

To add to my previous comment about whine, go to XJ CHAT : `GET RID OF MIDDLE GEAR WHINE`.

 

I'm very glad I read this. I had my bike to a mechanic, he said I had 2 loose 2 tight valves and I had suspected he only 'fixed' the tight ones.

I knew that the valves tighten over time, but now I know that was the right thing to do to loosen the tight ones and do nothing to the loose ones.

But the sound does start to bug me... :?