Cam chain rattle... Time for a new cam chain?

Hello everyone,

Recently i've noticed my Maxim getting noisier when i do hard stops and accelerating from them. The noise is coming from the head and i can clearly hear something rattling. I've been going through the old threads and i've come to the conclusion that it is a loose cam chain hitting/rubbing. I figured this was just a typical cam chain tensioner problem so i took out the cam chain tensioner (it's automatic), cleaned it, oiled it and reinstalled it. The next morning i took out the Maxim to go to school and it worked fine until i arrived at the school parking lot (lots of stop signs) where the cam chain just started rattling again. This time the sound was worse; it was much louder and sounded as if it was rattling at more areas now. Again, the rattling only happens when i stop completely and when i accelerate enough from a stop, so after class i was able to ride it home safely by going on the freeway (for the first time ) to avoid stop lights and stop signs. Of course, i still had to go through the parkng lot and traffic to get there, but the Maxim held up till i got on the freeway.

THe only other causes for the rattling that i can think of are:

1. Tensioner spring is worn out
2. Cam chain has stretched out to a point beyond the tensioner's ability to tension it
3. Something inside the engine becomes loose when it warms up.

My Maxim has 17,600 miles. I dont think the cam chain or the tensioner should need replacing at such a low mileage, but i suppose it all depends on how it was ridden. I plan on taking the valve cover off during my winter break and taking a look to see what could be the problem, but until then, she's going to have to sit outside in the cold winter unridden. Can anyone please shed some light to my Maxim's problem?

 

Your diagnosis sounds reasonable. It wouldn't hurt nor take a whole lot of time to see if just retensioning the chain takes care of the problem. Do you have a service manual? If not, search our forum archives, the process is outlined in there (somewhere). You have nothing to loose and can eliminate one of your biggest questions right off the bat.

 

My first thoughts are how did you reinstall the tensioner? The end plug should have been off and the tensioner pushed all the way back in. Set the timing plate to the "C" mark and install the tensioner body. Then istall the end plug. When installing you should hear the tensioner clicking as it takes up the slack. Like you I don't think the camchain should be done at such a low milage , but it also is dependent on how the PO rode it.

 

It's NOT the chain and tensioner. Not at no 17-thousands miles. Remove the tensioner, clean it, thumb-check it, to make sure it springs-out to take-up slack, re-load it and install it following the proceedure to the letter.

Do a > few < Manual slack adjustments. Make sure the sllack is out even if you have to pop-off the cover and do a couple of test "lifts" on the chain to make sure you got it right.

The noise you are hearing may sound like a Coke can full of ball bearings being shaked like crazy. Might not be the Cam Chain making all the noise.

Check your valve clearances.
Check your exhaust pipe collars for leaks.
Use a long dowel and probe for rotational noises.
[Put one end of the long dowel on the block where you want to probe and cover the other end with your thumb. "Listen" by placing your ear on your thumb.]

Last, but not least ... for the next three times you get gas ... run High-Test!
If what you are hearing is pre-ignition detonation ... you HEAR it just like you described.

Severe pre-ignition is an engine killer. Run the High-Test and make sure you aren't hearing your pistons taking a beating.

 

BlueMaxim: I set the timing plate to the "C" mark and took out the bolt with the two springs that jump out behind it. Then i removed the two allen bolts and removed the entire tensioning assembly. The installation was opposite. When i pushed the plug in, i only heard about 5-6 clicks.

RickCoMatic: I have never heard the sound of preignition before. Ball bearings in a coke can eh? SOunds very much like what i am hearing. I'll try that "High-Test" to confirm it.

 

That is correct. So I would check Rick's suggestion on preignition and the exhaust headers. I would also look under the bike and make sure the bolt that holds the collector in has not fallen out.

 

Update on the rattling noise!

Haa-Zaaaah!!

I found out where the noise is coming from (if anybody cares)!! This rattling noise i have been hearing turns out to be unrelated to the engine (i feel stupid for thinking it was the cam chain). I took it out for a short ride to do the "high tests" during thanksgiving break and listened real carefully for the noise. After hearing the noise faintly over the wind, I pulled into a parking lot and as i was slowling down i can hear the rattling, grinding noise coming from the front. When i stopped, the noised stopped, but when i slowly began creeping forward, this godawful noise would be screaming out from the front. I shut off the engine and moved the bike back and fourth, and sure enough, it made that "rattling" noise i described earlier. It has GOT to be the front wheel bearings. I am very very glad it is not an internal engine problem. I was grinning like an idiot while i was riding the bike back home...

I would like to thank you guys for your help. This forum is great!

 

Re: Update on the rattling noise!

I think most of us do; IMO post revealing causes of tricky problems are among the most interesting to read..

 

Bearing technology is 20 Years better, now. Find yourself some great sealed bearings from a Bearing Supply House.

You will get new Bearings of the Highest Quality at a fraction of the cost of the ones that come in Designer Labeled sandwich bags at the Dealer.

 

Darn right we care! One thing I don't like is 12,000 posts and not knowing what happened!
I had this same noise but not as prevalent as yours. You will need 2 6302RS bearings. To remove: Remove front wheel and set on a bench lieing atop two 2x4's. With a large screwdriver or punch or some other suitable drift drive out the opposite side bearing by striking the spacer that is between the two bearings. It can be moved to one side and struck on the edge. Try not to bugger up the end since it has to go back in the bike. Once the first bearing is out then remove the spacer and drive out the other. Pack the bearings in E.P. grease and gently set them in place with a socket that fits the outside edge of the bearing and will still fit inside the hub. It is important that the inner race of the bearing isn't struck. This would damage your new bearing. Don't forget the spacer before installing the second bearing!

 

Does anyone know the standard bearing number for an '82 XJ650J Maxim?

 

chacal, i think the 650 uses the same bearing as the 750

BlueMaxim, I have some disk brake grease that i use for my Honda Accord. Can this be used to pack the bearings?

 

The new bearings should be sealed, no need for packing.

 

The sizes are Laser etched right into the edge of the race. You might need to have someone with a magnifying glass read it for you, like I do, but at least it's there for reference.

 

Mac is right about the bearings being sealed. When I got mine they weren't packed very well. The RS seal comes out quite easily with no damage. So I removed it packed the bearings and re-inserted the seal. I also didn't know what grease it was packed with...but I do now!
xj750_pete I'm not familiar with that grease so I can't say,but a good bearing grease is what is needed. E.P. stands for "Extreme Pressure". I think my can was $5 bucks at Advanced Auto.

 

Same as the 750. Two 6302RS's in front and two 6203's in the back with one 6303.
Just so we all know the bearings designations. 2RS is a double sided and RS is a one sided rubber/plastic type seal. Z is a metal shield that doesn't seal at all. There is also ZZ which is two shields. The XJ's came with Z's so the switch to the R or S is desirable.

 

Finally changed the bearings... turns out the rattling noise is not caused by the bearings (strike 2 for me) , eventhough they were comepletely shot. After i finished bashing the new bearings in, i reinstalled the front wheel and gave it a spin. The rattling noise was still there. I sat in my garage spinning the wheel for a minute until i then realized that the entire time, the noise was coming from the intrument panel. Now what could cause a rattling noise in the instrument panel when the front wheel is turned??

I removed the speedometer cable from the panel and sprayed some chain lube down the cable and up into where the cable attaches to the panel. I spun the wheel again and the noise was gone. Wooo....

 

Well at least you don't have to feel bad about changing the bearings! That makes you a winner on three issues. Freshly oiled speedo cable, new front wheel berings and a well adjusted cam chain!
Isn't it amazing how those sounds are so hard to locate?

 

The noise of a leaking inside exhaust donut will drive you nuts. When the conditions are just right; it will mimic a bearing knock and make you think the engine's about ready to throw a rod and blow-up.

If you're a practical joke-ster ... spit some Coke on the brake pads of a (Insert Harley-Davidson here) and wait for the fun to begin.

Might cause the brakes to squeal "a little." Might smoke a bit; too!

Senator, I have NO recollection of ever spitting CocaCola, on any motorcycle, at any time in my life, what-so-ever!