Grinding noise in engine

I have an '82 Maxim XJ650. It makes a grinding noise in the engine that gets worse at about 5 rpm. It gets quieter when I shift or when it goes above 5. My Husband thought it was the timing belt, but he adjusted it and that did nothing. We just added oil this morning, which did nothing. We did notice that the o ring on the oil cap is bad. What could it be? Also, it does not like to start (it even whines!!) when it's cold (around 55). It takes a lot of effort, but is fine once it gets started. I have to open the choke all the way and sometimes open the throttle 1/2 way and it still dies. I keep doing it and it finally starts after a big whine. LOL Then, when I put it in 1st to take off, it often dies, but is fine in neutral.

 

Hi Skye,
Grinding noise could be quite a few things but a stretched cam chain could be the culprit if its more of a scratching/chattering type noise.
Not sure if the Maxim has an auto cam chain adjuster or not but when the chain gets damn stretched then typically the bike won't run efficiently because of valve timing issues also.

Hard to start is a symptom of... heaps of things... to name a few though,
- ignition system (bad battery, fouled plugs...)
- fuel system (blocked starter circuit or jets in carbs, sludge in carbs, carbs out of sync, air/fuel mixture out of whack...)

The biggest starting issue is the carbs, so if you want somewhere to start then that is where a lot of us have had to before we've gone further into the bike.

Check this out for instructions on the carbs,
http://www.xjbikes.com/Forums/viewtopic/t=2908.html


Have a read through the actual "FAQ suggestion" posts in this section and you will get a good idea of the bits and pieces that may need to be done.
http://www.xjbikes.com/Forums/viewforum/f=21.html

Good Luck!

 

Is cam chain stretching at sub 30k common?

I have adjusted her cam chain. I rode her bike last night the sound is only happening at 4500-5000rpm and sounds like a nut being spun on a dowel with an air gun, kind of a buzzing zinging sound.

Do the starters on these bikes work like on a car? IE solenoid is pushing gear out to engage only when starting then the gear returns once ignition returns to on state?

 

I may be completely incorrect here.... But I know our bikes commonly have a "buzz" around that range. If that's the case with hers and it's not an actual issue... It doesn't bother me very much. I normally cruise at higher rpm's like 6k.

 

Nope. There is a "centrifugal/sprag" clutch that the starter engages, once the motor is spinning faster than the starter clutch, it disengages. The (remotely mounted) solenoid ONLY supplies power to the starter.

What you need to know is that is the standard harmonic "buzz RPM" of the XJ series. They ALL have a "vibe bulge" right in that range. More than likely something (exhaust heat shield, relay with a broken mount, loose nut or bracket anywhere) is reacting to the vibration and producing a sound of its own. I had the rubber mount for one of my relays break, allowing the relay to just barely "dance" against the valve cover and make a singing sound right at that RPM range.
You're probably chasing a loose component somewhere.

 

It is definitely not the XJ gear whine/purr that starts around 3500rpm.

I told her I thought that because the sound wasn't changing with engine speed it was likely something that just vibrated in that range, maybe under tank or seat or shift lever, a syncro etc. I will check everything I can find that could be loose and hopefully get the sound to go away.

Thank you all for your help.