buzzing noise with vibration from 3000-3500 rpms

Hey there, I have an 82 xj650 Maxim with 17,000 miles or so the odometer says. I hear a buzzing noise and feel vibration when I'm cruising between 3000-3500 rpms. Anyone experience this before? Also, it consumes about a quart of oil every 750 miles or so. I see no smoke, smell nothing odd in the exhaust. I do have a little weeping around the head gasket but hardly enough to wipe. Where is it going? My air filter isn't oily either. What do you guys think?

 

Do you have your valve clearances in spec and carbs synced properly?

I can tell you that I have vibration at around 4k-5.5k but smooths out after that, and from what I understand it is fairly common with these bikes. "Engine harmonics".

But if your valve clearances are not in spec, that could be an entirely different issue.

 

Thanks, that made me feel a little better. My carbs are synced, my valve clearances and cam tensioner are my next project. My bike runs smooth as can be except in that rpm range. I even have a spare motor if i find something i dont like when I open her up. Gonna do a compression check and decide if i want to do some new rings while i am tearing her down. Like I said, I have a little weeping around the head gasket that I would like to fix as well and I still don't know why she is consuming a quart of oil every 500-750 miles?

 

If the compression checks out, I might want to check my valve seals. Still seems like I should see some smoke though?

 

I'm still learning too HardRock, but I would definitely make your valve clearances a top priority! If they haven't been checked yet and you are too tight you run the risk of majorly damaging your valves. Not to mention if they are not in spec, your carbs are not synced. Remember that the valve clearances need to be checked every 5,000 miles. The average PO of these XJ's likely did not do this critical maintenance step, so it's likely been much longer than it should have been on your 30 year old bike. Plus while you have the cover off that will give you an opportunity to slap on a new gasket!

After you get your valves in spec, that is when you want to check your compression and sync your carbs.

 

My 82 only buzzes around 4800-5100 rpm. You shouldn't be having much in the 3000's. Yes go with a compression check and then check & adjust your valve shim clearances, and check compression again. Valves in spec and carbs synced minimizes the vibration, but with that much oil use, you've got something else going on. What about the higher rpms? What's it do in the 6500-9500rpm range? (I'm not suggesting you redline it right now if you haven't already - get it right first.)

 

Jeez...I must have missed that. 8O

And you have no puddles of oil on the ground?? Might be on the road. Definitely check your compression.

 

The oil use would bother me more than the vibration.
I can go a whole year without having to add any oil.
When you do your compression test look at your plugs to see what they look like. Something isn't right.
I would do a valve check, then sync and color tune to solve the vibration problem. This should be an easy fix.

 

Thanks everyone! My plugs looked good which is even more perplexing. I'm gonna check it over real good before I ride it again. I parked it after I noticed the oil consumption. I am a stay at home dad so I haven't had the time yet to go over it. Figured I would get some feedback first and I have, so thanks again. I love my bike and I will fix it. Great thing about having an identical parts bike!