Metallic "whirring"

[LOBO3315a]

Just thought I'd post my issue here as well.

I have a 1999 GZ250 that I've been riding a month now. I've enjoyed the bike quite a bit, but due to its age, I realize there are some maintenance concerns. First and foremost, there is an oil seep, as I've seen the evidence of it around the crankcase. I was told by a local motorcycle mechanic, that it probably wasn't a huge deal to get it fixed, but I may want to clean up the oil to help identify where it is coming from. I've kept an eye on the oil level, and recently added some, because I couldn't see the level in the window.

More recently, in the past 2 days, I've noticed what I can only describe as a metallic whirring when I'm in higher gears, at low RPMs. I've also noticed it when I'm downshifting. It happens more noticeably after the engine is warmed up. I thought it might have been the chain needing lubed, but that wasn't the case. That's when I noticed that it was related to how warm the engine gets.

I'm a little worried that it may be the valves. I'm somewhat mechanically inclined, but I'm a little concerned about undertaking a dis-assembly of the bike, as it is my only means of transportation currently. I haven't noticed a change in how the bike handles, only in the way it sounds after warmed up in higher gears. Am I just being paranoid? Any advice would be appreciated.

Here's a video of what I'm talking about.

https://www.dropbox.com/s/3hbjn4oaclwwn ... sride3.wmv (https://www.dropbox.com/s/3hbjn4oaclwwn6h/lobosride3.wmv)

[5th_bike]

Well it seems like something metal is resonating along with the cylinder at lower rpms indeed, about halfway the video. I have no idea what it could be - I'd check for any loose bolts for instance at the top covers of the cylinder, and the front sprocket cover - is there anything loose and possibly rattling underneath the saddle, those kind of things.

To check the valves you don't have to disassemble the engine, just remove the tank and the two valve covers, and check the distance with a feeler gauge. OK, it's a little more involved -you need to remove the left engine cover and the spark pluk as well, and put the piston at the top in the compression stroke. Please check the manual on the subject of valve clearance checking.

[raul10141964]

Check the starter clutch

[Water Warrior 2]

Could be a variety of things making the sound. First and foremost is the oil level. The oil level should be read with the bike held upright. Another thing to consider is the amount of miles on the chain and sprockets. If they are badly worn you can get some strange sounds after things warm. Another thought is this. How long has the windshield been on the bike? If it is a recent addition you may just be sensitive to all the noise being reflected back from the shield.

[LOBO3315a]

Thanks for all the advice.

Road Warrior, The oil level is even with the top mark in the window, with the bike held upright. Looking at the chain and sprockets, there doesn't appear to be any wear, and the noise changes with the RPMs of the engine, not the speed of the bike.

I'm taking it to a local bike mechanic to do a check out ride. He's pretty confident that it's the valves, as the noise tends to smooth out after you get to higher RPMs and stay steady. They charge a $75 fee, and put that against any repairs they accomplish. I'd do the valve check myself if I had a garage to do the work in, but alas, I don't have the tools or the room to pull the tank off, or hand crank the engine with. He seemed to think it wasn't a huge deal to ride a week like that. As he put it. "You can hear my valves rattling all the time."

If nothing else, I'll get a laundry list of things that need to be done to the bike. But for $700, I can't say it was a bad deal purchasing it.

[jonathan180iq]

Give us a follow up when you can to make sure everything is sound and humming again.

[LOBO3315a]

After taking the bike by the same shop, the mechanic there said it sounded and smelled like the oil should be changed.

So tomorrow, I'll be performing an oil change. I have wrenches, 2 quarts of motorcycle oil and the correct filter. I've also decided a paint job is in order. I'll post some before and after pictures.

[JohnC]

Don't waste time and money painting it if you aren't sure it isn't about to grenade...

[jonathan180iq]

Agreed