More vibrations at higher rpms

Hey all, I've been driving my bike fore about 2 months now and it's been great. It's a 2008 WR250X with 21 inch front and 18 inch rear dot tires. I recently changed my back tire and at around the same time it feels like my engine is vibrating more as the rpms increase than it did before. Has anyone else felt something similar, is there any direction that someone could point me in? Thanks.

What tires are you running specifically?

Are they mis-matched now? Avon on front, Dunlop on rear or something like that?

What air pressure in tires?

Are you sure it's engine vibration, and not new knobbies doing the vibrating?

I'm not going to lie, this is my first bike and it's all pretty new. The only reason I think it is engine related is because if the bike is stationary and I rev it I can feel it, also the vibrations don't seem to be caused by speed so much as rpms. I can cruise at 60kmh in 4th but if I'm at 60 winding it out the bike vibrates much more. Do you suppose there could be something loose somewhere on the bike that is amplifying the vibrations from the engine?

Where do you live?
It's possible somebody here lives close to you and can help you out.

A single cylinder motorcycle vibrates. The more the piston moves the more vibration you might feel.

I would doubt something is seriously wrong and the bike keeps running.

Hard to tell from a few lines of text.

Is the bike leaking any fluids?
Does it start right up easily?
Is it a stock bike? Besides having R wheels that is.
Have you changed oil since you got bike?


You bought used I assume.
Is the original owner somebody you can ask questions?

Is there a Yamaha dealer close by?

Changed the oil yesterday and the bike runs really well, there is actually someone I know with a wr250r so I guess I could go talk to him.

Will B wrote:

Changed the oil yesterday and the bike runs really well, there is actually someone I know with a wr250r so I guess I could go talk to him.

Switch bikes for a 5-10 mile ride and see if his feels like yours and yours feels like his.

OK so I still haven't resloved this, and I never had a chance to ride my friends bike to compare yet. It seems to vibrate all through the rpm range but more so at high rpm's, so much that there is a very large tingle in the man area when 9000 rpm and up. Any thoughts on what it could be? Engine mount bolts, front sprocket or something causing a resonating vibration?

Will B wrote:

OK so I still haven't resloved this, and I never had a chance to ride my friends bike to compare yet. It seems to vibrate all through the rpm range but more so at high rpm's, so much that there is a very large tingle in the man area when 9000 rpm and up. Any thoughts on what it could be? Engine mount bolts, front sprocket or something causing a resonating vibration?

Ah, the dreaded "numb-nuts". My WR250R does the same thing at elevated highway speeds. This is not a problem at lower speeds or off-road. I just bought some riding pants that actually almost eliminated this effect. It sounds, to me, that it is entirely possible that you are experiencing normal vibration from this single-cylinder machine- there may be nothing wrong. Like motokid says, switch bikes with someone to gain some insight.