vibration at full throttle

[badboyracing]

New DRX 70 wc, oil pump disconnected and line crimped. Just completed the break in period. Changed the tranny oil. Drained the Gas tank. Now Running a 32:1 ratio yamalube 93 octane mix gas. I have just started to kinda feel/hear a slight vibration at full throttle. It seems it is coming from the cylinder area. Now it only does it at full throttle. Is this common? I have the same experience with a KTM Pro Sr 50 doing this same thing after about 30 hours and it was in need of a new piston and rings, however, this DRX 70 has only about 3 hours. Any similar experiences?

[dirttrack86]

Pull the jug and check it. It ony takes a few minutes and will give you piece of mind if nothing is wrong. 70 air cooled kits have a tendancy to try and seize. A quick looksie will let you know.:) Also remember that a 50 converted to a 70 is no longer a balanced rotating assembly. Expect a little vibration.:)

Oops, sorry, reading to fast. Didn't realize it was a factory 70. Never mind the info. lol:)

[hotquads1]

makes sure your exhaust bolts are tight , they tend to vibrate loose . We pull them out and put some high heat loctite on them. How does the plug look if it looks lean you might want to bump the main jet up a little to make sure detonation is not occuring .
marc

[humboldt hills]

Also, the exhaust springs make some noise.
Have had folks bring it back in and thats all it was.

[badboyracing]

Update on the vibration thing.
After checking everything over and checking all the nuts and bolts and being completely baffled as to where in the heck this vibrating sound/feel was coming from, I have figured it out.
The new XFR Nerf bars was the culprit. It fits a little loose over the rear adapter plate, (the part on the nerf bar that slides over the metal tube of the plate). I had the bolts tight enough, so what I did was wrapped a thin piece of plastic around the tube and reinstalled. Bingo!!! The vibration is gone.

[wvspeedfreak]

Glad you figured it out.That stuff is hard to track down sometimes.

[jetski_dawg]

Originally posted by badboyracing
Update on the vibration thing.
After checking everything over and checking all the nuts and bolts and being completely baffled as to where in the heck this vibrating sound/feel was coming from, I have figured it out.
The new XFR Nerf bars was the culprit. It fits a little loose over the rear adapter plate, (the part on the nerf bar that slides over the metal tube of the plate). I had the bolts tight enough, so what I did was wrapped a thin piece of plastic around the tube and reinstalled. Bingo!!! The vibration is gone. dont feel bad.. i had some AC bars that vibrated and i thought it was the clutch comming apart.. i pulled the cover off twice..ugghh

[hotquads1]

glad it was that simple , it had me baffled . I never had a vibration issue so didnt have any ideas for you to check . How is your son coming along with the new quad ?
marc