Hi Bird QH200GY Vibration at 7K r.p.m.

[Vaxian]

My bike is back on the road thanks to some guys on this site suggesting I get my parts at the local hardware store.

Thanks Guys!!!

The bike has a nasty vibration up front at 7K
Sounds like the bike is coming apart, it starts right at 7K, right after I break 7K it stops.

Anyone else experienced this? Have any werds of wizdom?

A guy who loves his bike, but not at 7000 r.p.m.!

Any Ideas? :idea:

[red2003]

Is it a pushrod Lifan?? Sounds like most of them shake pretty bad. Check all the engine mounting bolts for tightness and make sure none are broke. If everythings tight, my suggestion is keep it under 7000!

[katoranger]

MIne will start above 7K too, but with the new sprocket I only 6K to pull 50MPH. I don't travel much faster than that.

Allen

[blimpman]

One motor mount was loose on mine when I had a little vibration... Cinching it up stopped it.

[buymore]

Blimpman...where in the Falls do you live? I live fairly close to you...I'm in Berlin Center (out near Berlin Reservoir) I just got a Roketa DB-05 a couple of weeks ago and love it so far. I make it up your way once in awhile (usually the fairgrounds for gunshows) time I go 4-wheeling with the wife and kids, maybe you can meet up and go with us? I dont want to ride this thing hard, but I told my wife I can follow behind the 4 wheelers on easy trails. later

[NewEnglandTrails]

I told my wife I can follow behind the 4 wheelers on easy trails. later

You will be running circles around them atv's,, the DB-05 is alot faster and more maneuverable than atv's. Besides the atv's kick up too much dust... Let them eat yours lol..

NET

[culcune]

Originally Posted by red2003

Id it a pushrod Lifan?? Sounds like most of them shake pretty bad. Check all the engine mounting bolts for tightness and make sure none are broke. If everythings tight, my suggestion is keep it under 7000!

This is a good suggestion. Hi-Birds are either imitation Lifans or some kind of deal was made with Lifan, so the Hi-Bird probably inherited the vibration, too.

As Kato suggested, gear it for top speed, as I assume you still have the 56 tooth rear sprocket. Go with a 44 tooth and change the front out to a 16 tooth and you should see the vibration lessened.

[katoranger]

Yes, mine vibes lessoned alot after the I installed the 45t rear. I have a 17t front which means on my bike about 58-60 mph at 7Krpm. 50mph at 6K.

Still have some vibes, but it is alot better.

I removed the louvers that pop in place in front of the engine and the vibrating plastic stopped alot.

I am also going to try and balance my tires like I do on the street bikes. I think the knobby tires create a frequency at different speeds too.

Allen

[Vaxian]

Have a different rear sprocket on it.
Will try changing the front.

Will also check the motor mounts.

I absolutely love this bike, if I could iron out all the SMALL stuff it would be awesome.

Wish the Chinese would discover locktite!!!

[katoranger]

I think my 17/45 is about right for mixed use. I can cruise at 60mph. Might be geared a bit too high for hard offroad use. It is not a freeway cruiser.

I just about got mine completely sorted out. I think the tank fairings are going to be dumped or I will have to find out how to keep them from vibrating.

The rest of the bike is doing well. Just need to check it over for loose parts and bolts every few days.

Allen

[Savage]

Vaxian read my post
Very happy with my results and my 5k vibration is gone. (my last post is probably what you're dealing with)
http://chinariders.net/modules.php?n...ewtopic&t=1300