bad vibration

[dbblet]

Hello all,
I'm new here and was wondering if anyone had engine vibration problems at high speed (20 mph +)? I'm running an 80cc on a beach cruiser with only about 20 miles on the new engine. I searched for any posts on the subject but so far no luck. I have double spacers for the rear mount and single spacer mounted on front mount. I have rubber between the mount and frame on the rear but none on the front, might this be the problem or mounted so open I need another mount? I hate disassembling but It does'nt feel right.
any help is appreciated.
thanks

 

[drimpact]

Do you have any pics? might help...

 

[thatsdax]

Yes.. Post pics and.

Post pics of the bike and then close ups of the front and rear mounts.. Thanks..

 

[Scottm]

Here's a good thread on rubber mounts. I did a search on "rubber mounts " and this is one of the results I got. I hope it helps. http://www.motoredbikes.com/showthread.php?t=6631&highlight=rubber+mounts
To me it explains why not to use rubber mounts.

 

[gone_fishin]

my opinion about that...lock it down tight and be done with it, no rubber of any kind.

 

[WIZARDOFOZONE]

I gotta go with Augi ... I mess with my bikes sometimes over 10 hours a day ... and what's funny about the mount problems, especially the front mount is how most just assume that if the saddle config doesnt fit then its the thru bolt on rubber or thru bolt without rubber as the absolute only alternative. I'll tell you a secret but it's not for the total perfectionist. When the standard saddle and stems are too narrow for the downpipe, it's made to look even worse by what I see as an optical illusion. Oh,the 2 stems are too close thats true, but take your Dremel or whatever brand of rotary tool you have and attach one of those pink sanding (I call them rods) or wheels. It takes only a VERY shallow furrow along each side of the downpipe to make those 2 engine stems lay right in the groove. You havn't taken enough metal away to harm your safety in any way,and in fact I truly believe the original hole we drill with the single thru bolt method ends up widening either from our centering corrections,or from the constant jackhammering the engine is giving that single thru bolt,becoming larger and weaker than those 2 narrow channels you ground for the original saddle clamp studs. PLUS, with the two narrow channel cuts and the original saddle studs and saddle clamp in place, the studs are locked into the channel runs you ground and that annoying left hand lean the engine wants to take is eliminated. You can use rubber sheets against both the engine saddle and the bottom saddle clamp if you want,and this time the rubbery give of those dampers can't cause engine side slip as they do with the single thru bolt.

 

[alesterfeind]

My engine decrease in noise and vibration significantly after break-in, so give it time. Do what these other guys suggest and get rid of the rubber mounts. Secure the engine down tight to the frame. Also, make sure the sprocket attached to the spokes is true as possible. Take the chain off, give it a slow spin, and see if it wobbles any. If so, work your way around the sprocket by tightening the bolts until there is no longer any wobble. Any wobble will create vibration at higher speeds.

 

[WIZARDOFOZONE]

You said it Alester ! This is indeed a really un-noticed problem and the only thing I can add is after you remove the chain don't even trust your eye to see alignment .. I prop up the bike so the rear wheel can spin, stick a lump of clay ball on the ground with a stick stuck in the clay and srunning right alongside the sprocket as a sight guide ... I do it that way to choose the right spokes to tighten as well for that problem too.

 

[dbblet]

Thanks for all the feedback. I'll try the direct bolt down and alignment.