Jump to content
CBR1100XX.org Forum

Vibration with Big Bore???


jon haney

Recommended Posts

I just had a Wiseco 1195 kit installed and some mild port work done on my 99 Bird. All other engine components are stock. The vibration from the engine has noticeably increased, especially at lower revs. Is this normal or did my mechanic screw up the balance shafts? If so, I may have to lock-tite all the bolts.

Link to comment
Share on other sites

I just had a Wiseco 1195 kit installed and some mild port work done on my 99 Bird. All other engine components are stock. The vibration from the engine has noticeably increased, especially at lower revs. Is this normal or did my mechanic screw up the balance shafts? If so, I may have to lock-tite all the bolts.

I have a 1255cc kit in mine, and notice very little increase in vibration. When the engine was first installed, it vibrated like a bastard, though. The lower balance shaft was out of time, and easily remedied once the oil pan was removed.

First thing I would check is the balance shaft timing.

BTW, welcome to the board.

Link to comment
Share on other sites

Aftermarket big bore pistons are much heavier then stockers,there will be more vibration,,,,,,,,,,balancers are designed to work with stock pistons,rods, etc.Any weight diff. screws that up.

Check adj. on balancers,but some increase is unavoidable.

Link to comment
Share on other sites

Your counter balancers are out of whack.

I've got 1 mm overbore low compression pistons in mine and I think they are smoother than stock.

Northman is right about his, no vibration that I remember.

Link to comment
Share on other sites

Aftermarket big bore pistons are much heavier then stockers,there will be more vibration,,,,,,,,,,balancers are designed to work with stock pistons,rods, etc.Any weight diff. screws that up.

No problem with balance if you weight match your pistons, which any competent builder should do. Mine were lightened to match the weight of the stockers, as well as having the bottom end balanced.

Link to comment
Share on other sites

Aftermarket big bore pistons are much heavier then stockers,there will be more vibration,,,,,,,,,,balancers are designed to work with stock pistons,rods, etc.Any weight diff. screws that up.

No problem with balance if you weight match your pistons, which any competent builder should do. Mine were lightened to match the weight of the stockers, as well as having the bottom end balanced.

Yea,I remember pics,guy spent quality time reworking those pistons,"stock" Wiseco and JE are heavy like a brick and piston crown needs work.They are basically starting point and not so good if left unmodified,,,,,.

Are we talking about vibration or typical for 4 cyl. buzz ???????

Link to comment
Share on other sites

You guys were right. The lower balance shaft was about 180 degrees out of time. There is a casting mark on the weight that my mechanic must have thought was the timing mark. I re-timed it and now its as smooth as stock. Thanks again. :icon_biggrin:

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

Terms of Use