bore a motor?

03rcsezure · 07-04-2009, 12:12 AM

Hey everyone! I am looking at boring out my rc51 sp2 motor. Does anyone know how big I can go, or has anyone else done this? The motor ingested a screw from the butterfly valve and needless to say caused damage to the head, cylinder wall and piston head. I dont think that the cylinder wall is sleeved so replaing the sleeve is not an option and I don't think that the cylinder wall is pressed in or interchagible SO, boring is my only option other than getting a new motor as I see it. I would appreciate any help! thanks.

Anyone know a good OEM site?

-rob

zerogara · 07-04-2009, 7:42 AM

There are few services around the world that will repair such a cylinder, but it may be close to finding a cylinder and head on ebay.
The cylinders are plated not sleeved and the Honda process if unique and complex. The cylinder at 100mm is already too big and if you chnaged diameter on one you'd have to mess up the other cylinder too.
Im not sure if LA Sleeve works on such cylinders but they would bore the cylinder slightly to prepare for next plating, fill the scars up some, then replate them back to original size. Is your head salvageable?
I would recommend replacing the cylinder and head if not repairable with OEM parts, new or used. A replated cylinder has a risk of failing.
When I first opened the airbox on the RC and realized how those huge throttle bodys are arranged I instantly thought of the risk.
Also if a bolt ended up in the chamber there may be a chance the rod and bearing surfaces have shared some of the stress as well.

03rcsezure · 07-04-2009, 5:58 PM

Thanks for the post. The more I research this the more it looks like I will be getting a parted out motor. Does anyone know if the 2004 sp2 motor will fit/ be compatable with the 03 sp2 bike? thanks.

zerogara · 07-04-2009, 8:21 PM

As far as I know 02-08 are identical

selfinfliction · 07-05-2009, 10:21 AM

getting a new block would be your best option

zerogara · 07-05-2009, 10:43 AM

http://www.billscycle.ca/cool6/134.jpg

This is supposedly an RC51 sleeve, I know nothing about it but it may be worth your research time

Here is a thread that addresses your initial question directlyCylinder work: Bore Oversize or Nickasil Coating? - Speedzilla Motorcycle Message Forums

03rcsezure · 07-06-2009, 3:52 AM

Wow thanks for the info! I checked out the speedzilla post. Looks like it can be done for around 400 bucks but the work is by no means guaranteed. Does anyone have or know of a rc motor for sale? Thanks

ghbzorro · 07-06-2009, 4:42 AM

if you look here 2002 RC 51 ENGINE:eBay Motors (item 270419145101 end time Jul-08-09 11:51:25 PDT) you will see a complete motor for sale