Motorcycle Racing Forum

Racing Discussion => Racing Discussion => Topic started by: Jeff on March 14, 2003, 06:56:11 AM

Title: Nasty head
Post by: Jeff on March 14, 2003, 06:56:11 AM
http://www.cbr600f4.com/secondary_pages/bad_cam.htm

Title: Re: Nasty head
Post by: K3 Chris Onwiler on March 14, 2003, 09:03:04 AM
I'd hang on to it.  The parts you need can be found used, and you have a whole bottom end that's still good.  Ebay the thing, and the next weekend you'll throw a rod and waste the crank on your other motor...  Murphy's law.  Murphy was a racer!
Title: Re: Nasty head
Post by: K3 Chris Onwiler on March 14, 2003, 09:54:07 AM
Also, I wouldn't want to tell you how many motors I've had that looked just like that.  When you're racing leftover 80's tech like the FZR stuff I had last year, you use everything until it's worn out.  If everything specs out, I'd spin the cam in a laithe with some 1500 emory cloth to polish it a little, scotchbright the journal, and run it!  What's the worst case scenerio?  Those parts aren't going to suddenly sieze or fail.
Ask around about the junkyard dog I built on a card table at Blackhawk.  Properly cleaned, measured and assembled, nasty used parts can win races!
Title: Re: Nasty head
Post by: Jeff on March 14, 2003, 10:30:39 AM
Yeah, I'll hang onto it since I don't have the time to do anything else with it.

Worst that could happen??  Well, I'd think that if it seized (died or whatever) on my way into the kink at Road A, that'd pretty much be the sum of all fears...
Title: Re: Nasty head
Post by: K3 Chris Onwiler on March 14, 2003, 01:27:22 PM
Yeah, that's pretty much everyone's worst nightmare.  Really, though.  If the clearences are all good, the parts won't fail.  Ever see a motor burn a piston or frag a clutch basket?  Metal debris is carried to anywhere that gets oil.  Scoring in the cam journals and on the cams is common.  I've rebuilt dozens of motors like that.  All those mix & match FZR560 motors of mine were built from used stuff.  Not one head was without scored cam journals, and not one cam was without discoloration.  On an FZR, there is a circle of metal at the end of the shaft that rides in a groove cut in the head.  I had half that circle break off on me at the track.  I used the cam anyway!  3 weekends later, I took it apart.  No problem.
I really don't think your head or cam is junk.  I'll look at the stuff at Blackhawk if you'd like.  You can probably just polish it up and put it back together.  But...  If that would worry you to the point where it would affect your riding, throw the stuff away.  No one needs to be worried about their machine while trying to race.  The distraction factor could get you hurt without the parts ever failing.
Title: Re: Nasty head
Post by: Jeff on March 14, 2003, 01:37:10 PM
The web page you read was on my emotional downswing from finding it.  However, now as I learn more and think more about it, I might work on repairing it.  I'm certainly not going to toss it.

I'm fortunate enough to have a perfect motor (with gorgeous cams & journals) which I put back in the bike for the start of the season.
Title: Re: Nasty head
Post by: JamesC459 on March 14, 2003, 02:19:37 PM
Seriously, just clean everything up and put it back together.Run it.I've even aling-honed a scored head using a cordless impact gun with a 16mm socket and sandpaper rapped around it.I was 9 hours from home were my spare motor was.(that damned Murphy guy,"don't lug that motor all the way there,that one has been running great")long sleepless night but I raced the next day.That very same head is still in service now,four years later>
Title: Re: Nasty head
Post by: Protein Filled on March 15, 2003, 07:22:08 AM
I don't know about running it like that, but a good machininist may be able to do something about it though...

Hey K3, that's the way you treat your motor? No wonder you kept blowing through them like soap bubbles.  ;D ;D Where did you find so many used FZR 1000 motors anyway?
Title: Re: Nasty head
Post by: K3 Chris Onwiler on March 15, 2003, 10:53:51 AM
QuoteWhere did you find so many used FZR 1000 motors anyway?

www.wreckedR1.com   ;D