Rebuild or replace head?
08-22-2007, 04:22 PM
#1
Member
Squid
Thread Starter
Join Date: Aug 2007
Posts: 53
Rebuild or replace head?
CCT failure in the front cylinder = pooched valves. Cams, etc are fine. Should I rebuild this head or buy a known good used head? I have located a set of heads for about the same as rebuilding my current head.
If rebuilding is the route I should take, does anyone have a set of valves they want to part with? Do the guides usually end up damaged in this apparently common scenario?
If I buy the pair of heads I'd be selling the rear cheap as I don't need it. Anyone interested?
Thanx in advance for your responses...
If rebuilding is the route I should take, does anyone have a set of valves they want to part with? Do the guides usually end up damaged in this apparently common scenario?
If I buy the pair of heads I'd be selling the rear cheap as I don't need it. Anyone interested?
Thanx in advance for your responses...
08-22-2007, 05:19 PM
#2
Senior Member
MotoGP
Join Date: Sep 2006
Location: Austin, Tx
Posts: 4,138
CCT failure in the front cylinder = pooched valves. Cams, etc are fine. Should I rebuild this head or buy a known good used head? I have located a set of heads for about the same as rebuilding my current head.
If rebuilding is the route I should take, does anyone have a set of valves they want to part with? Do the guides usually end up damaged in this apparently common scenario?
If I buy the pair of heads I'd be selling the rear cheap as I don't need it. Anyone interested?
Thanx in advance for your responses...
If rebuilding is the route I should take, does anyone have a set of valves they want to part with? Do the guides usually end up damaged in this apparently common scenario?
If I buy the pair of heads I'd be selling the rear cheap as I don't need it. Anyone interested?
Thanx in advance for your responses...
08-22-2007, 08:21 PM
#4
Senior Member
MotoGP
Join Date: Apr 2005
Location: Montreal
Posts: 5,631
I'll be replacing the heads on my VTR shortly ("new" heads are currently being ported by dealer, will be mated to Yoshi Stage 1 cams) so I'll be looking at getting rid of the old ones. If you can wait a bit and are interested let me know.
cheers
cheers
08-22-2007, 09:37 PM
#7
Senior Member
MotoGP
Join Date: Apr 2005
Location: Montreal
Posts: 5,631
Hi again,
mailbox is now empty
IN terms of timelines, I would love to get it done within two weeks at most but as I'm getting a good deal from my dealer, well, I am in no position to turn the screws on them too much.
PM me and we can discuss this further.
cheers
mailbox is now empty
IN terms of timelines, I would love to get it done within two weeks at most but as I'm getting a good deal from my dealer, well, I am in no position to turn the screws on them too much.PM me and we can discuss this further.
cheers
08-22-2007, 10:34 PM
#8
Senior Member
Superstock
Join Date: Dec 2005
Posts: 428
You can usually get away without replacing valve guides but it depends on how well they faired. How are the valve seats? If you need to cut the seats the job turns into a clearance nightmare. I would recommend replacing the head. You should be able to find a good replacement. Its pretty obvious if the replacement head is damaged. Just look for unseated valves, cam bearing surface damage, and cracks. Remember the two heads are different. The cam chain tensioner mounts are reversed.
08-23-2007, 04:54 AM
#9
Member
Squid
Thread Starter
Join Date: Aug 2007
Posts: 53
Thanx SD, yes, I have noted the difference between front and rear heads. There are plenty of rear heads available but front heads are rare. I'm assuming these go bye bye far more often.
mikstr, I can't wait 2 weeks. Sorry man but thanx for the offer.
I'm taking the head to a reputable machinist today to get his opinion. What blows is that all 4 valves will cost more than a complete spare head (minus cams). Which brings up another issue - I'm not crazy about putting my cams in a different head. I can always plastigage them to check clearances but if they're out, then what? As I stated before, I can buy a set of heads complete with cams but I only need the front and really don't want the extra expense of buying both or the hassle of trying to sell the rear one.
I'll know more after I speak to my machinist.
mikstr, I can't wait 2 weeks. Sorry man but thanx for the offer.
I'm taking the head to a reputable machinist today to get his opinion. What blows is that all 4 valves will cost more than a complete spare head (minus cams). Which brings up another issue - I'm not crazy about putting my cams in a different head. I can always plastigage them to check clearances but if they're out, then what? As I stated before, I can buy a set of heads complete with cams but I only need the front and really don't want the extra expense of buying both or the hassle of trying to sell the rear one.
I'll know more after I speak to my machinist.
Thread
Thread Starter
Forum
Replies
Last Post
Generation450X
Technical Discussion
9
05-25-2009 07:14 AM
