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Discussion Starter #1
Guys hi,

im really sorry if this has been covered already,

heres the full story,

Decided to build a new engine for my track bike ( 05 zx10r )
spec:
stm slipper clutch
balanced and polished crank ( standard rod and pistons )
nova box
block jetted to keep more oil on the crank,
head built to kawasaki race manual spec, ( ported 1mm larger inlet and polished )
kent cams ( kaw 25's ) degree 105, 105 as they request.
uprated inlet valve springs and shimmed exhausts,
2 degree ignition advance
ngk race plugs ( yes the £200 ones )
micron full system
.40 kit head gasket,

Heres the problem:
put the engine through 200 miles soft running and 10/12 heat cycles
tunning on the dyno started well, hp was looking good but then right at the end on the last couple of full throttle top end fueling adjustments .....it let go!
11500 rpms the bucket on cylinder 3 inlet smashed and dropped the valve...as you can imagine i was over the moon :)
anyway i wanted to ask two things:
1, could i fit the 2006/2007 head to the 05 block as im struggling to find a head? ( i know the inlets are 1mm smaller )
2 is there any other mods or head work that ive missed that work well?
thanks in advance for your help guys :smile:
 

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so what exactally failed? the bucket? or the keeper popped out? or the valve sheered off?
If the keepers are't settled when installing them they can pop out causing alot of trouble.
 

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Discussion Starter #8
With all the mess it's hard to say what let go but my guess is the valve bucket broke,
the retainers were Kawasaki kit parts and springs
Valve clearance was 1.2 exhaust and .65 inlet
Head decked .40 mm
Squish .65
The valve stem was bent at the top and the guide was snapped of so it def let go at the lobe end,
I spoke to Kent and they told me the buckets ( valve followers ) are the week point,
They gave me a part number which I gave to my local kawi centre
The number is 98/99 zx7r,
Kent say they are much better than than the zx10r followers and have never had one brake but have had loads of zx10r brake during testing.
What's your thoughts?? :dontknow:
 

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hmmm...have any pics of the failed parts??
 

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Discussion Starter #10
Sorry no,
The bucket was found in a million pieces, the cam lobe is scrap where it rode the keeper and valve tip
the head where the bucket runs has lumps out of it.
I've just picked up a 2007 head complete this morning,
Planning to do the following
Port ( as per the Kawasaki race manual )
Deck to get the comp up,
Picked up a .40 and .50 kit gasket today,
New cam chain ( maybe OCD but could not re build using the same chain after that sort of stress went through it.
Now kent have told me to use the standard springs and retainers as they do,
They tell me as I'm not upping the rev limiter it will not bounce at all
"we always use the standard spring and retainers"
They tell me to use the zx7r buckets
Kent have received my spare inlet cam this morning and are grinding it to kaw 27 spec, it will run with my kaw 25 spec exhaust.
I've been told you can shape the valve stem in the port to reduce restriction
Have you heard of this, is it worth it?
Cheers guys :thumbsup:
 

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I have yet to experience a shattered bucket...def not cool.

i typically hack off any of the valve guide poking into the intake port...and shape the exhaust guide or hack off depending on how much work I wanna do.

This last build i used the metal epoxy to fill the low spots around the valve seats...this worked out very nice....my next head is going to get hi-velocity ported to make the head flow better,as the 05's are too big and later generations have shrunk the intake.
 

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I clipped off the guides just as Badass described above but haven't had a chance to dyno it yet. I used a dremel and the cable extension is necessary to get into those ports. The intakes ground down easily enough, but those exhaust guides are hardened and a mofo to grind down, 2-3 sanding drums per guide. I lightly plunged a tapered grinding bit into the tip of the guide to chemfer the edges.
 

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from a quick online search/check, a binding bucket can get hung up and get slammed by the piston driving it up against the camlobe as it spinns(speculation as to oil hydrolics or lack of oil) causing, a handfull of these and the bucket shatters/cracks and then valve failure just behind.....

Personally I'd say it's an assembly/fit error....I use plenty of moly paste/oil mix to make sure valves and guides have a healthy chance of living....BUT....BUT, say a sacked spring could cause such a problem too, losing tension and not keeping up to performance.

It happens, but "loads" of failures of shattered buckets....sportbikes?....I see alot from thumper dirtbikes and 4 wheelers.....

Good luck on the rebuild!!
 

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Discussion Starter #15
Thanks for all the info guys, I'll def trim off the guides,
I was looking at your engine build Jake ( pretty fricken awsome mate:cool:)
Guys I'll go and start the dremmel up and let you know when it's tuned how it all went,
Just a quick shout out to my dyno guy
Pete Alton at OTC performance, man that guy ( as those who know him ) is a god ( and mental as a barking snake, races side cars in the TT :lol: )
Lads anyone who wants a great race tech and tuner should see him, I've known a few ( my self included on single seat race cars to blow my own trupet) but this guy is tops:cool:.
All the best gents, sunshine is coming :cool:
 
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