This is what happens when you drop a Valve.(literally)

Jpbikeboy and i picked up James Laugesen's old ZXR750 L model engine for engine spares for our track bike project, seeing that jp's 750 motor's gearbox had taken a beating from the turbo, and that he was putting in the 900 for some turbo treatment.
After taking the head off our thoughts of a droped valve were true.

Check out the carnage.

Cheers,

Matt.

Attachments

Damaged Cyl Head Closeup.jpg (30.13 KiB) Viewed 2782 times

Damaged Cyl Head With Valve.jpg (35.46 KiB) Viewed 2783 times

DamagedCylHead.jpg (29.5 KiB) Viewed 2783 times

Piston hole.jpg (23.43 KiB) Viewed 2776 times

Piston hole1.jpg (33.04 KiB) Viewed 2777 times

Ouch!!! Is the valve train the archilies heel? I have been told that kwaka engines produce the goods, just make sure you respect the revs. I know the kwaka teams have been finding this.

Cheers

Gee I know bout Valve problems and yeap we was told that very common in the Kwaka's.

Been involved in racing a fair bit and oh yeah when something lets go it sure as hell makes a mess. Nasty.

Paul.

reminds me of when my old gsxr750j had a (very) loose camchain. i changed down one too many gears coming into a corner too fast with two guys on much newer bikes.

the a piston hit the valves and the resultant mess was similar. ouch.

Wooo!!!
Would've sucked to own that bike... oh... dammit .
Nice to see the photos though, taa

hmmm
just caught this thread

from experience ....
'dropping' a valve rarely occurs because of high revolutions...
its just that it happens at high engine revolutions
and
is usually caused by -
poor lubrication of the valve stem/guide which results in galling of the stem (the stem will jam in the guide or break)
or
metallurgical failure of the valve due to poor filling of the valve stem (especially zorst valves)
or
a material stress failure due to incorrect valve clearances or incorrect manufacture of the valve.

What is also attributed as 'dropping a valve' occurs when the
collet fails and releases the valve.....

it is my experience that an Ottocycle (4stroke) engine which has proper lubrication and clearances of the overhead valve will normally break something else...
a pushrod or rocker arm or pivot ...maybe a even a valve spring before 'dropping a valve'

hth

cheers

i did that in my civic
ehheeheh very good job there i thought mine was a godo effort but tahst a lot better

i did that in my civic
ehheeheh very good job there i thought mine was a godo effort but tahst a lot better

Admins, can we put a spell check on kellz account ?? I'm getting headaches from reading her posts!

i did that in my civic
ehheeheh very good job there i thought mine was a godo effort but tahst a lot better

include a grammar check

i did that in my civic
ehheeheh very good job there i thought mine was a godo effort but tahst a lot better

include a grammar check

I think Kellz has the problem that she knows what she is saying but somehow the brain types faster than her fingers..... If that makes sense.... Although she is blonde

Ya know me luv's ya Kellz

hehe thanx lainie

luv ya to

heheh sorry guys i will try my best to make all my posts readable

See she already has done much better....


Poor Kellz

hehe thanx lainie

luv ya to

heheh sorry guys i will try my best to make all my posts readable

aaahhhhh *breaths huge sigh of relief*........*uncrosses eyes*......thanks Kellz

Smitty - what about valve-clipping at high revs ?? This will cause a valve failure as well, most m/cycle engines don't have pushrods/rocker arms etc (well, some do, but they don't rev too hard )

Smitty - what about valve-clipping at high revs ?? This will cause a valve failure as well, most m/cycle engines don't have pushrods/rocker arms etc (well, some do, but they don't rev too hard )

Gos
valve clipping???
not a term i have heard before in relation to an engine-
valve bounce, valve rotation , valve recession, valve galling
valve head loss
yep..seen 'em, fixed 'em
but clipping?

I am curious


cheers