TOPIC:

my engine builder told me to weld the crank if i want but i will just be throwing $100 away.
since he has been doing this for 30 years, i really should listen to him more often.
( sorry guys, shameless plug comming up )
www.kzkuztums.com/KZXtreme.html
we got a drag motor from another local here who blew it up at the track.
80 markII cases, 1105 piston kit and everything else stock, even the cams.
( believe it or not, the guy did get into the high 10's with this motor )
well we just got around to opening the motor tonight and everything he told me rang true.
the crank will break before it will twist.
small pin crank is just not suited for drag racing.



i knew you guys liked carnage!

Post edited by: kawsakiman, at: 2008/02/22 00:36

want to see the piston?
this is #2 piston.



do you think we can weld this up?

a little better view of the break.
who says these motors can't make power?

remember this was a drag bike running a slick.
we have had great success using 900 cranks on street bikes.

on the other hand, i now have 3 1105 pistons for free if anyone wants them.
one has a knick on the bottom so they are better suited for shop ashtrays.
but who knows, maybe someone has a old school motor with one bad piston and free is free.

Did this motor have the steel main cap support?

Jay

Post edited by: APE Jay, at: 2008/02/22 02:09

im pretty sure its not needed if the crank has never been apart(generally). but if it was ever pressed apart and pressed back together, the fit isnt as tight as it originally was, so it should be welded then

cool,carnage is good! ive seejn plenty of cranks that were a little out of alignment when it came time to weld them.on the other hand i know plenty of turbo bikes running small pin 900 cranks with nothing done to them other than checking/straightening them and welding the pins with no signs of crank breakage,my machinist/engine builders 1197 turbo runs the stock small pin 79 ltd crank with a slick and runs high 5s-low 6s with a 6" slick with no problems,my 1428 turbo still has a small pin crank(77-78 kz1000 crank)i wonder why you need to check a crank for straightness before you weld it if twisting is not a problem ?the biggest problem ive seen with the small pin 900 cranks has nothing to do with the center pin or even welding the pins,its the lack of counterweight to keep the motor spinning when you dump the clutch on a bike with a big sticky tire and it wants to fall on its face ifya dont get the tire smoking a little before it hooks up,or ya gotta slip the hell out of your clutch to get it rolling.

APE Jay wrote:

Did this motor have the steel main cap support?

Jay<br><br>Post edited by: APE Jay, at: 2008/02/22 02:09

rather.... is the main support worth anything since it's not tied to the case:ohmy:

when you tie it together with a good set of studs it makes a hell of a differance helping tie the cases and crank together;)