welded crank

I* was told today if i put a welded crank in my kz1000 it would be good for anothe 1000 rpm.
Any thoughts?

sounds right, but i dont know. But with anything if you run it in the red you risk a chance of blowing it up. My dad was telling me his friend took a bone stock kz 1000, and in 2nd gear proceeded to rev it out. Well he did that old girl pulled past 11000 rpm's then just blew the motor up.

We all no our limits but an extra 1000 would put me at ten before i had to worry and to hold it past ten you would be travellin some fast.

last year i was all about impressing everybody with my z1, but i realized there is no need to shift at 8500 rpm's, even though sometimes i do for grins and giggles. I also realized i have spent far less time this summer fixxing the old girl up. I guess riding like a sane person makes mor since to me now that im older(21 that is). I just got tired off constantly rebuilding and replacing things cause i had a speed bug up by arse.

well ricerocket i would say go for it then, more power is always better. And ya holding it past 10 my dad said that bike was pulling like a son of a gun, that is until he heard a bang, clunk and the exhaust pouring out white smoke like a mosquito sprayer, then the rear wheel locked up. Similar to what happened to goose's blue and silver kawi 1000 in madd maxx

well ricerocket i would say go for it then, more power is always better. And ya holding it past 10 my dad said that bike was pulling like a son of a gun, that is until he heard a bang, clunk and the exhaust pouring out white smoke like a mosquito sprayer, then the rear wheel locked up. Similar to what happened to goose's blue and silver kawi 1000 in madd maxx

Welded crank would be a very good insurance policy with these motors. If you do that, get it indexed before it's welded. Some places just weld what you bring in and the good places will index it first...makes a difference. It would make motor safer to rev higher but not sure if you will really gain much otherwise. These motors make their power around 9,000 rpm and revving them higher doesn't gain you much if anything. Now, if you have modified the motor some, then that's another matter.

ricerocket wrote:

I* was told today if i put a welded crank in my kz1000 it would be good for anothe 1000 rpm.
Any thoughts?

A stock motor is past being done making it's best HP by about 9000. Welding only helps the crank throws stay aligned but is a non-factor in the stock engines ability to make usable power past 8500-9000.

Actually- there is no way for a welded crank alone that would make an engine rev higher- the welded crank makes it live at higher RPMs, but it really has nothing to do with the engine making higher rpm, that is a function of air and fuel being able to enter and exit the engine. So, more cam and better ported heads will allow you to hit higher RPM, a welded crank may make the bottom end live a bit longer.

CruisingRam wrote:

Actually- there is no way for a welded crank alone that would make an engine rev higher- the welded crank makes it live at higher RPMs, but it really has nothing to do with the engine making higher rpm, that is a function of air and fuel being able to enter and exit the engine. So, more cam and better ported heads will allow you to hit higher RPM, a welded crank may make the bottom end live a bit longer.

if you are go to all the trouble of pulling it all apart to weld the crank why not just stick a welded 900 crank in it ?are you sure your crank isnt allready welded?

Welding the crank is more for torque than anything. If you have a slick on and launch at 7000 rpm you will twist the crank. I'm sure it will be able to rev higher but then you have to worry about the valve train. If you float a valve or spit out a shim your done.

Yes- welding the crank is for strength and to keep the crank "indexed"- as soon as you index the crank, you SHOULD weld it, it is cheap insurance if you know how to do it or can get it done reasonably.

Really, these bottom ends are pretty bulletproof in the mild-stock area, it is, as it has been said, when you put a hard shock on the crank, like in drag racing, as mentioned, or when hard core road racing, where hard down and upshifts are really loading things up, and jerking the bike around.

I made the switch from cars to bikes only about 2 years ago, as in total focus, I have had my bike since 83 or 84, can't remember which summer- and am lucky enough to have hooked up with some old kawi racers here, got some of thier cast- off parts now!

I have never back-cut the gears either- but I will be learning to do that soon- with some help from an old pro.

But the welded crank is really for longevity and reliability- and great, cheap insurance while you have the motor apart anyway.

If you dont plan on drag racing or splitting the cases anyway, i wouldn't bother.