Can anyone that has ridden one tell me how much improvement this is? I ordered all my parts and am already tearing the motor apart but can anyone give me there 2 cents?

 

My z motor is still stock other than a pipe (sparks)and filter. I have a friend who has a Lrd 440 kit and he can't keep it together ( head gaskets and rings ) . Another friend has a CT 450 kit and burned the motor up at last race . I am going to try a yosh kit ( 450 stroker ) supposed to be more dependably than the rest don't know yet .

 

The key is do one that doesn't require a sleeve. Use a place like Millenium Technologies to bore and replate your cylinder. I believe they will do your cylinder and sell you the piston/rings for $499. It should be as reliable as stock if assembled properly. The problem with the steel sleeves is they expand at a different rate then the aluminum cylinder. You get less then desirable results when this happens.

 

I mean ive seen some of the motor kits out there I ordered a steel sleeve because the aluminum sleeve and instelation were 500 then I had to buy the piston it seemed reall pricy to me and that was at cost through the dealership I work at. So I ordered the 440 weisco and the steel sleeve. So your saying it is a problem because the steel heats up differently then the alum block? I think I understand what you are saying but I have not heard any good or bad things about ths setup so anymore info you all can add would be great. I have a friend here that has a 450 with steel sleeve and has not broken or had any issues with it but not to say he wont. he has ridden on it for a year of regular riding but tell me about what you all know please. thanks for any imput you all have or have put in.

 

I guess I should of elabirated more then I did. The steel sleeve with a aluminum cylinder will work (obviously or they wouldn't sell them) but there is much more room for error. If the sleeve isn't pressed into the exact depth it needs to be you end up with blown head gaskets in most cases. I can't remember the tollerance for it but it's very small. Basically the sleeve has to be pushed in just past the top of the cylinder mating surface to allow for expansion. To far you have a problem and not far enough you have another problem. I'm not sure why they are so finiky on these bikes as they are quite common in the automotive world with aluminum block motors. None the less thats the case and it is what it is.

Thats why I recommended going with a place that will replate the cylinder. It removes the majority of problems you "could" experience with a overbore engine.

 

thank you for the advise jeff. It makes me rethink the whole plan.

 

what does replate your cylinder mean? ive never heard of that, i know im kinda in the wrong forum but what about the 400ex? what the difference in power when you replate the cylinder then anytihng else? what about price?

 

You can go to a 435 with the stock cyl and sleve. The cylinder is plated with a Nikasil, a very slippery and hard surface. It helps wtith cooling, friction, and durability. If you bore into the sleve, you have to replace the Nikasil.
Millenium technologies can do it.
Sparks, FST, and some others can do it.