thoughts on a 470 thumper kit

[scanz2k z400]

what does anyone have to say positive or negative about a 470 thumper kit for a 03 z400. will i need to upgrade certain things. is it worth it? will i get some good horse with that? i can get it for 300 bucks.

[scanz2k z400]

its the sleve and the cylinder and used gaskets.

[tar]

If it's in good condition I would get it. In dirtwheels they had a test on the Alba 470 kit and it made 50 hp!! They said that's also reliable hp.

[z rider2]

i dunno, thats pretty pricey i wouldnt get it. also its just a big bore piston, and most say that u shouldnt go any bigger than a 450 kit, without also lengthening the stroke. tha Alba 470 kit includes a stroker crank. you'd have to buy a new piston, gaskets, also if u dont alredy have em, cams, carb, ignition, exhaust. i'd look into an Athena 434 kit, its reliable, or for only around 250 you could get a weisco 440 kit which would have new gaskets and piston.

[scanz2k z400]

thank you so much for the input guys, i really appreciate it. i really dont know anything when you get into this boring stuff. will it still be reliable? what all comes with the kits? i will have to get other things to make it more reliable?

[z rider2]

i would definately pass on that. u can get a new 440 kit, that would be way more reliable, and come with more stuff like a piston, correct gaskets, and such. keep in mind though, you'd have to have your cylinder re-sleeved by a machine shop. what other mods do u have on your bike? if u dont already have stuff like an aftermarket exhaust, carb, or other things a big bore kit wont be very practical, you'd be better off getting some of the things i listed before a BB kit.

[superz400]

i have the thumper kit i have had it for three years now i ride/race every weekend i ran flat track for a while very hard on a engine reved high all the time now i m drag racing the bike its on alky and im spraying it with a 25 shot
so i think it is very reliable this bike is ran hard and put up wet every time
as for as performance i have never been beat by another z with another kit i also have a 450r with p &p head cam pipe and 13.5 comp on alky that my z is faster
i think this kit is very well worth the money, if i was to do it over i would go with the 510 stroker kit but it is pricey
you will also need to have some other mods done for the kit to perform well p&p head cams pipe cdi and a fcr 41 ive tried edelbrock fcr39 and it had much better performance with the 41

[z rider2]

no, i'm sure that kit is an awesome one, and probably runs VERY hard, i'm just sayin that for a used sleeved cylinder, and some old gaskets he could do much better than 300$ and be farther ahead.
i'd buy a DRZe kit from Advantage cycle and maybe a few other things, way before i bought an old cylinder. he'd probably have to dump another 800-1000 into it with cams, carb, ignition, exhaust, a piston to go with that sleeve, etc. not a good deal at least i dont think.

[scanz2k z400]

i understand what youre saying rider. i dont think im gonna do anything more really. ill just go a tooth down on the front sprocket and that might be it. i have the k and n and dyno jet and a slip on yoshi an that is about it. thank you so much for your input fellas. i dont know wht id do without it

[z rider2]

hey man, not a problem. i also have a 13 tooth front sprocket, its a good cheap mod, but if i were u i'd also consider getting the headpipe that matches your slip-on. theres a pretty good gain to be had there too. just another option. good luck, and let me know anytime i can help!

[z400quad]

dont get it get a z440 or z455 alot more efficient check this out http://www.maxpower-engines.com/big-bore-kits-ATV/ltz510-icecube.htm you dont need a real big engine to win just 440 or 455 will beat out the new 450s.