I'm looking into a big-bore kit for my yamaha warrior 350. Can someone tell me about big-bore kits and are they worth it. Also where would i be able to find one and is there certain brands i should or shouldn't buy from. Thanks

 

How big do you want to go? JE has a 366 kit that uses the stock cylinder, just bores it out 80 over. A lt of people sell this kit, Vito's is the first that comes to mind. That kit is about $200 and about $300 installed if you do most of the work. The 10.5:1 compression will allow you to run 93 octane and not race fuel.

Four stroke tech (fourstroketech.net) has up to a 446 Big bore & stroker that will run about $800, $1500 installed if you do a lot of the work yourself. I had one and it's not worth it IMO.

Wiseco pistons are OK, but are heavier than JE, which will make the engine rev slower. Leave the Wiseco pistons to the 2 stroke guys.

 

so wat would be my other options to get some more power? Throw on a pipe and an air filter????

 

Warriors are not powerhouses, so don't expect to get 50 HP out of it. But there is a lot you can do before you get a bigger piston, like a slip-on exhaust, K&N or foam filter, and proper jetting will help matters. This will make a noticable difference for around $300. Depending on your riding style and terrain, proper gearing & tire selection can make a huge difference in performance. For instance if you ride a lot of deep mud, big 22" rear tires with a 12 tooth front sprocket would work better, but if you ride fast, wide-open trails, lightweight 20" rear tires like the Holeshot GNCC and a 14 tooth front sprocket would be the ticket.

It would not be wise financially to dump a ton of money into your Warrior. Unless you just want a little bit more power, 9 times out of 10 if you are not happy with it now you will not be happy with mods, and you will never see a return on your investment if you sell to upgrade.

 

Would a JE 12:1 stock bore piston require race fuel???

 

12.1 is alot of compression id think ud have to use race gas for that, its best to not go over 10.5.1, thats wut im using. you can look at my mods in reference of some things to get that wont break the bank too bad. the maximum potential and i mean maximum is really just under the performance of a 450, but can never handle the same and is nowhere near worth it. if i were you look into a big cam like a hotcam stage2 or webcam 430 or a megacycle cam, and get a K&N filter, edelbrock carb, kibblewhite valves, springs, retainers, HMF, Yoshi, or whiteborthers pipe, then later when ur cylinder is worn out bore it, dont waste ur cylinder life if u plan on keeping it for a while, just get it bored .040 over or something, and get a JE high comp piston, or wiseco high comp, but i kinda agree with raptor450 wiseco is better known for 2 strokers, ive never used JE but i know they make nice stuff. just my two cents! lol

 

<div class="FTQUOTE"><begin quote>Originally posted by: yotatrailrunner

Would a JE 12:1 stock bore piston require race fuel???</end quote></div>

Yep, 11:1 is as high as you can go on the Warrior and still run 93 octane pump gas, so go with the JE 10.5:1 or the Wiseco 10.75:1 if you don't want to run race fuel. I like the JE better, and I don't know what you do with your Warrior, but I think it would be dumb to run race fuel on a trail machine.

 

I race it in a 350cc limit class so no 366cc piston. I would rather run the lighter JE piston but wonder if I can take a little off the top of the JE piston to lower it from 12:1 to 11:1. should not take much metal off to do that.

 

Oh ya I already have a HMF pipe, K&N and dynojet kit. I've got a edlebrock carb for it but the thumb effort it quite a bit so I'm not sure if I will use it. It is for sale BTW.

 

<div class="FTQUOTE"><begin quote>Originally posted by: yotatrailrunner

I race it in a 350cc limit class so no 366cc piston. I would rather run the lighter JE piston but wonder if I can take a little off the top of the JE piston to lower it from 12:1 to 11:1. should not take much metal off to do that.</end quote></div>

JE used to make pistons in all sizes and compressions, not just 366cc. Buying a 10.5:1 would be easier than guessing at how much to shave down to get 11:1 compression, but the only piston JE makes is 366cc in the 10.5:1.

http://www.jepistons.com/cat/j...rrior-raptor_350.shtml