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Discussion Starter #1
i know this has all been discussed many times. but what i am looking at is this. i recently put a 80mm big bore kit in my 250x. it still has the stock cam. i had a nice newer model 300ex carb which is a 32mm, so i put it on and rejetted. problem is, i don't think that it is getting enough gas. i have a 400ex carb on its way from gdh racing so this should help. i know i need a bigger cam with more duration but i really don't want to change valve springs and rockers. i don't have so much of a problem with getting the hard weld rockers as i do running those stiff a** springs. i have seen what they do to the valve tips, not to mention the extra stress on the timing chain parts. i guess what i am asking is; will the hotcams stage one be enough to make my big bore kit run good? if not, what cam do i need to buy and can i even get a cam that would make this engine run well without having to change the valve springs. i don't need to squeeze every ounce of power out of it, but i do know that my current cam and carb set up is not enough. my big bore kit is rated at 11.5 to 1 compression. i put new valves, guides, etc. in the head. i have a 400ex carb coming and i am running a fmf megamax 2 exhaust. my sprockets are still stock 13/38 with 20 inch rear tires. any help or tips much appreciated.
 

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Wow your going to faster than the MOOSE!!! lol on the cam issue a stage 1 webcam does not require the springs just hardface rockers. try running 104 octane race fuel what size jet are you at now? main and pilot (slow jet)?
 

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Discussion Starter #3
well, according to the instructions with the kit i could leave the slow jet stock or go up one size, it is a 38. they recommended going up at least 4 sizes on the main, which i did and eventually went two more. so the main wound up at a 140 and i also raised the needle one notch. there is no hesitation and it runs good with the plug burning a light brown color at wide open. this is with the 32mm 300ex carb. it runs good, but i cannot tell that it has much more than the stock engine that i had in it. the only thing i have to compare it to is the old fords i use to have. you can tell when a engine is not getting enough fuel.
 

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I would up the slow jet to a 40 you said you raised the clip on the needle one notch? if so you leaned out your mid throttle drop it to the 4th ring remove the airbox lid if you havent. the main jet should be fine at 140 and fyi the 300ex is the same carb as the 250X they are the same engines only the cranks are different. with the 80mm piston you are sitting at 288CCs 46 more than stock so you should fly bro. I have a 76mm piston bored 60 over 12:1 CR stage 1 cam ect ect I ran mine last weekend with the GPS taped yes I said taped to the top of the headlight and I got 62 out of mine. you should atleast see that maybe 65.
 

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why don't ya'll just drop a jet engine in your bikes ??.lmfao..sheshh..i'm happy to just go 35 to 40 !!..lmfao.
 

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why don't ya'll just drop a jet engine in your bikes ??.lmfao..sheshh..i'm happy to just go 35 to 40 !!..lmfao.
I'm not happy with mine and it goes 45-50.lol
 

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Im not happy either!!! LMAO I wanna be like my mentor.....MONSTER!
 

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