300 xc getting it to rev a little more?

[norcal_hoss]

I been going back and forth over the 250 sx and 300 xc. I ride motox only and ride a 350 sxf right now which I love. Im trying steer away from FI and fuel pumps as much as I can ( for my own reasons).. Like a lot of people here I rode two strokes from the late 80's until 2002 when the crf 450 came out , ive been on thumpers since. After riding the 12' 250 sx yesterday on hard/int dirt compared to the sand track I rode them on a week or two ago the 250 is a bit harder for me to go fast on. Its nervous feeling granted it is not set up perfectly for me it is still set up well. Im sure over time I could get used to it and change how I select lines. Im thinking the 300 would be good and /or better for me since im a big dude. I can get a 250 sx and put the 300 kit on it but of what ive read it's like a 250 sx still just on steroids. I like the 300 xc power but it revs out so fast. What are the best ways to make it rev a little more? I know it has a flywheel and the box probably has different map in it than the sx but there has got to be a way of getting it to rev more. Gearing, map, power valve springs, exhaust ect..Also has anyone tried the wider front tire? Just looking to hear from people that have either the 300 xc or 250 sx converted to a 300 sxs and what you found worked well. Im leaning more towards the 300 xc for a couple reasons mostly the resale value will be much higher than the 250 sx and I also may like the 18inch wheel more. I planned on stripping the starter and everything along with it off the bike along with kick stand and I think one other thing. My buddy did this on his 12 ' 300 xc and weighed the parts that came off and the bike lost 9 lbs which brought it to the 250 sx weight almost exactly. When I sell it ill just put it back on. The 300 seems to hold it's value way more than the 250 sx around here.

Be great to hear what people have done to there 300's to make them more for motox.

Thanks in advance.

[racerxx276]

I had a 2010 300xc and had dick at dicks racing do the taper bore on my carb. I sat on the starting line at Glen Helen with 39 450s around me and beat them to the first turn on both starts.... It really opens up the mid to top end

http://www.motocrossactionmag.com/Main/News/MXA-TEAM-TESTED-DICKS-RACING-INTELAJET-CARB-MOD-8464.aspx

[norcal_hoss]

Nice, I know Dick well his shop is down the street and I saw that carb mod in mxa . Glad to hear it worked as described its something I would definitely want done.

[pantra]

A 300 wont ever rev like a 250 does I have an 05 250 MXC and an 11 300 XC. I really like the 250 motor alot better. I've been on the lookout for a 250 cylinder and head to convert my bike but no luck yet.

[1st4stroke41]

Yea and a 250 will never rev like a 125 and a 125 like an 85......dam I get sick of hearing that.

[fish10]

I am thinking that you don't like how it revs out too quick especially in 2nd gear. i had the 09 and set it up for Vet Class MX, MX Tech Suspension, pipe, high compression head, and played with gearing. i actually added a tooth to the rear and ran alot of corners in 3rd and that worked well. It brought that 4 stroke pull over big jumps even in 4th gear. I took the High Compression head off as it was too much. It will run with 450s if you shift right and stay off concrete start pads. the best front tires i have found, (east coast riding) are the Pirelli Scorpions. I have never liked the larger front tire as it only works better on pure hard pack. with all that i have just written, i will tell you that I would consider the 250 sx and add the xc300 kit to it if it were available, other wise I would choose the near stock 300xc over the 250 sx as I get to ride both of them regularly. Good luck. BTW I have an 11 450sxf and had the 350sxf.

[norcal_hoss]

ZFish thanks for the info, how do you like the 300 on the track compared to the 350? I had an 11 450sxf but didnt care for it a whole lot but love the 350 because it revs so far. I like the simplicity of two strokes tho.. I rode both and yes the 300 revs out way too fast, did the pipe help? Have you played with the power valve springs? I like the 250 sx in sand but on hard pack I was all over the place. I can get either just leaning more towards the 300 tho.

[fish10]

I liked the 350 as far as fun factor and keeping me on my toes riding. However this 450 is just so hard to beat. I will say that I am having as much fun leading the motos because of the better starts on it. I believe that the 300's torque is substantially better than the 250 sx, but not as much as the 350. I'm not gonna lie, there were one or 2 jumps that I never did on my 300 that i do regularly on the 4 strokes. However, i let a national caliber mx racer ride the 300 and he went crazy over it. The best pipe was the KTM Hardparts or the stock pipe. It is much better on hard pack then the 250 but not the 350. It was crazy how i learned to ride it, off the pipe on huge doubles blipping the clutch in 4th gear. I set the bike up to run 3rd and 4th gear and that gave m ethe rev that i wanted. It is about the same as the 350 as far as speed, but it is lighter and will have less headaches, and turns a lot of heads. Ill try to send you a picture, not sur ehow to do it on the post.

[imotormz450]

if you want the 300 to rev do the dicks carb mod and a pc pipe. i have a 250sx with the 300 kit and these mods and it rips on the top end.