My performance upgrades list.

So over the course of the summer, I will be doing some performance upgrading to make my bike into the ultimate freestyle bike. Bottom end is definitely a must in freestyle. I also was thinking about it, and all engines are the same, before you can upgrade the engine, you should definitely try getting the max airflow and exhaust flow before you do anything to the engine. With that said, here is my list.

1.) Twin Air Performance intake kit

2.) Pro circuit ti-4 Exhaust system

3.) Athena 290cc Big bore kit

4.) Stage 2 hot cams

I will also be upgrading from my already 50t sprocket to a 52t driven sprocket. If thats too much, ill just go back to 50t, but I still wanted to try it.

The biggest problem with the thumpers in freestyle is the quick run-in's to the jumps in arena's. with 2 strokes, they have such godly acceleration to powerband you can hit the jumps so easily just in 2nd gear up to about 70-80 feet. Some run ins are about 35ft to jump 65ft, and with a stock 250f, i will not be accomplishing this. Blake "Bilko" Williams uses a 302 big bore kit on his crf250, so I wanted to get this done before not too long.

And to weed out the comments about it, no, it isnt wise to just save the money and buy a 450. There is no point in adding weight and bulkiness, that cons of the 450 in freestyle cancel out the pros. By this, I mean yes, you do get that extra power, but the bike is so big, with much more engine brake in the air [the biggest problem].

So thats my post. Any comments on my upgrades list?

edit: Does anyone know if the washer trick still works on the clutch bolts? to make it so you can kick it over in gear? or just go and buy 6 new clutch springs or was this all just for the 01-03 bikes?

If you are looking for low end power, stage two hotcams and a pro circuit Ti-4 are not a good combination. These are both aimed at adding top end power and add little to nothing on the bottom. Unless you are trying to get the top end back that you may or may not lose with the big bore, you might want to consider a different set up as far as that goes. I'm not sure how much top end you are willing to sacrifice in your search for low end. There are ways of getting huge low end gains, but most come at the expense of top end.

Well yea, using my example. Im going to have a 35 foot run in to a 65-75 foot gap. I need lots and lots of low end. All i do is freestyle, i ride on the mx track just for my riding practice but i never actually race. I am never too worried about top end.

Maybe im just a little confused, maybe im not looking for complete bottom end specifically, maybe i'm just trying to beef up the power all around. So it doesnt matter if I have bottom end or top end specifically, whatever I need it for, it will be there. I'm not positive, but I know I always get the direction I need from the people on this site.

I will also be upgrading from my already 50t sprocket to a 52t driven sprocket. If thats too much, ill just go back to 50t, but I still wanted to try it.

QUOTE]

Honestly you should be going down if your doing the 290 kit. I had 13/50 on my bike and when I bumped the displacement, I went to 14/50. Couldn't be happier. Gearing is personal prefference but honestly I think you'll be wasting your money on a 52T. Just my $.02

Honestly you should be going down if your doing the 290 kit. I had 13/50 on my bike and when I bumped the displacement, I went to 14/50. Couldn't be happier. Gearing is personal prefference but honestly I think you'll be wasting your money on a 52T. Just my $.02

Two questions for ya bud. So you think i should just go up one on the front? I know doing that eases on your clutch.

Can someone explain to me the specific advantages of the bigger displacement. All I personally know right now, is that its going to give my bike more power without adding the weight i dont need.

And on the exhaust situtation. there is three reason I am going with that.

It is lighter.

It is shorter

It will free up any restricted airflow i will have coming out of those extra 40cc's.

Also question for you smcdonn, what other mod did you do to get your bike to the 306?

Going to a 14T front doesn't make it easier on the clutch, it makes it easier on the chain. With a 13T it has to wrap around a tighter radius causing it to stretch quicker. With the added power (especially low end) of the 290 kit, the last thing you need to do is gear down. When you gear up, this makes the available power more usable. The reason people don't do it stock is because the motor doesn't have the power to pull the taller gearing very well. To get the added displacement of 306cc, I put in a hot rods 3mm stroker crank. Honestly if you can do it yourself it's an OK mod but if you have to pay someone, I don't think the benefits outweigh the cost. Just my opinion though.

Going to a 14T front doesn't make it easier on the clutch, it makes it easier on the chain. With a 13T it has to wrap around a tighter radius causing it to stretch quicker. With the added power (especially low end) of the 290 kit, the last thing you need to do is gear down. When you gear up, this makes the available power more usable. The reason people don't do it stock is because the motor doesn't have the power to pull the taller gearing very well. To get the added displacement of 306cc, I put in a hot rods 3mm stroker crank. Honestly if you can do it yourself it's an OK mod but if you have to pay someone, I don't think the benefits outweigh the cost. Just my opinion though.

Alright, i was just wondering. i am still learning on these 4 stroke motors though, so i dont know if it will be worth it unless i find a friend who wants to help me out on it.

why would you want bottom end power, when you hit the jump, your going to be using mid-topend, right? wont taking all that top end away, bog your bike down even more?

I thought 2 strokes has bad bottom end and good top end.

if your so concerned about weight and power, why didn't you just get a 250?

if you get stage 2 hotcams, they will aim the breathing of your engine for higher rpms, engines breathe differently at different rpms, so you loose bottom end and gain top. vise versa with the stage 1.

and arn't 2 strokes supposed to have way better throttle response, wouldn't that be more important?

4 strokes are the future of the sport. i used to do it on a 2 stroke, but have since switched to the 250f to be ahead of the game

oh, what about the other questions though?

I have a friend who had to get brain surgery, his steering linkage broke coming down the mountian and he plowed into it.

he used to do freestyle. Hated 2 things, Yamaha, and 4 strokes. so we naturally became friends. LOL

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