250f have enough mid-top?

K

KAWA200'sRule

Member

Mar 15, 2004

213

0

• Oct 11, 2004

• #1

Well I currently have a '99 yz 125. Its bored out to 133, flat top piston,ported and polished race head, fatty pipe and runs on race gas. Well onto my question... At the track sometimes I catch myself a gear too high or needing to clutch to get on the pipe and I am starting to think 250f? Well I know the 250f would have the low end to pull me up through the gear easier but will it have enough mid to top like my modded 133 has. If not I will just focus on riding better but i am thinking I will be able to save money in the long run. No more race gas! And plus my dad is a huge car nut so he knows four strokes really well. With two strokes we are picking it up as we go. Any opinions are helpful. Also the bike i am considering is the yz250f. Either '01 or '02 but is there any like teething problems with he '01 since it is the first year? Thanks alot.

 

Last edited: Oct 11, 2004

G

GhostRider32

Member

Feb 10, 2004

473

0

• Oct 11, 2004

• #2

I doubt you would save any money if that's a concern. It costs way more money to do a top end on a four stroke compared to a 2 stroke. Another thing, if you buy one used that old, it may already need a new top end. Four strokes are nice but there's a lot more to the racing 4 strokes than just put in gas and go, especially for someone who races quite often.

 

K

KAWA200'sRule

Member

Mar 15, 2004

213

0

• Oct 11, 2004

• Thread starter
• #3

Well actually doing the top end is like $175- 200 its just that people are not doing that and thats when the problems are starting. Am I right?

 

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GhostRider32

Member

Feb 10, 2004

473

0

• Oct 11, 2004

• #4

From what I understand all the expensive problems come in when a new top end is not done and the piston craters and it ends up being a $1500 rebuild with new cylinder and all.

 

K

KAWA200'sRule

Member

Mar 15, 2004

213

0

• Oct 11, 2004

• Thread starter
• #5

Just forget about the rebuilds and all. Right now I just want to know about the performance of the bikes. The top ends and all I will save for another thread.

 

F

flying W

Member

Mar 30, 2002

78

0

• Oct 14, 2004

• #6

Maybe you could try changing the final drive ratio by going with a larger rear sproket or smaller front?

 

B

biglou

• Oct 15, 2004

• #7

GhostRider32 said:

It costs way more money to do a top end on a four stroke compared to a 2 stroke.

Click to expand...

BS! Don't you ever get tired of blowing the "Two-strokes are superior" horn? All this 2 v 4 crap is so full of misinformation and heresay it's pathetic. Give it a freaking rest.

 

CaptainObvious

Formally known as RV6Junkie

Damn Yankees

LIFETIME SPONSOR

Jan 8, 2000

3,331

1

• Oct 15, 2004

• #8

Kawa200,

Having not ridden your highly modified YZ133, it would be impossible to pass judgment as to whether a 250F would provide you with the power that you are looking for. My advice would be to ask someone to turn a few laps on their bike. This way you could make that decision for yourself.

I recently made the switch from a KX125 to a YZ250F. I have never been so confident on a bike. When compared to a two-stroke 125, the mid-range punch is something to experience.

 

K

KAWA200'sRule

Member

Mar 15, 2004

213

0

• Oct 15, 2004

• Thread starter
• #9

Ok thanks for the advice guys. Biglou thanks for the BS horn lol.I knew it would be hard to tell me if it has the power I want. I recently looked at a dyno of a stock 125 and a stock 250f. The 125 pretty much crawls up to 8k rpms then drops a little then shoots straight up and signs off at about 11k rpm. So were lookin at a sweet spot of only about 3k rpms. The 250f looks like it pulls almost as hard as the 125 when the 125 is in the sweet spot just about the whole time. Does this sound about right? These dynos arent quite fair because it is an '02 yz and an '04 yzf but that sthe only ones I could find.

 

M

motoflat

Member

Dec 9, 2004

6

0

• Dec 10, 2004

• #10

it does not cost $1500 to do the top end the cylinder is not even the expensive part. the expensive stuff is all in the head. it could cost about $600 to freshen up the head. That having a professional do it. the head on these four strokes is nothing for someone not knowing what there doing to mess with. The five valves are very touchy and its best to have a proffessional do.