Input needed - 03 YZ250 Build

Derick5
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Derick5
Edited Date/Time 2/6/2015 8:08pm
Well as some of you know from my other thread I was planning on converting my 2003 YZ250 to the aluminum frame with the upgraded SSS forks. Well, that went south. So now, I ask for advice from those who have or has had a 250 2 stroke. What would be idea modifications for a 2003 YZ250. I know the motors for this year are pretty much race ready out of the crate, well that was in 2003 Tongue

My bike has:
- Pro Circuit Platinum 2 Pipe w/ R304 shorty
- Stock reeds
- Pro Action Suspension w/stock spring rate.

...and the some small stuff like Pro Taper bars, etc.

For 2015 I will be racing in the 250C and 450C class. (Legal in the PAMX series.)

I came up from riding 125's for a couple years, so I have no idea what to upgrade on a 250 2 stroke.

I was thinking:
- Oversized front rotor
- New Mika Metal Bars
- Levers. (ARC, ASV, or Renthal)
- New Exhaust? Doesn't hit up top like I would want it to, but I only have a couple rides on the bike at a small track I ride at, not an actual motocross track.
- Maybe a Rekluse EXP clutch or a Hydraulic clutch. I was thinking Rekluse for several reasons, seems like it would benefit my riding style a bit more.

Need some input guys! Thanks! Cool
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chillrich
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chillrich 1/24/2015 6:16pm
1/24/2015 6:16pm
Matthes swears by Pro Circuit pipe and Vforce reeds. DV12 swears by FMF. Some guys like the heavier flywheel on slick tracks.
SeaClassExpert 1/25/2015 10:20am
1/25/2015 10:20am
In order of what I would do with a modest budget

1. Suspension

2. Brakes/Clutch (Avoid hydro and get Hinson, you don't need a Rekluse)

3. Clamps/Levers (You'd be amazed at what 22mm does to these things)

4. Cylinder Bore/Head mods (I'd get an EG 295 kit if you're keeping it long term)
Derick5
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Derick5 1/25/2015 10:27am
1/25/2015 10:27am
SeaClassExpert wrote:
In order of what I would do with a modest budget 1. Suspension 2. Brakes/Clutch (Avoid hydro and get Hinson, you don't need a Rekluse) 3...
In order of what I would do with a modest budget

1. Suspension

2. Brakes/Clutch (Avoid hydro and get Hinson, you don't need a Rekluse)

3. Clamps/Levers (You'd be amazed at what 22mm does to these things)

4. Cylinder Bore/Head mods (I'd get an EG 295 kit if you're keeping it long term)
What brand of clamps? I've heard good things about them. I might invest in a Hinson basket to start, then eventually get a full Hinson.
Dragoo168
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Dragoo168 1/25/2015 11:43am
1/25/2015 11:43am
If you're happy with what you have so far, then you could enhance that, or keep upgrading what's left. You have a good pipe, but if you add a V-force, and eventually have motor work done, you'll really love it. Rotors, clutch, etc., are all great ideas, but only you know what you can afford, and when, so that's up to you. I always do my suspension first, so clamps are a part of that for me. I use Pro Circuit for most mods on my bikes, but it's really a personal preference. As far as clutches, I always use Hinson, but then i'm not trying to change how my clutch works, just make it better and more durable.

The Shop

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mxrose3
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mxrose3 1/26/2015 7:10pm
1/26/2015 7:10pm Edited Date/Time 1/26/2015 10:38pm
If you don't already have them, get the SSS forks and clamps. Thank me later.
The steel frame is better IMO. Also, Eric Gorr makes a few big bore options.
Nystrom
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Nystrom 1/27/2015 11:12pm
1/27/2015 11:12pm
I dont think neither vforce or boyesen does anything with or without aftermarket pipe. Just a waste of money i think. You can try and remove the reed spacer and see how you like it best. You have a smoother hit and little more bottom end with the spacer but withou it you get more top end a harder hit.
YamiRy239
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YamiRy239 1/30/2015 7:22am
1/30/2015 7:22am
IMO there are a few mods that are a must for the YZ250.
- head mod to have the squish set and rechamered for either pump gas or race fuel whatever you are going to use. There is a lot of info on this over at thumpertalk. Makes the engine very crisp and a lot earlier to jet.

- set your timing. Almost all YZ250's come from the factory with the timing off. Again good info on thumpertalk on how to set it.

- flywheel weight. I use the GYTR off-road flywheel. It is 8.4 oz its heavy enough to make a difference, but not so heavy to loose throttle response.

-SSS suspension. I have an '03 that I put SSS on and a '13 as well. I actually like the feel of the steel frame with SSS better than my aluminum frame. Aluminum frame is more ridged.

A few have mentioned a big bore, but if you are going to race 250c you will have to keep the stock bore.
Eddie_E
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Eddie_E 1/30/2015 11:35am
1/30/2015 11:35am Edited Date/Time 1/30/2015 11:42am
The best improvement in my 2000 YZ250 was an 11oz flywheel weight, or better yet the GYTR flywheel like YamiRy239 said.
Having the suspension done is big on the older steel framed bikes. I had my rear shock done by my local Racetech shop with their specs and the rear was amazing and was way better than the stock stuff on my 09 YZ250F.

My forks had the full setup from Pro Action when I bought it. It was horrible and beyond harsh, worse than a 2003 KTM stock fork setup. After lots of chasing the fork valving it turned out that Pro Action replaced the base valve piston with their own model. Their BV piston was completely solid with only 4 mm holes where the triangular ports would normally be. To be fair , I don't know what setup the previous owner asked for, only that it had stock springs when I bought it. Maybe it could
have worked for a 300 lb pro SX rider(with bigger springs).
YZed250
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YZed250 1/30/2015 1:02pm
1/30/2015 1:02pm
^^ What YamiRy said.

Service the bike so it's in good working condition. Call Pro Action and confirm you're in the ballpark for your speed and weight and that your settings (mainly sag) are what they recommend. Get the squish and jetting adjusted and the jetting so you don't blow it to pieces. Get an hour meter. Save your bucks for fresh tires. Great bike! Check out thumpertalk's YZ 2-stroke forum when you have a chance ... lots of YZ250 guys over there.
Derick5
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Derick5 1/31/2015 7:11am
1/31/2015 7:11am
YamiRy239 wrote:
IMO there are a few mods that are a must for the YZ250. - head mod to have the squish set and rechamered for either pump...
IMO there are a few mods that are a must for the YZ250.
- head mod to have the squish set and rechamered for either pump gas or race fuel whatever you are going to use. There is a lot of info on this over at thumpertalk. Makes the engine very crisp and a lot earlier to jet.

- set your timing. Almost all YZ250's come from the factory with the timing off. Again good info on thumpertalk on how to set it.

- flywheel weight. I use the GYTR off-road flywheel. It is 8.4 oz its heavy enough to make a difference, but not so heavy to loose throttle response.

-SSS suspension. I have an '03 that I put SSS on and a '13 as well. I actually like the feel of the steel frame with SSS better than my aluminum frame. Aluminum frame is more ridged.

A few have mentioned a big bore, but if you are going to race 250c you will have to keep the stock bore.
I was thinking about taking the SSS fork route on this bike, to be honest. Would I need the triple clamps as well? Also, I've head of people putting a YZ250F shock on this bike, I guess the shock is more plush and is overall better.

mxrose3
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mxrose3 1/31/2015 9:06am
1/31/2015 9:06am
Derick5 wrote:
I was thinking about taking the SSS fork route on this bike, to be honest. Would I need the triple clamps as well? Also, I've head...
I was thinking about taking the SSS fork route on this bike, to be honest. Would I need the triple clamps as well? Also, I've head of people putting a YZ250F shock on this bike, I guess the shock is more plush and is overall better.

Yes, you need the triple clamps, and will probably also need to trim up the steering stop on the frame.

The shock to me isn't as much of a performance increase as swapping out the forks.
Derick5
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Derick5 1/31/2015 9:27am
1/31/2015 9:27am
mxrose3 wrote:
Yes, you need the triple clamps, and will probably also need to trim up the steering stop on the frame. The shock to me isn't as...
Yes, you need the triple clamps, and will probably also need to trim up the steering stop on the frame.

The shock to me isn't as much of a performance increase as swapping out the forks.
Gotcha! Sounds good. Will it matter if I get the forks from a 250f or 450f? I know the clamps would have to match....right?Dry
SeaClassExpert 1/31/2015 9:42am
1/31/2015 9:42am
mxrose3 wrote:
Yes, you need the triple clamps, and will probably also need to trim up the steering stop on the frame. The shock to me isn't as...
Yes, you need the triple clamps, and will probably also need to trim up the steering stop on the frame.

The shock to me isn't as much of a performance increase as swapping out the forks.
Derick5 wrote:
Gotcha! Sounds good. Will it matter if I get the forks from a 250f or 450f? I know the clamps would have to match....right?Dry
No, just be sure to have them set up for your weight.
YamiRy239
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YamiRy239 1/31/2015 2:37pm
1/31/2015 2:37pm
YamiRy239 wrote:
IMO there are a few mods that are a must for the YZ250. - head mod to have the squish set and rechamered for either pump...
IMO there are a few mods that are a must for the YZ250.
- head mod to have the squish set and rechamered for either pump gas or race fuel whatever you are going to use. There is a lot of info on this over at thumpertalk. Makes the engine very crisp and a lot earlier to jet.

- set your timing. Almost all YZ250's come from the factory with the timing off. Again good info on thumpertalk on how to set it.

- flywheel weight. I use the GYTR off-road flywheel. It is 8.4 oz its heavy enough to make a difference, but not so heavy to loose throttle response.

-SSS suspension. I have an '03 that I put SSS on and a '13 as well. I actually like the feel of the steel frame with SSS better than my aluminum frame. Aluminum frame is more ridged.

A few have mentioned a big bore, but if you are going to race 250c you will have to keep the stock bore.
Derick5 wrote:
I was thinking about taking the SSS fork route on this bike, to be honest. Would I need the triple clamps as well? Also, I've head...
I was thinking about taking the SSS fork route on this bike, to be honest. Would I need the triple clamps as well? Also, I've head of people putting a YZ250F shock on this bike, I guess the shock is more plush and is overall better.

I used the forks, shock and triple clamps off of an '09 250f. To do the swap you need the forks, triple clamps, front axle, wheel spacers and caliper bracket. Rear shock optional, but recommended. If you get the triple clamps off of a 250f you will have to swap your '03 stem into the 250f clamps. The 450f clamps bolt right on. The steering stop on the steel frame is a little to short and will need to be lengthened to have enough contact area with the stops on the newer clamps. If it is not extended it could push past the stops. Any SSS fork, shock and triple clamp from a '06-'09 250f or 450f will work as well as '06-'14 2 stroke.



Derick5
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Derick5 1/31/2015 6:11pm
1/31/2015 6:11pm
YamiRy239 wrote:
I used the forks, shock and triple clamps off of an '09 250f. To do the swap you need the forks, triple clamps, front axle, wheel...
I used the forks, shock and triple clamps off of an '09 250f. To do the swap you need the forks, triple clamps, front axle, wheel spacers and caliper bracket. Rear shock optional, but recommended. If you get the triple clamps off of a 250f you will have to swap your '03 stem into the 250f clamps. The 450f clamps bolt right on. The steering stop on the steel frame is a little to short and will need to be lengthened to have enough contact area with the stops on the newer clamps. If it is not extended it could push past the stops. Any SSS fork, shock and triple clamp from a '06-'09 250f or 450f will work as well as '06-'14 2 stroke.



Doesn't seem difficult, I'll keep that in mind!
I'm looking at a Vertex (or Vortex, whatever it's called) ignition box. Yay or nay?

Got the bike down to pieces ATM, getting ready to replaced all suspension bearings and wheel bearings.

Also soda blasting some parts


Thinking about getting some V-Force reeds...
DBerg
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DBerg 2/3/2015 12:09pm
2/3/2015 12:09pm
mxrose3 wrote:
If you don't already have them, get the SSS forks and clamps. Thank me later. The steel frame is better IMO. Also, Eric Gorr makes a...
If you don't already have them, get the SSS forks and clamps. Thank me later.
The steel frame is better IMO. Also, Eric Gorr makes a few big bore options.
I have to somewhat agree. I can't say with certainty which is better because I can only compare a steel framed 125 to an aluminum framed 250, so the power affects the handling but ergonomically I preferred the 125. Again, different bikes but just my view point.
I do have to disagree with Nystrom though. While running the stock exhaust I swapped to a V-Force setup and it was a night and day difference for me.
Derick5
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Derick5 2/3/2015 1:10pm
2/3/2015 1:10pm
General question about yz250 2 strokes. Do they have a broad powerband? My bike seems to hit good down low and mid but flattens up top. The PV is working just fine. Stock reeds, no cracks or chips. PC Platinum 2 with r304 shorty. Running 13/48 or 49 gearing.
mxrose3
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mxrose3 2/3/2015 1:29pm
2/3/2015 1:29pm
Derick5 wrote:
General question about yz250 2 strokes. Do they have a broad powerband? My bike seems to hit good down low and mid but flattens up top...
General question about yz250 2 strokes. Do they have a broad powerband? My bike seems to hit good down low and mid but flattens up top. The PV is working just fine. Stock reeds, no cracks or chips. PC Platinum 2 with r304 shorty. Running 13/48 or 49 gearing.
YZ250's have a fairly wide powerband, but if your used to a 4 stroke, it revs a lot quicker and you have to shift more.
If your used to riding a 125, the 250 will feel like its got no top end. That is the way they are designed.

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Derick5
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Derick5 2/3/2015 1:39pm
2/3/2015 1:39pm
mxrose3 wrote:
YZ250's have a fairly wide powerband, but if your used to a 4 stroke, it revs a lot quicker and you have to shift more. If...
YZ250's have a fairly wide powerband, but if your used to a 4 stroke, it revs a lot quicker and you have to shift more.
If your used to riding a 125, the 250 will feel like its got no top end. That is the way they are designed.
THANK YOU! That's what I was thinking but I didn't think it was true. I just ordered $300 dollars in parts. (Bearings, number plate, grips, and misc.) I'll change the forum topic to "YZ250 build" since that's what this will turn into. It'll be picture heavy, so stay tuned! Thanks for the input so far guys!
Derick5
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Derick5 2/3/2015 1:45pm
2/3/2015 1:45pm
This is where I'm currently at. Motor is back in the frame but forgot I was going to rebuild the darn thing, so I have to take it out again Pinch

Going to upload as many photos as possible guys, so bare with me. Still have somethings from the wish list to go on the bike, but have to take it a week at a time...maybe a little bit longer!















alexk417
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alexk417 2/3/2015 5:27pm
2/3/2015 5:27pm
I did a 2003 not too long ago.

I had race tech do my suspension (46mm kyb), vforce reeds with fmf factory fatty and silencer, jetted according to PC and that's about it. Other than some cosmetic stuff and adding OS front rotor. I thought the bike was really fast, but always wanted a newer yz250 just bc the aluminum frame is easier to upkeep IMO. Now I have a 2002 yz125, but love it.



fulltime wrench 2/3/2015 5:38pm
2/3/2015 5:38pm
alexk417 wrote:
I did a 2003 not too long ago. I had race tech do my suspension (46mm kyb), vforce reeds with fmf factory fatty and silencer, jetted...
I did a 2003 not too long ago.

I had race tech do my suspension (46mm kyb), vforce reeds with fmf factory fatty and silencer, jetted according to PC and that's about it. Other than some cosmetic stuff and adding OS front rotor. I thought the bike was really fast, but always wanted a newer yz250 just bc the aluminum frame is easier to upkeep IMO. Now I have a 2002 yz125, but love it.



Were you happy with the revalved 46mm forks? I have been debating on getting mine worked on or doing a SSS swap.

Sorry for the hijack OP, just a question I've had for sometime so I needed to jump at the opportunity.
Hondas4Life3
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Hondas4Life3 2/4/2015 10:10am
2/4/2015 10:10am
Regardless of what others say I'm a firm believer in v-force reeds. The difference it made on top end for a cr85 build I did was outstanding. Accompany this with porting (and a pipe that you already have) the bike will be a rocket.. IMO
Matt Fisher
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Matt Fisher 2/4/2015 10:47pm
2/4/2015 10:47pm
alexk417 wrote:
I did a 2003 not too long ago. I had race tech do my suspension (46mm kyb), vforce reeds with fmf factory fatty and silencer, jetted...
I did a 2003 not too long ago.

I had race tech do my suspension (46mm kyb), vforce reeds with fmf factory fatty and silencer, jetted according to PC and that's about it. Other than some cosmetic stuff and adding OS front rotor. I thought the bike was really fast, but always wanted a newer yz250 just bc the aluminum frame is easier to upkeep IMO. Now I have a 2002 yz125, but love it.



fulltime wrench wrote:
Were you happy with the revalved 46mm forks? I have been debating on getting mine worked on or doing a SSS swap. Sorry for the hijack...
Were you happy with the revalved 46mm forks? I have been debating on getting mine worked on or doing a SSS swap.

Sorry for the hijack OP, just a question I've had for sometime so I needed to jump at the opportunity.
A friend of mine is a Race Tech certified tech, he said the earlier open bath forks can be made to work very well.

For me, it's easier to swap out the fluid in open bath forks, thereby increasing the likelihood that I'll keep fresh fluid in them.
fulltime wrench 2/5/2015 5:18am
2/5/2015 5:18am
Matt Fisher wrote:
A friend of mine is a Race Tech certified tech, he said the earlier open bath forks can be made to work very well. For me...
A friend of mine is a Race Tech certified tech, he said the earlier open bath forks can be made to work very well.

For me, it's easier to swap out the fluid in open bath forks, thereby increasing the likelihood that I'll keep fresh fluid in them.
Thanks Matt.
alexk417
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alexk417 2/6/2015 3:47pm
2/6/2015 3:47pm Edited Date/Time 2/6/2015 8:01pm
alexk417 wrote:
I did a 2003 not too long ago. I had race tech do my suspension (46mm kyb), vforce reeds with fmf factory fatty and silencer, jetted...
I did a 2003 not too long ago.

I had race tech do my suspension (46mm kyb), vforce reeds with fmf factory fatty and silencer, jetted according to PC and that's about it. Other than some cosmetic stuff and adding OS front rotor. I thought the bike was really fast, but always wanted a newer yz250 just bc the aluminum frame is easier to upkeep IMO. Now I have a 2002 yz125, but love it.



fulltime wrench wrote:
Were you happy with the revalved 46mm forks? I have been debating on getting mine worked on or doing a SSS swap. Sorry for the hijack...
Were you happy with the revalved 46mm forks? I have been debating on getting mine worked on or doing a SSS swap.

Sorry for the hijack OP, just a question I've had for sometime so I needed to jump at the opportunity.
You know, I wish I could compare the revalved 46mm forks to the newer SSS, but I cant, because I've never ridden a newer yz. I will say it was night and day between stock if you don't decide to do the swap.
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Falcon 2/6/2015 4:57pm
2/6/2015 4:57pm
I may be able to give you guys some insight on the suspension, as I've had several Yamahas in a row from those years, including:
2001 YZ125
2002 YZ250
2003 YZ125
2004 YZ250F
2005 YZ125
2006 YZ250

(The '06 250 has the SSS suspension.)
I used to have Enzo revalve my suspension and I'd go with slightly stiffer springs (one step stiffer.) When I got the '06, the suspension felt so good, I didn't revalve it. I could probably go with slightly stiffer springs and it would be perfect for me, but it's close enough that I don't even care.
BoGT12
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BoGT12 2/6/2015 7:52pm
2/6/2015 7:52pm
The biggest difference I found was going to the 06 plus shock. Mine is mostly off road so I can't say for moto, but the 46 revalued I thought were great.

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