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El Diablo Rojo

YZ250 trails conversion

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Quick question, aside from the internal gearing on a 250x seems like only the head/CDI/powervalve actuator are the only differences.  I'm not going to split the cases at this point so I'd think these other mods would be pretty affordable, but are they necessary?

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Are they necessary? Depends on how good of shape you're in. In my early 20's I loved the stock yz for tight single track.That explosive power came in handy. Now, not so much. As far as the power valve goes, many including myself are removing a washer on the x to wake it up a little. But out of all those mods you mentioned, if you're going to do one thing, pass on those and get an 18" rear wheel.

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9 minutes ago, Clutch44 said:

Are they necessary? Depends on how good of shape you're in. In my early 20's I loved the stock yz for tight single track.That explosive power came in handy. Now, not so much. As far as the power valve goes, many including myself are removing a washer on the x to wake it up a little. But out of all those mods you mentioned, if you're going to do one thing, pass on those and get an 18" rear wheel.

Thanks, already have the rear wheel and a 9oz flywheel. So I'm not 20 LOL would you suggest the other mods?

Edited by El Diablo Rojo

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1 hour ago, El Diablo Rojo said:

Thanks, already have the rear wheel and a 9oz flywheel. So I'm not 20 LOL would you suggest the other mods?

Fixing the squish in the head is always good. You can have them add or subtract volume from the dome if you want. You can try to run it with the tps disconnected, I've never done this but I've heard it makes it more mellow and is easy enough to just try.

Also, IF you want to adjust the power valve, there's a whole 20 something page topic about guys trying to make their yz's into the x. Halfway through that topic it turns into guys with an x trying to make it open more like a yz (which is what I preferred.)

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No one has mentioned the suspension,

stiff MX settings more often than not will have you bouncing off typical trail obstacles (deflection) rather than absorbing them,

negatively affecting the handling, traction and comfort.

Successive small sharp hits (rocks & roots) require different internal valving than what is ideally set up for mx track jumps.

Edited by mlatour
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3 minutes ago, mlatour said:

No one has mentioned the suspension,

stiff MX settings more often than not will have you bouncing off typical trail obstacles (deflection) rather than absorbing them,

negatively affecting the handling, traction and comfort.

Successive small sharp hits (rocks & roots) require different internal valving than what is ideally set up for mx track jumps.

Forks and shock are going to Racetech for exactly that right after the holidays.  The suspension was going to be gone through anyway since the guy who owned the bike before me weighs over 60lbs more than me anyway.  Think I'll get the X head (they are actually cheaper than having the stock head reshaped) and retard the timing a couple of degrees and see how she runs.   

 

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What year YZ250 are you converting? (steel or aluminium frame)

 

Edited by mlatour

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I would get the R-tech head over the stock X head. The 5WM X head (Same as 99-02) has way to much volume and would need to be cut. I traded a guy, the E-line stator I had, for a complete top end w/PV and both stock and R-Teck heads. The volume between the 99-02, and 15-20 X 5WM, and the R-Tech is significant. If you give me a day to dig them out, I'll shoot some pics and show you what I mean. 

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18 minutes ago, YZDOC said:

I would get the R-tech head over the stock X head. The 5WM X head (Same as 99-02) has way to much volume and would need to be cut. I traded a guy, the E-line stator I had, for a complete top end w/PV and both stock and R-Teck heads. The volume between the 99-02, and 15-20 X 5WM, and the R-Tech is significant. If you give me a day to dig them out, I'll shoot some pics and show you what I mean. 

Thanks man I'm in no hurry.

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4 hours ago, El Diablo Rojo said:

Forks and shock are going to Racetech for exactly that right after the holidays.  The suspension was going to be gone through anyway since the guy who owned the bike before me weighs over 60lbs more than me anyway.  Think I'll get the X head (they are actually cheaper than having the stock head reshaped) and retard the timing a couple of degrees and see how she runs.   

 

How so? I see the x head on sale for $111.60 when you can get yours cut for $60-100. Plus, my x head had a squish of .108, no bueno. And like YZDOC said, it has too much volume, in my opinion.

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8 hours ago, Clutch44 said:

How so? I see the x head on sale for $111.60 when you can get yours cut for $60-100. Plus, my x head had a squish of .108, no bueno. And like YZDOC said, it has too much volume, in my opinion.

Who did you send your head to for <100? The prices I've seen have been 150+

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6 hours ago, El Diablo Rojo said:

Who did you send your head to for <100? The prices I've seen have been 150+

A local ktm mechanic did mine for $60. Seeing that you are also in California you shouldn't have a problem finding someone. I will send you a PM.

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0293CE5D-2359-4F3B-BEAA-42C57FA7605E.thumb.jpeg.9b1704f38685edc60ddb3e6f409c8684.jpeg

Stock 5WM YZX head. 

4F62F398-A9F2-45B1-AD19-9E260EB7D420.thumb.jpeg.62102512fa7f83c19b18b01aa46972f7.jpeg

Stock 5UP

That lip around the edge should be 1/2 that to correct squish. 

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Doc I think you might have them backwards. The bottom one looks more like an X head.

As far as prices go Apex is the cheapest in the country, for a full squish correction and re-chamber back to the proper volume. I think he's doing it for $70. I also think he's doing it on borrowed equipment. I can't touch that. I charge $100, which is really to low for time involved. On a real head mod you are looking at a lot of time and effort to get them just right and that doesn't account for the time you've invested in coming up with a good cut. People don't realize what has to go into designing a properly cut head. If you think it's cheap and easy then go buy the equipment see for yourself.

If you just want the deck shaved then yeah, any machine shop can knock .035" off a YZ and get your squish in the ballpark. But, you're going to have a two wheeled grenade unless you live in Denver.

Just saying.

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36 minutes ago, 218 said:

Doc I think you might have them backwards. The bottom one looks more like an X head.

As far as prices go Apex is the cheapest in the country, for a full squish correction and re-chamber back to the proper volume. I think he's doing it for $70. I also think he's doing it on borrowed equipment. I can't touch that. I charge $100, which is really to low for time involved. On a real head mod you are looking at a lot of time and effort to get them just right and that doesn't account for the time you've invested in coming up with a good cut. People don't realize what has to go into designing a properly cut head. If you think it's cheap and easy then go buy the equipment see for yourself.

If you just want the deck shaved then yeah, any machine shop can knock .035" off a YZ and get your squish in the ballpark. But, you're going to have a two wheeled grenade unless you live in Denver.

Just saying.

Nah, I have those right. The 5MW ZYX head is on my bench, and I had to dig out the 5UP from the boxes in the back of the shop. I almost thought I took them all to AZ. 

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1 hour ago, 218 said:

Doc I think you might have them backwards. The bottom one looks more like an X head.

As far as prices go Apex is the cheapest in the country, for a full squish correction and re-chamber back to the proper volume. I think he's doing it for $70. I also think he's doing it on borrowed equipment. I can't touch that. I charge $100, which is really to low for time involved. On a real head mod you are looking at a lot of time and effort to get them just right and that doesn't account for the time you've invested in coming up with a good cut. People don't realize what has to go into designing a properly cut head. If you think it's cheap and easy then go buy the equipment see for yourself.

If you just want the deck shaved then yeah, any machine shop can knock .035" off a YZ and get your squish in the ballpark. But, you're going to have a two wheeled grenade unless you live in Denver.

Just saying.

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Here's what I would do with that bike:

a. Suspension, suspension, suspension suspension.  Get a good revalve (respring if needed) for your riding conditions.  Everything else you do will seem like a TOTAL WASTE OF MONEY compared to suspension.  The stock suspension is going to beat you silly on the trail and make your life miserable.  A good revalve will get you 97% of the way there to having a great high performance trail bike.

b. 18" wheel.  Lots of nice tire options with the 18", and it will help the ride.  If you can lace your own, the Tusk rim/spoke kit works great with the stock Yamaha hub for about $130.

c. Don't worry about the engine if it runs fine.  It has way more power in every area of the powerband than you will probably ever need.  A FWW is good, but a throttle cam system (e.g., G2) is a better bang for the buck.   It will keep you from killing yourself in the tight stuff.

d. Steering stabilizer.  It will keep you from killing yourself in the fast stuff, and when your bar tags a tree in the tight stuff.  This last one is really important for me, but I certainly understand that people differ in their opinions on stabilizers.  Folks complain about the price, but I actually think it's far better money spent than most of the silly mods people do to their bikes.  I have had my stabilizer for over 10 years now.  It is currently rotated between three bikes (two YZs and a KTM), and has been used on every single bike I've owned in the last decade.  How many dirt bike products have that kind of versatility and value?

Edited by rpt50

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1 hour ago, rpt50 said:

Here's what I would do with that bike:

a. Suspension, suspension, suspension suspension.  Get a good revalve (respring if needed) for your riding conditions.  Everything else you do will seem like a TOTAL WASTE OF MONEY compared to suspension.  The stock suspension is going to beat you silly on the trail and make your life miserable.  A good revalve will get you 97% of the way there to having a great high performance trail bike.

b. 18" wheel.  Lots of nice tire options with the 18", and it will help the ride.  If you can lace your own, the Tusk rim/spoke kit works great with the stock Yamaha hub for about $130.

c. Don't worry about the engine if it runs fine.  It has way more power in every area of the powerband than you will probably ever need.  A FWW is good, but a throttle cam system (e.g., G2) is a better bang for the buck.   It will keep you from killing yourself in the tight stuff.

d. Steering stabilizer.  It will keep you from killing yourself in the fast stuff, and when your bar tags a tree in the tight stuff.  This last one is really important for me, but I certainly understand that people differ in their opinions on stabilizers.  Folks complain about the price, but I actually think it's far better money spent than most of the silly mods people do to their bikes.  I have had my stabilizer for over 10 years now.  It is currently rotated between three bikes (two YZs and a KTM), and has been used on every single bike I've owned in the last decade.  How many dirt bike products have that kind of versatility and value?

Suspension is going to Racetech in January (see earlier post)

Have 18" wheel (see earlier post)

Steering stabilizer, funny I have one on my other bikes and never thought about it for this one! Now I have LOL

Bike screams I'm not looking for more power just a little better low and more linear power. 

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