Jump to content
Sign in to follow this  

06 YZ250 awesomeness report- head question

Recommended Posts

We had our first date at the track Saturday and I'm impressed to say the least. It was more of a tighter type track with some big doubles and triples out of corners and generally not a track I was too fond of with my KX. All I did to the bike was put on some non bent bars, better chain, and that was it. It had a worn out front tire and a chunked 100 rear maxxis IT, can't get any worse than that I suppose. Stock suspension was a little soft so I had rebound all the way out and comp all the way in. I tried to put the PC pipe off my 02 on it but the header hit the frame and wouldn't seal up all the way. Whatever.

This thing hauls ass! Even with the PC2 pipe it still revved decent and the low and mid was just fat fat fat! I didn't open the carb but I know i'm rich. With the old gas from the previous owner it pinged a bit so I drained it and put in a mix of avgas and pump (about 1/3 avgas) and that seemed to do away with most of it.

Handling- It feels so light and agile I'm amazed. It carves corners like a dream. Even with the soft suspension it still performed amazingly well. Getting it flat over the big step up at this track is effortless. I can't wait to get the right springs put in this week. Even with the crappy rubbers on it still stayed pretty well planted and hooked up well. There's this triple step up step down right out of a 90 degree right hander and I tried all night to clear it but was just coming up short barely. Not bad considering the crappy 100 rear. Love it love it love it!

Now for the head question. I got an extra head with my 02 and it looks exactly like the 06 head but has different numbers: 5cU and below, 0G1

Any idea its a 99+ head? I also want to send it to RB for mods, can I just send it to him without the solders? Doesn't he have some sort of template? I really don't want to deal with the solders.

👍

Share this post


Link to post
Share on other sites

The solder is to determine how much needs to be cut. Every bike is different due to tolerance stack up from the factory. The exact same head on one bike might be .045" clearance at the squish, the other might be .060". You really need to measure make sure they can get it right.

Share this post


Link to post
Share on other sites
The solder is to determine how much needs to be cut. Every bike is different due to tolerance stack up from the factory. The exact same head on one bike might be .045" clearance at the squish, the other might be .060". You really need to measure make sure they can get it right.

Damn. So no way eh? haha Any idea what the numbers mean on the head?

Share this post


Link to post
Share on other sites

The numbers were/are from the respective model years. This works as long as one realizes 2003-2010 is the same model year with regards to the head.

The old head will be 1/2 cc larger in the dome area for slightly less compression. It is the one I would modify as it really does not matter when someone is cutting it anyway.

It might be fun to try and see if it reduced the detonation. It is still the head used in many foreign countries.

When we describe measuring with the soldiers, I think we make it sound ten thousand times harder than it is. In reality, it takes about 10 minutes.

Dont forget to check the timing first. I believe most of the 06's have been off by a small amount. This increases the detonation.

Share this post


Link to post
Share on other sites
The numbers were/are from the respective model years. This works as long as one realizes 2003-2010 is the same model year with regards to the head.

The old head will be 1/2 cc larger in the dome area for slightly less compression. It is the one I would modify as it really does not matter when someone is cutting it anyway.

It might be fun to try and see if it reduced the detonation. It is still the head used in many foreign countries.

When we describe measuring with the soldiers, I think we make it sound ten thousand times harder than it is. In reality, it takes about 10 minutes.

Dont forget to check the timing first. I believe most of the 06's have been off by a small amount. This increases the detonation.

Rc, are you saying the numbers indicate it being.the 98 head?

Yeah I guess its not too difficult I just wanted to ship it off ASAP. Do I have to have a dial indicator to check timing? Thanks guys

Share this post


Link to post
Share on other sites

Well now you:re getting all technical on us now. Solders and head mods and dial indicators...... you must be on a Yamaha now...👍

Glad you are having fun!

Share this post


Link to post
Share on other sites
Well now you:re getting all technical on us now. Solders and head mods and dial indicators...... you must be on a Yamaha now...👍

Glad you are having fun!

Hahaha it feels good! Sorry you left Shrub don't know what you were thinking:smirk:

Share this post


Link to post
Share on other sites
Rc, are you saying the numbers indicate it being.the 98 head?

Yeah I guess its not too difficult I just wanted to ship it off ASAP. Do I have to have a dial indicator to check timing? Thanks guys

No, not the 98 as it woudl be different enough to not fit. I think the spare you have is an 99-01 head. I dont have anythign in the garage to compare it to, but a part number search would be easy. No big deal. It might be a nice option to have. Besides, setting timing is as important, maybe more as it really works.

Share this post


Link to post
Share on other sites
No, not the 98 as it woudl be different enough to not fit. I think the spare you have is an 99-01 head. I dont have anythign in the garage to compare it to, but a part number search would be easy. No big deal. It might be a nice option to have. Besides, setting timing is as important, maybe more as it really works.

Yup just searched and its an 00 head. What a score, I was gonna practically give it away cause I thought it was a 98 head. Awesome. Gonna be sending out a head to RB!

Share this post


Link to post
Share on other sites

If the AV gas cleaned up the detonation my guess is your 2-3 degrees advanced roughly.. The cost of the dial indicator to performance ratio of tuning your timing will equate to good amount of power for the buck, more than any silencer.. My 06 was 2.5 deg advanced stock.. now its 2 deg ret.

Keep in mind you shoudl look to rejet if your changing your timing. At least try the needle and main after doing it to see if you can extract even more juice!

Share this post


Link to post
Share on other sites
If the AV gas cleaned up the detonation my guess is your 2-3 degrees advanced roughly.. The cost of the dial indicator to performance ratio of tuning your timing will equate to good amount of power for the buck, more than any silencer.. My 06 was 2.5 deg advanced stock.. now its 2 deg ret.

Keep in mind you shoudl look to rejet if your changing your timing. At least try the needle and main after doing it to see if you can extract even more juice!

Agree completely!

As far as the timing and soldiers go, the directions are slightly intimidating. It sounds a bit rocket science like and looks like it will take hours.

Truthfully, its none of that. Its not hard once your sitting in front of the motor with the proper supplies. And its probably the place to start, not the place to finish as I did. I have a feeling I would have been dollars ahead to start there.

True, neither mod was a 300cc big bore, but it would have saved several hundred on pipes. What good is worrying about exhaust when combustion is not happening properly?

Share this post


Link to post
Share on other sites

I need to get the head mod done on mine, sounds like it makes a decent difference in how the bike runs.

And thanks for the rad 2strokenut, I got it this morning in the mail already 👍

Share this post


Link to post
Share on other sites

What happened to the KX? I guess you're a Yamaha guy now. BTW now that youve had a newer KX, RM, and YZ, which one would you say is the best overall bike, or which one has certain attributes. I know the Honda 2T is a POS so no need for that one. I've got a 07 RM250 but a YZ or even KTM maybe in the future.

Share this post


Link to post
Share on other sites
If the AV gas cleaned up the detonation my guess is your 2-3 degrees advanced roughly.. The cost of the dial indicator to performance ratio of tuning your timing will equate to good amount of power for the buck, more than any silencer.. My 06 was 2.5 deg advanced stock.. now its 2 deg ret.

Keep in mind you shoudl look to rejet if your changing your timing. At least try the needle and main after doing it to see if you can extract even more juice!

Yeah I might just go buy miyself a dial indicator or just take it to a local engine builder and have him do it. I probably wont touch it again.

Agree completely!

As far as the timing and soldiers go, the directions are slightly intimidating. It sounds a bit rocket science like and looks like it will take hours.

Truthfully, its none of that. Its not hard once your sitting in front of the motor with the proper supplies. And its probably the place to start, not the place to finish as I did. I have a feeling I would have been dollars ahead to start there.

True, neither mod was a 300cc big bore, but it would have saved several hundred on pipes. What good is worrying about exhaust when combustion is not happening properly?

Exactly. I don't think I've ever bought a brand new pipe just used ones. I don't think 200 + is worth any of the performance gains. I found a guy on craigslist with a used works pc pipe for 80 bones.

I need to get the head mod done on mine, sounds like it makes a decent difference in how the bike runs.

And thanks for the rad 2strokenut, I got it this morning in the mail already 👍

Your welcome man, glad you didn't have to pay the 40 bucks for next day or 2 days whatever it was.

What happened to the KX? I guess you're a Yamaha guy now. BTW now that youve had a newer KX, RM, and YZ, which one would you say is the best overall bike, or which one has certain attributes. I know the Honda 2T is a POS so no need for that one. I've got a 07 RM250 but a YZ or even KTM maybe in the future.

I traded it for an 06 CRF450 then traded that for this bike. I really can't compare the two fairly because I never tried the KX just stock. The suspension shop I took it to effed up the suspension. I should of had my buddy do it right the first time. Oh well. Right now I really like how the YZ is stock. That says a lot right there. In order I would place them like this: YZ, KX, RM. But I think all can be equally good you just need to start with the suspension on the others. Both stock they were way to soft for any serious MX. The YZ is only gonna get better. The KX revs forever, handles great and was the most durable bike I ever had. The bike must of had over 250 hours on the stock engine. Never had any problems. And I'm not slow. I only had the RM for a few months until the stock piston came apart and I put a 265 kit on it, which I never got to run right. All 3 are awesome bikes. I'm surprised people say the YZ doesn't turn very well, it actually turns very well.

Share this post


Link to post
Share on other sites
I'm surprised people say the YZ doesn't turn very well, it actually turns very well.

In my opinion one of the reasons people say that is quite simple reason. The "YZ HI" handle bar bend has no sweep in it! With alot of the other bikes they have the sweep in the bars which makes it feel like you turn better.

Just somethign I noticed recently.

Share this post


Link to post
Share on other sites
In my opinion one of the reasons people say that is quite simple reason. The "YZ HI" handle bar bend has no sweep in it! With alot of the other bikes they have the sweep in the bars which makes it feel like you turn better.

Just somethign I noticed recently.

Interesting. I wonder what bar I put on? I couldn't see any markings besides Renthal. It does feel like a good bar. The last 3 bikes I had I ran the Easton bar setup and didn't take it off my KX. Don't remember the specs tho...

Share this post


Link to post
Share on other sites

Damn my Rm is in last place.👍

Glad you like the YZ, I have to try one out one day.

Share this post


Link to post
Share on other sites
Damn my Rm is in last place.🤣

Glad you like the YZ, I have to try one out one day.

It's OK. Soon he'll buy a 250SX and profess it to be the kingdog. Your time will come 'round. 👍

Share this post


Link to post
Share on other sites
Damn my Rm is in last place.🤣

Glad you like the YZ, I have to try one out one day.

I didn't really have the RM long enough to provide a good review. They are all pretty damn good

It's OK. Soon he'll buy a 250SX and profess it to be the kingdog. Your time will come 'round. 👍

Don't spoil my next test... haha

Share this post


Link to post
Share on other sites
Interesting. I wonder what bar I put on? I couldn't see any markings besides Renthal. It does feel like a good bar. The last 3 bikes I had I ran the Easton bar setup and didn't take it off my KX. Don't remember the specs tho...

YZ HI is very strait across, like no sweep, good height. Very similair to stock KTM. The henry/reed is a good compramise between all the bars. Kind of the middle bar. And the CR HI, Woods HI, Carmichael and RM HI/LO are the more mis matched configs.

Easton bars have way more options than the other companies, could be anything and could be non standard.

It's OK. Soon he'll buy a 250SX and profess it to be the kingdog. Your time will come 'round. 👍

Haha!!! That's pretty funny actually. But there is one thing. After riding all those Jap bikes, he may not be able to adapt to the "euro" feel (ergonomics) of a ktm/gasgas. It's a big difference. Depends what kind of person you are and if you one that can ride any bike or one that likes their bike a "certain way". I find with a lot of riders, they feel the YZ ergos are is easly adaptable.. I had 3 friends switch last year to the YZ 250. One honda, two KTM.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×
×
  • Create New...