Jump to content
Sign in to follow this  

07 CRF 250 R exhaust valve spring question

Recommended Posts

I just got in a "new" '07 CRF 250R cylinder head with valves ,cam,etc. that I am currently setting the valve clearance and noticed how extremely easy it is to push down the exhaust valve with just my thumb! I was calculating for clearance on the ex. valve and noticed if I went up a size too big on my feeling guage size ,the valve would easily move.I have done valves on alot of the older rockers and never felt this...Is this the norm ?... Titanium valves run softer springs than steel/s-s correct...any ideas 

THANX

Share this post


Link to post
Share on other sites

You could have weak springs, wrong springs, etc. You can check seat pressure at installed height and the spring rate, if those check out, braaap.

Share this post


Link to post
Share on other sites

I just got in a "new" '07 CRF 250R cylinder head with valves ,cam,etc. that I am currently setting the valve clearance and noticed how extremely easy it is to push down the exhaust valve with just my thumb! I was calculating for clearance on the ex. valve and noticed if I went up a size too big on my feeling guage size ,the valve would easily move.I have done valves on alot of the older rockers and never felt this...Is this the norm ?... Titanium valves run softer springs than steel/s-s correct...any ideas 

THANX

 

Yeah something is wrong with that picture, it shouldnt be easy-especially on a exh valve to move it or push it down. I would not be running the engine like that, need to figure out whats going on there.

Ask whoever you got the new head from and see what they have to say.

Share this post


Link to post
Share on other sites

I thought I was being over cautious ,but rather be safe than sorry. I was thinking about running the old springs from the '04 (alot stiffer) but I am not sure if this area was modified before I got a hold of this bike(stainless with heavier springs,etc) ...looked up the parts between '04 -'07 and the intake valves are the same / intake springs changed ; exhaust valves are same / exhaust springs same but changed after a certain manufacture date. No word back from guy I purchased cylinder head from yet.... :banghead:

Thanx again for the input.

Guscycle

Edited by guscycle

Share this post


Link to post
Share on other sites

I thought I was being over cautious ,but rather be safe than sorry. I was thinking about running the old springs from the '04 (alot stiffer) but I am not sure if this area was modified before I got a hold of this bike(stainless with heavier springs,etc) ...looked up the parts between '04 -'07 and the intake valves are the same / intake springs changed ; exhaust valves are same / exhaust springs same but changed after a certain manufacture date. No word back from guy I purchased cylinder head from yet.... :banghead:

Thanx again for the input.

Guscycle

 

Are you sure its a new head and are you sure what year the head is?

If it really is an 07 head thats great but IMO its important to know what valves are installed. Does it have SS intake valves and springs or the OEM ti int valves and springs?

 

Like whatwentwrong said above the OEM exh valves are steel.

 

04-07 use the same int and exh valves, but in 08 the OEM exh valve specs were changed along with the springs, etc. but the OEM int valves stayed the same.

 

Post some pics if you can when you take it apart, you might be able to get some help and ID some of the parts.

Share this post


Link to post
Share on other sites

Heres some pics..I was told the blue colored spring that I have is suppose to be on the intake not the exhaust (as it was delivered to me) !?!? And the exhaust should be white (mines orange)!?!

IMG_0550.jpg

IMG_0542.jpg

IMG_0511.jpg

IMG_0541.jpg

IMG_0562 (1).jpg

Share this post


Link to post
Share on other sites

Have you been running that head with the springs you were describing? If so and nothing bad has happened I think you got lucky, better go buy a lottery ticket!

 

OEM springs are easy to tell apart, because the free length of the exh springs is approx 1/4" longer than the int springs.

 

The head in the pics looks just like a 06 head based on the ports. Im sure its not an 07R head.

Edited by TDW

Share this post


Link to post
Share on other sites

I haven't installed the head ...just getting the valve shimming done prior to install...FastHeads told me about the valve spring identification- never heard of orange code for springs(unless from aftermarket),just white for exhaust and blue for intake .

Share this post


Link to post
Share on other sites

..I thought this was going to be easy...yeah right,but these are interesting things I am finding out (and learning not to believe what some people are selling) some info on the "new " head that was to be off an '07:

Measurements;

Exhaust:

stem width =.176"

valve head diameter = 26.00 mm

valve length = 3.232 "

Intake:

stem width = .1960"

valve head diameter = 31.00 mm

valve length = 3.280"

 The pic shows the valve springs removed from the "07? head -the left one was on the exhaust and right side one was on intake -THESE ARE BACKWARDS! I had a helluva hard time getting keepers off the intake and I noticed 1 of the stem seals was brown and the other 3 green.Looks like just to be safe I am going to put new seals and keepers on.I was able to decide what retainer caps belonged on it's corresponding valve.

Could this be an 08 head/ and if so will the head and all it's valve train work on my 04?

IMG_0563.jpg

Share this post


Link to post
Share on other sites

..I thought this was going to be easy...yeah right,but these are interesting things I am finding out (and learning not to believe what some people are selling) some info on the "new " head that was to be off an '07:

Measurements;

Exhaust:

stem width =.176"

valve head diameter = 26.00 mm

valve length = 3.232 "

Intake:

stem width = .1960"

valve head diameter = 31.00 mm

valve length = 3.280"

 The pic shows the valve springs removed from the "07? head -the left one was on the exhaust and right side one was on intake -THESE ARE BACKWARDS! I had a helluva hard time getting keepers off the intake and I noticed 1 of the stem seals was brown and the other 3 green.Looks like just to be safe I am going to put new seals and keepers on.I was able to decide what retainer caps belonged on it's corresponding valve.

Could this be an 08 head/ and if so will the head and all it's valve train work on my 04?

 

Yeah good thing you checked into this more because there was a definite problem waiting to happen with the springs being mixed up.

 

The 4.5mm stem size on the exh indicate an 08 exh valve or newer, 07 and below used 5.0mm sized valve stems.

 

With what youve found so far it seems like it would be a good idea to get everything- the head, all the valves and springs, valve seats and guides

 

all checked out before installing it and trying to use it, or maybe just getting your $ back and start fresh.

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  

×