Jump to content

Buy a new head?

Recommended Posts

Hey guys!

I bought a 2005 CRF450X that is just fantastic but it certainly has been used - but got a great deal on it! First thing I did was shim the valves. I ended up with 1.2mm shims which I know is about as low as you can go. The shims resulted in 0.18mm and 0.17mm  of clearance (on the loose side of spec). 

I took the bike out for a weekend trip, put about 6 hours on it and checked the valves yesterday. They are at 0.16mm and 0.14mm now. Obviously they are shot. So time for some new valves. I was planning on replacing with kibblewhite so I don’t have to deal anymore and while I’m at it, do the piston, cam chain and tensioner. 

So here is a little extra tidbit of info: I noticed the valve bolt threads have been helicoiled. When I took the valve cover off the first time, I noticed this and have been VERY careful putting the bolts back in (Setting the torque wrench to 5 ft lbs and not even engaging it). Well, putting the valve cover back on, the small bolt stripped out.

My question to you guys is: should I just get a new head? My plan is to replace all 4 valves with SS so I’d have to pay a machine shop to cut 4 valve seats as well as re-tap all three valve cover bolts or helicoil them again and just be careful. Amazon has an OEM head for $315.  What do you think a machine shop would charge for the work needed? Would it last / be better than OEM? Just need advice. I will do all the work except for the machining.

Thank you so much for any input. 

Share this post


Link to post
Share on other sites
10 hours ago, 1hp said:

call AS racing (661) 993-0466. they have an excellent reputation here.

Thank you! They are only about an hour from me. I’ll keep them in mind. 

Share this post


Link to post
Share on other sites
1 minute ago, Jim Dettman said:

Big Bore Thumper's also has new heads all setup with SS valves for just under $600:

http://www.bigborethumpers.com/newheads.html

Jim.

This is probably going to be the way I go. I found CRFs Only had the same thing for $750 which seemed a bit expensive. At $550, it may be worth it. The kits for all four valves with springs and everything go for about $300 so they are charging $250 for the head and all the labor. Not sure I can beat this price. Thank you so much!

Share this post


Link to post
Share on other sites

I bought a new head this year for a 2015 450R. Added new SS valves and springs for far less than a rebuilt worn head.

  • Like 1

Share this post


Link to post
Share on other sites
7 minutes ago, Leardriver said:

I bought a new head this year for a 2015 450R. Added new SS valves and springs for far less than a rebuilt worn head.

When you bought the new head, did it have the valve guides installed already or did you have to have them pressed in? Big Bore Thumpers has the head with SS valves already installed for $609 to my door. I think that’s gonna be my best bet. 

Share this post


Link to post
Share on other sites

A cylinder head can be had for just over $300, and 4 new SS valves and the new intake springs are maybe $200 more. As far as value, A new one is a much better deal to me. Yes, valve guides are installed.

  • Like 1

Share this post


Link to post
Share on other sites
You can rebuild your existing head for about $335...


Interesting! That includes SS valves/springs, but no new cam assume?

Share this post


Link to post
Share on other sites
40 minutes ago, BMRFlagstaff said:

head = apple

cam = orange

Understand that, was just clarifying, since there are a few package deals floating around. 🙌

  • Like 1

Share this post


Link to post
Share on other sites

Thank you everyone for the info, I now have my options... time to do some soul searching and just figure out what one I wanna take while I save up my pennies. Looks like my KDX200 is gonna get some miles over the next few months.

Thanks again!

  • Like 1

Share this post


Link to post
Share on other sites
21 hours ago, amcjen said:

 


Interesting! That includes SS valves/springs, but no new cam assume?

 

Correct... just complete head rebuild, valves, springs. seals, retainers, etc. and complete blasting, surfacing, seat cutting, assembly.

 

  • Like 1

Share this post


Link to post
Share on other sites
On 8/12/2019 at 7:06 AM, CRF DOC said:

You can rebuild your existing head for about $335...

Hi Doc, thanks for the info, I am going to PM directly with a few questions.

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:


×
×
  • Create New...