kx450 head rebuild advice

nickg
Profile picture for user nickg
Posts
28
Joined
5/26/2021
Location
Spartanburg, SC US
nickg
2013 kx450, looking for a reputable pace to rebuild the head...or should i just buy a new one and not bother . Its complete but warped and needs guides, it runs but pushes coolant and has oil from the guides ...sucks cause i bought i as a good used one ...well it isnt so good.
should i cut losses and just get a new one? or rebuild it ?
|
Moto520
Profile picture for user Moto520
Posts
3388
Joined
2/4/2013
Location
Schaumburg, IL US
Moto520 7/27/2021 7:50pm
7/27/2021 7:50pm
Rebuild and make it better than stock. Talk to TZR Motorsports and get a quote to rebuild.
1
walent215
Profile picture for user walent215
Posts
2417
Joined
12/6/2014
Location
Ridgecrest, CA US
walent215 7/27/2021 8:42pm
7/27/2021 8:42pm
Can be rebuilt for less than new head / parts etc...
SilverSpurs
Profile picture for user SilverSpurs
Posts
561
Joined
2/5/2021
Location
Sarasota, FL US
SilverSpurs 7/27/2021 9:27pm
7/27/2021 9:27pm
LOL. How much is a complete new head?

It sounds like your head is soft and has problems that will require quite a lot of custom machining- guides and seats for a start- from a very experienced machinist/engine man.
2
kb228
Profile picture for user kb228
Posts
6161
Joined
1/31/2018
Location
Mansfield, OH US
kb228 7/28/2021 5:55am
7/28/2021 5:55am
Its cheaper to rebuild what you have. A new head is $500-600 and thats not including the valves either.

The Shop

See All »
Moto520
Profile picture for user Moto520
Posts
3388
Joined
2/4/2013
Location
Schaumburg, IL US
Moto520 7/28/2021 7:35am
7/28/2021 7:35am
TZR Racing did all the work on mine for my 2019 KX450....new valves.....new everything with some machining work on the lathe. This is everyday work for them. i'm picky as hell and my bike runs great right now.
1
willbilly
Profile picture for user willbilly
Posts
340
Joined
6/28/2016
Location
Corpus Christi, TX US
willbilly 7/28/2021 4:00pm
7/28/2021 4:00pm
If head is warped I would see if you can lap it into spec before I rebuilt it. May have to take off too much material.
1
Rider 5280
Profile picture for user Rider 5280
Posts
2014
Joined
11/9/2011
Location
Denver Metro, CO US
Rider 5280 7/28/2021 6:54pm
7/28/2021 6:54pm
willbilly wrote:
If head is warped I would see if you can lap it into spec before I rebuilt it. May have to take off too much material.
TZR would check this and have recommendations, too.
1
nickg
Profile picture for user nickg
Posts
28
Joined
5/26/2021
Location
Spartanburg, SC US
nickg 7/28/2021 8:07pm
7/28/2021 8:07pm
willbilly wrote:
If head is warped I would see if you can lap it into spec before I rebuilt it. May have to take off too much material.
Rider 5280 wrote:
TZR would check this and have recommendations, too.
i will contact them...thanks!
1
Sandusky26
Profile picture for user Sandusky26
Posts
2677
Joined
7/28/2021
Location
Eastern, NC US
Sandusky26 7/29/2021 1:08pm
7/29/2021 1:08pm
willbilly wrote:
If head is warped I would see if you can lap it into spec before I rebuilt it. May have to take off too much material.
Rider 5280 wrote:
TZR would check this and have recommendations, too.
nickg wrote:
i will contact them...thanks!
I have a 2020 RM-Z450 that needs new valves and the seats cuts. I’m not having any luck finding anyone local, are there places closer to NC that could do it?
nickg
Profile picture for user nickg
Posts
28
Joined
5/26/2021
Location
Spartanburg, SC US
nickg 7/29/2021 1:14pm
7/29/2021 1:14pm Edited Date/Time 7/29/2021 1:24pm
Rider 5280 wrote:
TZR would check this and have recommendations, too.
nickg wrote:
i will contact them...thanks!
Sandusky26 wrote:
I have a 2020 RM-Z450 that needs new valves and the seats cuts. I’m not having any luck finding anyone local, are there places closer to...
I have a 2020 RM-Z450 that needs new valves and the seats cuts. I’m not having any luck finding anyone local, are there places closer to NC that could do it?
i think i found a place to rebuild it...but in the mean time i ordered a new head....which like anything else i need...it is back ordered lol
walent215
Profile picture for user walent215
Posts
2417
Joined
12/6/2014
Location
Ridgecrest, CA US
walent215 7/30/2021 5:19am
7/30/2021 5:19am
Rider 5280 wrote:
TZR would check this and have recommendations, too.
nickg wrote:
i will contact them...thanks!
Sandusky26 wrote:
I have a 2020 RM-Z450 that needs new valves and the seats cuts. I’m not having any luck finding anyone local, are there places closer to...
I have a 2020 RM-Z450 that needs new valves and the seats cuts. I’m not having any luck finding anyone local, are there places closer to NC that could do it?
If you want to go with steel valves we can help with that but we are in California .
Sandusky26
Profile picture for user Sandusky26
Posts
2677
Joined
7/28/2021
Location
Eastern, NC US
Sandusky26 7/30/2021 7:05am
7/30/2021 7:05am
nickg wrote:
i will contact them...thanks!
Sandusky26 wrote:
I have a 2020 RM-Z450 that needs new valves and the seats cuts. I’m not having any luck finding anyone local, are there places closer to...
I have a 2020 RM-Z450 that needs new valves and the seats cuts. I’m not having any luck finding anyone local, are there places closer to NC that could do it?
walent215 wrote:
If you want to go with steel valves we can help with that but we are in California .
I plan on using stock valves again, and I’m looking for somewhere in NC to have the seats cut. I’ve called Barr’s Competition and everything but the turn around time sounded good. My goal is the send it out on a Monday and have it back by Friday.
Sandusky26
Profile picture for user Sandusky26
Posts
2677
Joined
7/28/2021
Location
Eastern, NC US
Sandusky26 8/1/2021 9:44am
8/1/2021 9:44am
Polishhammer wrote:
Check with Dean Baker in NC.
I called him and he never got back. I’m going to try again Monday, I also called Bundy Built and same thing.
garagedog
Profile picture for user garagedog
Posts
842
Joined
4/23/2014
Location
Tulare, CA US
Fantasy
722nd
garagedog 8/1/2021 2:20pm
8/1/2021 2:20pm
I've seen warped heads be more of a problem than just the cylinder surface warpage. Its rare, but if the cams rotate freely when torqued, then you may simple need surface lapping.

If money is not a hinderance, then just buy new and you will have no worries. Better selling point too.
willbilly
Profile picture for user willbilly
Posts
340
Joined
6/28/2016
Location
Corpus Christi, TX US
willbilly 8/2/2021 5:04pm
8/2/2021 5:04pm
I have had good luck with PRO 1. Seats replaced (copper) and valve guides.
LKHill
Profile picture for user LKHill
Posts
853
Joined
9/8/2020
Location
NY US
LKHill 8/13/2021 3:14pm
8/13/2021 3:14pm
Cut your losses. That thing sounds smoked.

Post a reply to: kx450 head rebuild advice