Planet Minis

zfiveO · 02-15-2006, 02:59 PM

Are these interchangable? Need to buy one for my Z and found a CRF head for cheap.

cg5 · 02-15-2006, 03:13 PM

if the cams are the same style, they are interchangible

zfiveO · 02-15-2006, 03:16 PM

Well, I don't know what year bike the CRF head came from but I know it will be bare? I would have to toss my cam, rocker arms, valves, springs, etc. in there from my 76 Z. Hmm, maybe I should just steer clear.

zfiveO · 02-15-2006, 03:30 PM

oops

jigracing · 02-15-2006, 03:36 PM

Cams are diff.

zfiveO · 02-15-2006, 03:38 PM

Well that blows.

Thanks for the info, guys.

jigracing · 02-15-2006, 03:40 PM

I have put a CRf head on my Z50 but I had the CRf cam for it.
I have a few heads here I'll look to see if I have a complete one.

SprNtrl · 02-15-2006, 03:52 PM

Your going to need a newer style roller bearing camshaft and a new cam gear. Everything else is interchangeable.

BartW · 02-15-2006, 04:00 PM

depending on the year Z50 you might also be running into a problem with the head having a different combustion chamber and smaller valves than some of the old heads.

thorwarrior915 · 02-15-2006, 04:52 PM

the "long rod" Z50 motors used a way different head than the newer ones. If you have a long rod Z50 motor which would be like mid eighties and up... you can run an XR/CRF head and piston. There is a lot of variation in the Z50 heads and pistons.

dirtbkr188 · 02-15-2006, 05:32 PM

I think you'll find that the valves will not seat properly in the CRF head, and I believe are a bit larger than the CRF valves. Also, with the '76 models, as Thor mentioned, they are a short rod engine, with a taller deck height on the piston. The piston will bottom out on the relatively flat surface of the CRF head, as the Z heads have a deeper combustion area, as BartW said. The '82 and newer engines use the long rod, with the shorter deck height.

turboglenn · 02-15-2006, 09:25 PM

the 2 posts directly above say it perfect. just contact a TB dealer and tell tehm what year head and what year bottom end your mating together and they can probably get you teh correct piston to clear everything

mikep · 02-16-2006, 12:39 AM

I've got a spare head for an early z but I'm in Australia. And they are different to crf's,

50mAfIa · 02-17-2006, 01:22 PM

Quote:

Originally Posted by dirtbkr188

I think you'll find that the valves will not seat properly in the CRF head, and I believe are a bit larger than the CRF valves. Also, with the '76 models, as Thor mentioned, they are a short rod engine, with a taller deck height on the piston. The piston will bottom out on the relatively flat surface of the CRF head, as the Z heads have a deeper combustion area, as BartW said. The '82 and newer engines use the long rod, with the shorter deck height.

not only are the valves different sizes, the stem size of the valves are different and u couldnt put them in if u wanted to

Vcook · 03-18-2006, 10:10 PM

So If I had the entire top end off say an '05 crf50 I could swap it to the tired top end of the '85 z50r I just got, right?

boy I wish I hadn't tossed the stock top end off my crf in the garbage when I went 88/head. I'm such a tard.

dirtbkr188 · 03-19-2006, 08:43 AM

Quote:

Originally Posted by Vcook

So If I had the entire top end off say an '05 crf50 I could swap it to the tired top end of the '85 z50r I just got, right?

Yes, you could use the CRF top end, but....you would lose a bit of compresssion due to the fact that the CRF piston is flat-topped, and the '85 Z50R piston has a very slight dome to it. You could use the CRF cylinder, and just buy a new Z50R piston, from DRATV

corybride · 02-10-2008, 05:11 PM

I know this is an old thread but I have some other questions...

I have a 94 z50 motor that I want to put in my 05 crf...

Are the bottom end of the motors the same? (94 vs 00+)

Will I be able to use a 00+ 88cc big bore kit?

Thanks for any help...

FastMC · 02-10-2008, 05:21 PM

Yes and yes you can...Same same.

dirtbkr188 · 02-10-2008, 05:25 PM

Yes, both bottom ends are 12V CDI ignition engines, and use the same aftermarket big bore kits. The only main difference between the two is that the countershaft sprocket shafts have different spline patterns.

02-15-2006, 02:59 PM	#1 (permalink)
zfiveO PM Newbie Join Date: Feb 2006 Posts: 30	Z50 Head Vs. CRF50 Head Are these interchangable? Need to buy one for my Z and found a CRF head for cheap.

02-15-2006, 03:36 PM	#5 (permalink)
jigracing Super Moderator Join Date: Jan 2004 Location: Hesperia, Ca Posts: 3,265 My Mood:	Cams are diff. __________________ Scott

02-15-2006, 03:40 PM	#7 (permalink)
jigracing Super Moderator Join Date: Jan 2004 Location: Hesperia, Ca Posts: 3,265 My Mood:	I have put a CRf head on my Z50 but I had the CRf cam for it. I have a few heads here I'll look to see if I have a complete one. __________________ Scott

02-15-2006, 04:52 PM	#10 (permalink)
thorwarrior915 3rd Gear Member Join Date: Dec 2003 Location: Malone, NY Posts: 4,549 My Mood:	the "long rod" Z50 motors used a way different head than the newer ones. If you have a long rod Z50 motor which would be like mid eighties and up... you can run an XR/CRF head and piston. There is a lot of variation in the Z50 heads and pistons. Last edited by thorwarrior915; 02-15-2006 at 05:33 PM.

02-10-2008, 05:11 PM	#17 (permalink)
corybride 3rd Gear Member Join Date: Jan 2008 Location: Towanda, Pa Posts: 1,240	Re: Z50 Head Vs. CRF50 Head I know this is an old thread but I have some other questions... I have a 94 z50 motor that I want to put in my 05 crf... Are the bottom end of the motors the same? (94 vs 00+) Will I be able to use a 00+ 88cc big bore kit? Thanks for any help...

02-15-2006, 03:13 PM	#2 (permalink)
cg5 3rd Gear Member Join Date: Oct 2005 Location: r. hill Posts: 1,700	if the cams are the same style, they are interchangible

02-15-2006, 03:16 PM	#3 (permalink)
zfiveO PM Newbie Join Date: Feb 2006 Posts: 30	Well, I don't know what year bike the CRF head came from but I know it will be bare? I would have to toss my cam, rocker arms, valves, springs, etc. in there from my 76 Z. Hmm, maybe I should just steer clear.

02-15-2006, 03:30 PM	#4 (permalink)
zfiveO PM Newbie Join Date: Feb 2006 Posts: 30	oops

02-15-2006, 03:38 PM	#6 (permalink)
zfiveO PM Newbie Join Date: Feb 2006 Posts: 30	Well that blows. Thanks for the info, guys.

02-15-2006, 03:52 PM	#8 (permalink)
SprNtrl 3rd Gear Member Join Date: Jul 2005 Location: Toronto, Canada Posts: 1,183 My Mood:	Your going to need a newer style roller bearing camshaft and a new cam gear. Everything else is interchangeable.

02-15-2006, 04:00 PM	#9 (permalink)
BartW 2nd Gear Member Join Date: Jan 2006 Location: Trenton, MI Posts: 746	depending on the year Z50 you might also be running into a problem with the head having a different combustion chamber and smaller valves than some of the old heads.

02-15-2006, 05:32 PM	#11 (permalink)
dirtbkr188 3rd Gear Member Join Date: May 2004 Location: New Jersey Posts: 2,971	I think you'll find that the valves will not seat properly in the CRF head, and I believe are a bit larger than the CRF valves. Also, with the '76 models, as Thor mentioned, they are a short rod engine, with a taller deck height on the piston. The piston will bottom out on the relatively flat surface of the CRF head, as the Z heads have a deeper combustion area, as BartW said. The '82 and newer engines use the long rod, with the shorter deck height.

02-15-2006, 09:25 PM	#12 (permalink)
turboglenn 3rd Gear Member Join Date: Jul 2005 Location: Omaha, NE Posts: 1,941	the 2 posts directly above say it perfect. just contact a TB dealer and tell tehm what year head and what year bottom end your mating together and they can probably get you teh correct piston to clear everything

02-16-2006, 12:39 AM	#13 (permalink)
mikep PM Newbie Join Date: Jan 2006 Posts: 85	I've got a spare head for an early z but I'm in Australia. And they are different to crf's,

03-18-2006, 10:10 PM	#15 (permalink)
Vcook 2nd Gear Member Join Date: Jun 2005 Location: Chicagoland Posts: 319	So If I had the entire top end off say an '05 crf50 I could swap it to the tired top end of the '85 z50r I just got, right? boy I wish I hadn't tossed the stock top end off my crf in the garbage when I went 88/head. I'm such a tard.

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02-10-2008, 05:21 PM	#18 (permalink)
FastMC Sporting the Merkin Join Date: Mar 2004 Location: boston area Posts: 5,072 My Mood:	Re: Z50 Head Vs. CRF50 Head Yes and yes you can...Same same.

02-10-2008, 05:25 PM	#19 (permalink)
dirtbkr188 3rd Gear Member Join Date: May 2004 Location: New Jersey Posts: 2,971	Re: Z50 Head Vs. CRF50 Head Yes, both bottom ends are 12V CDI ignition engines, and use the same aftermarket big bore kits. The only main difference between the two is that the countershaft sprocket shafts have different spline patterns.