Question about bore size on CR 125`s

[Gage`s Dad]

I was looking around on the internet for a head gasket and the part number I got (from the guy who sold us the bike) brings up a gasket for a 98-99 CR 125. I am going to put it on a 95 CR that has been bored out. Did the 98-99 models have a bigger bore size than a 95? The web site says the bore is 58mm and I think stock bore size for a 95 is 56mm ( I think).
Im new to all this kind of stuff and Im kinda confused :whoa:

Thanks in advance for any help...

 

[Matt90GT]

stock bore is 54 mm, and the stroke is 54.5. pretty square there. same bore size till the end of the bike in 07

GASKET, CYLINDER HEAD 12251-KZ4-701 $15.58

that is the OEM honda number for the stock headgasket and motosport.com pricing on it.
now if you have an aftermarket sleeve and piston to make it a big bore unit, you will need to match up the head gasket. largest bore I see is 56mm which is a 2mm overbore from stock on wiseco's site which is a 134cc kit. Wiseco will make gaskets, cometic and other companies make gaskets up to 2mm overbore. larger than that, you need to find out who made the piston to find the maker for the kit like a 167 stroker/bore kit on the bike. You can always contact Eric Gorr for more info, but be sure to know what piston is in there and the bore size before calling.

 

[Gage`s Dad]

I was told Eric Gorr prepared this top end Im talking about. I have a head gasket coming from Cometic. This bike is supposed to have a 150 kit on it. Im not even sure what that means.

Thanks for your reply.

 

[madmike90]

I was told Eric Gorr prepared this top end Im talking about. I have a head gasket coming from Cometic. This bike is supposed to have a 150 kit on it. Im not even sure what that means.

Thanks for your reply.

150 kit meaning 150cc rather than the stock 125cc

 

[Gage`s Dad]

So I should be able to buy a head gasket for a CR 150 and it will fit? Im going to try a search for the specs of the CR 150 and maybe the bore size will be there.

I just did the search and only found a CRF 150. Its a 4 stroke.
Is there a 2 stroke 150?

Again, thanks for your help.

 

[Pete Payne]

best bet , measure what you have and call Eric Gorr . Or www.ericgorr.com

 

[Matt90GT]

Honda did not make a CR150.

You need to call Eric Gorr for a replacement gasket

 

[IndyMX]

I don't think Eric ever made a 150 kit for a CR.. He told me that the best he could do on my CR125 was 134cc overbore.

Here's a thought. Since you claim Eric built the engine, and since Eric is still alive and doing business, and is very easily accessible from his website (www.ericgorr.com), why don't you contact him to see if he can supply the head gasket?

I know, that was way to easy.. Couldn't possibly work.

 

[DirTasteGood]

Honda did not make 2 stroke 150. Ktm does. I have heard of a 125 bored out to a 144, but it was sure pushing it. Just call up the guy for 5 minutes and get your answer. If youhave calipers, use them

 

[madmike90]

the only way i can see you having a 150cc kit on the 125cc is if the kit came with a shorter connecting rod to increase the stroke.

 

[Gage`s Dad]

I was told Eric prepared this top end. It has a after market crank and rods made by "Hot Rods". Foward Motion 150 kit.
I guess a call would be the best way to find out. I need a caliper.
Thanks again for all the help.

 

[madmike90]

I was told Eric prepared this top end. It has a after market crank and rods made by "Hot Rods". Foward Motion 150 kit.
I guess a call would be the best way to find out. I need a caliper.
Thanks again for all the help.

are you sure that the bike is not just stroked to 150cc and maintaining the stock bore of the 125cc cylinder?

 

[Gage`s Dad]

Im not sure about the stroke and bore. I do know the part # for the head gasket says 58mm. Thats what the guy that sold it to us told us to buy. My son ordered a stock gasket and its hole is to small, meaning it covered to much of the cylinder hole. Heres a list of all the mods it has....

Factory Connection woods suspension valving
Foward Motion cr150 kit
Hot Rods crank
Steahly Flywheel
V-Force Reeds
Boysen Magneto Cover
FMF Fatty Pipe
Answer Racing SA Muffler
A few other things like pegs, bars, skid plates, frame and pipe guards.
At the bottom of the ad it said
150cc overbore cylinder prepared by Eric Gorr at Foward Motion.
Im new to all this stroke and bore talk. I know what it is but have never really dealt with it before.
Thanks for all your replies
Sorry for the long read
EDIT:
It does have a stamp on the cylinder that says 124cm