Two Stroke Motocross

Two Stroke Motocross Forum => Technical => Topic started by: snook620 on December 29, 2010, 08:36:17 PM

Title: interchangable yz cylinders?
Post by: snook620 on December 29, 2010, 08:36:17 PM
Ive got a 2000 yz125 (clylinder # 5HD00) that puked a crank. The cylinder has a few scratches and the head is pretty beat up. Does anyone know if any other year cylinder will work on a 2000. I know just about all of them will bolt up to the motor but Im looking for one that would use the same pipe and frame mounts as a 2000.

I know I can replace/replate the cylinder for $200 but then Ive still got a beat up head. I was thinking about just sending the cases and top end to Eric Gorr for a 144, that way everything (including the head) would be fixed. $500 for the whole service including the top end doesnt seem to bad.

I would still like to get away cheap with another top end if possable, any insight would be appreciated.
Title: Re: interchangable yz cylinders?
Post by: eprovenzano on December 30, 2010, 07:50:38 AM
I'm pretty sure the 99 is the same, but I'd check using Yamaha's part numbers cross references between different years.
Title: Re: interchangable yz cylinders?
Post by: snook620 on December 30, 2010, 08:07:35 AM
I'm pretty sure the 99 is the same, but I'd check using Yamaha's part numbers cross references between different years.

Im thinking your probably right, on Eric's website he has a list of extra cylinders for sale. The way he has them listed are from 96-98, 01-04, and 05-11. He must not have any of mine available right now.

What about triple clamps? Can I use a newer set on my 2000 chassis? I would love to run a set of 04 and up 48mm forks, stock clamps were 46mm untill 03.
Title: Re: interchangable yz cylinders?
Post by: Charles Owens on December 30, 2010, 01:05:10 PM
96-04 is the same cylinder, but in 02+ I believe they changes the exhaust outlet from male to female.
Title: Re: interchangable yz cylinders?
Post by: snook620 on December 30, 2010, 02:52:06 PM
96-04 is the same cylinder, but in 02+ I believe they changes the exhaust outlet from male to female.

I knew they are all the same bore but will those years (96-01) work with my motor mount and pipe?
Title: Re: interchangable yz cylinders?
Post by: Charles Owens on December 30, 2010, 03:13:31 PM
Yes. :) a 96-01 will work fine, you can even use a 02-04 if you grab the expansion chamber to match.
I put the Athena kit on my 97 YZ 125, and it required the 02+ pipe.
Title: Re: interchangable yz cylinders?
Post by: snook620 on December 30, 2010, 04:46:27 PM
Sweet. Thanks for the help!

Do you know if any of the newer triple clamps interchange also? I want to run the newer 48mm forks instead of the TRASHED stockers.



Title: Re: interchangable yz cylinders?
Post by: Charles Owens on December 30, 2010, 05:06:36 PM
That I am not sure about.
Title: Re: interchangable yz cylinders?
Post by: mj4trax on January 17, 2011, 06:50:28 AM
I have a similar question as I just tore down my '01 yz125 cylinder to find the plating worn off on the exhaust bridge.

I'm trying to decide between sending the cylinder and powervalves in to have the exhaust bridge widened (and PV's ground to match) or just pick up a different cylinder alltogether.

Is there any significant porting differences between any of the '96-'01 years. ..  or even on the '02-'04. ..  What years had the poor exhaust bridge like mine?  Did they widen the bridge for the newer models? 
Title: Re: interchangable yz cylinders?
Post by: mj4trax on January 17, 2011, 08:21:53 PM
One other question. ..   I may decide to go the route of a big bore cylinder.

If I jumped to an Athena 58mm bore cylinder, would it require the cases to be machined to fit, or is that a bolt-on mod? 
Title: Re: interchangable yz cylinders?
Post by: rbigair40 on January 19, 2011, 05:38:47 PM
bolt on
Title: Re: interchangable yz cylinders?
Post by: mj4trax on January 20, 2011, 12:49:23 PM
I ended up deciding to leave the bike stock size and cylinder and sent my OEM cylinder off for replating, welding to widen the exhaust bridge by 3mm and match grinding of the powervalves.  Can't wait to get it back!!