Posts
38
Joined
9/10/2015
Location
Cobb, GA, USA
Edited Date/Time
4/9/2016 8:26am
I just picked up a 2002 Honda CR125 for a restoration project. This bike will be ridden regularly, so I am trying to consolidate as much info as I can on the various motor mods to help make it at least somewhat respectable in that regard.
I have searched the forums and found some threads on the subject. However, with the exception of a few, many of them were from several years ago. I am curious to hear anyone's input on the matter - cylinders, pistons, cranks, manifolds, etc.
Going off of memory for what I have read so far:
the '02 bottom end can run the 96/97 HPP cylinders, which was a good mod.
the '07 crank (which is lighter) can be used in the '02 bottom end
the '04? carb manifold has a larger volume and when the '02 cases are matched up to it, provides an improvement
the '07 air box assembly offers better flow
If using the '02 cylinder, run the '01 exhaust manifold
the PWK carb
Also, does anyone have details on the bike that was built for Lamson when he ran the 125 in Hangtown...'07, I believe. The only thing I could find on it stated it was a long rod engine and combination of parts from the '02, '03, and '04 engines... all factory stuff, of course, but reportedly the best 125 engine Honda racing had produced.
I have searched the forums and found some threads on the subject. However, with the exception of a few, many of them were from several years ago. I am curious to hear anyone's input on the matter - cylinders, pistons, cranks, manifolds, etc.
Going off of memory for what I have read so far:
the '02 bottom end can run the 96/97 HPP cylinders, which was a good mod.
the '07 crank (which is lighter) can be used in the '02 bottom end
the '04? carb manifold has a larger volume and when the '02 cases are matched up to it, provides an improvement
the '07 air box assembly offers better flow
If using the '02 cylinder, run the '01 exhaust manifold
the PWK carb
Also, does anyone have details on the bike that was built for Lamson when he ran the 125 in Hangtown...'07, I believe. The only thing I could find on it stated it was a long rod engine and combination of parts from the '02, '03, and '04 engines... all factory stuff, of course, but reportedly the best 125 engine Honda racing had produced.
Mxking what pipe setup did you run on your hpp setup?
The Shop
DeCal Works Huge Plastic Inventory of UFO and Polisport kits.
Luxon 4-Post Bar Mounts
$189.95 - $239.95
Great looking bike. What plastics are those? That's the look I am going for with mine.
I'll try and find the thread I was reading, but I think I remember they suggested using a regular Pro Circuit pipe for an '02 model with the HPP set up, or even a stock '02 pipe. However, there were fitment issues and the pipe would need to be modified slightly. Apparently, Pro Circuit made some special pipes for the 2000+ model bikes that were running the HPP cylinders, but they are very rare.
From what I have read, the '02 cylinder can be made to work decently, but has an odd port arrangement where one of the ports is staggered 3mm higher. The 2000 model cylinder was regarded as being a better platform than the 2002 model. Also, I think the '02 model benefited from a 7mm bushing mod on the power valve linkage arm that helped keep the power valve closed tight and help boost low end performance.
I've been reading off and on the last few days and it's all starting to run together in my head. I'll try and go back and pin down some of the specifics from a few of the articles I found.
Thanks for the information on the bodywork.
I've run across the same findings with regards to the cylinders, some say the 00 & 02 are very capable, others say the HPP's are the way to go. I'm not looking to spend a lot of money on my project as well. It will just be a play bike. However, while I am rebuilding it, I at least want to make an effort to maximize what I can. I've ridden some Tom Morgan engines before, and they all ripped. My last few 2 strokes from back in the day had Eric Gorr engine mods, which I was very pleased with how they performed. I've seen comments here and there regarding the 134/139cc kits. They seem to be a good compromise for getting a little more torque out of them without losing too much of the 125 aspect.
http://www.ebay.com/itm/281968972539?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649
Make me an offer if you are interested.
Might've been dreaming, but i sort of remember reading something about someone using an 89 crank assembly in later cases, the crank ends are different so they had to put the 89 electrics on also, stator, flywheel etc.
02 Cr125-
96 Hpp top end with PV governor & arm
38mm PWK Airstryker carb
05+ airboot
05+ crank
modded 03 KX125 stock pipe
PC silencer
TX Race 2015 plastic kit.
Just put 2007 CRF forks on it.
I have both a stock and a 144 cylinder for it. Both run extremely well.
What intake manifold and reed assembly are you running? Which PC silencer, the standard or shorty? I take it the silencer is the one for the 02 honda?
Thanks.
97 HPP 139 cc big bore RPM 97 governer and linkage 99 powervalves
Boyesen rad valve has a bigger intake diameter
02 Plano Honda PC pipe made for the cylinder swap.
07 crank and bearings all OEM
07 air boot
38mm air striker carb
The bike ran really good for a cr 125. I will be honest though my 13 ktm 125 has a faster motor stock. I would just have to say technology differences.
only ol small problem is the bike would flatten out up top and that because of the big bore it really needed a stroked crank to go with the big bore.
Building a 01 cr 125..
Pc shorty silencer for an 02 Cr125. Bike sounds gnarly.
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