'00 cr125 mods?

C

clown

Member
Jan 5, 2006
25
0
Hi, i am have been reading the archives on mods for cr125s, but i am a bit confused now!

Reeds & intake manifold- what year is the best reed cage and intake manifold? what is the best to put in a '00? about the reed spacer, should i keep this or remove it?

Cylinder head- ive read 2000 has the most potential, is this still true?

Piston- what is the best piston to put in? ive read a race vertex piston for a husky cr125 is good?

Carburettor & air boot- I am getting a 38mm carb soon, so what is the best airbox boot to put on?

Cylinder shortening & thinner base gasket- Will increasing the compression take alot of top end power on a stock cylidner head? wont port timing be affected and performance reduced?

Are there any engine parts from different models that i should replace with my stock parts? (manifolds etc)

I cant afford performance reeds, porting or pipes yet, and am about to do a top end rebuild, so i need to no whats best to do while the cylinder is off.
Any help is greatly appreciated!!!!1
 

marcusgunby

LIFETIME SPONSOR
Jan 9, 2000
6,450
2
If it was me i would just sell it and buy something else(anything) its honestly a real waste of time and money to tune a cr125-harsh but true.
 
M

MX851

Member
Jun 14, 2005
62
0
If I were you I would first get my suspension revalved and respring for your height and weight and riding type. After you do that I would save up and look into a aftermarket exhaust system, reed system, and engine modifications.
 
C

clown

Member
Jan 5, 2006
25
0
''If it was me i would just sell it and buy something else(anything) its honestly a real waste of time and money to tune a cr125-harsh but true''

Im not doubting you, but dont cr's around this year go very well once modified?

If i were to sell it, what bike would you reccomend i get? (can afford around a 2000 model)
 
F

flattie

Member
May 19, 2005
148
0
marcusgunby said:
If it was me i would just sell it and buy something else(anything) its honestly a real waste of time and money to tune a cr125-harsh but true.
Click to expand...


dont take two-stroke tuning tips from somone who rides a fourstroke!
 
F

flattie

Member
May 19, 2005
148
0
 
F

flattie

Member
May 19, 2005
148
0
i have a 96 model cr125 fitted with a 00 model cylinder, the best bang for the buck with that cylinder is erics top end porting and 2mm over wiseco piston. with that set up it alows me to pin the throttle and not let go. no need to worry bout shifting gears to keep in in the power band. run a gear lower than you think and wick it wide open. his top end porting will make it a screamer. i also am running a pro circuit pipe and v-force reeds. if money is a concern take more time to properly tune your bike. 00 is a good year for that cylinder design. but when you get ready to spend your money take it to eric first.
 

oldfrt613

Feeble Sponsoring Member
Member
Jun 29, 2005
443
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You may want to check Eric's "garage sale". He very well may have a refurbished cylinder already ported for a realy reasonable price - check out thread in Erics Forward Motion forum.
 
C

clown

Member
Jan 5, 2006
25
0
i was looking at eric's site, and am asking about cylinder kits.
For that $475, the cylinder is bored to 133cc or 144cc, ported, polished, new gaskets and re-plated? is the piston, ring, pin and clips included?

he said the 144 kit when ported for top end the rings need to be replaced every 5 hours, i like top end power, but i dont like replacing rings every 5 hours :nod: so would the 133 kit ported for top end need the rings replaced so often? what is the reccomended ring replacement for the 133 kit?

Would a stock or mildly modded rm or yz etc be faster than a 133 kit ported for top end power?

flattie, honestly do you think it was worth the money?
 

marcusgunby

LIFETIME SPONSOR
Jan 9, 2000
6,450
2
If you got a newer YZ 125 /ktm etc(for your $500) it would go as good as a cr133 anyway and its resale would be higher, a modded cr133 goes very well, i put up a dyno of one with over 38hp at the rear wheel, it was terrible to ride however.
 
F

flattie

Member
May 19, 2005
148
0

first things first, 00 model can only be bored to the 134cc, eric charged me 450 for porting, head work, pistion kit, and gaskets. all inclusive kit. the 134 kit does not require the more frequent ring changes. stick to what ever brand your comfortable with, theres not enough power diff between them to make that big of difference. and yes honestly bar none worth it. like i said before the motor will not quit pulling it revs forever nothing better in my book
 
C

clown

Member
Jan 5, 2006
25
0
hey marcusgunby, what year was that cr? what else had been done to it?

38hp at the wheel is about 43-45hp at the crank?

also, what made it so terrible to ride?
 

marcusgunby

LIFETIME SPONSOR
Jan 9, 2000
6,450
2
it was a 2001 with a 00 EG 133 kit ported for top end, it had about 43hp at the crank i suspect, the problem is the engine is based on a RS125 road bike and thats how it likes to be ridden, i had to use 1st gear in some corners my 250f would easy pull 3rd.It was just plain hard work and slow in lap times.
 
M

morganbike

Member
Jan 31, 2005
24
0
Clown,
12 Months ago I asked Marcus and the people on this forum the same questions.I have had the last season to tune the
00-02 CR 125 motor. Depends on how you ride but we found that :

Keep the standard Reed cage and inlet manifold.Carbon reeds are better than plastic.Honda ones are fine.
NO reed spacer = improved Top end takes bottom away.
With Spacer =oposite no top bit of bottom.

Put a Wiseco GP or Race piston in it and always use Honda Gaskets.

The 38mm TMX carb will make an improvement on top end on a ported cylinder.It makes it hit harder once in the power band. Standard motor wont breath enough to make a gain.

Taking metal off the cylinder base (lowering) will take the over rev away and narrow the power band.Lifting it makes it rev.Standard is best overall.

The standard exhaust manifolds differed by 5 to 10 mm between 00-02 but its trial and error.Only a good racer would notice the difference and fitting a pipe for REVS,BOTTOM OR OVERALL improvement is better.The seal between pipe and manifold is very important as you can loose 3-4 hp here.Oil residue around this area is a sign its not.

At the end of the day its the overall package you need to improve on and The 134 will give you what you want with no fuss and still remain reliable.
Its like the new 250 four strokes.The improvements start with the head and then altering the other parts to suit that modification and riding style. Heres a link to look at

http://dirtrider.net/forums3/showthread.php?t=110534

Consider this.
Eric can sell you a used cylinder
add to this
Head and Power Valve mods
Gaskets
Piston Kit
Shipping

I know we are not to advertise here but have a look at this I have for sale.

http://dirtrider.net/forums3/showthread.php?t=127092

It is for a 2001 Honda CR 125 and will sit perfectly on your 00.
I was in the same boat as you 4 months ago and I went and spent $950 on it but never used it.It is a BRAND NEW barrel,head and valve done to 134cc.
Have now sold CR 125.

E Mail me at p.greenwo@tesco.net if interested.

Phil

http://i26.photobucket.com/albums/c122/morganbike/bigbore1.jpg
http://i26.photobucket.com/albums/c122/morganbike/bigbore5.jpg
 
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C

clown

Member
Jan 5, 2006
25
0
morganbike, i would genuinly be interested if i had the cash, but am a bit broke after getting the bike :fft:

With the pistons, i had a look at the wiseco site, and cannot find any 'race' pistons. I found the gp piston and the pro-lite.

Should i go with a piston for the cr125, or go with the husky piston?

Does the gp piston have any real performance gains over the pro-lite or stock piston?

Do the race/gp pistons last just aslong as the pro-lite/stock pistons?

Sorry for all the questions :) and thanks for the help!!
 
M

morganbike

Member
Jan 31, 2005
24
0
The GP piston is very light and strong for full on 100% racing.It will be thrown in the bin after 2 hours.I have about 6 used ones on the shelf over 9 months!.Unless you race dont go there.The Vertex is the same.
I can see my sons bike loose performance as soon as the piston has done its best.

Why put a husky in it.Yes it helps only on stock motors to stop it making that low rev rattle noise and keep the noise down.It fits tighter but only on a new bore.

Wiseco make the piston variations by testing and to sell product variations depending on your budget.

Go to Service Honda or Thumper talk OEM parts and fo $90 you can buy genuine Honda head $7 and base £5 gasket,piston $45 ,rings $8.50,small end $5,pin $10 and circlips $3.

It sounds to me this is the way you should go on your budget to keep the motor sweet.If your cylinder bore is unhealthy dont bother at all. Sell it or invest
As Marcus said get shut of it and step aboard the new generation of engines.I love two strokes but they are on their way out and I have forced my son to go four stroke.Its a new learning curve again but interesting and expensive.Look at the 2002 Yamaha 250F.Its the cheapest way of upgrading.
Phil
 
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C

clown

Member
Jan 5, 2006
25
0
does the pro-lite wear out any faster than a normal wiseco?
 
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V

viking20

Sponsoring Member
Aug 11, 2002
428
0
Just buy a Wiseco pro-lite , or a Vertex. The Vertex for the Honda can be ordered without the holes at the sides. This will give you a bit extra at low revs , but remember we are talking minute changes here ! Same with all the other mods , nothing will make this bike the fastest on earth. The Honda is a fine bike , and unless you are able to ride it near its full potential ,it will do just fine.....Lots of guys didnt have any problems riding these bikes , untill they read /heard about how weak it is ?
Keep the top end fresh , change the oil ,airfilter, and tires frequently and enjoy the bike.
Ride as much as you can afford , you dont need to spend all the money modding he bike.
FWIW , we had the EG 133 on my sons bike , it was an improvement for sure , and fun to set up.Great value , its just not nessecary !
 
C

clown

Member
Jan 5, 2006
25
0
thanks viking20! i knew this wasnt the fastest bike power wise when i bought it, but some people led me to believe it wasnt worth riding :|
 
I

ihone

Member
Jan 10, 2006
49
0
I'm currently riding a 00' CR125 also. I haven't really done much to it in the lines of hardcore performance but....here's what I've done thus far. It seemed to make it just about right for me. By the way, I'm not racing...just riding for fun and the most competition I see is just trying to show the guys up @ work when riding w/ them. lol

Pro-Circuit works pipe and R304 shorty
Wiseco Pro-lite piston kit
a good jetting (via my bud, he's a wiz)
a bit hotter plug
36:1 mix

and that was all we did and it runs alot better, and lets just face it.....It's still a 125, so you're not going to get screaming performance compared to a 2-fitty but in my opinion...it's plenty for me.
 
C

cr125-

Member
Jan 10, 2006
2
0
I'm currently riding a 00' CR125 also
Click to expand...

me too :)

There not the fastest bike in a straight line, but they handle and jump very nicely. Unless you can ride the bike as fast as it can go, its fine even when stock.

Hey ihone, can i ask you what numbers or letters are on the 'caged' side of your airbox boot?

I bought my bike with a 250 airbox boot and carby,
Fatty pipe and powercore 2 silencer. Its fine for me. Are you using the br8eg plug ihone?
 
I

ihone

Member
Jan 10, 2006
49
0
the plug is a BR9EG, and the letters on the boot are KG4S. Dunno wtf that means but those being the only letters that I found in 10 seconds, I'd guess those are the ones you were looking for.
 
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