Want to beef up the low end on a 2001 CR125

[oldguy]

Last fall we talked to Eric Gorr about how to improve the low end response in thekids 2001CR125 cheaply. He suggested putting the exhaust manifold from a 2002 CR125 on. Well we finally got around to it yesterday and the results were great :yeehaw: . Thekid was testing it in the backyard and his first reation was look out holeshots.
Totally cost after purchase and shipping from Service Honda $35 and about 30 minutes.

 

[Moto Squid]

hey old guy...is he going to be racing @ gravity again? What classes, I seem to be thinking it is 125jr but have a foggy memory. what about C?

 

[oldguy]

He will be in 125 Jr maybe a couple C's as well. Definately will be at Gravity it is his favorite track.

 

[enduroman]

Hey Old Guy,
That sounds like a mod I could do to my son's 01 CR125. Would you have part numbers handy, so I could order it? Plus any tips on any problems you encountered when you installed it, would be appreciated. Thanks

 

[oldguy]

Enduroman
Exhaust flange (joint,EX. PIPE) 18352-KZ4-L20
Rubber exhaust ring (GASKET, EX. Joint) 18291-KZ4-700
Metal seal (SEAL, EX. JOINT) 91304-KZ4-L11
You could probably get by without the rubber o-ring and the metal seal but it isn't a bad idea for about $7 to get em.
The flange is a bolt on (3 bolts) 5 minute fix. Pull the 2 springs off, remove the pipe from the cylinder, unbolt the old flange and then bolt on the new one. The flange is about 1/4 inch longer so once you replace the pipe and springs you will have to loosen the bolts where the pipe braces go to the frame- 2 spots (1 by the expanaion chamber and one right in front of the pipe/silencer joint.
Total parts and shipping from service honda (DRN sponsor :thumb: ) $37.87

 

[Nevada Sixx]

i wonder if there is a mod lke that for the 01 cr 250?

 

[enduroman]

Thanks Old Guy! That is just the info I needed. Appreciate the help!

 

[CRrider125]

i just ordered the flange. i hope it's as good as you say it is.
whats the difference? shape?size? or what?

 

[oldguy]

1/4 inch longer and has an obstructed lower quadrant

 

[trevor_zr600]

can comeone draw out what needs to be done to make one for my bike i have a lathe that i cna use and a milling machine so draw it out someone u say it has an obstructed lower quadrants wats thatdraw it please

 

[Moto Squid]

when you match the manifold to the cylinder the holes are not exactly the same (I think this is what you're talking about oldguy) , I've done just the opposite and put an 01 on my 02. All you got to do is take a dremel and do a little bit of grinding.

 

[oldguy]

Moto squid it matched up perfectly for us.

 

[motometal]

is that metal gasket a thin steel band? if so, you may try leaving it out and using black high temp silicone...it won't leak no matter what, and is cheaper

 

[oldguy]

Yes that is the thin metal gasket

 

[evworld]

Will you be able to run pump gas with this mod.?? I run pump gas now.

 

[oldguy]

Yes it will not change the compression so whatever you run now will still work the same

 

[motoman542]

will that mod work on a 2000 cr125

 

[Racercr125r]

Yes the flange will work on the 2000 CR125. I have one along with a reed spacer. This 2 worked good together and helped out my bottom end a lot.

 

[evworld]

I tried the mod today. It did beef up the bottom. But, my jetting is all messed up. I didn't have time to play with it other than the air screw. It helped some but not much. I was going riding so put the old stuff back on. What Jetting did you have to use. mine is 40pilot, 3clip, and 380main.

 

[CRrider125]

i just added the reed spacer and the new flange today and it made the bike feel like it had NO power! could it be my jetting or what? it acted like a 65

 

[oldguy]

We didn't change the jetting at all. Right now he is running a 400 main not sure on the clip or pilot. We had richened it at the end of last season because of cold weather (which still won't leave :( ).
CRider you will probably have to play with jetting with the reed spacer (not sure which way I have never put one on). When you had the carb off did you move the float at all or could rersidue in the bowl clogged a jet or vent?

 

[evworld]

If anyone tries this and can figure out the jetting please post. The jetting on mine after I started the bike was way off. I couldn't get the bike started and had to catch in gear. The bike was spot on before I installed the flange. I replaced with orginal flange so I could go riding and it was right on again.

 

[Moto Squid]

how in the heck can a 5mm longer flange make a bike go from running awesome to not starting?

CrRider, if the bike feels like a 65 that is an indication of quite severe lean jetting...

 

[evworld]

I wish I new why a longer flange screwed up the jetting. I know I don't as much about bikes as most of you on here. All I can say I'll leave it off tell I have more time to screw with the jetting. If I can figure it out I'll let anyone who wants to know what I did.

 

[enduroman]

We got the new flange installed this weekend on my son's bike, and it ran great! No changes to jetting needed on ours. I think I will try the reed spacer next. We may make this CR have a little bottom end power after all...... Thanks again for the help Oldguy!