CR125 low-end power?

**krasher** · 28th March 2009, 23:53

Hullo. Perhaps I am chasing the impossible however, I want more power at the low end. What can be done?

Honda CR125 2002

She goes like stink in powerband but is pretty shy until she hits it.

Also, what gas should I be running. I am currently using 91 and 50/1 fully synthetic.

What options do I have?

**barty5** · 29th March 2009, 07:10

most would be usein 96 to start with
what pipe and muffler you got can make a difference

**krasher** · 29th March 2009, 08:19

Stock exhaust with a med/small dent in it. Small leak too up by the motor. I think the seal might need doing.

Ok I will change to 96. I just ran out of mixed fuel so that's easy.

**honda_power** · 29th March 2009, 08:23

125s are made for top end, a pipes not gonna do fuck all for the cost of them, a flywheel weight would prob help a little though

**Rupe** · 29th March 2009, 08:28

Originally Posted by krasher

Hullo. Perhaps I am chasing the impossible however, I want more power at the low end. What can be done?

Honda CR125 2002

She goes like stink in powerband but is pretty shy until she hits it.

Also, what gas should I be running. I am currently using 91 and 50/1 fully synthetic.

What options do I have?

50/1 doesn't sound right, I'd say you'd fuck it in time running at that. I'd expect it to be 32/1 but wait to see if any owners know.

A pipe (fmf gnarly has great bottom) and muffler would help, and a flywheel weight. But it is a 125cc they don't have much bottom and you have to use the clutch a lot, but master it and you'll be a quick rider.

**driftn** · 29th March 2009, 09:00

Buy a 250.

**clmintie** · 29th March 2009, 09:13

I always run 32/1 in 96 (TTS with about 20ml of castor per 10l) in the KX125 and 85. My understanding is that less oil = richer mixture, so you may have lost that 'fat' feeling at the bottom. I'm only a slow old guy, but in my favour is the fact I only weigh 66kg, I find the 125 has plenty of mid range (and a clutch that screams "abuse me" in several languages )

The copy/paste from Holeshot below is interesting.....
..................................

Here is what we run in Shaun Fogarty's 2008 KX125 race bike running a FMF Factory Pipe and Powercore 2 Muffler.
Main Jet 390
Needle-jet 6CHJ10-84
Clip 3
Pilot 37.5
Air Screw 1 3/4
Fuel 98 octane
Fuel/Oil 28:1 full synthetic Silkolene

**Buddy L** · 29th March 2009, 09:18

I ran my 02 on 96 octane and 32/1 mixture, it had a pro circuit pipe.
One if found out the main jet was too big and replaced it with standed sizing the bike had a heap more bottem end and ran alot better.

**cheese** · 29th March 2009, 14:50

I got a flywheel weight if you want one? $100. Its for a 250 though

**Danger** · 29th March 2009, 16:02

Originally Posted by clmintie

I always run 32/1 in 96 (TTS with about 20ml of castor per 10l) in the KX125 and 85. My understanding is that less oil = leaner mixture, so you may have lost that 'fat' feeling at the bottom.

Sorry mate you got that backwards, less oil = richer mixture due to the fact the fuel flows through the jets quicker, common mistake. Regardless I would run 32/1 in a 125 and a flywheel weight would kill any bottom end it has so flag that idea too.
If you must ride a 125 but want more bottom end look at the YZ or the KTM, they have the most bottom end out of the 125's. The CR even modified will not run as strong as either of them, although the '05 and up with a FMF fatty and a shorty was better, but still not up to the YZ, RM or KTM.
There are 144 kits for many of the 125's, these will give you more torque.
Other wise make sure your top end is fresh and try going up a couple of teeth on the rear sprocket.

**krasher** · 29th March 2009, 16:55

Thanks for the replies! I better look into my mix. Don't want to break my bike!

I know that 125's don't have much bottom end but it seems it has less pep than another 125 that I rode. It has more top end though.

I'll try changing my mix for starters.

**clmintie** · 29th March 2009, 19:21

Originally Posted by Danger

Sorry mate you got that backwards, less oil = richer mixture due to the fact the fuel flows through the jets quicker, common mistake.

Oops, my bad..... Wrong again....

**vr4king** · 29th March 2009, 19:34

Abother 125 rider here........LOVE your clutch but punish it too and keep it on the pipe,If you cant keep it just of the pipe but NEVER let it bog down as it will stop and trust me thats no fun half way up a hill climb

**theblacksmith** · 29th March 2009, 20:57

Ive been running 32-1 in my kdx250.
Ive also changed to 95/96 fuel and am now using Maxxol racing castor oil(Cant mix with petroleum based oils).Goes really crisp and heaps more bottom end torque but stinks for miles man!