01 Cr125 Bottom Hit (none)

[JANDERSON]

Ok, here goes: I ride this 01CR125 in the woods, tight trails, engine is tight (less than 20 hours on original top end), mods include PC pipe, PC spark arrestor (repacked fresh). I've gotten advise on jetting from many of the readers and I've tried a multitude of combinations ie. pilots from 37.5 to 60 and all inbetween, mains from 360 to 390 same as before, 2068, 2070, 2170 needles clipped from 1 to 3, A/S from 1 to 2.5, mucho variations. 32:1 HP2 w/93pump, BR9EG and BR8EG and 600 ftSL.
My issue is no bottom hit (and excessive spooge which I can live with). I feel air may be the issue. Without major mods to the engine I want to know if anyone has had this same issue and any luck finding the low hit. I have heard of using the v-force low tension reeds and cutting the slide. My belief is the reeds will allow the engine to gulp more air when initial load is placed which may be my cure. The slide cut could cure some spooging but then I may run too lean with gas to air ratio (I'm slightly afraid of seizure). Anybody with real results?

 

[marcusgunby]

Its very hard to get more bottom out of a 125, nearly all mods add power above 8000rpm which isnt where you want it.V force on a low setting with a 02 reed spacer will help as will a 7mm powervalve stop pin spacer.A cometic base gasket with 2 head gaskets is also advisable.Cut the slide by 0.5mm(you wontr seize a bike from a lean slide and anyway the std one is very rich) and with those mods i would think it would pull well for a 125.

 

[JANDERSON]

Motomad, not really bubba...I also ride a YZ125 that pulls hard on the bottom and does not act anything like the CR. I also ride a CR250 that pulls my "small" bottom around too well. Just because I'm 43 years old does not imply I'm a large spode, oh no, and I've been riding for 3 decades now so I think I got some of this "figered" out. Now back to eating my bonbons, ha ha.

Marcus thanks for the info. I'm gonna try the v-force first and then I'm gonna try the slide cut, probably up to 1 mm. I want to get this thing breathing better.

 

[honda62]

Hate to say this but youll never find the bottom-end that your looking for.Been there done all that the 7mm spacer actully made my bike run worse. the only mod that I didnt try was the cut slide.But the vforce give it slightly more which is more than what it currently has but has a tendency to wind the crank and cause lots of problems Watche 2 01cr125 an 1 02Rm125 cranks wind then blow after the v-force.plus it really gives you more mid to top.I have a 01cr125 to and the only way you'll get the bottom you want is with a port job.You should do like im doing though get a 03 yz125, YZ250F or CR125 heard its a all new engine this year. If the engine is almost as good as a YZ or KTM I think I might stay on aCR

 

[JANDERSON]

When the YZ250F first came out I was excited, now I've kinda mellowed on having one, starting them seems to be a BIG issue (unlike the new CR450). Who knows maybe I will get one but I sure love the way my CR125R sounds and runs (except for the bottom). My YZ125 is sooo different, it's got plenty of bottom-mid-top, it's probably the best 125 I've ever ridden. I'm really getting tired of my son laughing at my CR125R, he thinks it's a joke although he enjoys abusing my clutch whenever I'm not looking. He's a tried and true yamaha man!

I think I'll leave it alone and enjoy it the way it is. Thanks for the advise.

 

[marcusgunby]

I rode a 250f and it was a good bike but nothing special-it had more bottom than a 125 but the top was flat-it felt slow compared to my cr.The one place it was good was out of a slow corner leading upto a big hill.It felt just as heavy as a 450(which i think it is?)and starting them after a stall is just a nightmare.I will regret the day i cant ride a screaming 125 2 stroke.

 

[Mxrracer973]

Well on my 2000 cr 125 it hits good all around but it hits best from mid to top I have bills pipe, fmf shorty silencer, delta v-force high setting tmr cylinder head work and fresh bottom end also runs on c-12 with stock 13-52 gearing, now with that done and when i had 12-50 gearing my bike had so much bottom it wasnt even funny it hit hard bottom all the way through but lacked a liltle top just a lilitle and but with stock gearing its awseme top but lacks bottom but not much i will probabbly end up swicthing to a 53 also when i first got my bike when it was stock i had a 12-52 crazy heh yes major bottom no top lol, but first things i would do is to get the bike jetted properly then I would do gearing it really makes a differnece.....

p.s I know my pipe and silencer set up is crazy but it works

 

[KTMKyd]

Umm, would a PC R (short) series silencer help at all?? I mean I know it does add a little low end having more back pressure....

But my advice is worth what you pay for it...

 

[Rockey5000]

Try a PC Shorty Silencer and gear the rear sproket down one or 2. (from a 51 to a 52 or 53)

 

[CR-For-Ever]

Wait 52 rear on 2000 CR is stock I think cause that's what I got on mine...

My friend is in love with my CR he has a very junky 94 KX125 he said my CR had great bottem I find it not to have a whole lot but a killer mid!