02 Cr125 is fast-revisited

[marcusgunby]

I got to go out on a friends 02 today-he installed a vertex full race piston(says its for a Husky CR on the box) and a SRS shorty tailpipe and the thing just flies now-it comes out of corners better than my 01 race bike and it only has a bit less top end.The engine sounds soo much less rattly and the silencer sounded lovely-really impressed.I could clear jump easlily that before was a do or die job.
Jetting only need to drop one on the main for the cold Uk weather using super unleaded.

 

[alanreeves]

Can you tell any difference between unleaded and super unleaded?

 

[marcusgunby]

My 2001 Cr would not run properly on std unleaded i was playing with the pilot circuit all day-went back to super and it was back to mormal.

 

[mxracer724]

Marcus, if you have ridden an 02 YZ125 would you say that with those mods the 02 CR125 is as fast as the 02 YZ125? Also how much does that Vertex full race piston cost, and what is Super Unleaded? Is that 92 octain or race fuel?

 

[marcusgunby]

Im glad you brought up the topic of the 02YZ125-the modded Cr seemed to me every bit as fast as the YZ maybe a tiny bit less bottom but for our tracks i dont think the difference will impact any. The full race vertex piston in the Uk costs £5($7.50) more then the normal vertex.It is still well priced.
Super unleaded is equal to your 92octane i beleive-basically our best pump gas.

 

[<HONDA>]

;)

I have a 2002 cr125 as well and i am looking for some good mods to it.
I was thinking about getting it ported and polished but im not sure how much better it will make it.

Also what is the best piston to put in it?
And i've never heard of that pipe u mentioned (SRS) is it UK?

 

[cr-man]

SRS products are imported in the U.S. by Hot Boost Telephone is 631-725- 5726 website for SRS is www.srsracing.it they have some neat products. their CR125 slim ring piston is $100 in the U.S. I think that's the piston Marcus is talking about.

 

[mxracer724]

Thanks Marcus. Now I have to reconsider my new 125 I'm going to get before next season. If the CR with those mods is as fast as the YZ I will probably get it because I was sitting on a 02CR125 at my local shop and it fits me better than the 02 YZ125, but my only problem with it was the engine was supposed to be weak, but I don't think that will matter when I'm done setting it up for racing. I plan on getting an aftermarket pipe and silencer (not sure which ones), getting a Pro Circuit Cylinder & Head mod, Vertex Full race piston, and I want some aftermarket reeds but I am not sure what ones(Could use some advice).

 

[mxracer724]

Accually I'm not sure what mods I want because I don't even know exactly what goes with the Pro Circuit Cylinder and Head mod, but I figured it was like porting and I supply my own piston.

 

[marcusgunby]

SRS do have pistons but thats not the one i used-if using the SRS piston i would reccomend the std type flat top -not the racing version-these are reccomended to be replaced at 7hrs i think and have seen them brake at 12hrs.The normal ones will last 20hrs at expert level.

MX racer i would not go for porting as the 02Cr comes ported for top end -there are many ways to get different types of power without resorting to PC.Tell us the type of power you are after and the info will come.

The v force reed blocks are IMO one of the best bangs per buck of all mods-more power from just above the low end to max rpm.

IMO with a good piston/shorty tailpipe/v force this bike could do well upto (not at)national level.
If more is needed a bigger carb could be used.

 

[mxracer724]

I would like to get more power everywhere but mostly focus on more bottom. I would like 2-4 more hp's on top, I don't know if this is possible to do and still get more bottom. But I was looking at the fmf dyno tests after putting on the FMF SST pipe and silencer and it gained more power everywhere. This was the 2001's though. The 2002 dyno's aren't on there yet, but basicly I am looking for more power everywhere, but mostly focusing on low end power.

Thanks for the help

 

[marcusgunby]

For your needs i would go for the vertex piston(full race)
Shorty tailpipe
V force reed block(01 model with the rubber boot modified to match the reed block opening)-do a search on the 01/02 Cr125 for loads of past info.
Cylinder lowering 0.3-0.5mm(depending on how much bottom end you want) with the head modified to suit.
This should give a nice boost to bottom end and more power overall.
On my 01 i had 35.8 hp(up 5 hp) with more bottom end than std but i think the 02 has more potential and has a better powercurve.
If you do these mods and want more top end a 38mm carb would be next.

Ive seen independant tests on the FMF SST pipe on a 01 CR and it didnt gain as much as the website suggests-way overpriced pipe and the 01 would detonate badly unless richened with the SST.Also the SST tailpipe sounded horrible IMHO.On CRs the tailpipe is where the gains are-no front pipe does much at all.

 

[mxracer724]

Marcus thanks a lot, I'm not much of a mechanic, so I really thank you for helping me out. also 5 hp gain! That is great. About lowering the cylinder 0.3-0.5mm how do I do that? Can I have a shop do it, or do I send it to someone, or is it pretty simple and can I do it myself? As I said I'm not much of a mechanic, but if it is pretty simple I can probably do it.

Also where can I get info on the Vertex full Race piston? Do they have a website?

Thanks again I really am happy with all the help you have given me and this is the last of it that I need to know. I should be able to take it from here. Thanks.

 

[shaggy829]

hey marcus
i have got a 01 cr 125 it is 2mil over ported and head done for race fuel
all done by eric. mx intermediate usage .
my question to you or any one with a suggestion is would a keihin pwm 38
be a good choice for a carb . also have a mikuni tmxs off of a 00 yz 125
that is bored to a 37mil .:think

thanks guys

 

[marcusgunby]

MXracer for lowering the cylinder any good machine shop can do the work but ensure they are competant as its easy to wreak the cylinder-Eric Gorr is IMO the best person to go to for cylinder+head work.

The vertex piston is available from any vertex stockists as its basically the Husky CR125 piston-i dont know of places near you-can any memebers help here?

Shaggy ive never worked on a PWM only the PWK-the PWK requires a 99 reed manifold to make it fit as the outer bore of the carb is bigger than a TMX.Basically offer it up and see if it fits-if it does then it- when jetted will give about 1hp more than the 36mm std.
The 37mm mikuni will bolt straight up and is a good choice for the Cr-you should get a small increase across the range-37mm carbs is what most tunes use on the CR.I like the 38mm carb as it smooths the power-if you like a hit then the 37mm may be better.

 

[mxracer724]

Thanks again Marcus, When I get it I will be doing that stuff too it. I should be getting it in Febuary and no later than March. I don't know or think that there is any Husky dealers around my area, but I'll call all my local shops and see if the can get it for me.:)

 

[<HONDA>]

Hmm

Should i get a SST pipe then? and what is the best tailpipe for this since the tailpipe is the largest improvement? so milling the cylender only improves bottom right? But it must take away from something. What do u mean by husky? is that just the type of cr125 piston thet vertex makes? the husky cr125 full race piston? well i have about $1000 dollars saved out of my own money for some goods mods for my bike and im only 14 so i want to spend my money wisely. So give it to me straight the best mods thanks :)

 

[MXP1MP]

Hey MXRACER724 where in washington do you live? if you live over here on the west side of the state, or if you'd be interested in going ridding with me I'll let you try out my '02 yz125. My bike is mostly stock other than a few minor tweaks to the jetting and gearing added two teeth to the rear and it really hooks up on the bottom now. You have a bike i'd be really interested in trying out a yzf250 :) email me or private msg if your interested.

 

[NO HAND]

on the V-Force, do you guys run hi or low tension?

 

[marcusgunby]

Honda -i personally would not get the SST-it does add power but at many $$$$$$.As for the silencer i love the doma(available from Grant langston racing ive read).You can just cut down the std silencer (do a search on 'cutting down silencer' for full instructions).But it never sounds as good as a Doma or SRS.DEP make nice silencers(another euro pipe) but i dont like PC as they are too loud.Euro pipes have to comply with lower noise regs than FMF and PC.

Lowering the cylinder doesnt necessarily mean any loss anywhere.If the ports are tuned to work at peak efficiency at say 13000rpm but the rest of the engine is tuned for a peak of 11000rpm then lowering the cylinder may give more bottom/mid and top end.This is what tuning is all about-making sure each component peaks at the same rpm so all components compliment each other.Eric Gorrs website has all the tuning info needed to understand the basics of this interesting area-his books are also like a bible to most-ive been reading his work since 1990 and its the best info available and with it you could build a engine to compete at any level.My 2001 was mostly done to his specs and it had more power everywhere than std.If anyone interested to see the dyno charts e mail me.

The vetex piston is available from any dealer that stocks vertex-not just husky(husqnarva) dealers-i will try to get the part no soon.

No Hand-BTW how did you choose that name? the reed setting i left as it came-high tension i think.

 

[marcusgunby]

Pistons are available here but dont order till i get the part no as its not obvious which one it is.

http://www.sudco.com/vertex1.html

I must be mad gone into the freezing garage (half naked)at 11.54pm and got the part no:
On the box it says 'Husqvarna WR125 97-01 CID 22600A 53.95'
so on sudo it must be the 626-729-can someone phone sudo and confirm the part nos match the description on the box.

 

[KiwiBird]

marcusgunby wrote

I must be mad gone into the freezing garage (half naked)at 11.54pm

LOL! In 9 months this will seem normal!!

 

[<HONDA>]

Sorry for asking so many questions but i am totally lost as to why there are husky cr125 pistons and just cr125 pistons? whats the diff?:uh: were talking about a honda right?

 

[01HondaCR]

Husky calls there bikes CR just as Honda does. If I am reading correctly Marcus is talking about putting a Husky Cr125 piston in a HondaCR125. Don't hold me to that though I could be wrong. You'll have to wait for Marcus to confirm.

 

[NO HAND]

Originally posted by marcusgunby
No Hand-BTW how did you choose that name?

lol..I was practicing no hands landings at that time. It was fun until I started to look like someone planting carrots with a dirtbike helmet:confused:
Thanks for the info;)