2001 CR125 jetting - continued

[morg_nz]

Finally found time to have a look at my carb - after playing with the air screw and having to get it out to about 5 turns to make it run better.

Anyways - according to city honda in PN, the factory settings for a 2001 cr125 are as follows:

Main Jet 360
Pilot 50
Needle 3rd from top
Needle 6beg20-69

what i found in my carb however was:
Main Jet 350
Pilot 32.5
Needle On top
Needle 6beg21-68

any ideas what this means? from the position of the clip on the needle, i'd say that the last owner was trying to go leaner - which would fit with my impression of the bike being rather rich (a lot of black crap on the exhaust and a badly fowled plug).

I understand that having the needle on the top clip is not idea, so I should prob get a leaner needle that I can run in the 3rd clip or so? But how do I find out what needles are leaner, and where could I get one? (I cant seem to find anyone in nz who sells jetting stuff on the net)

Any help would be much appreciated - Cheers Morgan

[Jinxycat]

you could either,
1. buy the jets and needle from honda.
2. buy a dynojet kit or jd jet kit, these both come with jets,needle and full fitting and set up gide.

try your needle 3rd clip from top and see, glad to see you found the factory set up:scooter:

[Reckless]

Hey morgan
From the look of what you have written above your quite close to factory as long as the 32.5 figure is the size of the pilot.
You have similar settings except for a couple of clips leaner on the needle. I would be hesitant to go leaner than factory until you have checked the other things hereunder. The bike should go ok??

I'd be looking for another problem! ie, blocked vent hoses, broken or cracked carb boot, wrong float level, float needle valve not seating and leaking fuel, dirt some where, broken reads, leaking crankcase seals, Carboned up/jambed power valve, check and de-coke your pipe!

When was the top end done last?? Compression? And was the Power valve serviced?? Is it working properly?

Thoroughly clean every ventury in the carb, everything, set float levels, check float needle valve for seal, remove the vent hoses and clean, check as many of the things as you can (listed above) before you go buying leaner jets/needles than standard.

PS don't start new threads all the time, people offering fixes need to know the history or the advice you get may be false?
Previous thread http://www.kiwibiker.co.nz/forums/showthread.php/119209-2001-Honda-CR125-jetting

Thats my take???

Btw: Don't look for good power from a 125 way down low, but if you have a flat spot or a complete dead spot from zero throttle to say 1/4 or half its still the pilot circuit or something effecting it. IMHO!

Best advice I can give over the net??

EDIT: make sure the floats (or one of them) are not holed/cracked and filling with fuel?

OH shit forgot the first thing you should always try on a smoker LOL!! A fresh plug?

Thats my smoko well gone lol!! Back to designing additions!

[morg_nz]

Thanks for that reckless - will try another plug too.

MORE INTERESTINGLY THOUGH - I just put the carb back together (all i changed was the position of the clip on the needle - down to 3rd), and went to start the bike. it started first kick, but for some reason the clutch wouldnt disengage when i tried to ride it. any ideas what i've done, as it was working when i rode it into the shed the other day?

[Reckless]

Thanks for that reckless - will try another plug too.

MORE INTERESTINGLY THOUGH - I just put the carb back together (all i changed was the position of the clip on the needle - down to 3rd), and went to start the bike. it started first kick, but for some reason the clutch wouldnt disengage when i tried to ride it. any ideas what i've done, as it was working when i rode it into the shed the other day?

If you have moved the C-clip from the top of the needle down to the 3rd clip position, what you have done is raise the needle and let more fuel in? If you thought it was rich before it should be worse now? What has actually happeded I reckon (as long as it rides ok) is you have cleaned or fixed something un-knowingly with your maintenance regime. Probably the float needle seat or a blocked vent?? Often happens!

Clutch is a completly different problem. How often do you change your gearbox oil? Some do it every ride on a 125 but every second or third should be ok for trial riding. 125's give their oil and clutch asrsholes! Oil your cable, check its pulling ok. If its ok your gonna have to strip the clutch out and check the plates, springs and spacers for wear, check the widths with a micrometer against factory. Then look for notches on the clutchbasket which catch on the plates. You can gently file these smooth making sure all the basket teeth are the same width at the end. ie don't file the shit out of one of the clutch fingers so plates don't drive off them all evenly! you will only renotch the widest one really fast!

OK thats it for one day! You owe me a beer! I have to do some freckin wrok now LOL!!!

[Jinxycat]

Thanks for that reckless - will try another plug too.

MORE INTERESTINGLY THOUGH - I just put the carb back together (all i changed was the position of the clip on the needle - down to 3rd), and went to start the bike. it started first kick, but for some reason the clutch wouldnt disengage when i tried to ride it. any ideas what i've done, as it was working when i rode it into the shed the other day?

on the cr carb you can pull the throttle cable and the outer dosnt sit back into the carb top properly, it will if you grab it and push it in, just a cr thing to look out for as it wont run/start if this has happened

[morg_nz]

still having no luck with the clutch? any more ideas?

[Jinxycat]

does the basket fingers have notches, are the steals flat and not blued?

[morg_nz]

I havent pulled the clutch out yet - thats tonights job. but what confuses me is taht it was working perfectly when i put it away, then i started playing with the carb and now it doesn't work - im thinking i knocked something but i cant figure what?

[Reckless]

You could only have twisted or pinched the clutch cable making it inoperative when putting the bike back together.

Nothing you do to the carb can affect the clutch except for the above!

You best check the cable first as its sounding very much like you should be getting someone that knows bikes better to look at it for you?

But it could be coincidence and your clutch may a have failed just then?? We can't tell over the net?

[Jinxycat]

You could only have twisted or pinched the clutch cable making it inoperative when putting the bike back together.

Nothing you do to the carb can affect the clutch except for the above!

You best check the cable first as its sounding very much like you should be getting someone that knows bikes better to look at it for you?


But it could be coincidence and your clutch may a have failed just then?? We can't tell over the net?

yup, i agree with reckless, if it was ok before you pulled the tank off (i assumed the clutch was poked along with the jetting......that will teach me to assume) it is probably cable routing.:yes:

[morg_nz]

so i pulled the clutch apart last night - I think it was the springs that are the problem as I have an "old" cr125 clutch, and the springs in that are longer than the springs that i pulled out of my bike by about 1mm on average - which would account for why its not disengaging (i hope) so its a new set of springs - oh and the friction plates and steels looked in mint condition, no warpage or discolouration, nad the basket was sweet too. maybe the previous owner replaced the springs at the same time as the rest and they were just shit/the wrong ones?

anywhoms - after reading an ADB magazine i decided to lay the bike on its side to change the clutch (to save changing the oil at this stage). what is intersting though is that i've come back to the bike today, and all the gearbx oil is on the ground - it seems to have come out an overflow pipe. i didnt think there was an overflow from the bottom of he engine? or is there definately not one and i have a leak somewhere?

[B0000M]

isnt there an breather/ overflow from the top of the gearbox on those? at the back end somewhere

longer springs shouldnt cause it to not disengage, unless its preventing you from pulling in the lever.

things that cause poor disengagement are usually a worn clutch basket - look for ridges down the sides of the 'fingers' remember the clutch plates need to be able to slide against these whilse having pressure pushing on them toward the fingers in order for them to disengage. another thing that causes poor clutch action is the wrong oil. - what kind of oil are you running? i know honda reccommends engine oil of some sort, but most people i know use a standard automatic trans fluid as gearbox oil and are yet to run into problems (about 16 years worth of use for me)

also, honda clutches never disengage that well anyway, eg its likely to stall when you first put it in gear for the day, and its unlikely youll be able to start the bike in gear with the clutch in.

[morg_nz]

Yeah i thought it must be an overflow becuase of how freely it was coming out.

As for the springs, what i think has happened is that the ones that are in there are worn, and have been compressed (i.e. are shorter) and are not long enough to allow the clutch to release any more.




isnt there an breather/ overflow from the top of the gearbox on those? at the back end somewhere

longer springs shouldnt cause it to not disengage, unless its preventing you from pulling in the lever.

things that cause poor disengagement are usually a worn clutch basket - look for ridges down the sides of the 'fingers' remember the clutch plates need to be able to slide against these whilse having pressure pushing on them toward the fingers in order for them to disengage. another thing that causes poor clutch action is the wrong oil. - what kind of oil are you running? i know honda reccommends engine oil of some sort, but most people i know use a standard automatic trans fluid as gearbox oil and are yet to run into problems (about 16 years worth of use for me)

also, honda clutches never disengage that well anyway, eg its likely to stall when you first put it in gear for the day, and its unlikely youll be able to start the bike in gear with the clutch in.

[B0000M]

short springs will cause the clutch to slip, it is the pressure of the springs that make the whole thing work.

[morg_nz]

thought i'd resurrect this post following my first mx race at the weekend. Join the MOMCC club and went along to my first club day yesterday. Really enjoyed the racing - it was definately an eye opener. I already knew I wasn't very quick, but the track showed me just how slow I was. Even though I was racing mostly 450's in the novice class (vs my cr125), I thought I would have stood a bit of a chance given how tight the track was. But I got smoked, as I just couldnt find any power out of the corners. Now I know that 99% of that is probably down to my riding ability, but until I've got more practice i'll try and find some power in the bike (its a good workman that blames his tools ay? :-) )

So I think the bike is running quite rich (I got side tracked from my last efforts to sort this out while I fixed the clutch), as it has no power down low, and seems to be spitting quite a bit of black oil out the pipe (i'm running a deps fatty pipe with a FMF shorty on the back, and motul oil at 1:50). I've had the carb apart and this is what I found:


................ Currently in Bike .....................Factory Specs
Main...................350........................ ............................360
Pilot....................32.5..................... ..............................50
Needle Clip..........3rd from top.......................................3rd from top
Needle................6BEG21-68..........................................6BEG20-69

Any ideas on what I might need to do to get it running better - oh and im not interested/concerned in top speed, just looking for some speed/response down low.


Anywhoms, I really enjoyed the racing so will be doing as much as I can! Just trying to sus out a place to practice at the moment - just looking for a flat paddock that I can practice some drills in like cornering and starts etc.

[Rupe]

thought i'd resurrect this post following my first mx race at the weekend. Join the MOMCC club and went along to my first club day yesterday. Really enjoyed the racing - it was definately an eye opener. I already knew I wasn't very quick, but the track showed me just how slow I was. Even though I was racing mostly 450's in the novice class (vs my cr125), I thought I would have stood a bit of a chance given how tight the track was. But I got smoked, as I just couldnt find any power out of the corners. Now I know that 99% of that is probably down to my riding ability, but until I've got more practice i'll try and find some power in the bike (its a good workman that blames his tools ay? :-) )

So I think the bike is running quite rich (I got side tracked from my last efforts to sort this out while I fixed the clutch), as it has no power down low, and seems to be spitting quite a bit of black oil out the pipe (i'm running a deps fatty pipe with a FMF shorty on the back, and motul oil at 1:50). I've had the carb apart and this is what I found:


................ Currently in Bike .....................Factory Specs
Main...................350........................ ............................360
Pilot....................32.5..................... ..............................50
Needle Clip..........3rd from top.......................................3rd from top
Needle................6BEG21-68..........................................6BEG20-69

Any ideas on what I might need to do to get it running better - oh and im not interested/concerned in top speed, just looking for some speed/response down low.


Anywhoms, I really enjoyed the racing so will be doing as much as I can! Just trying to sus out a place to practice at the moment - just looking for a flat paddock that I can practice some drills in like cornering and starts etc.

Wouldn't run a 125cc mx bike at 50:1 myself. Don't forget your jetting mixture is air-fuel, not oil-fuel as most get confused and mess around with the pre-mix ratio...this won't help

[morg_nz]

oh not trying to fix jetting that way - its just its easier to do the maths for 50 to 1 in my head than 40 to 1 lol! maybe i should just write it on the bottle?

[noobi]

250ml of oil per 10L of fuel = 40:1

[CRF119]

OK if you want to make a CR125 really sing and you are planning on keeping it here is what ive done and do for all of my mates.

I tell them to buy a race Expansion chamber and matching rear pipe, most of the time there front pipe is dented and rusty any way. (not a shorty they are crap a 125 is ment to rev not have bottom end power) You should pick a up a FMF or Pro Ciruit for a round $600 for both.

V-Force 3 carbon reeds make a huge differance huge gains can be had from this even more then the pipe. (dont bother with boysen i dont find them as good)

Thats the easy part next is the hard part, On my bike i bored the carby out 2mm polished before the slide and left the other side matt finnish to help with fuel mixture. You can nearly double the size of the reed block intake also the rubber joiner between the carb and reed block can be made alot larger and alow to flow easier. If you are still after more you can have the engine reported and Electrosil plated in Aus.

After this it will need a full tune by sombody that can tune and not just guess. ( I tune 2 strokes for a job so i have done mine and about 4 others) this can take over a day to get perfect.

Always run 98, good 2 stroke oil and at least 40:1

When i sold my 02 CR125 to jump to my CRF450 the guy that brought it sold his near new 06 CRF250 to by it as it was faster.

Ill never forget beating 2 450s in a drag race and the guy said to me thats a fast CR250 lmao

Also by changing your Fuel ratio from 32:1 to say 40:1 the fuel is thinner because you have less oil in it so you will end up with a richer mixture so keep this the same all the time and dont change oil brands. Ive run to 45:1 but didnt notice much gain so went back to 40:1 for more cyclinder protection and bearing protection. You can run less oil in the bigger 2 strokes as they rev less.

[morg_nz]

I've got a DEPS fatty pipe (in mint condition) and FMF shorty silencer which were on the bike when i got it - I paid $2k for it so not really looking to replace them. I'm interested in reeds though - its crossed my mind, but after a quick serach of the net I cant seem to find anyone who sells them - online at least.

What sort of performance can i expect to gain from boring the carb? I take it boring it makes for greater air flow into the cylinder? What about just going for a 38mm carb?

I woudl like to get some more performance out of my bike but I am mindful of how much I want to spend on it. I bought the 2 stroke 125 to learn to ride (well) on, as I think its a bike that needs to be riden properly to go fast. This was made quite evident to me yesterday racing 4 stroke bikes. I will eventually move to a 4 stroke 250, but I want to be nailing the 125 first as I fear I will be too lazy on a 4 stroke otherwise.


OK if you want to make a CR125 really sing and you are planning on keeping it here is what ive done and do for all of my mates.

I tell them to buy a race Expansion chamber and matching rear pipe, most of the time there front pipe is dented and rusty any way. (not a shorty they are crap a 125 is ment to rev not have bottom end power) You should pick a up a FMF or Pro Ciruit for a round $600 for both.

V-Force 3 carbon reeds make a huge differance huge gains can be had from this even more then the pipe. (dont bother with boysen i dont find them as good)

Thats the easy part next is the hard part, On my bike i bored the carby out 2mm polished before the slide and left the other side matt finnish to help with fuel mixture. You can nearly double the size of the reed block intake also the rubber joiner between the carb and reed block can be made alot larger and alow to flow easier. If you are still after more you can have the engine reported and Electrosil plated in Aus.

After this it will need a full tune by sombody that can tune and not just guess. ( I tune 2 strokes for a job so i have done mine and about 4 others) this can take over a day to get perfect.

Always run 98, good 2 stroke oil and at least 40:1

When i sold my 02 CR125 to jump to my CRF450 the guy that brought it sold his near new 06 CRF250 to by it as it was faster.

Ill never forget beating 2 450s in a drag race and the guy said to me thats a fast CR250 lmao

Also by changing your Fuel ratio from 32:1 to say 40:1 the fuel is thinner because you have less oil in it so you will end up with a richer mixture so keep this the same all the time and dont change oil brands. Ive run to 45:1 but didnt notice much gain so went back to 40:1 for more cyclinder protection and bearing protection. You can run less oil in the bigger 2 strokes as they rev less.

[CRF119]

Boyds in hamilton can get you V-Force Reeds. They are dear between 300 and 400. The Reeds you have may be tired anyway so replacing the stock petals mite help a bit. V-Force reeds give better responce in bottom to mid range and a harder pull. The job of the reed is to open when piston goes up and close when it goes down to hold crank pressure if it dosent close fast enough you lose crank pressure so less air fuel mixture will end up in the combustion chamber so there for less power is made. Carbon petals respond faster and V-Force blocks are in a W configuration so you have 4 petals. Standard Reed blocks in CRs have a V reed configuration so only 2 larger slower responding petals there for less performance.

Im working on a 03 CR125 at the moment, We havnt done carby but we have done the rubber manifold and made the std reed block flow %100 more. Had some strange nylon block in this one. It has made a huge differance already and we are yet to get a FMF or Pro circuit system for it. He to tight to buy a reed block as its his first mx bike.

Ask you local store about No toil air filters and No Toil air filter oil to.

As for the carby the more flow the better but id try the other stuff before you do, that its a big job. If a newer model has a larger one and u can get it cheap do it. I dont think id go any biger then 3-4mm over std i only went 2mm

If i were you id inspected the reeds for any clearance issues, if they not closing they are stuffed. Also make sure your power valve is moving freely and is clean. While you are in there cheek how much restriction is in between the carb and the engine. If you havnt done ring/piston in the last 50 hours do that when u do the power valve makes it easier to clean and pull apart etc.