Casper250

Motosapien
Dec 12, 2000
579
1
I just bought a 2001 cr125 and the bike has a low end bog. From just off idle to maybe a quater throttle, there is definatly a hesitation but once it gets the revs up, it has normal crisp throttle responce.

When i got the bike, there was a fair amout of oil from the tailpipe dripped all over the back hub, brake and rim. Either the guy i bought the bike from was a little heavy with the 2-stroke oil, or didn't like to rev the bike. I pulled the plug and put a new one in and still the bog is there. I also ran the bike hard for about 10 minutes and the oil from the tailpipe has slowed, but it still drips out.

I was wondering if this bog is a carburator issue or is this bog just the nature of the beast on a 125cc?
 

marcusgunby

LIFETIME SPONSOR
Jan 9, 2000
6,450
2
The 2001 doesnt have much bottom but good jetting helps alot-do a search and it should throw up a few threads on this topic, i ended up with a 40 pilot and a 2169 needle i think.
 

shnalln

~SPONSOR~
Nov 11, 2002
268
0
Sounds like you're alittle lean on your pilot...mess with your airscrew before you tear into it too deep...Eric Gore has a good general jetting info page on his web site...helped me alot. Good luck!
 

Casper250

Motosapien
Dec 12, 2000
579
1
Originally posted by marcusgunby
The 2001 doesnt have much bottom but good jetting helps alot-do a search and it should throw up a few threads on this topic, i ended up with a 40 pilot and a 2169 needle i think.

Thanks!!! this seemed to do the trick. I put the needle in the middle clip for now. I also bought a 350 main and a 360 main when i ordered the pilot and needle. I didn't write down the numbers for the jets and thought that some one metioned a 350 or 360 main. Do i need to mess around with the main jet at all or needle position?

Also, when my jetting is all set up, do i need i mess around with it as the weather changes? My last bike, a 2000 kx250, i never had to touch the jetting from the day i bought it and it ran fine even in the snow of winter.
 

ericlachance

Member
Feb 16, 2003
171
0
if the bog you are experiencing is in 0 to 1/4 throttle openings only, do not touch the needle jet, jet needle or main jet. You want to go richer on the pilot jet.
 

dirtsurfer31

Member
Aug 6, 2003
20
0
Hey guys, what makes you think that his bike is lean?? If it is dripping oil that suggests a rich condition not a lean one. If it was lean most of the time it would surge and not just bog like a rich pilot would do. Also, i think the main is a 360 stock. It is on the 2000 any ways. Do a throttle chop test and check out the color of the plug, if it is mocha tan then don't get any leaner or richer on the main. You can mess around with the needle bit, it will give you a good idea of which is lean and which is rich and put the clip where it feels best. The pilot can usually be dropped two sizes from stock. The stock i believe is a 50. Order in a 45 and a 40. Keep the one in that feels the best and then mess with the air screw for best throttle response. That should take care of all of your jetting problems.

Good Luck!
 

shnalln

~SPONSOR~
Nov 11, 2002
268
0
"If the engine is slow to respond and bogs (engine makes a booooowah sound) then the carb jetting is too lean. You can verify lean
jetting by engaging the carb's choke to the halfway position."

This comes directly from Eric Gorre's website, the quick link to his site is right here on the side of these threads. Do yourself a favor and check it out. As far his bike spooging goes then yea, that would indicate that his mains are rich. But his low end circuits are saying that they're lean.
 
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dirtsurfer31

Member
Aug 6, 2003
20
0
This may sound stupid but take a peice of paper and tape it to the end of your silencer (with it repacked) and ride from 0 1/4 throttle for a little bit. If there is any spooge it is rich.
 

ericlachance

Member
Feb 16, 2003
171
0
yeah, but the bike could be lean on the pilot but rich on the main or needle... Notice he said that he had noticed spooge dripping when he got it. It wasn't dripping after he got it. So for example, if the last owner was riding it in mid rps's all the time and the needle is rich, you just got yourself nicely soaked silencer packing and a spooge dripping exhaust...

Eric

PS most of the time, a bog means a lean condition. You can easily tell if a bike is running rich by the weird rough sound of the engine. you can really hear it loading up.
 

NO HAND

~SPONSOR~
Jun 21, 2000
1,198
0
Originally posted by ericlachance
yeah, but the bike could be lean on the pilot but rich on the main or needle...
Also, this is a very common scenario with Hondas lately. My 03cr250 was 2 steps too lean on the pilot and 2 steps too rich on the main.
 

Casper250

Motosapien
Dec 12, 2000
579
1
Originally posted by ericlachance
yeah, but the bike could be lean on the pilot but rich on the main or needle... Notice he said that he had noticed spooge dripping when he got it. It wasn't dripping after he got it. So for example, if the last owner was riding it in mid rps's all the time and the needle is rich, you just got yourself nicely soaked silencer packing and a spooge dripping exhaust...


I thought that the oil from the exhaust wold stop after i rode it for a while so that all the oil in the exhaust would come out. After i changed the pilot, the bike ran great but the oil drip from the silencer is still there. I don't know what the stock main jet is but i bought a 350 and a 360 main to play with. I haven't had a chance to take out my bike since i rode it the one time after changing the pilot and needle so i haven't touched the main or the air screw. So is changing the main jet now where i should be looking to get ride of the oil drip?
 

ericlachance

Member
Feb 16, 2003
171
0
depends, hows throttle response at 0 to 1/4 throttle opening? and from 1/4 to 1/2? 1/2 to 3/4? and 3/4 to wot? do a plug chop on at wot to check the condition of the main jet.

What type of riding do you do? trails, mx... And do you usualy ride at wot, 1/2 throttle or do you ride it in very low rpm's? Also, change the packing in the silencer, if it's dripping, It's soaked with spooge.
 

SK 250

Member
Sep 19, 2003
42
0
MX Rider 031 where abouts in Saskatchewan are you, I'm always kepping my eyes and ears open for tracks across the prov. let me know. I'm in Melfort,1 hour south/East of P.A. just a couple farmer field mx tracks here
 

Casper250

Motosapien
Dec 12, 2000
579
1
I mosty ride sand or MX tracks so i'm in the upper RPMs most of the time. The bike runs great at low revs now but it's still a little querky. If i run at low to mid RPMs for a little while and then i run it at WOT, it has sort of a delay like it's clearing out a gas build up. It only happends every once in a while and i havent had a chance to mess with it. From what it sounds like from people telling me, my main might be a little rich. Does this sound right?
 

ericlachance

Member
Feb 16, 2003
171
0
Casper, loading up and bogging are 2 different conditions. please be more precise in your description. Usually, loading up=rich and bog=lean. Without being sure wich condition you are experiencing, I really can't help you.
 

Casper250

Motosapien
Dec 12, 2000
579
1
Thanks, that site seemed to explain it pretty well.
 

Casper250

Motosapien
Dec 12, 2000
579
1
Originally posted by marcusgunby
casper it sounds like you are rich on the pilot or needle, as this is why its loading up on low throttle openings.

marcusgunby,

I switched over to the 40 pilot and a 2169 needle that you recomended. The low end bog is now gone but when i set the needle, i just put it in the middle position. I bought leaner main jets also.

I think that the bike is loading up because it only happens when i ride around for a bit at low to mid throttle openings. I don't think its a bog because the low end bog that i had would happen every time i gas it.

I wasn't sure if this was caused by the needle position or my main jet as from what i read, both the main and needle jet effect this part of the throttle postion.
 

TNUTT

Member
Jul 18, 2002
45
0
Marcusguby,

I know you did a lot of experimenting on the '02 cr125 and you had decent results. I am also having problems with the jetting. Please tell me what you were running in what climate. I am in so cal with 27 pilot, 2ND clip, 390 main and i have that trasitional hesitation (probably rich -steve 125 settings 25 & 340 with yz needle)from 1/8-1/4. I also have the sst pipe & rad valve, and i just got a vortex ignition i have yet to try. I have pulled a lot of old threads up regarding steve and your research..thanks.

I am thinking about putting the 00 pc with mod '02 exhaust and eg porting and head mods. Any other advice would be greatly appreciated.
 

marcusgunby

LIFETIME SPONSOR
Jan 9, 2000
6,450
2
TNUTT you are already leaner than i went on the 02 due to your location-steves settinga may well work better for your local.

caper you may need a needle thats 0.5 clips leaner-could be a 2170-i had both to fine tune from winter to summer.You could try a leaner clip on the needle you have but be careful.
 

evworld

Member
Jun 22, 2002
30
0
I had the same problem when I bought my 2001 CR125 used and Marcus helped me. I tried 40 pilot and the needle he suggested on 2nd clip from top and a 380 main. That's Stock main. It helped a bunch. However,I still had the spooge. I had the the top end done and that stopped the spooge and the bike ran great. After a few weeks, I put V-force reeds in and it really made it rip. Now after many hours the spooge is coming back, I believe its time for new top end again. I am not sure if the spooge was from worn rings but it made it go away. After the top end rebuild, I went back to a 45 pilot which is also stock, that made it better. I hope that helped, it worked for me.
 

Telemaqq

Member
Sep 5, 2003
18
0
i just got this bike, and it seems like after i ride it there are little oil dots around, kinda liek the tail pipe was "spitting" the oil, i meen its not alot like if i were to ride it for 4 hours it would still just look like a buncah sprinkles, is this normal?
 

Casper250

Motosapien
Dec 12, 2000
579
1
Originally posted by Telemaqq
i just got this bike, and it seems like after i ride it there are little oil dots around, kinda liek the tail pipe was "spitting" the oil, i meen its not alot like if i were to ride it for 4 hours it would still just look like a buncah sprinkles, is this normal?

This is what me and evworld are talking about when we mention the oil out the tail pipe. I don't think this is normal so to say because the oil seems to be comming from the jetting of the carburator or worn rings from what evworld mentioned.

I have two more questions about jetting. My first is do main jets come in half sizes? And how often do you rejet your bike? Only when you feel a change in the motor or do you do it according to the weather?
 


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