Jump to content

Recommended Posts

I feel like ripping my hair out! I bought a 2005 cr125 years ago, brand new. From day one it was a fouled. Eventually I had it tuned kind of good. A couple of years ago someone stole my bike. Obviously I recovered it. My crank bearings were shot. So I split the cases and changed them and both seals. After assembling the bike it smoked and bogged like crazy. I thought I may have fudged up the right crank seal when I installed it...nope changed it and still smoked and bogged and fouled. It sat up for about a year and I just broke it out again. It doesn't smoke as bad. If I idle for about 10 seconds it'll blubber and shoot out smoke before fouling a plug. The strange part it that it rides pretty good on the pipe, but out of the blue with blubber and eventually die. Now After cleaning the spark plug and kicking it, it'll turn over for a sec and die. The spark looks weak so I check it with a new plug and it looks good (so I'm assuming it's not the ignition system) anyone else have this problem? I'm beginning to think this bike is a money pit...but on the same hand I feel like it's something small causing all of this.

Oh and also it's dripping that black crap from the tailpipe and plugs are always wet. I went down a size on the pilot...didnt help.

Share this post


Link to post
Share on other sites

Could be several things....if it's sat that long, I'd rebuild the carb for starters and check other areas for air leaks like around the reed block and carb boot. You say you changed the pilot, but did you try moving the needle clip up a notch....adjusting the airscrew?? Couple of things to try before you throw in the towel....sounds like it's awfully rich and carb related if you're wet fouling plugs. You didn't mention what plug you're using either so I assume a BR9xx ? Reply with more info as to what you've done or haven't yet and folks can steer you in a better direction as to what to try next.

  • Like 3

Share this post


Link to post
Share on other sites

I've rebuilt the carb and only use br9eg plugs. I've also done a pressure test and it passed. My reeds look fine except for 1 very very small chip right in the corner of one. My needle is on the third notch. It's really hard to adjust the carb while it runs so rich because adjustments don't show. Also my compression is like 132psi.

Share this post


Link to post
Share on other sites

I'd try to post a video but idk what time type to convert it to. Every time I try to attach it, it says file type not supported.

 

 

Share this post


Link to post
Share on other sites

Sounds really rich...

Are you at a high elevation? Are you running less oil in you premix than stock? It may need an even smaller pilot and the clip raised if you pull the plug and its oily, black and you have excess exhaust spooge. Where's you airscrew? If its more than 2 turns out you prob need to go with a smaller pilot.

Also, its difficult to jet correctly with worn reeds. The fact that it has a visible chip may mean it needs to be replaced. If you hold the reed assy in front of a light, can you see light through the gaps?

It is frustrating and time consuming to get it right....but feels great when you do !!!

 

 

Share this post


Link to post
Share on other sites

I'm in louisiana so elevation is probably around 100ft. I moved my clip up 1 so now it in the 4th position from the bottom. I believe my air screw is out 2 turns. And my ratio is 32:1. What causes the bike to be rich if it idles for like 30 second and puffs smoke out when I pull the throttle? Pilot jet, or needle clip position? I'm going to try to post the video td

Share this post


Link to post
Share on other sites
How come the idle is so high? Sounds like it has an air leak, how'd you air leak test it? Also, do you have a manual for it?

The idle is high I admit, but I'm sure I can idle it down a lot. And yes I have the manual and service manual.

Share this post


Link to post
Share on other sites
Sounds really rich...
Are you at a high elevation? Are you running less oil in you premix than stock? It may need an even smaller pilot and the clip raised if you pull the plug and its oily, black and you have excess exhaust spooge. Where's you airscrew? If its more than 2 turns out you prob need to go with a smaller pilot.
Also, its difficult to jet correctly with worn reeds. The fact that it has a visible chip may mean it needs to be replaced. If you hold the reed assy in front of a light, can you see light through the gaps?
It is frustrating and time consuming to get it right....but feels great when you do !!!
 
 

Just pulled the reed cage off. Yes you can see light if you shine the light through the engine side. Does that mean they definitely need to be change. (Is it a big problem?)

Share this post


Link to post
Share on other sites
The bike will start and run with worn reeds. It will idle poorly and not have a crisp throttle response. Power will be down. That was my experience.
 

Any recommendations on a good set of reeds?

Share this post


Link to post
Share on other sites

If you are on a tight budget, cheapest thing would be to just replace the petals on your existing Reed Assy if it is in good shape. With new reeds, It will be much easier to get jetted correctly and I bet you are going to have more fun riding it. Sounds like you are near sea level and are running a stock premix ratio so, if it were me, I would start with stock jetting.

Share this post


Link to post
Share on other sites

Try adjusting the idle to where it should be, if you adjust the idle to where it needs to be (nice and low, but not too low) and the engine wants to idle up on its own that would be a symptom of an air leak, unless the reeds are obviously damaged/have a big gap where the flaps seal up I wouldn't change them. 

Sweet CR125 by the way

Edited by BrandonCR125

Share this post


Link to post
Share on other sites
If you are on a tight budget, cheapest thing would be to just replace the petals on your existing Reed Assy if it is in good shape. With new reeds, It will be much easier to get jetted correctly and I bet you are going to have more fun riding it. Sounds like you are near sea level and are running a stock premix ratio so, if it were me, I would start with stock jetting.

I started with stock jetting, but it blew smoke like in the video, so I went down a size on the pilot and it's still smoking pretty bad. What reeds do you recommend if I decide to change them?

Share this post


Link to post
Share on other sites

Has to be a lot of threads on that topic for your bike. My bike is so old I couldn't buy OEM and the only aftermarket reed I found was a Boyesen Pro Series dual-stage reed. Sounds like my old reeds were in better shape than yours and I felt an immediate and obvious difference. Mine sealed on the end, but had gaps on the side.

Share this post


Link to post
Share on other sites
Try adjusting the idle to where it should be, if you adjust the idle to where it needs to be (nice and low, but not too low) and the engine wants to idle up on its own that would be a symptom of an air leak, unless the reeds are obviously damaged/have a big gap where the flaps seal up I wouldn't change them. 
Sweet CR125 by the way

They have some small chips on the edge, but it's just a sliver of light shining through the reeds.

Share this post


Link to post
Share on other sites

Lol, good idea on adjusting the needle setting, bad reeds wouldn't cause it to smoke like that, good luck

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:


×