A Noob's Journey to Fix His BD125-11 (STILL BROKE)

[durtyrice]

Hello all,

Figured I would just compile my journey into one thread. Hopefully, this will help a future noob out so he doesn't have to do 20+ hours of wasted research and 20+ hours of tinkering! At this point I'm still not able to get it to ride, but the journey is close. REALLL close.

Okay, so I bought a used BD125-11 (ninja clone) with 300 miles on it on December 26. I have no motorcycle experience whatsoever, and my tool proficiency is questionable at best. BUT, I've learned a lot. This forum has helped a lot. I've lost a ton of screws, nuts, 10mm sockets, my sanity etc. but I still have a few days of tinkering left in me. I've always wanted to own a motorcycle and here's my chance * (I work 12-13 hours a day, 7 days a week and my garage doesn't have any light so I've been trying to fix this #### every single night since the 26th with a cell phone light in one hand and tool in the other) ANYWAYS let's begin.

The day after I bought the bike I was riding it around the neighborhood and it would often just sputter and stall at random times. The next day, the motorcycle wouldn't start at all. After doing some research, many people suggested an upgrade to a Mikuni carb for performance and for the fuel/air screw and idle screw.

https://www.amazon.com/VM22-26mm-Carburetor-Carb-CRF70/dp/B07HNW4QC6/ref=sr_1_4?keywords=mikuni+carb&qid=1578957164&sr=8-4

Okay, great. So I get it installed. I'm hit with some confusion. The stock intake manifold has a nipple with a hose going to it.. but the Mikuni intake manifold does not.

https://i345.photobucket.com/albums/p392/dkimoh1/EGR%20SILVER%20BOX_zpsqv2vpmi4.jpg (https://s345.photobucket.com/user/dkimoh1/media/EGR%20SILVER%20BOX_zpsqv2vpmi4.jpg.html)

Hmm... Okay. I post about it and get some help from this forum. Turns out the silver box has something to do with emissions and long story short, I don't have emissions in my state so I can just remove it.

EXTRA: There was a hose that went from the top of the engine to the stock airbox. I wasn't sure what to do with it after upgrading to mikuni carb, so I just plugged it. Picture of the hose with yellow clamp
https://s345.photobucket.com/user/dkimoh1/media/engine%2520air%2520hose_zpsnpgcrkof.jpg.html?sort= 3&o=0

****EDIT!!: Don't plug this hose that comes from the top of the engine to the stock air filter.
"That hose has to breathe. It is designed to allow pressure out of the bottom end of the engine; if the hose is plugged, pressure will find another way out and that usually results in an oil leak. Route the hose behind the engine and point it at the ground at the very least. Ensure it is not plugged." Thanks Weldangrind!!

One of the hoses coming out of this silver emissions box goes to the front of the engine. With my limited knowledge I figured that a hole where a hose and gasket used to be wasn't good, so I asked this forum. A member of this forum suggested I buy a Universal EGR Block off plate for a GY6, and he told me it would fit my BD125-11. Off to Ebay I go. Four days later I go to see if it fit. It did.

OKAY. Good start. Intake manifold nipple crisis averted. I go to install my new mikuni carb.. It doesn't fit. @#$@#$@#@$. Okay, so after some research and forum posts, people have bought something called a Carb Spinner Adapter to fix their issue. Something like this

https://www.amazon.com/Alloy-Adjuster-Carburetor-Spinner-Adaptor/dp/B078NTH4YX?th=1

I wait two days and it arrives. Uh oh, no screws. After multiple trips to multiple different Home Depots, I settled with a M6-1.0 screw. You want to be at around 20-25mm in length. The 30mm M6-1.0 screws will NOT work. Don't even try with the 12mm because it won't even clear the O ring. The M6 home depot screws don't sit perfectly flush with the carb spinner, so I had to buy a dremel and see if I can get the screws to seat properly. At this point I'm 90% sure the grinded down screws are not the cause of a vacuum leak (more on this later) After further research a respected member from this forum suggested buying a new 26mm carb spinner but the one without an o-ring and with the supplied screws. It ships out of China, so that's what I'm currently waiting on now.

Anywho, at this point I'm super excited and finally got my carb spinner and mikuni carb installed. I can't get the bike to start. After some research, I learn about fuel, compression and spark. I buy a new spark plug, and go to check out the gas. There's a BUNCH of rust. I go buy two gallons of evaporust on Amazon. I pour it in, then find out that I have a 4 gallon tank. Oof. Each gallon is roughly 25 bucks so I'm SOL. A member from this forum suggests electrolysis. A few hours of research later I go buy a steel plate from Home Depot, and a battery charger. After two days of electrolysis, I'm feeling good.

This black canister had two hoses that attached to the bottom of my gas tank. Supposedly it's better to leave them attached to the gas tank for better MPG, but I left them unplugged for now since I didn't want to deal with it. The two nipples at bottom of my tank have hoses that go nowhere for now.
https://i345.photobucket.com/albums/p392/dkimoh1/Black%20cylinder_zps8nvhsrtl.jpg (https://s345.photobucket.com/user/dkimoh1/media/Black%20cylinder_zps8nvhsrtl.jpg.html)

FINALLY, rust is gone. Carb is installed. FRESH gas is in.. She starts.. but idles extremely high 7-8k rpm range. Oh no. The idle screw does nothing to the idle. Even with the idle screw completely off the rpm doesn't go down.

This is what I'm currently stuck on. I'm hoping that it's a leak somewhere between the carb to manifold, or manifold to engine since that's the only part I've been working on.. but I'm not quite sure how I would check that. As soon as I turn on the bike it idles at 7-8k rpm and I'm worried. I know that I've seated the throttle cable needle correctly to the carb itself. The throttle is not sticking. I have no 'play' in my throttle though. The throttle cable itself is not pinched. Not sure if that would affect the high RPM or not. I think this is indicative of a air leak but I need some advice. The ONLY thing right now that I could see being the cause of the leak if the grinded down screws... but it's unlikely. I can't do anything about the screws until the kit ships from China. Any suggestions?

[ikeus685]

Good on you. The getting to know you'r bike is an interesting journey that will lead you
to many amazing discoveries!

[Bruces]

Check that the throttle slide is not 180 degrees out for the over revving ,it’s a very common thing just about every one of us has done a time or two .

[Emerikol]

Check that the throttle slide is not 180 degrees out for the over revving ,it’s a very common thing just about every one of us has done a time or two .

I second this. I would say disconnect the cable from the carb and then try to run the bike WITHOUT the cable even installed. It's possible the cable is mis-adjusted or improperly installed. Also a possibility is that the new carb moves the position of the throttle cable far enough that it pre-tensions the cable. Running the carb without the cable installed at all will allow you to do some troubleshooting and set the idle as a first step, and also eliminate the cable as a cause of your high revving idle. If the bike still runs at 7-8k with the cable removed, you know you have to bark up another tree for your issue. Keep us posted.

[durtyrice]

I second this. I would say disconnect the cable from the carb and then try to run the bike WITHOUT the cable even installed. It's possible the cable is mis-adjusted or improperly installed. Also a possibility is that the new carb moves the position of the throttle cable far enough that it pre-tensions the cable. Running the carb without the cable installed at all will allow you to do some troubleshooting and set the idle as a first step, and also eliminate the cable as a cause of your high revving idle. If the bike still runs at 7-8k with the cable removed, you know you have to bark up another tree for your issue. Keep us posted.

THANK YOU THANK YOU THANK YOU THANK YOU!!!!!! I ran the carb without the cable installed and it idled perfectly. You called it - the new carb position put a bit of tension on the cable (me losing 'throttle play' was indicative of this). Now, she idled in optimal range! It's 11 pm here, but I'm about to hit the neighborhood and practice!!

There is one last thing that is bothering me. My carb seems to be making this strange noise. I posted a clip of it. WARNING, I think I dropped a curse word in the video. Is this sound normal??

https://www.youtube.com/watch?v=dofer3xm4gs&feature=youtu.be

[franque]

That's either an intake leak somewhere, or it's just induction noise. Putting a pod on like that tends to be a whole lot noisier than an airbox. If you want to check for intake leaks, you can spray ether/carb cleaner/contact cleaner (if it is alcohol based) near the connections between the carb and intake, and the intake and engine. If it revs up a bit, you've found a leak. Do not spray it on the air filter, it would normally idle up if you do that.

[Weldangrind]

There was a hose that went from the top of the engine to the stock airbox. I wasn't sure what to do with it after upgrading to mikuni carb, so I just plugged it.

That hose has to breathe. It is designed to allow pressure out of the bottom end of the engine; if the hose is plugged, pressure will find another way out and that usually results in an oil leak. Route the hose behind the engine and point it at the ground at the very least. Ensure it is not plugged.

Please upload pics directly to the forum, rather than linking to Photobucket. PB takes a long time to load. :thanks:

[Oddball Matt]

-Tinker time is NEVER lost.
-10mm sockects are ALWAYS lost.
-You tend to learn to work on these things through the hard way, trust me we've all been there. Practice makes masters.
-That chooga chooga sound is perfectly normal with a power filter. You should hear the SCHOOOOP a 900cc Ducati twin makes with a pair of those when spooling up!

[Emerikol]

There is one last thing that is bothering me. My carb seems to be making this strange noise. I posted a clip of it. WARNING, I think I dropped a curse word in the video. Is this sound normal??

https://www.youtube.com/watch?v=dofer3xm4gs&feature=youtu.be

"I'll take high idle for $300 please, Alex"

Yes, the curse words sounded perfectly normal to me! :lmao::lmao::lmao: On a slightly more serious note, my Hawk has a pod filter and make a similar sound. I would definitely say to check your valve lash, as that will cause significant changes in the noise the air makes as it rushes into the head/cylinder. These engines tend to come from the factory with the valves set WAY too tight. Remember, tappy valves are happy valves!

[durtyrice]

Thank you all again for your input. She runs pretty well (in my limited experience) and am now looking towards different jets for a further tune =)

I do have an issue, though. My battery indicator flashes during the ride and I've lost charge according to my multimeter. Can someone please point me in the right direction? Battery is only four months old and will hold charge using maintainer/charger. With the bike running, I unplugged the positive terminal to the battery to see if the stator maintained charge - it does not. This leads me to believe that the stator is bad... right? If so, can someone please post me a link as to where I can buy a replacement? Perhaps the GY6 will work again?

To save me a bit of money, is there anything I can clean or do maintenance-wise to get my stator back up and running??!

[franque]

Check the stator first, it could be a bad regulator/rectifier. Backprobe the yellow wires while the engine is running, there should be between 30 and 60 volts AC while it's running from each of the yellow wires. You can also check for continuity between the poles of the stator by unplugging it (engine off) and checking for continuity between the yellow wires, there shouldn't be any. Also, when the stator fails, the oil gets a distinct smell, like burning peanuts and ATF. If the oil smells normal, I'd think it's the r/r.