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Discussion Starter · #1 ·
Hi Folks, I have a 87 125 Honda 4 trax. Put on new carb and changed oil. Bike started right up for about 20 secs then died as choke was pushed back in. Started one more time and the same thing happened in abou10 secs. Plug is wet every time I check it. When grounding plug and turn the motor over the spark looks very weak. Found a lot of films on internet about checking 125 4 trax coil, and not one of them show a coil even remotely like mine off a 125 4 trax. They do mention 3 to 4 ohms reading for good coil on the ones they showed. The 2 leads on mine only show .5 ohms, but as I say the coils I saw were all different so I don't have a confirmation on the ohms reading. My dad had trouble with this bike many years ago and they sold him a new cdi box that never solved the problem. Some times it would run great and other times he would crank it forever to get it going.The spare box is no where to be found. I haven't tried the secondary check yet but will today. The film I saw said to keep 1 meter lead on 1 of the 2 leads and put the second meter lead on the end that plugs on the spark plug and should show around 14 to 15K.
Please advise. Thanks!! JC
 

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Welcome to the forums... New carb?? eBay China carb??

Have you adjusted the air/fuel mixture screw??
Pull the boot off the coil and clip about 1/4" off your plug wire and see if that helps your spark..
New spark plug??


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Discussion Starter · #3 ·
Thanks for the advise. I did use a new eBay China carb. I could only go by the original manual carb settings. I will get new plug tomorrow and cut 1/4 off of plug wire and try it again. I'm still looking for verification on the ohms on the 2 incoming leads of the coil that is only reading .5 ohms. The secondary winding reading from 1 of those 2 leads to the end of the plug wire is reading 9.5K Thanks again and I'll repost what results were tomorrow. JC
 

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Thanks for the advise. I did use a new eBay China carb. I could only go by the original manual carb settings. I will get new plug tomorrow and cut 1/4 off of plug wire and try it again. I'm still looking for verification on the ohms on the 2 incoming leads of the coil that is only reading .5 ohms. The secondary winding reading from 1 of those 2 leads to the end of the plug wire is reading 9.5K Thanks again and I'll repost what results were tomorrow. JC


The only manual I have is for 85-86. The readings in the manual say Primary is .18 and Secondary is 4.1


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Discussion Starter · #5 ·
TO CManningjr, WOW, what a difference a day makes. I got the new plug and set at 26 thousandths and replaced. Took the boot off the plug wire and it had about 3/8ths inch of wire bent over on the end. I cut off a 1/4 inch and screwed it on til it was tight. As you suggested. Turned on the gas and waited about 2 minutes. Full choke and hit the starter and it fired right up and was very responsive with the throttle. It tried to die wen I closed the choke so I let it die. Re-choked and hit the starter and it fired right up again and was very responsive with the throttle again, so I shut it down. Looks like I need to set the air- fuel different now and see what happens. It smelled like it was running reel rich. I do not have the air box and filter on at this time. Do you think I should replace them first before attempting to set the air-fuel mixture?? It hasn't started and run like this for quite some time. Thanks again, and please advise. Joey C.
 

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Yes, you want it to be put together when you set your mixture... you'll restrict your airflow when you put it on...

Glad you got it going in your favor!!


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Discussion Starter · #9 ·
Hay CManningjr, Hope yer well tonight. WOW what a great day. I had stuff I wanted to get done, butt!!!, the atv kept on my mind, SO, I went ahead for the heck of it and moved the air fuel mixture out one more half a turn and screwed the idle in a half turn because wen I first started it with the choke it don't wanta run wen I pushed the choke in. To my surprise it started right up and ran fine with great response on the throttle. I spent a lot of time putting on the air box. Took an hour to get the darn hose on the carb from the box. (old hard hoses). Once I finally got those on and the filter in, I hit the starter and it fired up without the choke and ran great. I know yer spost to do the carb settings wen warmed up, but the small adjustments I made before and the air box restriction made the bike run like brand new. I'm still in shock. I'm sure I got a little lucky. I really think between the new plug and the new carb cause the old one was leaking bad and especially cutting the end off of the plug wire made the real difference. Thanks so much for the advise and help. I will be checking out the site for a while . I don't have any idea what the top crankcase breather hose that comes out above the carb in front of the breather box at a 90 degree hooks to, so if you see where yours is let me know. It hooks over the top of the hose that hooks to the outlet of the carb. Take care . JC
 

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Awesome!! I'm glad you got it going...

If it's the hose I'm thinking about, without looking, there's one that goes under a tad on the backbone under the tank.. If I remember right.. I'll try to look tomorrow and let you know...




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Discussion Starter · #11 ·
Good morning , just another note on the crankcase breather tube. It is hooked up on the engine in 2 places and tee's off to the top of the frame, just behind the gas tank is where it is with the 90 bend on it. That actually came up along side the big hose that hooks to the carb from the air box, helping to make it hard to get it on. JC
 

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Discussion Starter · #12 · (Edited)
Not sure how to do a new post on my 125 87' Honda 4 trax, however, thanks to advise well taken and used from CManningJr, I not only got the bike running well, but I'm almost finished putting it together and I have an important question to anyone who might know the answer. I can turn on the key now and pull the starter rope with no battery hooked up and the bike fires right up and runs well. !!!!!!!!!!Is it ok to run the machine all I want on the mag with no battery hooked up??? Please advise!!! Thanks Joey C
 

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The battery helps the v regulator stabilize the voltages on the bike. Also, without that battery as a load, there is less of a place for the stator to dump excess power into. So the wiring in the stator gets hot, the enamel insulation on its wire breaks down and you can soon have a cooked, dead shorted stator.

Rick

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Discussion Starter · #15 ·
Thanks so much all for the help and reply's. I am currently searching a battery now. I only ran the motor for a few seconds without the battery. I was running on my trolling battery while working on it in my shop. Had to disconnect the battery to take it off the blocks and jack stands which prompted me to try it without the battery. Take Care==JC
 
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