Question about Honda CM 125 C Motorcycles
1982 honda CM 125 Custom, only runs on one cylinder, even when plugs changed over. have replaced the cdi unit and coil. still only running on one.@
Hi, Angela you need "FIVE" things in order for a cylinder to run properly:
1. FUEL: in order to validate your not getting fuel spray some starting fluid into the air cleaner and hit the starter button, if it fires up and runs for a few seconds then you know you have a fuel delivery issue. Multi carb banks should be bench "SYNC"
2. SPARK: remove the spark plug and with it connected to the spark plug cable ground the threads to something metal you should see a bluish white spark if not you have a faulty spark plug, spark plug cable, ignition coil, condenser, CKP, ECM, sensor or the wiring in between.
3. COMPRESSION: you must have at least 80-100 PSI for most bikes, multi-cylinder engines should be within 10-15% of each other if not perform a leak down test you may have a burnt or bent valve or hole in the piston or broken rings.
4. CAM TIMING: confirm your timing marks are aligned to see if the cam chain or adjuster are worn out and the chain has skipped a couple teeth.
5. IGNITION TIMING: on older bikes check to see if your points have not closed up, timing plate has not become loose and confirm with a timing light for proper retard and advance functions, on newer bikes where timing is controlled by an ECM and is nonadjustable check you CKP, TPS, MAP, O2, sensor or its counterpart for integrity.
For more information about your issue and valuable "FREE" downloads that you will need for viewing or printing please click on the blue links below. Good luck and have a wonderful day.
honda cm 125 running intermittently on one cylinder
One cylinder not firing
Honda CM250 Custom Owner Manual
Posted on Oct 20, 2017
a 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of.(from cars to computers, handyman, and even drones)
click here to download the app (for users in the US for now) and get all the help you need.
Posted on Jan 02, 2017
The 12v coil on a 6v system will only give a weak spark at best. The coil in the photo should work very well assuming the wires are long enough. Any 6v twin coil should work. If you fit another coil and the bike has spark but will not start, swap the wires at the points. Don't purchase a condenser unless the old one has gone bad. If needed, get a 6v condenser matching the old one.
A “very helpful” rating for this answer? Thanks from Dallas Texas!
Posted on Jun 16, 2009
Are you saying that 2 & 4 got gas with external tank but not with gas tank? If so something else has happened ,if gas is getting to the carb it cannot by-pass 2 to get to 1. Take the tank back off ,connect to external, again. See what happens.
Posted on Sep 11, 2009
check all earthing connections on the ignition system and in fact on the whole cycle. A loose or dirty connection may be the cause.
Posted on Sep 17, 2009
I would follow the fuel line all the way check the filter it should be inline and check the pump as well i would say its one of them two.
Posted on Jun 21, 2010
Tips for a great answer:
Jul 14, 2017 | Honda CB 750 Motorcycles
Sep 19, 2013 | 2005 Aprilia Mojito Custom 125
Feb 21, 2013 | 2000 Honda CM 125 C
Nov 29, 2012 | 2002 Honda CM 125 C
Sep 09, 2011 | Honda Cb 400 F Motorcycles
Aug 03, 2011 | 1982 Yamaha XJ 650
May 18, 2011 | Honda XL 125 R Motorcycles
Nov 07, 2010 | 2000 Honda CM 125 C
May 27, 2009 | 1996 Honda CBR 400 RR
45 people viewed this question
Usually answered in minutes!
Step 2: Please assign your manual to a product: