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CD175 Sloper only firing on one cylinder

reeboguj

Member
Joined
Feb 27, 2022
Total Posts
20
Total likes
0
Location
Brisbane,Australia
Hi Guys, This bike will surely be the death of me,the bike will start and run for about 1-2 mins then will only run on one cylinder and if I change the plugs around the other plug works fine,the same plug doesn't want to fire,I would say dud plug but we bought eight of them so when it plays up I change the plug and it runs good for anywhere up to half an hour or so(sometimes less),I have changed the points,condenser and coil,I have not done a compression test. I will buy a gauge tomorrow and check.The plugs are very black but this is my wife's bike and she has no licence yet so she is idling it around the backyard,so I just put the plug colour down to this.
Thanks in advance.
 
Just the fact that the bike is only idling around the backyard for a half hour tells me the battery could be the issue. These charging systems don't have any positive output at idle like a car alternator does, they actually discharge. The engine has to stay above at least 3000 rpm or more for the charging system to begin to recharge the battery. When it quits running on one cylinder, check the battery voltage. If it's below 12.6v then it needs a charge (not over 2 amps for any significant length of time, it's probably a 9 or 10 amp battery) and then try letting it rest after charging for at least a half hour. If it's not showing 12.6 after resting off charge, it likely needs to be replaced. I just did a quick search to see if it's a 6v system and could not find anything definitive, though some of the earlier smaller models were.
 
Thanks ancientdad,I did check the battery and it is showing 6.3volts,I did see a post on here about battery's and didn't think to much of it,all my other bikes are SOHC fours this 6v stuff is all new to me.I will have to source another charger as the one I have doesn't want to charge.
 
Thanks ancientdad,I did check the battery and it is showing 6.3volts,I did see a post on here about battery's and didn't think to much of it,all my other bikes are SOHC fours this 6v stuff is all new to me.I will have to source another charger as the one I have doesn't want to charge.

Yeah, and after I posted I thought about the possibility it was 6v and couldn't confirm it with searches but I suspected it might be. Could be time to convert it to 12v, it isn't a real big deal.
 
Sure, many have done it. As long as you can find compatible components for all electrical functions and a large enough 12v battery to fit in the stock location, it's doable. The alternator doesn't care if it's creating a/c charging voltage for a 6 or 12v system, the rectifier/regulator combo unit you should use will take care of converting the available a/c current flow from the alternator to the appropriate 12v charge level needed for the new 12v battery and then you just replace the components that will need to be compatible with 12v, like the ignition coil and bulbs. The original electric starter will survive if used in short bursts, and the horn will be louder and will last if also used in short bursts (and if not, horns are cheap anyway)
 
Please verify you are getting adequate AC voltage from your stator....
Some 6V units only output around 8.8V at 5K revs....
In this case you should replace with a CB or CL 175 12V stator.....
 
66Sprint,O.K,If I decide to go down the 12v route I should check this and replace with a CB/CL175 Stator.I have a motor from a GL175 but I think this is still 6v,will the pionts and condenser but fine to leave as they are?
Thanks for this info,very helpful.
 
ancientdad,thanks,strangely enough I replaced the plug once again and all seems well,hopefully all I have to do now is sort out the hesitation to accelerate and all will be good.
 
The points will be fine and the condenser should be too but even if not, they're cheap. You'd start out just leaving those parts in place and if the condenser failed later it's a simple replacement.
 
so the bike was running fine on wed with a new plug,went to start it today(Sat) and once again it's only running on one cylinder,changed the plug and away it went(for now)
I did a compression check and got 90psi hot and then I saw a post on not to check just after putting in new rings(which presumably the previous owner did)
I haven't checked the battery again but if the voltage is low could this possibly be causing the spark plug issue?
 
Absolutely yes, as I mentioned above (despite not remembering it was a 6v system). If the battery is below the minimum for the coil to fire both plugs at the same time (wasted spark system) then it will likely only fire one of them. A fully charged 6v battery should hold 6.3v at rest, and since the charging systems on these bikes don't start to "break even" until at least 3000 rpm or higher the battery is being discharged from the moment you start riding it around the yard in first gear. The dead plug is overcome with fuel and gets fouled due to battery voltage not high enough to let it continue to fire both. The low compression probably isn't helping things either though.
 
we took the bike for a good run today and it struggles to get to 70kph checked the valves yesterday and they were fine, battery is at 6.2 after sitting overnight and after the short run around the block(about five klms)we rechecked the compression and it is 76 and 80psi,so it is less than when it was cold yesterday,and battery is at 6.5volts.
I think that I will put pistons and rings in it,I rang the old owner and he said that it measured in spec so he put the old rings back in.I cleaned the carb and rechecked the timing and I can't think what else would make it struggle to get up to speed.
 
time for an update..put new pistons and rings in and the bike was still struggling to get up to speed,the timing was spot on so I thought it must be a fuel problem,it has a 100 main so I went to a 105 and it was worse so back to 100 and dropped the needle,big improvement so have ordered 98(stock)95 and 92 jets.
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we took the bike for a good run today and it struggles to get to 70kph checked the valves yesterday and they were fine, battery is at 6.2 after sitting overnight and after the short run around the block(about five klms)we rechecked the compression and it is 76 and 80psi,so it is less than when it was cold yesterday,and battery is at 6.5volts.
I think that I will put pistons and rings in it,I rang the old owner and he said that it measured in spec so he put the old rings back in.I cleaned the carb and rechecked the timing and I can't think what else would make it struggle to get up to speed.
 
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