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Discussion Starter #1
Sorry for the long post but want to minimize the number of threads I create.

'78 CM185T
1. Service manual says to check the coil there should be continuity between both primary wires black/white and blue. Check

Also says there should be continuity between both secondary wires. Fail.

This looks like a new coil but that doesn't mean much. Is the manual correct or is it a typo that should say "there should be NO continuity between secondary wires"?

If the manual is correct and the secondary wires should have continuity, would the bike still run?

2. Engine runs but only on Full Choke, sometimes I can get it to run with choke off but either way it will die when I let go. Will not idle unless I have the idle speed turned way up and full choke. Then as it is running it will back fire through the left exhaust and keep running then backfire again. The right muffler is hot and the left is cool so obviously it isn't firing on both. The condenser reads .2-.3 which the book says is within range.

I pull the plugs and the right plug is good and dry, the left plug is wet like it isn't burning all the time but when it does it backfires. I set the points, checked valve clearance. Cam chain seems good and not loose but I didn't perform the adjustment procedure.

If I pull the plugs and ground them to the block and crank it over, there is good spark at both plugs. Not like the left one is only firing once in a while.

I had my grandfather come over and take a look at it and it doesn't make sense to him either. I can't keep the bike running well enough to adjust the carb using the pilot screw like the manual wants and my timing light must be a 12v unit since it won't read when hooked up. It is a digital unit.
 

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I am having similar problems with a Cb450 Nighthawk. One thing that makes the bike run and warm up is to replace the left spark plug,but it fouls after a while.
I suspect that the fuel is not at the correct height in the fuel bowl. You should test yours by attaching a clear tube to the drain screw and checking how the level of gas differs from side to side.
The idle screws you mentioned sometimes benefit from carefully removing them and blasting a little carb cleaner through a straw.Be careful of the little O-ring and washer and spring that is in the bottom of the air screw thread. They should be removed and placed over the cleaned air screw and carefully put back in the threaded hole [after blasting cleaner through] the idle passages in the carb.

Hang in there
 

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yes there should be continuity between secondary wires but the resistance will be high, kilo ohms if i remember correctly. gap a good plug to something like a 1/4 inch and test for spark again. if it wont gap that out of the engine it wont spark the standard gap under compression. clear tube method mentioned above is also great to help determine if you are just fouling the plug.
 

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I have the '79. I just replaced the coil in mind because it was causing rough running when it got hot. It wasn't expensive. You can make a little timing light with a battery, piece of wood and a flashlight light from Radio Shack or similar, but I use my multimeter on it all the time with no problems. Agree re the carb; might benefit from cleaning and checking float level. Mine likes lots of choke until it warms up but not being able to keep it running is a PITA. Good luck.
 

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Discussion Starter #5
So I have a question about checking float setting using a tube. Since the fuel bowl is one open area with a float that is one piece, how can there be a difference from side to side? I could see if the bowl was divided or the float was two separate pieces, one for each side, but it isn't.

So how does moving the tube from one side to the other make a difference. Especially since there is only one drain screw.
 

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Discussion Starter #6
Alright, I think I have figured out an issue that may be causing all my problems. I pulled the intake tubes off and looked inside the heads. I manually cranked the engine while shining a light onto the back of the left intake valve. I could see gas bubbling around the valve seat during the compression stroke. The back of both valves looks pretty crusty and need cleaning.

I'm figuring it is loosing compression due to this and not allowing it to create all the power it should.
 

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Discussion Starter #7
I got some carb cleaner and a bottle brush and cleaned the intake valves and seats. Seems to run better now and I can start it without choke but now the problem in I can't get it to idle. It will run with partial throttle but not on its own.

I have adjusted the pilot screw to all sorts of levels. Closed will not start but anything over that will run but no idle. The idle screw does nothing for me.

Any ideas?
 

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Discussion Starter #8
I found there was a jet that was totally plugged. Took a long time to get it cleared. Once I did I could get carb cleaner to go through but I found the pilot seat was torn and the screw was missing the spring. I ordered another set and will see how it goes then.
 
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