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Discussion Starter · #1 ·
Greetings everyone,

With the weather getting a bit colder and the holidays here, it's resulted in me having to get up very early in the morning for work and taking the car instead of the bike. The issue with my 1980 CM400A is that after is sits for a bit, like a week, it'll have a hard time starting. I'm 99% it's from the carbs. It it sits for multiple weeks it becomes very hard to start. If the bike is ran on a regular, daily basis it starts up each morning just fine. For the hard starting I simply just keep cranking it over, applying choke doesn't help it, until it starts to cough and finally fire up.

The carbs were rebuilt, fully cleaned, and professionally synced early this spring. It would occasionally have the hard starting back then but I was riding it almost ever day and as long as it was ran daily, the hard starting rarely came up. The rebuild kit I used was not OEM as I was not able to find a true, full OEM kit. I kept the original jets and floats, the float needles were switched out. New air cuts offs, new accel. pump, almost new everything except for the O-rings that seal the tubes that allow fuel into the right carb as the kits O-rings were not the right size. I have new carb boots connecting the carb to the head, and the fuel line is new and very tightly installed. It seems like the carb as made the issue more pronounced.

I don't want to kill my battery or worse cause unnecessary wear to the started motor. I did run some fuel system cleaner through it a couple month ago which made the throttle response a touch better but did not help the starting issue. Any advise would be appreciated.. Heck probably a tiny speck of dirt got into the system and just needs to be cleaned.

Thanks,
David
 

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This isn't terribly uncommon with colder weather, the CM400T and the T1 are both boogers to start after parked a couple of weeks or more. The T1 is really hard since it's a kick only. I think it has more to do with the fuel than anything with the bike.
 

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Discussion Starter · #3 ·
The fuel quality around here isn't the best, but I do try to get it filled with fresh. The standard octane here in West Texas is 86, with 87 being hard to find, and 88 and 89 being more common. I use 86 normally as it's everywhere but try to use 87 when I can. Could this cause an issue?
 

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86 octane should be fine since it's the same grade as called for by Honda originally. I've failed to get the T1 kicked over at this point so in the next couple of days I'm going to replace the fuel with non-ethanol. There's an Android app called "Pure Gas" that lists gas stations selling non-ethanol. If that doesn't work I'll try fresh plugs next even though they're only 100 miles old.
 

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Discussion Starter · #5 ·
A set of fresh plugs might be a good idea for both of us, and I'll look into that app.. I've heard from many people locally that our fuel is crap. It does make me feel a bit better knowing that it's not the bikes fault and just bad gas! :p

Would old spark plugs cables have any involvement? Mine are still the original ones from 1980 haha.. They still supply decent spark as I got shocked when checked for spark! :lol:
 

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Check secondary coil resistance w/o the plug end caps in place, those are 5K ohm pieces. Spec is 7.2K to 8.8K ohms. That checks the wires and coil in one shot
 
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