[arthursdoyle]

Hi there, I'm new here.
I'm having a herd time figuring out exactly what I have. I'm pretty confident it's an 81 cm400t. But I can't find vin specifics to decode it.
The vin is #nc0129bm008954
Yet everything I find says it's either a 12 character or 17. Not 14.
Also, I think I have a carbon issue, the bike was barn kept in tx for 20 something years. 8k original miles. Single owner.
All I had to do was quick clean the carbs and put in a new battery and she fired right up! (not bad for $600) but anyway it smells richer that rockafeller when it's running and bogs down at about 3k, but if I restrict the airflow it climbs rpms smoother still but great thoughi. Any thoughts?

 

[dtsmjr8dan]

Welcome to the forum. Great to see another 400 series here. Got any pics of it?
You may find the vin info you seek here @ motorera.com.

 

[arthursdoyle]

[img=http://s27.postimg.org/f2ionq4fj/1411599689126.jpg]

 

[arthursdoyle]

 

[jimbir]

Looks exactly like my '80 CM400T sissy bar and all.

 

[J-T]

You can check your serial number against those listed here:

Honda Custom 400 (CM400) Motorcycles

 

[longdistancerider]

VIN says it's 1981 as well as the paint color.

 

[arthursdoyle]

from everything ive read it says the letter B indicates 1980
this is why im so confused.
also, on the mixture screws there is a strange tab the restricts it from being tightened or loosened more than about 7/8th of a turn, i feel like its running rich any remedy to this "cap"

 

[longdistancerider]

No, the year/lettering system came into use in 1980, A=1980, B=1981, C=1982, etc.
That's a mixture limiter cap. You can heat the cap up and remove it since it's glued in place or take a Dremel and cut the stop off the float bowl. I cut the stop so the screw is easily adjustable sitting on the bike and I can visually see if they are set much different side to side which will indicate to me I got it wrong or there is a problem.

 

[arthursdoyle]

Excellent! Thank you very much, is factory spec 2-1/4 turns out?

 

[longdistancerider]

That could be right for the base mixture setting to run the engine before actually setting the mixtures correctly. It's 1.5 to 2.5 turns out for all the different years and carbs.