Motorcycle Repair: Honda ct 70h, honda ct90, honda ct70

Question
Hello,

I have a 1971 K1 CT 70H, when I purchased it the guy said the carb on it was
from a diffrent ct 70 but he gave me what he said was original carb for
that bike (was all gummed up, he couldnt get bike running with it)I have
begun cleaning it up and noticed a little metal nub on same side of carb as
fuel on and off control I have not seen before. After investigating a
little I found out it is a high altitude knob (plastic knob is missing)
however I can only find it mentioned on ct 90's parts list's and forums. my
question is this, was a high altitude knob carb installed on my or any 70
ct model ? Thank you very much.

Answer
Pete.  Are you sure it isn't the large drain knob instead?

http://www.cmsnl.com/honda-ct70h-trail-70h-k1-usa_model617/partslist/E++13.html

or

http://images.cmsnl.com/img/products/gasket-set_big16010102305-01_97e8.jpg

or

http://www.cmsnl.com/honda-ct70-trail-70-1982-usa_model7458/partslist/E++1301.ht...

I looked at all the listings here:

http://www.cmsnl.com/search/?q=ct70  

Nothing listed with a high-altitude knob option.

Did you remove the shaft to ensure that it is a high-altitude plunger?

http://www.cmsnl.com/honda-ct90-trail-90-k2-usa_model621/partslist/E++13.html

If it looks like that, then it is a CT90 carb.

Bill Silver