Well the mushroom season is coming to an end in the mountains of NM for the year.
This is the second time I have taken the 110 up to nearly 11,000 ft altitude in the mountains near Sipapu ski resort in northern NM.
The first time I just headed out and hoped for the best and had very little trouble but when I returned the plug was pretty black so I decided
to make some changes to lean out the mixture (or the apparent mixture) and looked into the high altitude jet #70.
One thing lead to another and it was time to leave before I had installed the new jet so I decided to use some of my old tricks from
the old Datsun 510 that I used to drive while I lived in northern NM. 
The 4 things I did were:

1. I removed the baffle from the exhaust to reduce back pressure this causes the mixture to act leaner.(some of you might be mistakenly thinking that I removed the spark arrestor but none of the 110 came with a spark arrestor just a baffle to reduce noise and tune the back pressure).

2.  I advanced the spark as much as the little wire attached to the pickup would allow, I estimate it was about 10 degrees but I never measured it so if you try this you may need to make your
own amount of adjustment. By the way I did this before I went to the mountains and it still didn't show signs of preignition, detonation or any other knocks ( I live at 640 ft altitude).
3.  I leaned the idle mixture screw by a full turn.

4.  I filled the tank with gas from a station up in the mountains where 86 octane is common and sometimes 85 can be found.

The combination of these measures gave me a bike that performed beautifully and when I got back I swapped out the spark plug and it was a light greyish tan!! Ye Haw!!!

I actually did a 5th thing and that was switch the tires for real knobbys and that made a huge handling difference from last year when I had my Golden Boys mounted.

Everything has been put back to normal AND I now have my SOP for trips to high altitude and I didn't have to remove or disassemble the carb.

Please let me know your results if you try this approach.

Billy



1983  CT110 daily driver  (mpg range 83 - 105)
1984  CT110 restoration project
1973   CT90 in pieces
Last Edited By: mycoguy Sep 18 14 12:44 PM. Edited 1 times.