110ct trail carb stuff

[jjc]

According to Clymer, when riding over 5000 ft continuely, the jet should be changed to a 70. Less air = less gas needed per RPM.
Now I'm at 6800 ft and before I read this I would have guessed (by looking at the clean white of the plug), that adjusting for a bit more gas was called for. And the bike came from sea level.
Being that my bike is running opposite to suggestions, I am still going to experiment with a bigger main jet if sizes are clear & readable so I can see what the next bigger size is.
Anyone else fiddle with there jet for altitude sickness? What did you end up with?

 

[Old Guy Too Many Bikes]

If your bike is still running fine at that altitude, then just leave it alone. You can try raising or lowering the carb needle a couple of notches and see what effect that has. A main jet change really only affects full throttle operation.

 

[Gary]

I thought these bike had a self adjusting carb or was that the ct 90's?

Ok just found out the 110 do not have that only the 90's

 

[jjc]

Old Guy -
Max speed(approx) is where I test plugs. Or should I say at full main jet operation. At that point the plug should show a very slight brown tint. Mind is bright white meaning to me a lean mix. Could be ok,but is also a bit starving the motor. That is my belief.
The needle jet is a transition jet from idle circuit to main jet. Moving the needle up gives more gas at idle and pulls it off idle sooner as it transitions/moves up to the main. The needle should be fully 'out of the way' at full main operation. It does not effect main jet mix if adj properly(out of the way). So moving the needle will/should not effect main jet operation burning and that is where I check the plug.

(Thought I posted something on this previously but it isn't pulling up on my phone now,so here's a repeat. All info is my opinion of the operation of a carb)

 

[Old Guy Too Many Bikes]

I was always under the impression that although the needle is the transition from idle jet to main jet, it affected more like 20% to 80% throttle and even at full throttle, the needle is still in the main jet, albeit it's the skinny end of the tip. I would still play with the needle position. Do you get any lean surges at part throttle?

 

[jjc]

Ya the needle is in the main enough to stabilize its reentry but it has no effect persay on full throttle. Its transaction is done except for being in the way of air flow through the throat. There is a little overlap. I guess it depends on the carb as to where and when the transaction starts & ends.Of course moving it up speeds up transaction. I'm not getting surg but i go by the thought that a little rich is better than a little lean,which is what the Gov wants for pollution.So pure white to me is not what I strive for.
This is not how webbers work with there transaction 'tube' but it is still a transaction feature. I could agree on 20% depending on the carb because of overlap, but not 80%.
I think we both understand carb enough to fiddle with them where ad a kid was never taught anything about them.

 

[Old Guy Too Many Bikes]

When I was setting up the chinese 26 mm carb on my CL90 I thought I was getting a lean surge under light loads, so I raised the needle two clips and it got worse. So I lowered the needle two clips and the problem went away, so I guess sometimes it's counter intuitive and trial and error is the best solution. Webers are great since they have so many jets and tubes that are removable, but you really got to know what you're doing. I used to have webers on my VW, but I prefer my dellarto 45's. Set, balance, and forget.

 

[CT-110]

probably safe to say the stock jet may not be whats in there any longer, BUT before changing main jet (provided its a 70) id check for a partially clogged jet/ emulsion tube.

 

[jjc]

Old Guy -
FYI - The 1982 110ct has no needle adjustment. It is clipped in 1 grove w/o other groves being available.
Everything else is about normal.

 

[-Nate]

Things to consider :

unleaded fuels burn cleaner so very little browning on the spark plug's center is acceptable these days .

If you have a larger main jet (lightly larger, not a #80 ! . give it s try at altitude because chances are you'll loose power across the board from over fueling .

As mentioned : remove and check the emulsion tube very carefully .