Honda CT90 (Trail 90) CARB Tuning

If you're struggling to get your Trail 90 to start and idle right, or if it stumbles off the line, this video is for you! For the record, my CT90 is a K3 built in 1971 and sold in 1972. It is the only model year with stripes on the downtube cover and the long "T" on the airbox. So classic!!

Previously, I made a video about how I had trouble with my CT90 starting and idling. I showed some basics about the idle air screw and the importance of having a good ignition coil that's correct for the bike.

That video is here if you'd like to check it out.

[mikemcclair]

Thank you!!! I couldn't get my idle right and every time mine revved high like that I turned the air back down thinking it was bad when I should have turned down the throttle instead. I get it now! I think my recently revived 77' might actually get to go on its first ride in 40+ years thanks to this video!

[nhaukap]

I just acquired a 74 CT90, and as a COMPLETE motorcycle newbie, this video is excellent and SUPER helpful, THANKS for taking the time to make this! Cheers from Iowa!

[quadsquadgarage]

It always baffles me when people say they would rather have a carbed bike. "It's simple to repair and maintain." Meanwhile, the EFI bike starts right away and rides away lol. For context, I'm in my mid 40's and a heavy duty mechanic and I fix and repair motorcycles and dirt bikes for fun. Been doin it since I was a kid.

[KneelMore_CacheTales]

Great instruction. Hope to use your info soon as I start to work on my herd of step-throughs.

[sjensen]

Very helpful video..thx..
You mentioned a full throttle adjustment technique at the beginning of the video but all I picked out was idle and mid-range adjustment technique..?

[kentomko]

Great video, need some advice, I have a 75 ST 90, stumbles from idle but runs well. When it comes off of WOT it also will sputter. I am thinking I need to lean it out with the throttle valve. All problems go away when I pull out the high altitude knob. Thanks.

[garryanderson]

My 90 seems to be running rich even though the clip is at the top of the needle. Is there any way to lean it out more?

[boathemian]

My 1978 carb is nothing like this one.