Thread: 1980 Ct 70 carb problem

I ve had this bike for 4 months & it has never been able to go faster than 25 mph. It does not smoke runs great and has 506 miles on the clock. I pulled of the air filter box and noticed Ive been running it on the choke closed the whole time. When I open the choke, it will not idle unless I keep it revving, however in 2nd or 3rd gear if I open the choke I can go 40mph. The carb is a PB37B Keihin with the black plastic ckoke lever. I believe Im getting to much air when its idling, but on the top end it will run fine (open).I took a look at the main jet and its a #55 will a bigger main jet solve this?? Also the needle jet is none adjustible unlike my 1969 trail 70. Anybody thank you ahead of time

Take apart your carb and clean it. The idle jet is probably plugged. Use plentiful amounts of carb cleaner. Hold jets up to light and make sure you can see light through every tiny hole.

thanks hondaman, I just got done cleaning it and it seems to run a little better though you still have to give some revving so it will not die . I am going to clean it again and see if I can get it even better, the only one I did not check the first time was the idle jet , thanks

The pilot jet orifice is minuscule and easily plugged. It can be difficult finding a jet file small enough to fit. That said, you might try using the inner wire from a twist tie (outer covering pulled off). Whatever's in the jet itself should be easily dislodged.

thanks Super Moderator I have been using my tip cleanig files from my cutting torch but they are not quite as small