Honda CB400 T Hawk high revving?

Question

after I twist the throttle the engine stays revving high until I turn it off, then it happens again

Answer 1

sounds like your throttle cable is sticking. either that or your linkage on the outside of the carb is dirty and sticking. or the actual throttle slide inside the carb is sticking.

i'd check these things first. work you throttle on the handlebars a few times while watching the end of the throttle cable and the linkage---anything sticking? you may be able to diagnose the problem just by visually watching how the cable and linkage interact so you don't have to tear into the carb.

at any rate, now is a good time to grease the exposed end of the cable with some lightweight grease. clean the outer linkage and oil it up so that it works without a hitch.

does the 400 T have one carb or two? you'll need to repeat the process if there is more than one carb.

lastly, it could be the throttle sliding plate inside the carb is sticking. for that you can just lubricate it with some lightweight oil and work it back and forth several times to loosen it up.

best of luck to you!

Answer 2

-Frist sync the carbs just to rule that out.
-Remove the carbs and check the vacuum slides.
-Some times the tops get corroded and prevent the slides from dropping.
-When you remove the carbs, with your fingers, raise both slides (before taking them apart). Make sure they drop and bottom out at the same time.
-Clean slides and tops to fix this. Polish the tops to make smooth or use scotch brite pad.
-If they are still slow to drop -
-Check slide springs (to see if they're to weak).
-Clean slides (try dropping without tops).
-Make sure the "slide lift hole" is clear (look in the slides, it's the hole off center).