Very vague information. Could be the main jet in the carburator.
rev limiter
Check wires aren't crushed or exposed. You might want to look at the throttle switches on the carbs and thumb box which are for limiting the RPM with a stuck throttle. You might want to temporarily disconnect the rev limiter box to test for this- just unplug it. Lastly pulloff the flywheel again and recheck the flywheel key.
you broke it!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! dumb bo
NO. 1987 - 1989 are the same. When they changed the J arms to A arms they changed the connectors on the harness. The CDI on the newer years have a extra black wire also . DO NOT use this wire ( or ground it) if you use it on older years, or banshee wont rev out. This wire cuts the ignition to only over idle when you have parking brakes on. Just solder on connectors to interchange old and new.
the idle speed air control controls the amount of air going in to the engine so it idles at a certain rpm so it wont stall when you stop at stop signs or so it wont over rev
Broken/disconnected throttle cable
Sounds like the throttle cable is broken.
If you haven't done a tune-up lately (plugs and wires), do it. Do not "gap" the plugs, it will ruin the platinum coating. Install them right from the box.
no rev limiter on 98 model
The engine has a rev limiter while the transmission is in neutral. It will rev to higher rpm's when the transmission is in gear.
donny
Astra 1.7 cdti wont rev past 300 rpm