2 Stroke 2001 Honda CR80R High Idle

T

Ty80650

Hello, looking for some help with my cr80.
I picked up this bike not too long ago after the original owner had it sitting outside for years. Filled with gas mix/replaced filter/cleaned carb and was running great. After a few rides I parked it and when I went to go start the next day, it sounds almost as if the throttle is wide open on startup. Not hitting the rev limiter, but it’s extremely high rpms. I’ve emptied the gas mix and refilled, cleaned carb and checked all throttle components, and nothing seems wrong. I don’t have much experience working on these, as it’s the first dirt bike I’ve owned. Any help would be appreciated.
 
SRAD97750

SRAD97750

Moderator
Staff member
Usually this is from the throttle slide not seating completely. I'm sure you looked, but here's some ideas.
It can be the throttle cable, cable routing, throttle tube... etc... Sometimes or only when the bars are turned.
Some throttle slides can be installed backwards causing this symptom.
Sometimes an air leak/running out of fuel can cause light revving, but usually not right upon starting.
-BIG DAN:thumb:
 
SRAD97750

SRAD97750

Moderator
Staff member
It's always a possibility, but you can get a general check of health with a compression check, or take the head off and inspect the top end.
Your described symptoms do not tell me whether it needs a rebuild or not.
-BIG DAN:thumb:
 
jbird710

jbird710

Check the easy stuff as Dan described first. One thing to check on is the manifold/reed cage between the carb and the cylinder. If it sat out like you say, the rubber is probably brittle and possibly dry rotted. While it's running, you can spray some WD-40 around different areas to help locate an air leak; the RPMs will change if it gets sucked in from an air leak. Spray around the base gasket of the cylinder - I had one crack once causing an air leak and the same symptoms you are describing.
 
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