So basically I've just got my cr125 about 2 or 3 months ago. And after riding a couple weeks. The bike started to have a major delay in RPMs and when trying to exellerate rapidly. The bike would do this until you gave it enough gas for a long time. or until you hit the power band in 5th gear then it would be fine, unless you stopped riding for a small while then it would do the same thing and etc. it is as if it is not getting anough of something and then it finally kicks in. Does anyone know what could be causing this. And what I could do about it? :bang:
RPM delay while trying to exellerate.
- Thread starter MxRed
- Start date
dirt bike dave
Sponsoring Member
- May 3, 2000
- 5,349
- 3
What year is your CR125?
Try replacing the spark plug.
Make sure the power valve is working properly. Based on your smptoms, it sounds like it might be stuck open.
Try replacing the spark plug.
Make sure the power valve is working properly. Based on your smptoms, it sounds like it might be stuck open.
dirt bike dave
Sponsoring Member
- May 3, 2000
- 5,349
- 3
The power valves on a modern two stroke change the size of the exhaust ports.
At low rpm, there is less port area, for more low end power. When they open up, the exhaust ports are larger and flow more, for more high end power. Powervalve systems have been common on 125 and 250 MX race bikes since the early 1980's.
Different bikes have different designs. On some bikes (like the '00 CR250) there is an inspection plug on the side of the cylinder. On that bike, you can verify the operation of the valves by removing the plug, revving the bike in neutral and seeing if the shaft that operates the valves rotates. Not sure if your CR125 has an easy way to verify powervalve operation.
If the bike pulls strong on top but has no low rpm or mid range power, it COULD be the powervalve is stuck open. It could be overdue for service, or something came loose, stripped or is not aligned in the parts that open and close the power valve.
You might want to get an original Honda service manual for your bike. They are expensive, but excellent.
At low rpm, there is less port area, for more low end power. When they open up, the exhaust ports are larger and flow more, for more high end power. Powervalve systems have been common on 125 and 250 MX race bikes since the early 1980's.
Different bikes have different designs. On some bikes (like the '00 CR250) there is an inspection plug on the side of the cylinder. On that bike, you can verify the operation of the valves by removing the plug, revving the bike in neutral and seeing if the shaft that operates the valves rotates. Not sure if your CR125 has an easy way to verify powervalve operation.
If the bike pulls strong on top but has no low rpm or mid range power, it COULD be the powervalve is stuck open. It could be overdue for service, or something came loose, stripped or is not aligned in the parts that open and close the power valve.
You might want to get an original Honda service manual for your bike. They are expensive, but excellent.
dirt bike dave
Sponsoring Member
- May 3, 2000
- 5,349
- 3
Helm Inc. distributes the official Honda service manuals.
They have the original owner's manual for $16.95 (what came with the bike) and the shop manual for like $40 or $50 (that's the one you want).
Not sure if they sell a .pdf but they will ship you a hard copy.
http://www.helminc.com/helm/Result....00&Category=&Keyword=&Module=&selected_media=
They have the original owner's manual for $16.95 (what came with the bike) and the shop manual for like $40 or $50 (that's the one you want).
Not sure if they sell a .pdf but they will ship you a hard copy.
http://www.helminc.com/helm/Result....00&Category=&Keyword=&Module=&selected_media=
duncanstives
Member
- Sep 11, 2009
- 89
- 0
I hate it when my bike won't "exellerate"...
duncanstives said:
... and in another thread
duncanstives said:
How's the view from that glass house? ;)
duncanstives
Member
- Sep 11, 2009
- 89
- 0
Rich Rohrich said:
Freaking awesome but my the area around my rock thowing balcony is getting a bit banged up :rotfl:
