Jump to content
Sign in to follow this  

Lean Pilot vs. Top end

Recommended Posts

Will the symptoms of a lean pilot and bad top end present in the same way? My 90 CR250 all of a sudden became hard to start cold (must choke), idles high before returning to the normal low idle, and is smoking a bit off idle. We have had a weather change in this time also about 10-20* cooler at ride times. The compression hits 180psi on the 4th or 5th kick and acording to my book well it says nothing about compression. I am calling 180psi good based on others I have talked to and should rebuild when it drops to 150psi. So my thinking is a lean pilot but the smoke is saying top end. The bike once warmed up runs like a stripped assed ape and plug readings are good possibly a little on the rich side but would rather have it that way.

Share this post


Link to post
Share on other sites
Will the symptoms of a lean pilot and bad top end present in the same way? My 90 CR250 all of a sudden became hard to start cold (must choke), idles high before returning to the normal low idle, and is smoking a bit off idle. We have had a weather change in this time also about 10-20* cooler at ride times. The compression hits 180psi on the 4th or 5th kick and acording to my book well it says nothing about compression. I am calling 180psi good based on others I have talked to and should rebuild when it drops to 150psi. So my thinking is a lean pilot but the smoke is saying top end. The bike once warmed up runs like a stripped assed ape and plug readings are good possibly a little on the rich side but would rather have it that way.

I'd probably just close the air screw a little, or put in a larger pilot if the weather keeps getting cooler.

Share this post


Link to post
Share on other sites

Left and right crank seals? If they're both leaking, you can have both lean and rich symptoms at the same time.

Share this post


Link to post
Share on other sites

Crank seals that would make sense. Do you guys know if you can pull them with out splitting the cases? On my KX I used to own you could pull the covers flywheel and clutches and then thread a drywall screw into the middle of the seal, pull, and replace. I have a Clymers but it is worthless if I can do it with a drywall screw than I can do it in a afternoon if I need to split the cases then I will plan a weekend and possibly a bottom end and a complete reseal. Let me know so I can plan acordingly.

Thanks for the help!

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×