Jump to content

1/4 throttle/cruising surging

Recommended Posts

2006 supermoto, 3x3, FCR 39, hotcams, bigbore, ACT transmission, FMF pipe and probably more... I forgot because I did all that ~ 18,000 miles ago.  Valves in spec 2000 miles ago. 

When I'm on the highway cruising at 1/4 throttle I'm getting a surging condition.

Fresh tank of gas didn't help.

Im not sure where to start as the bike has been so solid for so long.

Im curious where the people in the know would check first.

 

Thanks for any replies

Share this post


Link to post
Share on other sites

First thing i would do is duct tape over 1/2 to 2/3 rd's of the 3×3 mod to see if its just a lean surge.

If that improves it raise the needle one notch, could need a carb rebuild.

Share this post


Link to post
Share on other sites

What's odd here is that "suddenly" jetting that was good is now lean. It points to a problem. Check for an air leak at the carb boot(s). Has the bike sat for a while? If so your carb may need to be cleaned.

 

Is it a lean surge or a misfire? I'd also check the coil.

Share this post


Link to post
Share on other sites

Bikes not been sitting, I ride year round in SoCal.

 

How do you test the coil?

Share this post


Link to post
Share on other sites
12 minutes ago, tbowdre said:

Bikes not been sitting, I ride year round in SoCal.

 

How do you test the coil?

Take a new plug and open up the gap about 3x the normal gap. Crank the bike over with that plug grounded and hooked to the coil wire, should have a good blue consistent spark.

 

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:


×