Project CBR600F: Lean Times My Friends...

Due to my loud work time (test rides, general vroom vroom work) being very limited, I needed to call in reinforcements from Furuhashi Racing. He has more motorcycle knowledge than I'll ever accumulate, and his availability is the reverse of mine in most ways.  After a test ride, which of course didn't include all of the bikes weird issues, the plugs were pulled.  The plugs are showing very lean.  

K enjoying the tight working spaces.

The K&N Air Filter and full Delkevic exhaust (no baffle) are definitely at work here.

At least they're all reading the same.

So,  a plethora of main jets, and a step up in pilots have been ordered from Jets-R-Us. Since they're only a few states away, I hope the shipping time is quick as I have a trip planned later this year.  FYI they have free shipping, so instead of paying $7.99 for shipping, I added a new magnetic oil drain bolt which bumped me up to essentially the same cost.  Shop smart, shop s-mart. 

K said the power difference should be noticeable once the jetting is correct.  Hell, it already feels super fast to me!  Fast bikes are fun, but I do enjoy wringing out a small bike vs holding back on a fast one.

Ah, I also have a vintage factory service manual en route from eBay.  You know things are getting serious when you call on the big book. 

Blessed are those that read from the good book. 

I'll be missing Ride To Work Day, but it's for the best. 

The excitement continues; stay safe out there. 


I pulled the carbs and stripped them down, then realized the main jets were 105s.  Stock size is 110, which I know I verified back in 2019; and it definitely didn't run this poorly then.  I did some digging and found that when I replaced the bowl gaskets in late 2019, I replaced the main jets too. They were the wrong size!  So, I ordered a replacement set of 110s, 115s, and 118s; rather have too many jets than not enough!   Now, to find the stock jets and float valves I removed in 2019 to compare with what I have.  I bet there may be other sizing issues related to this damn kit, like the float seat on 3 or 4.  

1 comment:

red said...

The Hurricane Bible should be here tomorrow, and the jets should be here Friday!