Honda Twins banner
1 - 2 of 2 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter · #1 ·
hey there, I bought a bike recently that needed some work. I decided to get rid of the airbox all together and have put pod filter on instead. I am in the process of cleaning and rebuilding the carbs right now and have come across a few question I was hoping someone might be able to help with.

I'm wondering if when running pod filter and a less restrictive exhaust system; do I need to use larger jets in the carbs to increase the fuel mixture to compensate for the increased amount of air. Would it be fine to just replace the jets? If so, is there a certain setting things need to be tuned to in order for them to run properly? If the jets need to be modified is there a way to do it with a drill bit?

any help would be greatly appreciated.
Thanks!
 

·
Sensei
Joined
·
27,182 Posts
The factory airbox is fairly restrictive, and the bike already runs on the lean to very lean side......
...So, YES, it is likely you will have to seriously up-jet...... This can be problematic as the slow jet is pressed into the carb body, and not removable, and thus difficult to change in sizing, so it will always be running exceptionally lean at idle and just above........the additional fuel needs must somehow be supplied by two main jet systems, the primary main, and the secondary main..... This will likely take quite a bit of trial and error attempts to achieve, you may have to enlarge the side holes in the primary nozzle as well...
...So, NO, it probably won't be as simple as "just up-jetting"...Could be, but not likely...
.......YES, there are clearance settings on the accel pump, pilot screw settings, and idle vacuum range specs, but you'll have to experiment as they may change with the other alterations you are making...
.........YES , you can drill jets, that's how they are sized, so you'll need a set of metric number drills....

It might be more expedient to use conventional slide throttle type carbs (Mikunis or Kei-hins) as opposed to the stock CV carbs as the jetting is readily available......
Either way, expect that you may have to invest a couple hundred dollars and/or quite a few hours into getting this exactly right.....

The above is "worst-case"....It could run fine with just bigger jets.... Reading the plugs will tell when you have it right..........
 
1 - 2 of 2 Posts
Top