OK, I did some hefty mods to my F3, one requiring me to put on a 47t rear sprocket to get clearance for my SSSA.

On the front, I run a standard OEM sprocket (15t i think).

Obviously my torque is high off the start, but i hit about 120km/h and my RPM's are pretty high (7k).

Was wondering how much I could expect to drop that number if i go a +1 in the front (16t)? I cannot reduce it in the back sadly... Frankensteining has its drawbacks. I need the larger sprocket to get clearance off the swingarm.

Anyhow, I have also gone from a single can (D&D) to no exhaust (wondering how much that has impacted things) and will be linking my R1 exhaust (dual exhaust) pretty soon.

I just read an article on re-jetting. And while im pretty handy in the garage, im feeling re-jetting my carbs is out of my league at the moment.

Does anyone have an idea what the implications are if i do not re-jet?

If I re-jet, will my RPM's come down a bit?
will my RPM's come down a bit when i re-attach my exhaust?
or will the +1 in the front help enough to live with higher RPM's?

Silly questions i know, but I don't want to cause prolonged wear on vital parts because I have not done my due diligence.

I have not done a lot of riding since completing my project, maybe 200-300km most.

Any feedback would be grateful.
Nick

 

www.gearingcommander.com

^^ That website will tell you what will happen when you change your sprockets.
Also re-jetting it will not bring your rpm's down, it will just make the engine run smoother especially if you are running no exhaust and have no back pressure.

 

thats great! thanks! +1 front sprocket it is!

 

How would I be able to tell if the bike I bought has different sprockets/gearing?

 

count the sprocket teeth first. Using the link jeffjones gave, you should be able to calibrate it to your bikes make and model. It will approximate the RPM you should be seeing at a specific speed (-/+) driving conditions.

If your not running 15/43 then your ratio will be different and so will your RPM readout. That's a good indication that you may not be running stock.

 

why would the rpm readout be different? i know the speedo would be off from actual, but i dont think the rpm readout would be. doesnt that run off of the engine? my f3 has 16/45 with a calibrated speedohealer and i run 84mph at 7k..

 

I think he meant your rpm's would be different at the same speed when you change your sprockets.
ie. say with yours 84mph @ 7k rpm's
If you were to drop a tooth in the front it may be at like 84mph @ 7.8krpm's.

 

Will,
at 7K RPM I'm traveling at around 110+ MPH. My gearing is stock.
Your gearing sounds completely out of whack. Check the Honda manual to see what your model should be running, front and rear sprockets. 84MPH at 7K is very low gearing, wheelie heaven, if that's what you're into. Each to their own but if you want accurate readings on your speedo you may want to think about fitting a speedo healer
Your speedo will be clocking up many more miles than it should if you leave your set up like this.

 

going simply -1 in the front made my rpms go up 500+, probably even higher

 

I know mine isn't the same as Will's but I have an F4i with stock gearing and I am at 88mph @ 7k. So he isn't far off from me?

110+mph @ 7k sounds a bit low?
So when your cruising down the highway at 60mph your under 4krpm's?
That doesn't sound right?