honda cb 400f

[sauspan]

Hi guys, first topic here!

So I bought a cb 400f from 1977 a while ago. The problem is, when I ride it, it builds up (if you handle the throttle carefully) to 6500 rpm, but if you just overdo it a little it holds back. I can't get above 6500-7000 rpm. Anyone who knows how I can get it to go to 10.000 rpm again?

I'm planning on rebuilding the carbs and installing K&N Air filters, but i'm a newbie in carb rebuilding or jetting.

Thanks for reading!

 

[Big R]

For now, I would just pull the carbs and clean them - hold off on the K&N pods until you get it running 100%.

 

[SONICJK]

For now, I would just pull the carbs and clean them - hold off on the K&N pods until you get it running 100%.

+1
The 400f requires a bit of jetting to run K&N's.
THe pilot jet and the mains need to be changed depending on your exhaust/intake setup.

Get it running right then modify after.
If you need a stock air filter shoot me a PM, i have a NOS one on my shelf ill probably never use.

 

[xb33bsa]

the centrifugal advancer may need service
as well you should do an ignition tune up

 

[sauspan]

Thanks for the tips!
I was planning on installing a Dyna S ignition.
The last owner put on some cheap aftermarket air filters, could this be a cause also?

 

[Big R]

Absolutely. If they are cheap Emgo pods, they are practically made to destroy engines.

 

[sauspan]

Absolutely. If they are cheap Emgo pods, they are practically made to destroy engines.

So what do you recommend, buy a stock air filter or go with the k&n's?

 

[Big R]

Stock for now. I know it sucks buying stock parts now and wanting to get aftermarket stuff later, but I think you'll be further ahead in the long run.

Getting it to run 100% right will be easy with stock parts. Then change 1 thing at a time and adjust from there.