Most motorcycle problems are caused by the nut that connects the handlebars to the saddle.

My CB500 performance upgrades


Posts : 1213
Location : Aarhus, Denmark

Re: My CB500 performance upgrades

Post by stormbringer on Thu 19 Sep 2013, 7:00 am

alexibrow wrote:<snip>If you fit a road legal can and leave the baffle in, on its own, it's OK not to re-jet; similarly, if you fit a K&N panel filter and nothing else, you can get away without rejetting. Your AFR will not be optimised in either case, but it will be so close to stock as to be hardly noticeable to most people, in most conditions (although plenty of people report a flat spot in the 3000-4000rpm range after fitting a K&N filter).

As soon as you start combining modifications, or even just remove the baffle from your Scorpion can (or whichever make you happen to have), you WILL notice the difference: there'll be a big dip in the power curve right where you spend most of your time when riding about. In my opinion (based on many years research and playing about with all kinds of normally aspirated carburated engines), it's absolutely essential to re-jet for these mods.
Meaning that if (when!) i buy that nice Fuel end can and add it to the bike - which already has a K&N fitted - I'll have 'combined modifications'. Bugger.

Think I'll try anyway. The bike had a rejet when it got the K&N, which hopefully means AFR is spot on atm. Leaving room for the skew introduced by the Fuel can... Time will tell.

Removing the baffle: I've feared exactly this. If removing the baffle upsets the AFR, I'll be unable to take it out (just for the fun of it, during eg. weekend) then put it back in for 5 o'clock monday morning tiptoeing through sleepy suburbia.

Oh well. This is the kind of fun you can only have when working with ECU-free machinery. I'll just think of it as a feature, not a bug Smile

Utterly OT:
Will I eventually try the monday morning tiptoeing thing - without the baffle in?
Oh yes - I'm sure I won't be able to stop myself. RROOAAARRR; Barking dogs, meowing cats and darkened bedroom windows lighting up.

Just once. To tell all those sleepyheads and pensioners there's life going on before the break of dawn. Rise and shine Smile
Four's a...something...
Four's a...something...

Posts : 162
Location : West Sussex

Re: My CB500 performance upgrades

Post by alexibrow on Thu 19 Sep 2013, 3:03 pm

My carbs don't need deep cleaning, but the needle jets are probably quite worn at 48k miles.

I rejetted to suit K&N with de-baffled can, so it runs fine (a little richer) with the baffle fitted for the weekday commute.

    Current date/time is Tue 19 Sep 2017, 7:44 pm