What jet size

Looks like I'm not going to get to the Dyno before I go on my next track day so what size jets should I fit to an SV 650 with BMC race filter and full Akrapovic Titanium system and can?

142? 150? 155? 160?

Tank is raised by an inch

[NedSVS]

I assume you are using a BMC RS race filter with the large oval hole in the top. This is the filter supplied with the Factory Pro stage 2 induction kit and they recomend (Mikuni sizes) 162.5 front cylinder and 160 rear cylinder with competition exhaust, but warn, could vary + or - 2 sizes. So there is a start point for you, but personally there is no way I would run it at a track day without a road test or Dyno run, or both. A Dyno run will tell you if it is making good power but it won't tell you what it is like to ride on small throttle openings. Hope this helps.

[yorkie_chris]

Richer at front?

Its the standard Race not the RS and its got 137.5's in at the mo'

I must admit I thought richer at the rear as it gets hotter in the rear cylinder though I have not heard of anyone till now running different jet sizes on an SV though its common on other twins.

[NedSVS]

Yes, richer at front. A lot of people say richer at rear because the rear will run hotter, but it's probably to do with the dynamics of the airbox. Anyway, I trust Factory Pro on this 100%.

[yorkie_chris]

Probably more down to airflow getting into cylinders rather than around them, it is LC motor after all.

OK that sound like a plan I'll get the 160 / 162.5 and a set one size lower. At least it will be on the safe side running too rich and I can do a quick swop in the lunchtime if it bogging down.

I also hear about turning the AF screw out 2.5 turns, does this work?

[yorkie_chris]

You got some balancing gauges?